effective: march, 1992 preliminary numerical distance ... automation, inc. substation automation...

ABB Automation, Inc.Substation Automation & Protection DivisionCoral Springs, FLAllentown, PA

Instruction Leaflet

Effective: March, 1992Preliminary Numerical Distance Protection

REL-300 (MDAR) RelayingSystem Version 2.50

40-385.2

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ABB Note

Go to Table of Contents to easily access each individual section. Click on the ABB logo to return to the Section TOC page.

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( Preliminary) I.L. 40-385.2

Table Of Contents

I. Introduction

(A) General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1(B) Major differences between Versions 2.50 and 2.01 . . . . . . . . . . . . . . . . . . . . . . . . 1(C) References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

II. MDAR Version 2.50 Functional Specification

(A) Functions for MDAR Version 2.50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

III. MDAR Version 2.50 System Assembly

(A) Backplane Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5(B) Interconnect Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5(C) Filter Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6(D) Power Supply Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6(E) Microprocessor Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7(F) Operator Interface Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8(G) Communication Attachments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8(H) Contact Module (standard for Version 2.50) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

IV. MDAR Version 2.50 Installation

(A) External Wirings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9(B) Jumpers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

V Description of Software

(A) Flow Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11(B) Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11(C) Background Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12(D) Fault Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12(E) Fault Mode Transition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13(F) Calibration Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

VI. Operating Principles of Sensing Units in MDAR Version 2.50

(A) Distance Measurement Principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

(1) Forward Step Distance Zones. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14(a) φG fault detection for Z1G Trip(b) φG fault detection for Z2G, Z3G (and pilot) Trip(c) 3φ fault detection for Z1P, Z2P, Z3P (and pilot) Trip(d) φφ fault detection for Z1P, Z2P, Z3P (and pilot) Trip

(2) Carrier Start Zone CRS for Carrier Start . . . . . . . . . . . . . . . . . . . . . . . . . . 16(a) φG fault detection(b) 3φ fault detection(c) φφ fault detection

(3) Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

(B) Faulted Phase Selection Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16(C) Phase Directional Unit (FDOP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

ABB Note

Click on the Section Title to access the desired section. To return to TOC, Click on the ABB logo on the first page of each section.

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(Preliminary) I.L. 40-385.2

(D) Ground Directional Units (FDOG, RDOG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18(1) Zero seq. voltage polarizing ground directional units(2) Negative seq. ground directional unit

(E) Fault Detection Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19(F) Negative sequence & Low Voltage Units. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19(G) Blinder Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19(H) Fault Locator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

VII. Operator Interface

(A) General Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21(B) Front Panel Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

(1) Display Selection(2) Entering Settings(3) Displaying Monitoring Data(4) Displaying Fault Record(5) Display Test Mode Functions(6) 16 Fault Records and Intermediate Targets(7) Programmable Output Contact Function(8) Reset Targets

(C) Display and Target Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23(1) Settings Display(2) Monitoring Display(3) Fault Data Display(4) Test Functions Display

VIII.Auto-Checking and Functional Test

(A) Auto Check/Continuous Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29(B) LOP and LOI Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30(C) Output Contacts Tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30(D) Functional Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

IX. Operation of MDAR Version 2.50 Functions

(A) Loss-of-potential Supervision (LOP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32(B) Monitoring of AC Current (LOI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33(C) Overcurrent Supervision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33(D) Zone 1 Trip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33(E) Zone 2 Trip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34(F) Zone 3 Trip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34(G) Directional Comparison Blocking System (BLK) . . . . . . . . . . . . . . . . . . . . . . . . 35

(1) Tripping Logic(2) Carrier Keying Logic

(a) Reverse fault keying(b) Signal continuation and TBM logic(c) Internal fault preference and squelch

(3) Carrier Receiving Logic(4) Channel Indication(5) Channel Simulation and Automatic Checkback(6) Programmable Reclosing Initiation(7) Dependable Pilot Ground Trip on High Rf Faults

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(H) Directional Instantaneous Overcurrent Trips . . . . . . . . . . . . . . . . . . . . . . . . . . . 38(I) Close-into-Fault Trip and Stub-Bus Protection. . . . . . . . . . . . . . . . . . . . . . . . . . 38(J) Unequal-Pole Closing Load Pickup Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 38(K) Inverse Time Directional or Non-Directional Overcurrent Ground Backup (GB) . . . . 38(L) Zone 1 Extension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39(M) Selectable Loss-of-Load Accelerated Trip (LLT) . . . . . . . . . . . . . . . . . . . . . . . . 40(N) Programmable Reclosing Instillation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40(O) Out-of-Step Block & Trip Function (OSB and OST) . . . . . . . . . . . . . . . . . . . . . . 41(P) Open Conductor Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43(Q) 16 Fault Records and Intermediate Targets . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43(R) Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43(S) Programmable Output Contact Function. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

X. MDAR Version 2.50 Setting Calculations and Selections(A) Calculation of MDAR Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46(B) Selection of MDAR Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

AppendixA Backplane Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76B Interconnect Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80C Contact Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83D Filter Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86E Microprocessor Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89F Display Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96G Power Supply Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99H Acceptance Tests V2.50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .102

H-I Full Performance Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .102H-II Maintenance Qualification Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .121

I Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .133J System Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .141

List of Figures

1. MDAR Relaying Assembly (photo). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 562. MDAR Module Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 563 MDAR Overall Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 574 MDAR Display Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 575 MDAR System External Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 586 MDAR Backplane Board Terminals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 597 Overall Flowchart for Microprocessor Software in MDAR Relay . . . . . . . . . . . . . . . . . . . . . . 608 MDAR Trip Zone Distance Unit Characteristic for φφ/φφG Faults . . . . . . . . . . . . . . . . . . . . . 619 MDAR Trip Zone Distance Unit Characteristic for ABC Faults . . . . . . . . . . . . . . . . . . . . . . . 61

10 MDAR Trip Zone Distance Unit Characteristic forφG Faults . . . . . . . . . . . . . . . . . . . . . . . . 6211 Characteristic of Distance Carrier Start Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6212 Double Blinder Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6313 LOP Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6414 LOI Logic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6515 Overcurrent Supervision on MDAR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6516 MDAR Version 2.50 Zone 1 Trip Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6617 MDAR Version 2.50 Zone 2 Trip Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6718 MDAR Version 2.50 Zone 3 Trip Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

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19 MDAR Version 2.50 Pilot/Zone 3 Trip Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6920 MDAR Version 2.50 Blocking System Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7021 MDAR Highset Trip Logic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7122 MDAR Close-into-Fault Trip & Stub Bus Protection Logic . . . . . . . . . . . . . . . . . . . . . . . . . 7123 MDAR Inverse Time Overcurrent Ground Backup Logic . . . . . . . . . . . . . . . . . . . . . . . . . . 7224 MDAR Zone 1 Extension Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7225 Load-Loss Accelerated Trip Logic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7226 MDAR Version 2.50 Reclosing Initiation Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7327 MDAR Version 2.50 OSBT Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7428 Open Conductor Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

A-1 MDAR Backplane Module PC Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77A-2 MDAR Backplane/Transformer Module PC Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78A-3 MDAR Backplane/Transformer Module Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79B-1 MDAR Interconnect Module Component Location Diagram . . . . . . . . . . . . . . . . . . . . . . . . 81B-2 MDAR Interconnect Module Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82C-1 MDAR Contact Module PC Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84C-2 MDAR Contact Module Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85D-1 MDAR Filter Module Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87D-2 MDAR Filter Module Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88E-1 MDAR Microprocessor Component Location Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93E-2 MDAR Microprocessor Module Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95F-1 MDAR Display Module PC Board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97F-2 MDAR Display Module Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98G-1 MDAR Power Supply PC Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101G-2 MDAR Power Supply Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101.1H-1 Test Connection for Single-Phase-to-Ground Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125H-2 Test Connection for Three-Phase Fault . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126H-3 Test Connection for Phase-to-Phase Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127H-4 Test Connection for Dual Polarizing Ground Directional Unit . . . . . . . . . . . . . . . . . . . . . . . . 128H-5 MDAR with Out-of-Step Block Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129I-1 CO-2 Curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134I-2 CO-5 Curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135I-3 CO-6 Curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136I-4 CO-7 Curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137I-5 CO-8 Curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138I-6 CO-9 Curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139I-7 CO-11 Curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140J-1 MDAR Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142J-2 MDAR System Logic Diagram (Sheet 1 of 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143J-3 MDAR System Logic Diagram (Sheet 2 of 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

Trademarks

All terms mentioned in this book that are known to be trademarks or service marks are listed below. In addition, termssuspected of being trademarks or service marks have been appropriately capitalized. ABB Power T&D Company Inc.cannot attest to the accuracy of this information. Use of a term in this book should not be regarded as affecting thevalidity of any trademark or service mark.

IBM and PC are registered trademarks of the International Business Machines Corporation.WRELCOM is the registered trademark of the ABB Power T&D Company Inc.INCOM is the registered trademark of the Westinghouse Electric Corporation

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NUMERICAL DISTANCE PROTECTION MDAR RELAYING SYSTEMS

(Version 2.50 for Korea Electric Power Co.)

I. Introduction

(A) General

MDAR Version 2.50 is a special design for KEPCO 154KV system. It is an extension of theMDAR Version 2.30. Its hardware is exactly the same as for the Version 2.30, only the softwarehas been modified to meet the KEPCO requirements. (note, the 2.30 software is the same as the2.01, except it includes the programmable output contact feature).

MDAR is a microprocessor-based line protection system. All measurements, protection, func-tions and logic are performed by numerical/digital means. The MDAR Version 2.50 providesblocking pilot scheme plus three step distance phase and ground zones, as well as instantaneousdirectional highset trip, directional inverse time overcurrent ground backing, close-into-faulttrip, loss-of-load accelerated trip, reclose block on breaker failure squelch, stub bus protection,out-of-step block/trip and open conductor protection functions. It also has metering, fault loca-tion, fault data and communication capabilities. RS-232C/PONI is installed in the assembly,however, it can be replaced with an INCOM®/PONI for local network communication if neededin the future without changing the hardware/software.

(B) Major differences in software between versions 2.50 and 2.02

There is no hardware difference between 2.50, 2.02 and 2.30. However, for Version 2.50, theposition of JMP2 on the microprocessor module should be set at position 1-2.

The differences in software between Version 2.50 and the standard 2.30 (or 2.02) are summa-rized below:

(1) Out-of-step Block/Trip function with selectable zone feature has been added to Version2.50. (OST logic in MDAR 2.50 is similar to the OSM logic in the special LDAR systemfor Utah Power & Light Co., except the ranges of the OST1, OST2 and OST3 timers aredifferent).

(2) Version 2.50 Zone 1 units include zero sequence mutual compensation feature.

(3) Version 2.50 does not provide DUAL polarizing feature, because the IP transformer inBackplane Module has to be used for Io‘ for mutual compensation.

(4) T1 timer range has been expanded to 15 cycles instead of 2 cycles, and is settible.

(5) Medium set overcurrent units IM have been added to Version 2.50 for all phase distanceunit supervision.

(6) Combine pilot and Zone 3, and relocate Zone 3 timers to the pilot trip logic circuits (T3P/T3G/PLTP/PLTG targets remain the same).

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(7) Replaced the Version 2.30 forward/reverse Zone 3 by a carrier start zone, CRS. TheφGand 3d fault units of the carrier start zone are non-directional. Independent settings forforward and reverse directions is provided. No separate setting for phase and ground unitsfor carrier start function.

(8) Carrier start logic includes the V2 signal for carrier start.

(9) Replace the software TK signal with an external DCB contact (digital checkback) for car-rier simulation.

(10) Provision for open conductor detection. A delay trip timer is included in the software.

(11) Version 2.50 provides 3PT on non-pilot, Zone 1 extension and blocking schemes only. ThePOTT, PUTT, unblocking and weakfeed schemes as well as the SPT features are notincluded.

(12 Wired out receiver-1 signal to contact terminals TB3, 9-10 and 11-12 (labeled as RI1-1 &RI1-2) for CR1 signal monitoring.

(13) 8 programmable output contacts will be provided for the following functions:

1—Pilot phase trip output (for remote supervision).

1—Non-pilot phase trip output (for remote supervision).

1—Pilot ground trip output (for remote supervision).

1—Non-pilot ground trip output (for remote supervision).

1—IoS signal with timer output (for open conductor fault scheme).

1—Carrier send signal output (for remote supervision of carrier channel).

1—CR1 signal monitoring (receiver-1 monitoring).

1—Spare programmable contact

(14) Setting displays are difference from Version 2.02. Refer to chapter VII for detail.

(15) Added special logic for DCB interfacing.

(C) References:

Catalog number for this order is MD-8B1SPFRK. The last letter “K” stands for “special logicfor KEPCO”.

System drawing numbers for this order are 2677F21 (2 sheets) and 2078D86.

(D) Remark:

As indicated in above item (B6), the MDAR Version 2.50 logic combines pilot and Zone 3 func-tions together as specified in the original KEPCO specification. It does not catch the latest spec-ification change which called for combining pilot and Zone 2 together. This latest change willbe included in the next Version 2.51. By that time all the existing Version 2.50 chips will bereplaced with 2.51.

(3/92) 3


II. MDAR Version 2.50 Functional Specification

(A) Functions for MDAR Version 2.50

(1) 3 forward phase/ground step distance and one pilot phase/ground distance zones, with onecarrier start zone (each zone has 4 impedance units).

(a) Z1P/Z1G (Zone 1 with settible T1 timer, 0 to 15 cycles in 1.0 cycle steps).(b) Z2P/Z2G (Zone 2 with separate phase & ground timers, each timer can be disabled

independently),(c) Z3P/Z3G (Zone 3 and pilot functions, with separate phase & ground timers for Zone

3, each timer can be disabled independently),(d) CRS (carrier start function, independent setting for forward and reverse reaches).

(2) Selectable instantaneous forward directional overcurrent function for high Rf ground faultsupplement to overreach pilot, with adjustable 0-15 cycle timer in 1 cycle steps or block.

(3) Selectable inverse time directional or non-directional overcurrent ground backup (GB,with similar CO-2, CO-5, CO-6, CO-7, CO-8, CO-9 and CO-11 characteristics).

(4) Directional high-set instantaneous direct trip including 3 phase and one ground overcur-rent units (ITP/ITG).

(5) Carrier start for blocking scheme, consists of the following elements:

(a) Dedicate non-directional carrier start zone distance phase and ground units, CRS.(b) Directional instantaneous ground overcurrent unit, RDOG/IoS.(c) ∆I, ∆V signals.(d) ∆2 signal.

(6) Scheme selection:

(a) Non-pilot 3-Zone distance.(b) Zone 1 extension.(c) Blocking carrier system.

(7) Additional/Unique functions:

(a) Current and voltage change fault detectors (∆I, ∆V).(b) Loss-of-potential supervision (LOPB).(c) Loss-of-current monitoring (LOI).(d) Close-into-fault trip (CIFT) with LV-unit supervision.(e) Unequal-pole-closing load pickup trip logic.(f) Selectable loss-of-load accelerated trip logic (LLT).(g) Transient block logic for power reversal (TBM).(h) Reclose block on breaker failure squelch.(i) Stub bus protection.

4 (3/92)


(j) Programmable reclosing initiation (RI) and reclosing block outputs (RB). Recloseinitiate can be enabled with the selection of: 1PR — reclose on φG faults

2PR — reclose onφG/φ/φG faults3PR — reclose onφG/φ/φG/3φ faults

(k) Selectable zero sequence voltage polarizing or negative sequence operated direc-tional element for ground unit supervision.

(l) Logic for load restrictions for long line applications.(m) Continuous auto-check and monitoring function.(n) Fault locator function.(o) 16 fault records, triggered by TRIP, Z2TR or Z2Z3.(p) Line voltage, current and phase angle monitor.(q) Real time clock.(r) Breaker trip circuit test.(s) Push-to-close test for output contacts.(t) Software switch RS1 for functional test.(u) Trip contact sealed in by trip current, and selectable dropout delay timer (0/50 ms).(v) Selectable trip alarm seal-in.(w) Contact converter with logic for external DCB contact connection for automatic

checkback function.(x) Overcurrent supervision to all distance units.(y) Out-of-step trip OST function with selectable zone feature.(x) RS-232C/PONI data communication attachment.(z) 8 programmable output contacts. (aa) Zero sequence mutual compensation for Zone 1 ground units.(bb) Open conductor protection with built-in delay timer.(cc) FT-14 switches.

(3/92) 5


III. MDAR Version 2.50 System Assembly

The complete MDAR Version 2.50 Line Protection System is housed in a 19-inch rack-mount pack-age, 4 rack units (7 inches, 177.8 mm.) height, 19.0 inches (482.6 mm.) width, 14.0 inches (356 mm.)depth, weight 35 lbs. (16 kgs), as shown in Figure 1. It consists of 6 basic and one optional contactmodules. The 6 basic modules are backplane module, interconnect module, power supply module, fil-ter module, microprocessor module and operator interface module. A RS-232C port provides remotedata communication is a standard attached element. Also, the FT-14 switches are standard element forVersion 2.50, as shown in Figure 2.

A contact module is added to the MDAR Version 2.50 as a standard module. It provides 8 extra relaysfor programmable output contact functions.

All user connections, including the serial data port for communication, are on the rear panel. The frontpanel presents controls and displays for the operator; on either side are type FT-14 test switches. Thetest switches permit convenient and safe disconnection of trip and ac input circuits, and make it easyfor the user to inject test signals.

An overall block diagram and the display panel of MDAR Version 2.50 relay are as shown in Figures3 and 4, respectively.

(A) Backplane Module

The analog input circuitry consists of seven transformers. Four currents (IA, IB, IC, and 3Io’) andthree voltages (VA, VB and VC). The 3Io’ (labeled as IP) is an input of zero sequence currentfrom a paralleled circuit, using for Zone 1 ground distance unit mutual compensation. The sevenisolation transformers are mounted on the transformer board which is attached to the backplanemodule (Figure 2). They drive resistive burdens to develop a secondary voltage which will beproportional to the primary input. The current transformers are non-gapped. DC offset attenua-tion is done with a digital filtering algorithm.

The first-line surge protection for each input and output terminals are also located on the back-plane module. The backplane module is mounted on the outer chassis. All of the relay circuitryis located on the other modules, mounted on the inner chassis, to which the front panel isattached. The inner chassis slides in or out of the outer chassis from the front.

The blackplane module receives all external connections via the FT-14 switches, and connectsdirectly to the interconnect module, through plug-in connectors which provide the connectionbetween outer and inner chassis. Mating connectors inside the case eliminate the need to discon-nect external wiring when the inner chassis is removed.

The RS-232C PONI is mounted on the backplate of the outer chassis and is connected to theBackplane module.

(B) Interconnect Module

The interconnect module becomes the floor of the MDAR Version 2.50 inner chassis: it provideselectrical connections from the backplane module to the other modules. Two dc power fuses,two alarm relays (failure alarm AL1 and trip alarm AL2), and seven optical isolation cir-

6 (3/92)


cuits are included on the interconnect module in addition to the signal routing and connectors tothe other modules. The failure alarm relay AL1 is normally picked up, but the processor willdeenergize it when a problem is found. The trip alarm relay AL2 will be sealed-in if the AL2S isset to YES.

Status input information is interfaced to the microprocessor via seven optical isolators. Theyare:

1 —the status inputs from the breaker auxiliary contacts (52a and 52b),

1 —the pilot channel receiver output (RVCR #1),

1 —the external DCB contact (RVCR #2),

1 —the external pilot enable switch, (it is equivalent to the 85CO device in a conventionalpilot system),

1 —the external target reset switch,

1 —the status input from the disconnecting switch auxiliary contact (89b) for stub busprotection if applied.

Terminals for these signal connections are located on the rear panel of the outer chassis (Figure6). The input voltage level of these optical isolators can be selected by setting the jumpers,JMP1 thru JMP6 and JMP13, on the interconnect module.

The trip alarm will be sealed-in, until externally reset (local or remote), if the AL2S (alarm-2seal-in) is selected to YES. The relay failure alarm (AL1) will self reset once the abnormal con-dition has been removed.

(C) Filter Module

The filter module contains the anti-aliasing filters for the analog inputs, IA, IB, IC, 3Io’, VAG,VBG and VCG. The 3Io’ (labeled as IP) is an input of zero sequence from the paralleled circuitfor Zone 1 ground distance unit mutual compensation. The analog inputs are supplied from theisolation transformers via the backplane and the interconnect modules. The filter analog signaloutputs are supplied to the microprocessor module. The active lowpass filters are third-orderButterworth filters with a cutoff frequency of 240 Hz. This meets the Nyquist criterion for theMDAR sampling rate of 8 samples per cycle (480 Hz at 60 Hz and 400 Hz at 50 Hz).

(D) Power Supply Module

The power supply module provided isolation from the station battery and includes overcurrentand overvoltage protection. Status monitoring and loss-of-power indication is accomplished viaa failure alarm relay (AL1). The failure alarm relay is normally picked up, but the processordeenergies it when a problem is found. A total power loss also drops out the relay. Front paneltest points are included for all power supply voltages. The power supply module is available inthree ranges:

38-70 Vdc, 88-145 Vdc, 176-290 Vdc.

(3/92) 7


Twelve output relays are also located on the power supply module. Their functions are:

Relay Function Type Contacts Rating

K1 Trip A Telephone SPDT 10 AK2 Trip A Telephone SPDT 10 AK3 Breaker failure initiate Telephone DPDT 5 AK4 Carrier stop (STOP) Mercury 1A1B 24 V, 700ΩK5 SRI (RI1)* Telephone DPDT 5 AK6 3RI (RI2) Telephone DPDT 5 AK7 RB Telephone DPDT 5 AK8 K1 Breaker current monitor Reed Form A 0.5 AK9 K2 Breaker current monitor Reed Form A 0.5 AK10 Carrier send (SEND) Mercury 1A1B 24V, 700ΩK13 System test Telephone DPDT 5 AK14 General start (GS) Mercury 1A 24 V,2500Ω

* Special software in Version 2.50, this relay is operated by CR1 signal for monitoring receiver-1.

Contacts from K1 thru K7, K10 and K14 are wired out for external uses. All trip, BFI, RI1, RI2and RB contacts are provided for two breaker applications (Figure 6). The trip output contactswill have a 50 ms. delay on dropout if jumper JMP4 on the processor module is on. The GeneralStart contact (GS) is provided for starting the external recorder.

Contacts from K8, K9 and K13 provide inputs to the microprocessor module. Reed relays K8and K9 are built-in the trip circuits for sensing the trip coil current flow and seal-in the trip out-put relay if the trip coil current is higher than 0.5 amps.

The System Test relay K13 is normally energized through an external jumper, terminals 13 and14 on 2FT-14, connected to the DC supply voltage (Figure 5). During system testing K13 is de-energized by opening an FT switch which disables the reclose initiate relays, K5 and K6. Theabove mentioned external jumper also direct control the power supply for the BFI relay K3.

(E) Microprocessor Module

The MDAR microprocessor module controls the MDAR system. It contains the A/D conVersioncircuitry, the I/O circuitry and the following components:

One microcontroller (U100) — The Intel 80C196KB microcontroller is a 16-bit CMOS proces-sor operates at 10 MHz frequency with 2 16-bit timer/counters,a high-Speed I/O subsystem, 230 bytes of on-chip RAM, awatchdog timer, a serial port and numerous I/O lines.

EPROMs (U103 and U104) — Two separate, easily-replaceable EPROM chips are for programmemory.

PAL (U105) — For programmable Array Logic.

RAMs (U200 AND U201) — Two volatile read-write memory chips are for working storage.

NOVRAM (U202) — One non-volatile RAM is for the storage of settings, targets and datawhen the relay is deenergized.

8 (3/92)


A battery back-up real-time clock (U501) supplies time and date information for time stampingtarget data. The real-time clock can be set through the front panel operator interface or using theRS232 port.

(F) Operator Interface (or display) Module

An illustration of the display module appears in Figure 4. It includes function and value displayfields. Each is a 4-character, 14 segment, blue color vacuum fluorescent, alphanumeric display,0.7 inch high. LED’s show display modes. Pushbutton switches, (no external equipment isrequired), are used to change modes, read target or operation data, call metering displays andenter settings.

A detailed description of the operator interface is included in Chapter VII.

(G) Communication Attachments

A PONI (Product Operated Network Interface) attachment, which is mounted on the backplateof the outer chassis and connected to the backplane module, is provided for the remote transmis-sion of target data. It can be accessed from the rear panel. Two options are available for interfac-ing between MDAR and a variety of local and remote communication devices.

RS-232C PONI — for local single point computer communication.

INCOM® PONI — for local network communication.

MDAR Version 2.50, MD-8B1SPFRK equipped with RS-232C PONI.

(H) Contact Module (It is a standard item for MDAR Version 2.50)

The contact module is a standard requirement on MDAR Version 2.50 for programmable outputcontact function. It plugs to the interconnect module, and is steadied by a center support bar.The contact module consists of 8 relays, 4 with heavy duty normally open contacts (OC-1 toOC-4), and 4 with normal duty form-C contacts (OC-5 to OC-8). Contacts OC-5 to OC-8 can beprogrammed for NO or NC by the jumper position of JMP1 to JMP4, respectively. Each of these8 contacts can be programmed based on any one or all of the 30 pre-assigned signals with AND/OR logic combination. These pre-assigned signal are listed in Chapter IX paragraph (S).

(3/92) 9


IV. MDAR Version 2.50 Installation

(A) External Wirings

As shown in Figure 5, the power system ac quantities VA, VB, VC, VN, IA, IB, IC and 3Io’, aswell as the dc source are connected to the left side 1FT-14 switch (front view). All the trip con-tact outputs are connected to the right side 2FT-14 switch (front view). Switches 13 and 14 onthe right side 2FT-14 may be used for disabling the BFI/RI control logic when performing func-tional tests.

The RS232 PONI communication box is mounted thru the backplate of the outer chassis andconnected to the backplane module, and remote setting.

Dry contact outputs for breaker failure initiation (BFI), reclosing initiation (RI2), reclosingblock (RB), carrier send (SEND), carrier stop (STOP), failure alarm (AL-1) and trip alarm (AL-2) are located on the backplane board (Figure 6). Terminals for the seven optical isolators forRCVR1, RCVR2 (for external DCB contact), Pilot Enable, External Reset, SBP, 52a (not used),and 52b, and the studs for chassis ground (GND) are also on the backplane board.

Eight additional programmable output contacts are on the contact board (standard item inMDAR Version 2.50).

(B) Jumpers

There are several jumpers on the interconnect and microprocessor modules for different func-tions. Proper jumper position should be set for different applications. The jumpers are:

(1) External Jumper

An external jumper is permanently wired to terminals 13/14 of 2FT-14 for BFI/RI enable(Figures 5 and 6). When either or both of these switches is opened, the BFI and RI outputrelays are deenergized to prevent BFI/RI contact closures during system functional test.

(2) Jumpers on Interconnect Module:

Positions forPower supply voltage

JMP1 External DCB contact 15/20, 48/125, 220/250 Vdc JMP2 Pilot enable 15/20, 48/125, 220/250 Vdc JMP3 Channel receiver 1 15/20, 48/125, 220/250 Vdc JMP4 External reset 15/20, 48/125, 220/250 Vdc JMP5 52b contact 15/20, 48/125, 220/250 Vdc JMP6 52a contact 15/20, 48/125, 220/250 Vdc JMP13 89b contact for 15/20, 48/125, 220/250 Vdc

stub bus protection

The above jumpers are factory set for 48/125 Vdc input when the relay is shipped.

Refer to Figure 6, set JMP7 and JMP9 to IN for stub bus protection (factory set), or set

10 (3/92)


JMP8 and JMP10 to IN for alarm-2 contact. Note, only one, JMP7/JMP9 or JMP8/JMP10,may be used at a time.

JMP11 to JMP12 are factory set for MDAR style with FT-14.

(3) Jumpers on Processor Module

JMP1, JMP8 and JMP9 are for EEPROM and RAM circuits, normally factory set to posi-tion 1-2, unless specified.

JMP2 for MDAR Version 2.50, this jumper should be set at position 1-2 for programma-ble output contact selection.

JMP3 and JMP10 to JMP12 are not used.

JMP4 should normally be set to OUT. Set it to IN position for enabling trip contact with0/50 ms dropout time delay.

JMP5 should normally be set to OUT. Set it to IN position for enabling output contactstests.

JMP6 should normally be set to OUT, except for making A/D convertor calibration.

JMP7 does not exist.

(4) Contact Module

The terminals and jumpers for the programmable output contacts are as shown in the fol-lowing table. The jumpers on the contact module are for the selection of the normally openor normally close form-C programmable output contacts.

Programmable Contact arrangementOutputContact Terminals For normal open For normal close

OC-1 2FT-14, 5 & 6 Normal open Not appliedOC-2 2FT-14, 7 & 8 Normal open Not appliedOC-3 2FT-14, 9 & 10 Normal open Not appliedOC-4 2FT-14, 11 & 12 Normal open Not applied

OC-5 TB-2, 5 & 6 JMP1 set at NO JMP1 set at NCOC-6 TB-2, 7 & 8 JMP2 set at NO JMP2 set at NCOC-7 TB-2, 9 & 10 JMP3 set at NO JMP3 set at NCOC-8 TB-2, 11 & 12 JMP4 set at NO JMP4 set at NC

(3/92) 11


V. Description of Software

All currents and voltages for MDAR system, as shown in Figure 3, are sampled and converted intodigital quantities and input to the microprocessor where all signal processing takes place. The sys-tem timing and software design is based on the power line frequency. The analog inputs are continu-ously sampled 8 times per power line cycle.

The first activity of each sample period is the sampling of the seven analog inputs and computation ofthe Fourier and sum of squares components. The remainder of the activity for each sample period isdetermined by the mode of operation (background or fault mode) and the number of the sampleperiod (0 or 7).

MDAR has an internal mode of operation which is generally controlled by the status of the protectedline. There are three normal software modes: Initialization Mode is maintained for one cycle after theMDAR relay is energized or reset; Background Mode is the normal operating mode; Fault Mode han-dles high-speed tripping. Calibration Mode is the fourth mode of operation which is entered after Ini-tialization Mode if JMP6 on the processor module is installed.

(A) Flow chart

The MDAR system software is written in 80C196 Assembly Language. The software flow isbased on the sampling rate and the 60 Hz line frequency. There are eight states per cycle, whichcorrespond to the eight sample per cycle sampling rate. Movement from state to state is con-trolled by a timer. The timer is loaded with a state time at the beginning of the state. The codeexecuted within a state should be completed before the timer expires. The software then waitsfor the timer to time out.

Figure 7 shows a simplified flowchart for the relaying programs in MDAR. All programs areincluded in a loop, as shown, which the processor repeats eight times per power cycle. Mostfunctions. An important detail not shown in Figure 7 is that many of the checks are broken intosmall parcels, so that the whole complement of tasks is performed over an one-cycle period,eight passes through the loop. Some of the checks are done more than once each cycle.

During non-fault operation, the programs follow the Background Mode loop. The processoruses its spare time to check its hardware, service the operator panel and check for a disturbancein voltage or current which indicates a possible fault. If a disturbance is seen, the programsswitch to fault mode, for several power cycles or longer, to perform phase and ground unitchecks for each zone and function.

The instantaneous voltage and current sampling values are converted to RMS and phasor valuesusing a Fourier notch-filter algorithm. An additional dc offset correction algorithm reducesoverreach errors from decaying exponential transients.

(B) Initialization

The initialization routine is executed upon power up of the MDAR relay. All microcomputerinput and output pins and internal control registers are initialized. The system auto-checks/con-tinuous monitoring are performed. If a failure is detected, the failure alarm relay is de-energized

12 (3/92)


and the failure code is displayed. The system remains in Initialization Mode for the first cycle ofdata collection. No tripping occurs during this cycle.

Upon successful completion of the initialization routine, the program jumps to the initial cycledata sampling routine where input signal processing begins.

(C) Background Mode

MDAR detects faults by direct computation (not analog). The relay normally operates in aBackground Mode when no fault is present. The input currents and voltages are sampled andprocessed to compute RMS and phasor values. The sum of squares and the sums of the Fouriercoefficients are updated each sample using information from the previous seven samples to pro-vide a full cycle of data. The RMS and the phasor values of the current and voltage are updatedonce a cycle. The values from the previous cycle are operated on while the present cycle of datais being collected.

The Fourier coefficients and sums, as well as the sum of squares of the inputs are calculated andaccumulated to provide RMS and phasor values of current and voltage for distance measure-ment and metering display. The RMS value of the ground current is also needed for inverse-timeground protection.

Several functions are performed only in Background Mode. The servicing of the operator inter-face is one of these functions; the display is updated, pushbuttons are acknowledged, and LED’sare controlled. Metering of the analog inputs, updating the target information for display pur-poses, and checking the validity of the settings in the nonvolatile memory are other functionsperformed only in Background Mode.

Fault detection is in effect at all times in Background Mode. Each sampled value of current andvoltage is compared to the sampled value from the previous cycle. If the difference exceeds theestablished threshold, a fault is suspected and Fault Mode is entered. The Zone 2 and Zone 3time delay distance protection are performed in both Background Mode and Fault Mode.

(D) Fault Mode

Fault Mode is entered when a current or voltage disturbance is detected on the power system.The RMS and the phasor quantities of pre-fault current and voltage are saved for phase selec-tion, display and “memory” purposes.

Data sampling and conversion is continued in Fault Mode. The dc offset compensation algo-rithm is implemented for the current signals. Servicing of the operator interface is suspended toallow time for the additional computation for high-speed tripping. If no fault is present, MDARremains in Fault Mode for only three cycles. This three cycle interruption of service to the frontpanel is not noticeable.

Following operation of the fault detectors and entry into Fault Mode, Zone 1, Zone 2, Zone 3and pilot protections, as well as high-set direct trip, inverse-time overcurrent protection, out-of-step blocking functions are conducted during Fault Mode.

(3/92) 13


For Zone 2 and Zone 3 faults, impedance computation and checking will continue throughoutthe specified time delay. Frequency of impedance calculation will be once every cycle.

The relay remains in Fault Mode at least three cycles. Some conditions have been setup for exit-ing Fault Mode. When those conditions are met the relay returns to Background Mode.

(E) Fault Mode Transition (Restricted Fault Mode)

To speed up tripping for severe faults, restricted fault testing has been implemented. The lasthalf cycle of prefault input samples and the first half cycle of Fault Mode input samples are usedto compute the current and voltage phasor and RMS values. No dc offset compensation is per-formed. High-set instantaneous overcurrent, Zone 1 and pilot distance unit tests are executed.This will speed up tripping by as much as one cycle for very high current faults.

(F) Calibration Mode

Calibration Mode is provided for factory testing and calibration of the analog input circuitry ofMDAR relay system. The installation of jumper JMP6 on the processor module prior to energi-zation causes MDAR to enter Calibration Mode. MDAR will not enter Fault Mode if JMP6 isinstalled; therefore, the display is always active for diagnostic purposes. The “ADC” function ofthe “TEST” display mode is active only in Calibration Mode.

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VI. Operating Principles of Sensing Units in MDAR Version 2.50

(A) Distance Measurement Principle

MDAR Version 2.50 consists of 3 step distance zones. The Zone 3 distance units also be usedfor the pilot trip function. An additional reverse and forward reach distance zone is included forcarrier start function when the blocking pilot system is used. Each zone consists of 4 variablemho distance units, threeφG-units and oneφφ-unit.

(1) Forward Step Distance Zones

(a) φG fault detection for Zone 1 (Z1G) tripThe Zone 1φG-units provide a limited mutual compensation feature. It is accom-plished by 3 quadrature polarized phase units,φA, φB andφC. Equations (1) and (2)are for operating and reference quantities, respectively. The unit will produce outputwhen the operating quantity leads the reference quantity.

The product of [(ZMR)(Io’)] is for mutual compensation. The compensation is lim-ited to a condition when [Io >1.25(Io’)], and let [(ZMR)(Io’)] = 0 if (I o) equals to orless than 1.25(Io’).

VXG - [IX + Ko(Io) + (ZMR)(Io’)] Z CG (1)

and (VQ) (2)

where VXG= VAG, VBG, or VCG

IX = IA, IB or IC

Io = (IA + IB + IC)/3

3Io’ = Zero sequence current from the paralleled line.

ZCG= Z1G ground distance reach setting in terms of Z1L∠PANG secondaryohms forφG faults.

Z1L, ZoL = Positive and zero sequence line impedances in relay ohms.

ZoM = Line zero sequence mutual impedances in relay ohms per phase.

Since the zero sequence mutual impedance value in “ohms per phase” is 3 times ofits value in “ohms per circuit”, therefore, it is important to use a correct ZOM valuewhen mutual compensation is applied.

PANG, GANG = Angles in degrees of Z1L and ZoL.

Ko = Zero sequence current compensating factor

=

ZR = Ratio of zero to positive sequence line impedances in absolute value.

Z0L Z1L–

Z1L( )-----------------------

Z0L

Z1L-------- 1–

ZR GANG-PANG -1( )= =

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ZMR= Ratio of ZoM/Z1L in absolute value.

VQ = Quadrature phase voltages, i.e., VCB, VAC and VBA for φA, φB andφC units, respectively.

It should be noted that the unit may lose its directionality if [IX + Ko(Io)+(ZMR)(Io’)] Z CG product is higher than the phase voltage VXG. Correction of thisproblem is to supervise the distance unit with FDOG unit.

(b) φG fault detection for Z2G, Z3G (and pilot) tripφG fault detection for Zone 2, Zone 3 (and pilot) trip are accomplished by 3 quadra-ture polarized phase units,φA, φB andφC. Equations (3) and (4) are for operatingand reference quantities, respectively. The unit will produce output when the operat-ing quantity leads the reference quantity. These units will not be mutual compensa-tion.

VXG - [IX + Ko(Io)] ZCG (3)

and (VQ) (4)

where ZCG = Z2G and Z3G (PLTG) ground distance reachsetting in terms ofZ1L∠PANG secondary ohms forφG faults

It should be noted that the unit may lose its directionality if [IX + Ko(Io)] ZCGproduct is higher than the phase voltage VXG. Correction of this problem is to super-vise the distance unit with FDOG unit.

(c) 3φ fault detection for Z1P, Z2P, Z3P (and pilot) trip3φfault protection is accomplished by the logic of any operation of one of the threeφG-units (φA, φB andφC), plus the 3φF output signal from the faulted phase selectorunit.

However, for 3φ fault condition, the equations for the computation of distance unitreach will be (5) and (6) instead of (3) and (4):

VXG - IXZCP (5)

and (VQ) (6)

where VXG = VAG, VBG, or VCG

IX = IA, IB or IC

ZCP = Z1P, Z2P and Z3P (PLTP) zone reach settings in terms of Z1L∠PANG secondary ohms for multi-phase faults.

VQ = quadrature phase voltages i.e., VCB, VAC and VBA for φA, φB andφC units, respectively.

Use pre-fault voltage for VQ when all 3 faulted voltages are:

• below 1.0 volt RMS for Z1P unit.

• below 7.0 volt RMS for Z2P and PLTP(Z3P).

The inner blinder can be set to restrict reach on heavy load (see VI(G) for moreinformation).

(3/92) 16


(d) φφ fault detection (for Z1P, Z2P, Z3P trip zones)Theφφ-unit responds to allφφ/φφG faults, and someφG-faults. Equations (7) and (8)are for operating and reference quantities, respectively. It will produce output whenthe operating quantity leads the reference quantity.

(VAB - IABZCP) (7)

and (VCB - ICBZCP) (8)

Note: Same setting reach of Z CP for both 3d and φφ faults.

(2) Carrier Start Zone CRS for carrier start (Note, the reverse looking direction of the carrierstart units is defined as the same direction as the pilot trip direction).

(a) φG fault detection.Non-directionalφG fault detection for carrier start zone is accomplished by one ofthe three quadrature polarized units,φA, φB andφC. Equations (9) and (10) are foroperating and polarizing quantities, respectively. The unit will produce output whenthe operating quantity leads the polarizing quantity.

VXG - (IX + Ko(Io)) ZF (9)

[VXG + (IX + Ko(Io))ZR]∠90° (10)

where ZF, ZR=Forward and reverse reach settings, respectively, in terms of Z1L∠PANG.

(b) 3φ fault detection for CRS carrier startNon-directional 3φ fault detection is accomplished by the operation of any one of thethreeφG-units,φA, φB andφC.

(c) φf fault detection for CRSF carrier startTheφφ-unit responds to all forwardφφ andφφG faults, and someφG faults. It is for-ward directional. The operating principle of this unit is the same as the trip zone dis-tanceφφ-unit, except it is designed to the non-pilot-trip direction as its forwarddirection.

(3) Characteristics

Refer to Figures 8, 9, 10 and 11.

(B) Faulted Phase Selection Units

Faulted phase selection includes determining if the fault is between phases or between one ormore phases and ground, and also identifies the specific phase or phases involved in the fault.

Faulted phase identification is necessary for providing information for distance unit and faultlocation computations.

The current phasors IA, IB, IC and Io are utilized in the fault identification algorithm. When afault occurs, the last set of current phasors prior to the fault are saved as the pre-fault load cur-rent values.

17 (3/92)


Fault Type

AG BG CG AB BC CA ABG BCG CAG

|∆IA|> 1.5 x |∆IB| x x x

|∆IA| > 1.5 x |∆IC| x x x

|∆IB| > 1.5 x |∆IA| x x x

|∆IB|> 1.5 x |∆IC| x x x

|∆IC|> 1.5 x |∆IA| x x x

|∆IC|> 1.5 x |∆IB| x x x

The following conventions are used:

3Io = IA + IB + IC Calculated zero sequence current from the measured post-faultcurrent phasors

IAL, IBL, ICL, Measured pre-fault load current phasors

IA, IB, IC, 3Io Measured post-fault current phasors

∆IA, ∆IB, ∆IC Resultant fault current phasors

To determine the resultant fault current, remove the zero sequence current from the measuredpost-fault current and subtract the measured pre-fault load current. The resulting fault current isthe sum of the positive sequence current and the negative sequence current of the fault.

∆IA = (IA - Io) - IAL = IA1 + IA2

∆IB = (IB - Io) - IBL = IB1 + IB2

∆IC = (IC - Io) - ICL = IC1 + IC2

Compare the magnitude of the resultant fault current phasors using the following table to deter-mine the fault type.

If none of the nine fault types in the table are identified, then the fault must be identified as athree-phase fault.

(C) Phase Directional Unit, (FDOP)

The inordinately high influence of ct lead resistance for a low voltage MPS test with the Motor-Generator set as one of the test sources, produces virtually a 90° phase shift in the polarizingvoltage with the angle between the sources, causing undesired operation. Even though this is anMPS-related phenomenon and would pose no problem for an actual power system, a forwardphase directional function FDOP and logic which includes AND-130 and AND-159, as shownin Drawing 2677F21, has been added for supervising the Z1P and PLTP 3φ unit trip paths. Theperformance of the FDOP elements (FDOPA, PDOPB and FDOPC) is 90°-60°, which is similarto the directional unit of the type CR relay.

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(D) Ground Directional Units

There are 2 ground directional units, FDOG (forward directional overcurrent ground) andRDOG (reverse directional overcurrent ground), in the MDAR Version 2.50 system. The operat-ing principle of these units can be selected based on the application. By scrolling the functionalfield to DIRU (directional unit) and selecting the ZSEQ (zero sequence) in the value field, bothFDOG and RDOG units will be polarized by zero sequence voltage 3Vo. However, both theFDOG and RDOG units will be operated by negative voltage/current quantities if NSEQ (nega-tive sequence) is selected in the value field.

(1) Zero sequence voltage polarizing ground directional FDOG/RDOG

The voltage polarizing directional element is determined by the angular relationship of the3Io and 3Vo phasors.

Forward direction is identified if 3Io leads 3Vo by 30°-210°.

Reverse direction is identified if 3Io lags 3Vo by 0°-150° or if 3Io leads 3Vo by 0°-30°.

The sensitivity of this element is 3Io > 0.5 amp and 3Vo > 1.0 volt.

(2) Negative sequence quantities operated ground directional FDOG/RDOG

The negative sequence quantities operated ground directional units utilize the negativesequence voltage V2 as the polarizing quantity and negative sequence current I2 as theoperating quantity. Its operation is determined by the angular relationship of the V2 and I2phasors. Maximum sensitivity for the forward direction unit occurs when V2 lags with I2by 98°.

The sensitivity of this element is V2 > 1.0 volt and 3(I2) > 0.5 amp.

(E) Fault Detection Units

MDAR Version 2.50 detects faults by digital computation rather than analog. The relay nor-mally operates in a Background Mode where it looks for phase current or phase voltage distur-bance. Once a phase disturbance is detected, the relay enters Fault Mode and starts theimpedance unit computations. During background mode, the four input currents (IA, IB, IC and3Io’) and the three voltages (VA, VB and VC) are sampled, at a sampling rate of 8 times percycle, to test for line faults. The criteria for determining a disturbance in the MDAR design isshown below, which comparing the instantaneous samples taken one cycle apart:

(1) Each phase∆I — if [I Kn - I(K-1)n] > 1.0 amp

and [IKn - I(K-1)n] / I(K-1)n x 100% > 12.5%

(2) Each phase∆V — if [V Kn - V(K-1)n] > 7.0 volts

and [VKn - V(K-1)n] / V(K-1)n x 100% > 12.5%

(3) ∆Io — if [(3Io)Kn - (3Io)(K-1)n] > 0.5 amp

where n = 1,2,3,4,5,6,7,8 and K = number of cycles

19 (3/92)


(F) Negative sequence and low voltage units

There are three low voltage units (VAL, VBL and VCL) in MDAR Version 2.50. Each unit sensesthe phase voltage condition in the background mode. The unit can be set from 40 to 60 volts in1.0 volt steps. For any phase voltage below its preset value, the LV logic will produce a logic“1” output signal. The LV units are used in CIFT logic in the system.

(Note: Three separate low voltage units fixed at 7 volts are used for the LOP logic).

MDAR 2.50 uses negative sequence voltage V2 for supplement the carrier start function. Thepickup level is fixed at 3V2 = 25 volts.

(G) Blinder Units

Single blinder 21BI for 3D unit reach restriction on heavy loads.

Double blinders, 21BI and 21BO, are included in MDAR Version 2.50 system for out-of-stepdetection. The following quantities are used for the blinder sensing:

Blinder Line Polarizing Operating

Left -j(VAG + IARC∠PANG-90°) IARC∠PANG-90°

Right j(VAG - IARC∠PANG-90°) IARC∠PANG-90°

Where RC is the setting of the unit (RΤ for inner blinder 21BI and RU for outer blinder 21BO).Operation occurs if the operating voltage leads the polarizing voltage. The characteristic curvesare shown in Figure 12. Inner and outer blinder reaches are determined by the setting of RT andRU, respectively.

(H) Fault Locator

The fault locator feature in MDAR computes the magnitude and phase angle of the fault imped-ance and the distance to the fault in both miles and kilometers. The fault impedance is calcu-lated from the voltage and current phasors of the faulted phase(s). Thus proper faulted phaseselection is essential for good fault locator results. The impedance calculations for the variousfaults are as shown below:

Fault Type Impedance Calculation

AG ZAG = VAG / [IA + Ko(Io)]

BG ZBG = VBG / [IB + Ko(Io)]

CG ZCG = VCG / [IC + Ko(Io)]

AB/ABG ZAB = VAB / IAB

BC/BCG ZBC = VBC / IBC

CA/CAG ZCA = VCA / ICA

ABC ZABC= VAG / IA

Since the Version 2.50 provides a limited mutual compensation feature for Zone 1 ground faults,therefore, the following equations should be used for Zone 1 AG/BG/CG fault location whenIo >(1.25 Io’).

(3/92) 20


Fault Type Zone 1 Impedance Calculation when Io >(1.25 Io’)

AG ZAG = VAG / [IA + Ko(Io) + (ZMR) (Io’)]BG ZBG = VBG / [IB + Ko(Io) + (ZMR) (Io’)]CG ZCG = VCG / [IC + Ko(Io) + (ZMR) (Io’)]

The distance to the fault is computed by multiplying the imaginary part of the fault impedance times(VTR/CTR) and dividing by the distance multiplier setting (XPUD).

Distance = imag(Z) x (VTR/CTR) / XPUD

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VII. Operator Interface

(A) General Description

The operator panel (Figure 4) provides an integral convenient means of checking or changingsettings, and of checking relay-unit operations after a fault. Fault location, trip type, phase unitswhich operated, and breakers which tripped are available for most recent 2 faults by using push-buttons to step through the information. Targets from the last 16 faults are stored even if therelay is deenergized and are available through remote communication (RS-232C port) only.

The operator panel contains 7 LEDs as follows:

Relay in service — When this LED illuminates the MDAR relay is in service, there is dcpower to the relay and the relay has passed the self-check and self-test.The LED will turned OFF if the relay has any internal failure shown inthe “Test” mode, and the relay trip output will be blocked.

Settings — For read or change settings.

Monitoring — The display shows three-phase voltage, current and angle.

Last Fault — When flashing, indicates new fault information available.

Previous Fault — When last fault LED flashes twice per minute, indicates information forthe fault proceeding the last fault.

Test — Use for verifying self-check and perform functional test.

Value Accepted — When the “Settings” LED is also ON, the “Value Accepted” LED flashesonly once, to indicate that a new setting value is accepted.

When the “Test” LED is also ON, the output contacts can be tested (with the JMP5 connectedon the processor module). The operator is notified that targets are available by flashing LED’son the panel, plus an output relay contact provided to operate an external annunciator.

The operator can also look at non-fault voltage, current and phase angle on the display.

Settings can be easily checked as well.

The display will be blocked momentarily, every minute, for the purpose of self-check; this willnot affect the relay protection function.

There are five test points on the MDAR relay front panel to measure power supply voltage. Thetest points provide measurement of the -24, +5, -12 and +12 Vdc voltages.

The RS-232C serial port on the rear panel (Figure 2) is provided for remote transmission of tar-get data and remote setting. It also can be used for future networking.

(B) Front Panel Operation

The operator interface consists of a vacuum display with four alphanumeric characters for thefunction field and four alphanumeric characters for the value field, seven pushbuttons, sevenLED’s and five test points. All relay functions can be locally set, monitored and tested from thisfront panel interface (Figure 4).

22 (3/92)


(1) Display Selection

The display selection pushbutton controls the type of information displayed. The optionsinclude settings, metered values, two sets of fault data and test mode. One of the five dis-play modes is always selected and is indicated by an illuminated LED. Depressing the“DISPLAY SELECT” pushbutton changes the display information to the next selection.

(2) Entering Settings

The operation of the MDAR relay is controlled through the settings. To access the settings,the “DISPLAY SELECT” pushbutton should be depressed until the “SETTINGS” LED isilluminated. The RAISE and LOWER FUNCTION pushbuttons are depressed to scrollthrough the settings. The RAISE and LOWER VALUE pushbuttons are depressed tochange the settings. When the desired value appears on the VALUE display, depressingthe “ENTER” pushbutton causes the displayed value to be entered for the displayed func-tion. The “VALUE ACCEPTED” LED flashes once to indicate that the value has beensuccessfully entered into the system.

(3) Displaying Monitoring Data

All three-phase currents, voltages and phase angles are available for on-line display duringnormal operation. Conditions such as out-of-step blocking, loss-of-potential, and loss-of-current can also be monitored. Select the “VOLT/AMPS/ANGLE” function using the“DISPLAY SELECT” pushbutton. Scroll through the metered data using the RAISE andLOWER FUNCTION pushbuttons. Upon initialization the display is set to show the IAcurrent.

(4) Displaying Fault Record

The last two sets of fault data are available for display. “LAST FAULT” is the data associ-ated with the most recent trip event. “PREVIOUS FAULT” is the data from the prior tripevent. Select the desired set of target data using the “DISPLAY SELECT” pushbutton.Scroll through the fault data using the RAISE and LOWER FUNCTION push-buttons.

(5) Display Test Mode Functions

The test display mode provides diagnostic and testing capabilities for MDAR. Informationof relay status, A/D calibration, testing of the carrier send and receive functions for thepilot systems, and trip relay test are among the functions provided. To access the test func-tion, the “DISPLAY SELECT” pushbutton should be depressed until the “TEST” LED isilluminated. The RAISE and LOWER FUNCTION pushbuttons are depressed to scrollthrough the desired function. The required information will display in the VALUE field.

Contact output test can only be performed when jumper JMP5 on the microprocessormodule is in. (Refer to Chapter VIII. Auto-checking and Functional test” for more detailinformation).

(6) 16 Fault Records and Intermediate Targets.

Refer to Chapter IX, Paragraph (Q) for detail.

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(7) Programmable Output Contact Function

Refer to chapter IX paragraph (S) for detail.

(8) Reset Targets

When a fault is detected, the “Last Fault” flashes once per second. If two faults arerecorded, the “Last Fault” flashes twice per second, and the prior fault will be moved from“Last Fault” to “Previous Fault”. The new fault data will be stored in the “Last Fault” reg-ister. By depressing the “Reset Targets” pushbutton, the flashing LED indicators arecleared, and the LED will revert back to the metering mode. The information in the “Pre-vious Fault” and “Last Fault” will not be reset from the front panel pushbutton switch, butwill be reset from the External Reset (terminals TB5/5 and TB5/6) and the remote resetthrough the Communication Interface.

(C) Display and Target Information (to be updated/revised later)

(1) Settings Display — The setting display shows the following information:

Display

Function ValueInformation/Settings Field Field

Software version VERS 2.50

Initiate OSC storage OSC TRIP/Z2TR/Z2Z3/∆V∆I

Initiate fault data storage FDAT TRIP/Z2TR/Z2Z3

CT ratio CTR 30-5000, (5)

PT ratio VTR 300-7000, (10)

Rated frequency FREQ 60, 50

CT secondary rating CTYP 5 or 1

Enable/disable readoutsin primary I & V values RP YES/NO

Reactance (Ω / unit distance)multiplier for fault, locator XPUD 0.300-1.5, in 0.001/DTYP

Fault location, displayedin Km. or miles DTYP KM or MI

Reclosing mode: TTYPa)3PT on all faults, no RI. OFFb)3PT on all faults, 1PR

with 3RI onφG fault.c)3PT on all faults, 2PR

with 3RI onφG/2φ fault. d)3PT on all faults w/3RI. 3PRRI on Z1 trip Z1RI YES/NO

RI on Z2 trip Z2RI YES/NO

RI on Z3 trip Z3RI YES/NO

RB on BF squelch BFRB YES/NO

24 (3/92)


Display

Function ValueInformation/Settings Field Field

Pilot control PLT YES/NO

System selection: STYP a) 3-zone non pilot scheme 3ZNP b) Zone 1 extension scheme Z1E c) Blocking scheme BLK

FDOG trip delay timer FDGT 0-15, in 1 cycle & BLK steps

Channel coordination timer BLKT 0-98, in 2 ms steps

Carrier start forward CRSF 0.01-50.00, 0.01 ohm steps Carrier start reverse CRSR 0.01-50.00, 0.01 ohm steps

Zone 1 phase unit Z1P #0.01-50.00, 0.01 ohm steps Zone 1 ground unit Z1G #0.01-50.00, 0.01 ohm steps Zone 1 delay trip T1 0-15 cycles, 1.0 cycle steps

Zone 2 phase unit Z2P #0.01-50.00, 0.01 ohm steps Zone 2 phase timer T2P 0.10-2.99,BLK,0.01sec.steps Zone 2 ground unit Z2G #0.01-50.00, 0.01 ohm steps Zone 2 ground timer T2G 0.10-2.99,BLK,0.01sec.steps

Zone 3 & Pilot phase unit Z3P #0.01-50.00, 0.01 ohm steps Zone 3 phase timer T3P 0.10-9.99,BLK,0.01sec.steps Zone 3 & Pilot ground unit Z3G #0.01-50.00, 0.01 ohm steps Zone 3 ground timer T3G 0.10-9.99,BLK,0.01sec.steps

Z1L impedance angle PANG 40-90, in 1.0 degree steps ZOL impedance angle GANG 40-90, in 1.0 degree steps ZOL/Z1L ZR 0.1-7.0, in 0.1 steps

ZOM/Z1L ZMR 0.01-5.00, in 0.01 steps Low voltage units LV 40-60, in 1.0 volt steps. Overcurrent units Low set phase IL 0.5-10, in 0.1 amp steps Med.set phase IM 0.5-10, in 0.1 amp steps Low set ground IOS 0.5-10, in 0.1 amp steps Low set ground timer IOST 0-5 seconds, in 1.0 sec steps Med. set ground IOM 0.5-10, in 0.1 amp steps High set phase ITP #2.0-150. 0, 0.5 amp steps High set ground ITG #2.0-150, 0, 0.5 amp steps

Out-of-step blocks Z1P/3d OSB1 YES, NO Out-of-step blocks Z2P/3d OSB2 YES, NO Out-of-step blocks Z3P/3d OSB3 YES, NO Out-of-step block/trip OST NO, WAYI, WAYO OS timer OST1 OST1 0.5-5, in 0.5 cycle steps OS way in trip timer OST2 OST2 0.5-5, in 0.5 cycle steps OS way out trip timer OST3 OST3 0.5-5, in 0.5 cycle steps OSB override timer OSOT #24-240, in 1.0 cycle steps, OSB inner blinder RT 1.00-15.00, 0.1 ohm steps OSB outer blinder RU 3.00-15.00, 0.1 ohm steps

Directional ground units DIRU ZSEQ, NSEQ

# Use “OUT” for disabling this unit.* Pilot option only.

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Display

Function ValueInformation/Settings Field Field (note 1)

Ground backup time curves GBCV #CO-2, CO-5, CO-6, CO-7,CO-8, CO-9 and CO-11.

Ground backup setting GBPU 0.5-4.0, in 0.1 amp steps Ground backup time dial GTC 1-63, in 1.0 steps Choice of directional or non-directional

ground backup GDIR YES/NO

CIF trip/Stub bus protection CIF CIFT/STUB/BOTH/NO

LLT trip LLT YES/FDOG/NO

LOP block LOPB YES/NO

LOI block LOIB YES/NO

Trip alarm seal-in AL2S YES/NO

Remote setting SETR YES/NO

Real time clock TIME YES/NO a) set year YEAR 1980-2079,in 1 year steps b) set month MNTH 1-12, in 1 month steps c) set day DAY 1-31, in 1 day stepsd) set week day WDAY SUN/MON/TUES/WEN/

THUR/FRI/SAT e) set hour HOUR 1-24, in 1 hour steps f) set minute MIN 1-60, in 1 minute steps

# Use “OUT” for disabling this unit.

(2) Monitoring Display

The metering group display shows the following information.Display

Function ValueInformation/Settings Field Field (note)

Phase A current (mag.) IA numerical, A “ (ang.) ∠IA deg.

Phase A voltage (mag.) VAG numerical, v “ (ang.) ∠VAG deg.

Phase B current (mag.) IB “ (ang.) ∠IB

Phase B voltage (mag.) VBG “ (deg.) ∠VBG

Phase C current (mag.) IC “ (ang.) ∠IC

Phase C voltage (mag.) VCG “ (ang.) ∠VCG

Date DATE XX.XX (month.day)Time TIME XX.XX (hour.minute)Local/Remote Setting SET LOC/REM/BOTHCarrier Receiver-1 RX-1 YES/NOLOP Indication LOP YES/NOLOI indication LOI YES/NOOut-of-step block OSB YES/NO

Note: All displayed phase angles are referred to VA as reference.

26 (3/92)


(3) Fault Data Display

The MDAR saves the latest 16 fault records, but only the latest two fault records can beaccessed from the front panel. For complete 16 fault data, RS-232C PONI communication inter-face is required.

Each fault target data display shows the following information:

Display


Fault type FTYP AG/BG/CG/AB/BC/CA/ABG/BCG/CAG/ABC

BKR. #1 tripped BK1 YES/NOBKR. #2 tripped BK2 “Zone 1 phase tripped Z1P YES/NOZone 1 ground tripped Z1G “

Zone 2 phase tripped Z2P “Zone 2 ground tripped Z2G “

Zone 3 phase tripped Z3P YES/NOZone 3 ground tripped Z3G “

Pilot phase tripped PLTP “Pilot ground tripped PLTG “

High set phase tripped ITP “High set ground tripped ITG “

Close-into fault trip CIF “

Load-loss tripped LLT “

Ground backup tripped GB “

OUT-of-step Trip OST “

Fault location Z In ohmsFault Z angle FANG numericalFault distance DMI/DKM In KM or Miles

Prefault load current PFLC numerical, APrefault phase voltage PFLV “ VPrefault load angle LP “ deg.

Carrier send SEND “RCVR #1 RX1

(3/92) 27


Display


Fault voltage VA (mag.) VPA numerical, V(ang.) ∠VPA “ deg.

Fault voltage VB (mag.) VPB “ V(ang.) ∠VPB “ deg.

Fault voltage VC (mag.) VPC “ V(ang.) ∠VPC “ deg.

Fault voltage 3VO (mag.) 3VO “ V(ang.) ∠3VO “ deg.

Fault current IA (mag.) IPA “ A(deg.) ∠IPA “ deg.

Fault current IB (mag.) IPB “ A(deg.) ∠IPB “ deg.

Fault current IC (mag.) IPC “ A(deg.) ∠IPC “ deg.

3Io’ current (mag.) 3IOP “ A(deg.) ∠3IOP “ deg.

Fault occurred at:a) date DATE XX.XX (month.day)b) year YEAR XXXXc) time TIME XX.XX (hour.minute)d) second SEC XX.XX (second)

Note: All displayed phase angles are referred to VA as reference.

Note: The “Relay In Service” LED indicates the MDAR is in-service. It will come on whenthe dc is applied and after the system is initialized.

(4) Test Functions Display

Four functions are available in the test function mode. They are: STAT, ADC, RS1, and TRIP.

STAT The STAT is the relay auto-check status. MDAR Version 2.50 jumps to the test modestatus display (STAT) to show the cause of the problem. A zero value indicates that noauto-check failure has occurred. A nonzero hex byte form value indicates hardware orsoftware failed. Refer to Chapter VIII for more detail.

ADC The ADC value display is for factory use in calibration of the analog input to KEPCO/MDAR and is only visible when MDAR Version 2.50 is in calibration mode (JMP6 onprocessor module installed). Field calibration is not required.

28 (3/92)


RS1, and TRIP

These selections are for functional tests. When the selector is in the test mode, scrollthe function field by the raise pushbutton. The value field display shows RS1, (Carrierreceiver #1). Refer to Chapter VIII (D) for more detailed information.

If jumper JMP5 on the processor module is set to IN position, the following 18 con-tacts can be selected for testing. Refer to Chapter VIII (C) for more detailed informa-tion.

TRIP Contacts BFI Contacts RI1 Contacts RI2 Contacts RB Contacts AL1 Contacts AL2 Contacts GS Contacts SEND Contacts STOP Contacts OC1 to OC8 Contacts

(3/92) 29


VIII. Auto-checking and Functional Test

(A) Auto Check/Continuous Monitoring

Auto-checking is a major benefit of microprocessor-based relays. At all times, MDAR monitorsits ac input subsystems using multiple A/D converter calibration check inputs, plus loss-of-potential and loss-of-current monitoring (as described in Chapter IX). Failures of the converter,or any problem in a single ac channel which unbalances nonfault inputs, are alarmed. The auto-checking covers the following areas:

(1) Analog Front End Test

One of the inputs to the analog multiplexer is for self dc voltage check. This input voltagecan be switched between +2.5 V and -0.3 V for input to the A/D converter. Periodic testingof these voltages tests the analog front end for proper operation. In this way the multi-plexer, sample/hold, ranging circuitry, and A/D converter are tested.

(2) Program Memory Checksum

Immediately upon power-up the relay executes a complete ROM checksum of programmemory. During operation, the MDAR relay continuously computes and verifies the pro-gram memory checksum.

(3) Power-up RAM Test

Immediately upon power-up the relay does a complete test of the RAM data memory.

(4) Nonvolatile RAM Test

All settings for the system operation are stored in non-volatile RAM (EEPROM) in threeidentical arrays. These arrays are continuously checked by the program. If all three arrayentrees disagree with each other, a non-volatile RAM failure is detected.

(5) Processor Tests

Several tests are included to verify the operation of the microprocessor. On power-up, theprocessor I/O status registers are checked while they are still in a known state. Other testsperformed both at power-up and during normal operation are listed below:

- Tests processor flags, stack, and timer.- Tests program counter, execution time, and RAM.- Tests addition and subtraction.

For failures which do not disable the processor, MDAR jumps to the TEST mode statusdisplay (STAT) to show the cause of the problem. The cause of the problem is representedby their corresponding bits (zero thru 5) in the value field.

Bit 0 External RAM Failure Bit 1 EEPROM warning Bit 2 ROM (EPROM) checksum error Bit 3 EEPROM Failure (Non-Volatile memory) Bit 4 Analog Input Circuit Failure

30 (3/92)


Bit 5 Processor Failure

All bits are expressed in a HEX byte form.

For example: If the display shows “STAT 1B”, whose binary representation is 0001 1011,the relay failed the self-test in the area of External RAM (bit 0), EEPROM(one-out-of-three failure, bit 1), EEPROM (two-out-of-three failure, bit 3)and Analog Input Circuit (bit 4). Normally, the test mode should show“STAT 0”. This means that the relay passes the self-test routines.

(B) LOP and LOI Conditions

MDAR contains loss-of-potential (LOP) and loss-of-current (LOI) logic which monitors theanalog inputs. The loss of a voltage or current input which is not caused by a fault conditionenables the alarm relay. In addition, tripping is disabled during a LOI condition if the LOIB set-ting is set to YES. However, only the distance measurement units are disabled during a LOPcondition if the LOPB setting is set to YES. The protection of overcurrent units (ITP, ITG &GB) will be remained functioning except converting to non-directional automatically. The LOPand LOI status displays are included in the monitored data.

(C) Output Contact Tests

The following 18 output relays can be selected for testing.

A “Push-to-close” approach, is included in MDAR Version 2.50 for checking all output relaycontacts. It is designed for a bench test only. The test is for used to verify the operation of thecontacts of the TRIP, BFI, RI1 (CR1), RI2, RB, AL1, AL2, GS, Carrier SEND and CarrierSTOP functions. It is supplementary to the auto-check because the microprocessor auto-checkroutine cannot detect the output hardware.

TRIP RELYBFI RELYRI1 (CR1) RELYRI2 RELYRB RELYAL1 RELY (with 3-balanced voltage source)AL2 RELYGS RELYSEND RELYSTOP RELYOC1 to OC2 RELY

If it is not a bench test, all the red-handled FT switches should be opened before performing thetest to avoid the undesired tripping during tests. However, due to the opening of the connectionbetween 2FT-14 terminals #13 and #14, the contacts of BFI, RI1 (CR1) and RI2 will not be ver-ified.

(3/92) 31


For performing the output contact test:

(1) Remove JMP3 (spare on the processor module) and place it in the JMP5 position.

(2) Change the LED mode to TEST and select the tripping function field and the desiredcontact in the value field.

(3) Push the ENTER button; the ENTER LED should be ON. The corresponding relay shouldoperate when the ENTER button is pressed.

(4) Remove JMP5 and replace it on JMP3.

(D) Functional Test

The functional test simulates the channel condition for verifying the relay system. The proce-dure of the test is:

(1) Change the LED mode to TEST and select the following desired function field: RS1

(2) Push the ENTER button; the ENTER LED should be ON. The corresponding function ofRS1 (receiver 1) will be simulated for the relay system.

(3) The functional test for the transmitter keying can be performed by operating the externalDCB contact via the RCVR-2 terminals.

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IX. Operation of MDAR Version 2.50 Functions

When the MDAR Version 2.50 functional display “STYP” is set to “BLK”, it will perform the pilotblocking scheme with three step distance zone supporting backing.

When the MDAR Version 2.50 functional display “STYP” is set to “3ZNP”, its pilot zone will be dis-abled, and will perform as a three step distance non-pilot system. However, the Zone 1 units performthe Zone 1 extended function if “STYP” is set to “Z1E”.

(A) Loss-of-Potential Supervision, LOP (Figure 13)

The ac voltage monitoring circuit is called loss-of-potential circuit.

In order to prevent undesirable tripping due to the distance unit(s) pickup on loss-of-potential,logic (low voltage and not VI) and (Vo and not Io) are included in the MDAR design as shownin Figure 13A. The low voltage and Vo units for the LOP logic are set at a fixed value of 7 volts.Under loss-of-potential condition, low voltage (or Vo) and not VI (or Io) satisfy AND-1. Theoutput signal of AND-1 starts the 8/500 ms timer logic. The timer output will satisfy AND-1C ifthere is no output from AND-1B. The output signal of AND-1C will block all the distance unittripping paths via AND-2, AND-3, AND-4, AND-5, AND-6, AND-172 (and AND-187, AND-191 if pilot is applied) if LOPB is set to “YES”. The LOPB blocking function can be disabledby selecting the LOPB value display to “NO”.

The output of the LOP timer will turn on the non-memory LOP indicator on the metering dis-play during the LOP condition via AND-1F after 500 ms delay. This output is also connected tothe failure alarm.

In selecting the LOPB to “YES”, the intent is to block all the distance units from tripping shoulda LOP condition exist. However, for a condition as shown in Figure 13B, a single-end sourceenergizes two parallel circuits without pre-fault load current. The MDAR at the remote end B ofthe protected line may fail to trip for an internal fault near the source-end A, because its LOPsets up before the terminal A trips. This is because the relay at B sees no current, but sees a lowvoltage condition before circuit breaker A opens.

Also, for a condition as shown in Figure 13C, an evolving fault at 50% location with symmetri-cal source impedances, MDAR’s at both A and B will not trip if LOPB is selected to “YES”,because neither MDAR sees a current change (or no Io) on the protected line to set up the LOPBlogic before the second fault is applied.

Logic AND-1A,-1B,-1C and OR-1D, and 150/0, 3500/200 ms timer circuits in Figure 13A arefor solving these problems. This logic unblocks the LOPB circuit and provides a 3500 ms tripwindow for the distance units to trip if the fault current is detected within 150 ms after LOP hasbeen set up.

For increasing the security, the application of LOPB supervision function is normally recom-mended.

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(B) Monitoring of AC Current, LOI (Figure 14)

The ac current monitoring circuit is similar to the LOP logic, except using IOM and not Vo as acriterion, as shown in Figure 14. Under a ct short circuit or open circuit conditions, IOM and notVo satisfies AND-23. The LOI output signal from AND-23 starts the 500/500 ms timer. The out-put of the timer will turn on the non-memory LOI indicator on the metering display during theLOI condition. This output is also connected to the failure alarm.

The LOI signal also can be used to block the MDAR trip outputs under LOI condition if theLOIB (loss-of-current block) is selected to YES.

(C) Overcurrent Supervision (Figure 15)

For coordination purposes, the ground trip units Z1G, Z2G, Z3G(PLTG) and FDOG are super-vised by the medium set ground overcurrent unit IOM, except the carrier start RDOG units issupervised by the low set IOS. The IOM and IOS settings must be coordinated with one another.

On MDAR design, the phase distance units do not require overcurrent supervision, because therelay normally operates in a background mode. They will not start the Zone 1 and pilot imped-ance computation until a phase current or a phase voltage disturbance is detected. This approachcan minimize the load current problem on setting the phase overcurrent units. Also, the 3-phaseunits are supervised by the load restriction logic, and the 21BI unit is restricted by the setting ofIL units, consequently the 3-phase units are supervised by the IL-units. However, for increasingthe security, an additional medium set overcurrent IM-unit is added to MDAR Version 2.50 soft-ware for supervising all the distance phase units, as shown in Figure 15.

(D) Zone 1 Trip (Figure 16)

For Zone 1 phase faults, the Z1P unit will see the fault and operate. As shown in Figure 16, the3D fault logic is supervised by the FDOP and the selectable OSB1 (OS block Zone 1). Output ofZ1P plus the operation of FDOP (if applied), faulted phase selector and IM, satisfies AND-2 andprovides a high speed trip (HST) signal from OR-2 to operate the trip output telephone relay.The trip circuit is monitored by a seal-in reed relay S, which is in series with each trip contact inthe tripping circuits. The S relay will pick up if the trip current is higher than 0.5 amp. The oper-ation of the seal-in contact “S” (i.e. after breaker trip coil has been energized) provides the tripseal-in signal. It feeds back to OR-4 to hold the trip relay in operation until the breaker trips andthe 52b contact opens (not shown in Figure 16). The TRSL signal from AND-8 plus the outputsignal from AND-2B turn on the Zone 1 phase trip indicator Z1P. The breaker trip and Zone 1phase trip indicators are sealed-in. They can be reset only after manually pushing the RESETpushbutton on the front panel.The Zone 1 3D fault trip logic AND-131 is supervised by the loadrestriction 21BI-unit (RT) and the selectable OSB1 (OS block Zone 1) logic.

Similar operations function for Zone 1 single-phase-to-ground faults. The Z1G unit sees thefault and operates along with the IOM and FDOG units, satisfying AND-3. Tripping is initiatedvia OR-2 with Zone 1 ground trip indication Z1G. Logic AND-3 is also supervised by the signalof RDOG (reverse directional overcurrent ground) for security.

A two-out-of-three “leading phase blocking” logic is included for solving the overreach prob-lem of the single-phase ground distance units which may respond to a φφG fault.

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The Z1G unit is also supervised by signal of the unequal-pole-closing logic.

The Z1G units provide a limited mutual compensation feature. The compensation is limited to acondition when [Io > 1.25(Io’)], where (Io’) is the zero sequence current from the paralleledline. Io’ current should be connected and ZMR should be set when mutual compensation isrequired. MDAR terminals 1FT-14 11-12 (labeled as IP) should be shorted and ZMR should beset to minimum (in order to minimize the noise) if mutual compensation is not required.

The T1 timer, range from 0 to 15 cycles in 1.0 cycle steps, as shown in Figure 16, provides timedelay on Z1P/Z1G trip. Normally, the T1 timer should be set to zero, unless it is needed. Forexample, when using MDAR Version 2.50 as a non-pilot backup with HCB for primary on ashort line application, set MDAR Zone 1 with delay to compromise the possible Zone 1 over-reach problem.

HST signal also is connected to the reclosing initiation logic.

Either or both Zone 1 phase and Zone 1 ground function(s) can be disabled by selecting the Z1Pand/or Z1G to OUT.

(E) Zone 2 Trip (Figure 17)

For Zone 2 phase faults, the Z2P unit will see the faults and operate the Zone 2 phase timer T2P.The Z2P output plus the T2P timer output satisfy AND-18 as shown in Figure 17. AND-18 out-put provides time delay trip signal TDT via OR-3. Signal TDT picks up OR-4 (Figure 16) andoperates the trip relay. The tripping and targeting are similar as described in Zone 1 trip exceptwith Zone 2 phase time delay trip indicator Z2P.

Zone 2 3-phase unit is supervised by the load restriction 21BI-unit (RT) and the selectableOSB2 (OS Block Zone 2) logic.

Similar operation occurs for Zone 2 single-phase-to-ground faults. The Z2G unit sees the faultand operates. This plus the operation of the IOM, FDOG and T2G, satisfies AND-19, and pro-vides the TDT signal via OR-3 with Zone 2 ground time delay trip indicator Z2G. The singlephase ground distance units may respond to a φφG fault. The output of the Z2G unit plus theoperation of theφφ-selection will trip the Z2P via OR-153, T2P and AND-18. Leading phaseblocking is unnecessary for an overreach Zone device.

TDT signal can be connected to the reclosing block logic.

Either or both Zone 2 phase and Zone 2 ground function(s) can be disabled by selecting the Z2Pand/or Z2G to OUT; or can be disabled by selecting the T2P and/or T2G to BLK.

(F) Zone 3 Trip (Figure 18)

For Zone 3 phase faults, the Z3P units will see the faults and operate the Zone 3 phase timerT3P. The Z3P output plus the T3P timer output satisfy AND-20 as shown in Figure 18. AND-20output provides time delay trip signal TDT via OR-3. Signal TDT picks up OR-4 (Figure 16)and operates the trip relay. The tripping and targeting are similar to Zone 1 trip, except for theZone 3 phase time delay trip indicator Z3P.

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Zone 3 3-phase unit is supervised by the load restricted 21BI-unit(RT), the FDOP signal and theselectable OSB3 (OS Block Zone 3) logic.

For Zone 3 single-phase-to-ground faults, the Z3G units see the fault and operates. This plusthe operation of the FDOG, IoM and T3G, satisfy AND-21. This provides the TDT signal, thentrips via OR-3 with Zone 3 ground time delay trip indicator Z3G. TDT signal can be connectedto the reclosing block logic. For security, the Z3G unit is supervised by the signal of FDOG vialogic OR-171A a as shown in Figure 18.

Either or both Zone 3 phase and Zone 3 ground function(s) can be disabled by selecting the Z3Pand/or Z3G to OUT; or by selecting the T3P and/or T3G to BLK.

(G) Directional Comparison Blocking System, BLK, (Figures 19 & 20))

The basic operating principles of the MDAR Version 2.50 directional comparison blocking sys-tem are:

(1) The pilot relays, PLTP/PLTG (same units for Zone 3 function), are set to forward over-reach.

(2) The major function of the carrier start elements is to detect the reverse external faults andstart the carrier. The ground elements of the carrier start distance units (CRS) are non-directional forφG/3φ faults. Its forward (CRSF, non-trip direction) and reverse (CRSR,trip direction) reaches can be set independently.

The phase-to-phase element of the carrier start distance unit (CRS) looks in the non-trip direc-tion only and have a reach defined by the CRSF setting.

Referring to Figure 20, the MDAR Version 2.50 blocking scheme also use∆2, ∆I, ∆V, andRDOG/IoS signals to start the carrier. The use of vI and∆V is for faster carrier start andprovides more security to the scheme. The use of V2 is because theφφ−element of the car-rier start distance unit is directional.

(3) Pilot channel is an ON-OFF type power line carrier. Transmitter frequency at each termi-nal can be the same.

(4) Channel is normally OFF until the carrier start unit(s) senses the fault and starts the trans-mitter.

(5) Pilot trip is performed when the pilot relay(s) operates and a carrier blocking signal is notreceived.

For MDAR Version 2.50, the same units Z3P/Z3G are used for both Zone 3 and pilot distance mea-surements. They are supervised by the LOPB, FDOP, OSB3, FDOG/IOM and IM units as shown inFigure 19.

The pilot function can be disabled by selecting the PLT setting to NO. (Note, the non-pilot Zone 3function still in service if PLT is set to NO).

For more dependability on high Rf faults, the pilot ground trip logic is supplemented with the FDOG/IOM units, as shown in Figure 19, via AND-188, OR-189. The FDGT delay trip timer provides a set-ting range of 0 to 15 cycles, in 1 cycle steps and BLK, for delay or to disable this supplement if

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required. The FDGT timer is recommended to be set longer than 3 cycles for security reason. Thisfunction can be disabled by setting the FDGT to BLK, if this supplemented function is not required.

The MDAR Version 2.50 blocking system, as shown in Figures 19 and 20, includes the followingportions:

(1) Tripping Logic (Figure 20)

(a) For a forward internal fault, the local pilot relay(s), Z3P(PLTP) and/or Z3G(PLTG),sees the fault. Output signal of OR-40 disables and stops the carrier start circuit(note, the∆I and ∆V starts the carrier before the distance unit picks up via AND-50A, AND-50) via OR-16, 0/150 ms squelch timer, AND-50 and AND-40B to pre-vent the local transmitter from transmitting (note, on an ON/OFF type channel, thereceiver receives the signal from both local and remote transmitters). At the sametime, output of OR-40 satisfies one input of AND-48, and also starts the channelcoordination timer (BLKT, range 0 to 98, in 2 ms steps).After the preset time of the channel coordination timer, logic AND-47 satisfiesAND-48 if there is no carrier signal received from either remote or local on internalfaults, and if the local TBM (transient block circuit) does not set up. Then, AND-48output will satisfy AND-52, and pilot trip signal PT will be applied to OR-2 (Figure16) from AND-30 (not shown). High speed pilot trip, HST, would be obtained. Tar-gets of pilot phase trip, PLTP, and/or pilot ground trip, PLTG, will be turned on afterthe breaker trips.

(b) For a forward external fault, the local pilot relay(s), Z3P(PLTP) and/or Z3G(PLTG),sees the fault and operates in the same manner as for the forward internal faults.However, at the remote terminal, the carrier start elements∆2, ∆I, ∆V, CRS orRDOG/IoS also see this external fault and turn on the remote transmitter via AND-50, OR-41, AND-40B, OR-18 and AND-35, sending a blocking signal to the otherterminals. Both the local and the remote receivers receives the blocking signal anddisables the operation of their AND-47. Therefore, both terminal’s AND-48 willproduce no carrier trip signal for AND-52.

(2) Carrier Keying Logic

(a) Reverse fault keying (Figure 20)For a reverse fault, the∆2, ∆I and∆V as well as the local carrier start distant unitsCRS, and RDOG/IoS elements, see the fault, operate the SEND relay and start thetransmitter, sending a blocking signal to the other terminals. This keying circuitincludes logic OR-50A, AND-50, AND-173, OR-41, OR-18, AND-40B and AND-35.Since the present keying practice on a BLK system uses either contact open (nega-tive or positive removal keying) or contact close (positive keying) approach, a formC dry contact output for SEND is provided in MDAR hardware.

(b) Signal continuation and TBM logic (Figure 20)On a reverse fault, the local carrier start elements and the remote pilot relay see thefault and operate. The local carrier start elements start the carrier and send a block-ing signal to block the remote pilot relay from tripping. After the fault is cleared bythe external breaker, the remote breaker may have a tendency to trip falsely if the

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local carrier start elements reset faster than the remote pilot trip unit. The 0/50 mstimer after the AND-51 holds the carrier signal ON for 50 ms after the carrier startunits have been reset for alleviating this problem.

This logic also provides TBM (transient block and unblock) function on powerreversal.

(c) Internal fault preference and squelch (Figure 20)On a close-in fault, the vI and∆V signal(s) will start the transmitter. This operationmay block the system from pilot tripping. The 0/65 ms timer allows the∆I and∆Vcarrier start for only 65 ms, and also logic OR-16 will disable the∆I and∆V carrierstart path immediately when forward trip unit is picked up. Output signal from OR-16 will pick up the STOP unit for stopping the carrier send via AND-120 providingthere is no TBM signal existed. These provide an internal fault preference feature fordependability.

The squelch 0/150 ms timer is required for improving the problem if the localbreaker tripped faster than the remote breaker on an internal fault. The logic disablesthe SEND circuit for 150 ms after any high speed tripping (HST), including pilottrip, Zone 1 trip and instantaneous overcurrent trip.

(3) Carrier receiving logic (Figure 20)

Carrier signal from the receiver output will be directly applied to AND-47 to disable thepilot tripping function.

(4) Channel indication (not shown in Figure 20)

Since the carrier channel turns on for external faults only, the channel indicators, SENDand RCVR, should not be memorized.

(5) Channel simulation and automatic checkback (Figure 20)

The TEST function selection provides the capability to simulate the RS switch functionfor receiving a blocking signal action without the operation from the remote transmitter.

The external DCB contact (via RCVR-2 terminals) is from the digital checkback devicefor automatic checkback keying action via OR-18 and AND-35 without the operation ofpilot relay units.

(6) Programmable Reclosing Initiation (Figure 26)

The basic programmable RI application is as described in Chapter IX. However, on pilotsystems, to activate the RI2 on any 3-pole high speed trip, the external pilot enable switchshould be ON, (refer to Figure 6, TB3 terminals 9 & 10), and the PLT and Z1RI should beset to YES. The operation will perform via the logic AND-89, AND-84 and OR-84A, asshown in Figure 24. (refer to section (N) of this chapter for more information).

(7) Dependable pilot ground trip on high Rf faults (Figure 19)

Pilot ground trip is more dependable on high Rf faults. Refer to Figure 19, the pilot groundtrip path is supplemented with the forward directional overcurrent ground unit FDOG/IOM via AND-188 and OR-189 with a delay timer FDGT. Trip delay is settible from 0-15cycles in 1.0 cycle and BLK steps. The FDGT timer should be set longer than 3 cycles for

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security reason. This function can be disabled by setting the FDGT to BLK position ifrequired.

(H) Directional Instantaneous Overcurrent Trips (Figure 21)

The directional instantaneous overcurrent units IAH, IBH, ICH and IOH are supervised by theFDOP (A, B and C) for phases and by FDOG for ground. These units are normally set high todetect those faults which occur in the Zone 1 area. Therefore, their tripping will occur via OR-2for HST, as shown in Figure 21. The use of directional supervision will minimize some settingdifficulties in applications. The setting of LOPB has no effect to the high-set trip function exceptthe units will become non-directional during LOP condition if the LOPB is set to YES. Thesehigh-set trip functions can be disabled by setting the ITP (phase) and/or ITG (ground) to OUT.

(I) Close-Into-Fault Trip and Stub-Bus Protection (Figure 22)

In order to supplement distance unit operation when the circuit breaker is closed into a fault andline side potential is used. The CIF close-into-fault trip circuit, as shown in Figure 22, includeslogic AND-22, OR-3, 100/180 ms and 16/0 ms timers. Logic AND-22 is satisfied and producesa trip signal for 180 ms after circuit breaker closing (52b contact opened) if the overcurrentunit(s), IAL, IBL, ICL or IOM, operate OR-11, and if any phase voltage is below the presetlevel of the LV-units (AND-22A). Tripping will be via OR-3, with RB and CIF target.

The stub bus protection feature protects a line terminal with the potential device on the line side.With the line disconnect switch open, the distance units will lose their reference voltage, andmay not function correctly when a fault occurs on the short piece of bus between the CT loca-tion and the opened disconnect switch. The logic for stub bus protection is independent of theoperation of the circuit breaker(s) and the line voltage condition. Also, it requires the informa-tion from the disconnect switch 89b. The stub bus protection logic, as shown in Figure 22,includes the contact convertor for the 89b switch, AND-22E and OR-22B logic.

The application of the “close-into-fault” and the “stub-bus protection” are selected by the set-ting of the value field CIFT/STUB/BOTH/NO of the function field CIF.

(J) Unequal-Pole Closing Load Pickup Control (Figures 16 & 19)

The ground units may pick up on a condition of load pickup with unequal breaker pole closing.The high speed trip ground units Z1G and FDOG should be supervised under this condition.This can be achieved, as shown in Figure 16, by inserting a 0/20 ms timer and controlling by the52b signal to supervise the Z1G trip AND-3 (Figure 16) and PLTG trip AND-188 (Figure 19). Itshould be noted that the 20 ms time delay will have no effect on a normal fault clearing.

(K) Inverse Time Directional or Non-Directional Overcurrent Ground Backup, GB (Figure 23)

The overcurrent ground backup unit GB is to supplement the distance ground protection on highresistance ground faults. Its selectable time characteristic curves, as shown below, are similar tothe conventional overcurrent type CO relays.

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CO-2 Short time curve CO-5 Long time curve CO-6 Definite time curve CO-7 Moderately inverse time curve CO-8 Inverse time curve CO-9 Very inverse time curve CO-11 Extremely inverse time curve

As shown in the setting table, the time curve can be selected by using the “GBCV” setting, thetime dial is set by the “GTC” value. The GB function can be set as either directional or non-directional by setting the “GDIR” to YES or NO. The directional GB function uses the torquecontrol approach as indicated in Figure 23. If the GDIR set to YES, and the DIRU is set toZSEQ, the GB-unit will be controlled by the zero sequence voltage polarized element; the GB-unit will be controlled by the negative sequence voltage and negative sequence current operatedelement if the DIRU is set to NSEQ (negative sequence). The pickup value of the overcurrentunit is controlled by the “GBPU” setting. The unit can be disabled by selecting the “GBCV” toOUT.

(L) Zone 1 Extension (Figure 24)

This scheme provides a higher speed operation on end zone faults without the application ofpilot channel.

If the MDAR functional display “STYP” is selected to Z1E, the Z1P/Z1G unit will provide twooutputs. One is overreach (reach to 1.25 times the Zone 1 setting) and one is the normal Zone 1reach.

A single shot instantaneous reclosing device should be used when applying this scheme. Thetargets Z1P/Z1G will indicate either Z1 trip and/or Z1E trip operations. The other functions,such as Z2T, Z3T, ac trouble monitoring, overcurrent supervision, IT, CIF, unequal-pole closingload pickup control, load-loss acceleration trip, etc. would remain the same as in the basic 3ZNPscheme.

For a remote internal fault, (Figure 24), either Z1P or Z1G will see the fault since they overreachto 1.25 (Z1P/Z1G), high speed trip will be performed via the normal Z1T path (Figure 16)AND-2 (or AND-3) and OR-2. HST signal operates the instantaneous reclosing scheme. Thebreaker recloses and stays closed if the fault is automatically cleared.

Target Z1P and/or Z1G will be displayed. Once the breaker trip circuit carries current, it oper-ates the logic OR-5 (not shown), produces output signal TRSL, and satisfies logic AND-26 for5000 ms (Figure 24). The output signal of AND-26 will trigger the Z1P/Z1G reach circuit, con-stricting their reaches back to the normal Zone 1 for 5000 ms. During the reach constrictingperiods, if the breaker is reclosed on a Zone 1 permanent fault, it will retrip again. If the breakeris reclosed on an end-zone permanent fault, the normal Z2T will take place.For a remote exter-nal fault, either Z1P or Z1G will see the fault since they are set to overreach. High speed tripwill be performed. HST signal operates the instantaneous reclosing scheme. The breakerrecloses and stays closed if the fault has been isolated by the adjacent line breaker. However, ifthe adjacent line breaker fails to trip, the normal remote back up will operate.

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(M) Selectable Loss-Of-Load Accelerated Trip, LLT (Figure 25)

The load loss accelerated Zone 2 trip logic senses remote 3-pole clearing on all faults except 3Dto complement or substitute for the action of the pilot channel, speeding up trip at the slow ter-minal. The logic includes AND-24, AND-25, OR-13, 0/32 and the 10/0 ms timers, as shown inFigure 25. Under normal system conditions, 3-phase load currents are balanced, and the low setovercurrent units IAL, IBL, ICL satisfy both AND-24 and OR-13. On internal end zone faults,Z2P, Z2G and/or FDOG/IoM picks up and satisfies the third input to AND-25 via OR-6. How-ever, the signal from AND-24 is negated to AND-25, therefore, AND-25 should have no outputuntil the remote end 3-pole trips.

At this time the local end current will lose one or two phases, depending on the type of fault(except 3-phases), and AND-24 output signal changes from “1” to “0”, satisfying AND-25.After 10 ms this output bypasses T2 timer and provides speedup Zone 2 trip. The 10/0 ms timedelay is for coordination on external faults with unequal pole clearing. The 0/32 ms timer isneeded for security on external faults with no load current condition. Targets LLT will turn onafter an LLT trip.

The LLT function is selected by the setting of “YES, FDOG, NO”, where YES = LLT with Z2supervision; FDOG = LLT with both Z2 and (FDOG/IOM) supervision; and NO = LLT functionis not used.

(N) Programmable Reclosing Initiation (Figure 26)

The MDAR system provides contact outputs for reclose initiation (RI) and reclose block (RB)functions:

RI2, used for reclose initiation on 3-pole trip.RB, used for reclose block.

The operation of RI2 and RB contacts is controlled by the setting of the programmable recloseinitiation logic as shown in Figure 26. The operation of either RI2 or RB must be confirmed bythe signal of TRSL, which is the trip output signal of MDAR operation. The External PilotEnable Switch (refer to Figure 6, terminals 9 and 10 on TB-5), is used for externally enablingthe pilot system. The PLT setting is similar to the external pilot enable switch, except it is setfrom the front panel (or remotely set via the communication interface).

For pilot MDAR with supporting non-pilot function, a most popular reclose initiation practice isto have reclosing initiation on high speed (pilot, Zone 1 and high set) trip only. Referring to Fig-ure 26, this can be programmed by closing the external pilot enable switch and selecting thePLT and Z1RI to YES. AND-84 will produce output to operate the RI2 relay when receivingsignals from TRSL and AND-89. The use of Z1RI signal to supervise the AND-84 provides aflexibility for disabling RI, if needed, when pilot function is in-service. The program is furthercontrolled by the TTYP setting.

TTYP set at OFF— 3PRN provides no output, therefore, RI2 will not operate.

TTYP set at 1PR— 3PRN will provide output “1” on single-phase-to-ground faults only(via OR-100 and AND 51A) for RI2 operation.

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TTYP set at 2PR—3PRN will provide output “1” on single-phase-to-ground fault or 2-phasefaults (via OR-100B and AND-51B) for RI2 operation.

TTYP set at 3PR—3PRN will provide output “1” on any type of fault (via OR-51) for RI2operation.

The Z1RI, Z2RI AND Z3RI settings combining with the logic of AND-62B, -62C, -62D andOR-62 provide for programming applications where the reclose initiation on Zone 1, Zone 2 orZone 3 trip is desired on a non-pilot MDAR system. AND-62A is controlled by the signal3PRN, therefore, the setting of 1PR, 2PR and 3PR also affects the Z1RI, Z2RI and Z3RI pro-gram.

In general, the RB relay will operate on TDT (time delay trips) or OSB (out-of-step block con-dition). However, it will be disabled by the setting of Z1RI, Z2RI or Z3RI signal via OR-62 andAND-86.

Logic for RB on BF squelch

For a pilot system, the BFI signal can be used to stop (for blocking scheme) or start (for permis-sive scheme) the carrier channel and allow the remote terminal to trip should the local breakerfail to trip. However, the problem is how to inhibit the remote terminal from reclosing.

MDAR solves this problem by the “RB on BF squelch” logic in the RI/RB software. This logicis as shown in Figure 26, which includes the AND-61A and a 132/0 ms timer. The logic will ini-tiate RB 132 ms (about 8 cycles) after the fault is detected by∆I or ∆V, if pilot is enabled andTRSL signal is received on any 3-pole high speed trip operation (Zone 1 trip, pilot trip or highset trip).

(O) Out-of-step Block & Trip Function, OSB and OST (Figure 27)

The Out-of-step block & trip logic used in MDAR Version 2.50 is a double blinder scheme. Itcontains two blinder units, providing 4 blinder lines. The nature of the logic shown in Figure 27is that the outer blinder 21BO must operate ahead the inner blinder 21BI before the OST1 time,in order for an OS condition to be identified.

For out-of-step block, the OSB signal is a negated input to AND-131 (for Z1P), AND-147 (forZ2P), and AND-160 (for Z3P) via AND-122 and the OST1 timer for supervising the 3-phasedistance trip if the OSB1, OSB2 and/or the OSB3 are selected. In addition to controlling the OSlogic, the inner blinder unit also may be used to supervise phase distance relay tripping. Phasedistance unit tripping cannot take place unless 21BI operates. This prevents operation of the dis-tance relay on heavy load condition. The OSB signal is also applied to the reclosing logic forinitiating RB.

For out-of-step block and trip, as described below, the scheme can be selected to have OSToperation either (not both) on the swing way-in or on the swing way-out.

In Figure 27, the 21BO and 21BI are the outer and inner blinder outputs, respectively, the 3φFsignal is the faulted phase selector output on a 3φ fault, and IAL are the outputs of the currentdetector. The operation of the scheme under different conditions are described below:

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(1) Normal load condition

On normal load flow condition, the system impedance is typically at the point labeledLOAD on Figure 27A. Logic AND-122 and OST1 timer in Figure 27 normally have alogic “0” output to allow tripping the distance 3φ-units, providing the 21BI has operatedand there is no output “1” from OST1.

(2) Fault conditions

(a) φG/φφ faultsOn φG/φφ faults, the system impedance is typically located at or near point 4 in Fig-ure 27A. There is no 3φF signal, from faulted phase selector, present at AND-122,the output of AND-122 and OST1 should remain at logic “0”, Zone 1, Zone 2, Zone3 (and pilot) trippings should be performed as normal.

(b) 3φ faultsOn 3φ faults, the 3φF signal will satisfy AND-122, and allow the OS block or trip tobe performed if an OS condition exists.

(3) Out-of-step condition

When a swing occurs in the system, and the swing impedance reaches point 1 or point 2(Figure 27A), the 21BO, 3dF and IAL signals appear at AND-122, but not 21BI, whichstarts the OST1 timer (OS timer, 0.5-5 cycles in 0.5 cycle steps). The relay will not tripbecause the 3d trip path is supervised with the output of 21BI.

If OST1 times out before the swing impedance reaches point 3, the swing is defined.OST1 output changes from logic “0” to “1” for blocking the Z1P, Z2P and/or PLTP(Z3P)trip, depending on the OSB1, OSB2 and OSB3 settings. The OST1 timer seals in via OR-202. It resets until either one of the IAL, 3φF or 21BO resets.

At point 4 it will trip after the way in OST2 timer times out, via OR-203, AND-204, OST2and AND-206 by the OST signal if the “WAYI” (WAY-IN) is selected on the OST setting.Memory is provided by the seal-in for OR-203.

However, at point 4, it will not trip if the “WAYI” setting is not selected.

The way out timer OST3 starts once the OST2 timer times out, and the inner blinder 21BIresets at point 5.

At point 6, the outer blinder 21BO resets to cause the out-of-step trip output OST toappear via AND-207 if OST3 has timed out, if the “WAYO” (WAY-OUT) is selected onthe OST setting.

However, at point 6, it will not trip if the “WAYO” setting is not selected.

The setting ranges of OST1, OST2 and OST3 are 0.5-5.0 cycles, in 0.5 cycle steps.

The system provides OS trip via the OS override OSOT timer (24 to 240 cycles, in 1.0cycle steps or OUT) and AND-123 after OS condition is defined if the inner blinder 21BIstays pickup after the OS override OSOT timer times out. This OS trip will not be affectedby the OST setting (either WAYI, WAYO or NO).

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(P) Open Conductor Detection (Figure 28)

The MDAR Version 2.50 provides the provision for open conductor detection. Refer to Figure28, it is accomplished by using one programmable output contact which is operated by the IOSsignal with a built-in timer. The range of this timer is 0 to 5 seconds in 1.0 second steps. Oneprogrammable heavy duty output contact (OC1 to OC4) can be assigned to signal IOSD for pro-viding the open conductor with time delay trip function.

(Q) 16 Fault Records and Intermediate Targets

The MDAR system saves the latest 16 fault records. The latest two fault records can be accessedeither via the front panel or via the communication port. The fault records 3 to 16 can only beaccessed via the communication port. On the front panel, the “LAST FAULT” information is ofthe last fault, the “PREVIOUS FAULT” information is of the previous fault. These displays con-tain the target information along with the “frozen” data at the second cycle of the fault. Whentargets are available, the LAST FAULT LED flashes. It flashes once per second if only theLAST FAULT contains targets. It will flash twice per second if 2 or more fault records are con-tained. The fault records are stored in non-volatile memory and are retained even if relay isdeenergized. These records can be deleted only by applying a rated voltage to the External ResetTerminals (TB5/5 & TB5/6), or through a remote communication interface. By operating thefront panel RESET TARGETS pushbutton allows the user to reset the flashing LED to Meteringmode only, it will not erase the fault information.

The activation of fault data storage is controlled by the selection of TRIP/Z2TR/Z2Z3 in theFDAT function, where

TRIP — start to store fault data only if trip action occurs.

Z2TR — start to store fault data if Zone 2 unit picks up or any trip action occurs.

Z2Z3 — start to store fault data if Zone 2 or Zone 3 unit picks up or any trip action occurs.

The intermediate target data is in temporary memory and will be lost when relay is deenergized.Intermediate target data can only be obtained through remote communication. If OSC isincluded, the intermediate target data is provided 8 sample per cycle. If OSC is not included, theintermediate target data is provided one sample per cycle.

(R) Communications

An PONI (Product Operated Network Interface) attachment, which is mounted on the backplateof the outer chassis and connected to the backplane module, is provided for the remote transmis-sion of target data. It can be accessed from the rear panel. Two options are available for interfac-ing between MDAR and a variety of local and remote communication devices.

RS-232C PONI — for local single point computer communication.

INCOM® PONI — for local network communication.

“INCOM®” is a registered trademark of the Westinghouse Electric Corporation, Inc., which stands for INtegratedCOMmunications. The “PONI” acronym stands for Product Operated Network Interface.

(3/92) 44


An IBM® XT or AT® compatible computer, with WRELCOM® software provided, can be usedto monitor or change the settings, 16 fault records, 16 intermediate records, oscillographicrecords and metering information.

IMAC, an optional separate unit, stands for INCOM® Multi-Access Controller, is a substationbased computer which can access the relays on the network, automatically monitor relay statusand provide remote communication through a telephone modem. It includes a CRT and printer.

(S) Programmable Output Contact Function

The MDAR Version 2.50 provides 8 programmable output contacts from the optional module. 4with heavy duty normally open contact, and 4 with normal duty form-C contact. The program-mable contact outputs can be set through the RS232 or INCOM® communication only. Each ofthese contacts can be programmed based on any one or all of the 30 pre-assigned signals withAND/OR logic combination. The pre-assigned signals are listed below: (note, signals WFT,PLTX, ECHO and CR2 will not be used for KEPCO system)

Approxi.Signal Ref.

Description (Selected signal) Value Location Figure

1 Z1P trip output Z1P OR2 16 2 Z1G trip output Z1G OR2 16 3 Z2P trip output Z2P OR3 1 7 4 Z2G trip output Z2G OR3 17 5 Z3P trip output Z3P OR3 1 8 6 Z3G trip output Z3G OR3 18 7 Pilot phase trip output PLTP AND52 20 8 Pilot ground trip output PLTG AND52 20 9 High set phase trip output ITP OR10 21 10 High set ground trip output ITG AND10D 21 11 GB trip output GB OR211 23 12 Close-into-fault trip output CIFT OR22B 22 13 Load loss trip output LLT AND25 25 14 Weakfeed trip output WFT — — 15 TBM signal output (BLK scheme) TBM AND51 20 16 Pilot in-service PLTX — — 17 Out-of-step block pickup OSB AND122 27 18 LOP picks up LOP AND1 13 19 Carrier send output SEND AND35 20 20 Carrier stop output STOP AND120 20 21 Breaker failure initiation output BFI AND8 16 22 Reclosing initiation output RI2 OR84A 26 23 Reclosing block output RB OR86A 26 24 IOS with timer delay output IOSD 2 825 FDOG/IOM/FDGT output FDOG AND188 1926 Weakfeed echo key output ECHO — —27 Inner blinder 21BI pickup 21BI 2728 Low voltage LV — — 29 RCVR-1 signal CR1 2030 RCVR-2 signal CR2 — —

45 (3/92)


For KEPCO application, the requirement of the minimum 14 output contacts can be arranged/selectedas below:

No. of Arrangementcontact or

Required Selection

1. Trip contacts1) For breaker trip 1 Use normal trip output contact2) For breaker failure 1 Use normal BFI

contact initiation3) For fault recorder 1 Use normal BFI or GS contact

2. Primary (pilot trip) for 1 Set one programmable contact to PLTPphase to phase faults1) For remote supervision

3. Backup trip for phase to phase faults1) For remote supervision 1 Set one programmable contact to “OR”

with signals of Z1P/Z2P/Z3P/ITP4. Primary (pilot trip) for 1 Set one programmable contact to PLTG

phase to ground faults1) For remote supervision

5. Backup trip for phase to 1 Set one programmable contact to “OR”ground faults with signals of Z1G/Z2G/Z3G/1TG/GB1) For remote supervision

6. Open conductor (Line) fault 1 Set one programmable contact to IOSD1) For remote supervision

7. Reclosing initiation1) RI for closing breaker 1 Use one normal RI2 contact2) For fault recorder 1 Use one contact on ALMM module3) For annunciator 1 Use one contact on ALMM module8) Carrier channel send 1 Set one programmable contact to SEND1) For remote supervision

9. Carrier signal receiving1) For remote supervision 1 Set one programmable contact to CR12) For fault recorder 1 Use one special wiredout CR1 contact3) For DCB circuit 1 Use one special wiredout CR1 contact

Total 14* 15

Total normal contacts to be used 6Total programmable contacts to be used 7Total special wired out contacts 2Total available spare prog contacts 1

* Contact for DCB circuitwas not included

(3/92) 46


X. MDAR Version 2.50 Setting Calculations and Selections

Assume that the protected line has the following data:

1.35 KM, line reactance 0.5 ohms/KM, 69 KV, 60 cycles.

Positive and negative sequence impedances:

Z1L(Pri) = Z2L(Pri) = 15∠77° ohms

Zero sequence impedance: ZoL(pri) = 50∠73° ohms.

Zero sequence mutual impedance per phase: ZoM = 70% ZoL(pri)

Current transformer ratio: RC = 1200/5 = 240,

Set MDAR CTR = 240

Voltage transformer ratio: RV = 600/1 = 600,

Set MDAR VTR = 600

Relay secondary ohmic impedances are:

Z = ZPri x RC/RV

Z1L = Z2L = 15∠77°x 240/600 = 6∠77° ohms

Z0L = 50∠73° x 240/600 = 20∠73° ohms.

(A) Calculation of MDAR settings:

(1) The ratio of zero and positive sequence impedances

ZR = ZoL/ Z1L = 20/6 = 3.33,

ZMR = ZoM/ Z1L =(ZoM/ZoL)(ZoL/Z1L)

= (ZoM/ZoL)ZR = 0.7 x 3.33 = 2.33

Set MDAR ZR = 3.3 PANG = 77GANG = 73

ZMR = 2.33

then, MDAR will automatically calculate the zero sequence current compensation factorko by using the value of ZR, PANG and GANG, i.e.

ko =(Z0L - Z1L)/Z1L = (ZR∠PANG-GANG - 1)

(2) Zone 1 distance unit settings:

A setting of 80% of the line impedance for Zone 1 reach is recommended, thus the Zone 1phase and ground reach should beZ1P = 6 x 0.8 = 4.8 andZ1G = 6 x 0.8 = 4.8

Set MDAR Z1P = Z1G = 4.80

47 (3/92)


Note: Z1P and Z1G can be set for different values as the application requires. Ei-ther Z1P or Z1G can be disabled independently by setting it to OUT positionif this function is not needed.

(3) Zone 2 distance units settings:

Generally, Zone 2 reach is set to underreach the shortest Zone 1 reach of the adjacent lineoff the remote bus. a practical setting is set for 100% of the protected line plus 50% of theshortest adjacent line off the remote bus. For this example, if the Zone 2 reach settingwould be:

Z2P = 6 + (20 x 50%) x 240/600 = 10 and

Z2G = 10



(4) Zone 3 distance unit settings:

Generally, Zone 3 reach is set to; underreach of the shortest Zone 2 reach of the adjacentline off the remote bus. a practical setting is set for 100% of the protected line plus 100%of the shortest adjacent line off the remote bus. For example, if the shortest Zone 2 reachoff the remote bus is 25 ohms primary, and infeed effect may increase its impedance by30%, then the Zone 3 reach setting should be:

Z3P = 6 + (25 x 1.3) x240/600 = 19 and Z3G = 19



(5) Carrier start distance unit settings:

The forward direction carrier start distance phase and ground reaches should be set at least50% over the remote terminal’s pilot trip relay reach, or it can be set either exactly ornearly equal to the remote terminal’s pilot trip phase and ground distance reach, whichdepends on the application.

The reverse direction carrier start distance phase and ground reaches setting depends onthe application.

For this example, set the forward reach equals to pilot trip units, and the reverse reachequals to 30% of the forward reach, i.e.

Set CRSF = 19.00 and CRSR = 5.70

(6) Overcurrent unit settings

(3/92) 48


(a) The low set phase overcurrent unit is used for supervision the OSB, the load-loss-tripand the CIF functions. It should be set higher than the line charging current andbelow the minimum load current if LLT function is applied, (note, it should be setabove the maximum tapped load current if applicable).These units can be set to higher than the maximum load current if LLT function isnot applied.

Assume that the line charging current is negligible for this line section, and the min-imum load current is 2.0 amperes secondary. Then the low set phase overcurrent unitsetting should be:

IL = 1

Set MDAR IL = 1.0

(b) The medium set phase overcurrent unit IM is used for supervising the Zone 1, Zone2 and Zone 3 phase distance units (Z1P, Z2P and Z3P).Generally, it is recommended to be set above maximum load current: For this exam-ple, maximum load current is 4.0 amp, then

Set MDAR IM =5.0

(c) The low set ground overcurrent unit is used for supervising the reverse directionalground overcurrent unit (RDOG). It should be set as sensitive as possible. A settingof 0.5 amperes is recommended:

IOS = 0.5 Set MDAR IOS = 0.5

(d) The medium set ground overcurrent unit is used for supervising the Zone 1, Zone 2and Zone 3 ground distance units (Z1G, Z2G and Z3G) and the forward directionalground overcurrent unit (FDOG). Generally, it is recommended to set 2X of the IOSsetting:

IOM = 2 x IOS = 1.0

Set MDAR IOM = 1.0

(e) The high set overcurrent phase and ground units, ITP and ITG, are used for directtrip function. The general setting criteria for the instantaneous direct trip unit is:

i) the maximum load or the maximum reverse fault current should not be higherthan the maximum forward end Zone fault current, and

ii) the unit should be set higher than 1.15 times the maximum fault on the remotebus, where the factor of 1.15 is to allow for transient overreach. For this exam-ple, assuming that the maximum load or the maximum reverse fault current isnot higher than the maximum forward end zone fault current, and the maximumphase and ground fault currents on the remote bus are 20 and 24 amperes,respectively, then the settings of the high set phase (ITP) and the high set ground(ITG) should be:

ITP = 20 x 1.15 = 23 and ITG = 24 x 1.15 = 27.6

Set MDAR ITP = 23.0, ITG = 27.6

49 (3/92)


Note: Either ITP or ITG can be disabled independently by setting it to OUT po-sition if this function is not needed.

(7) OSB blinder settings, RT and RU:

The requirements for setting the blinder units are:

(i) Inner blinder must be set to accommodate maximum fault resistance for internal3-phase faults.

(ii) Inner blinder should not operate on severe stable swings.

(iii) Outer blinder must have adequate separation from innerblinder for the fastest out-of-step swing to backnowledged as an out-of-step condition.

(iv) Outer blinder must not operate on load.

(7a) Setting the Inner Blinder (for heavy load restriction):

If the OSB is used to supervise tripping of the 3φ-unit on heavy load current, the innerblinders 21BI must be set sufficiently far apart to accommodate the maximum fault arcresistance. A reasonable approximation of arc resistance at fault inception is 400 volts perfoot. If a maximum ratio of “line voltage per spacing” is 10,000 volts/ft. for a high voltagetransmission line, minimum internal 3-phase fault current is calculated as:

Imin. = [E / 1.73(ZA+ZL)]

where ZA is max. source impedance, ZL is line impedance and E is line-to-line voltage.

then, Rmax.= 400 x FT./ Imin.

= 400x1.73(ZA+ZL)/10000

= 0.0693(ZA+ZL)

Adding a 50% margin to cover the inaccuracies of this expression.

Rmax. = 0.104(ZA+ZL) primary ohms.

RS = 0.104(ZA+ZL)RC/RV secondary ohms.

Set inner blinder to

RT = RS x COS(90° - PANG) (1)

This is the minimum permissible inner blinder setting, where it is used to provide arestricted trip area for a distance relay.

Another criteria that may be considered is based upon the rule of thumb that stable swingswill not involve an angular separation between generator voltages in excess of 120°. Thiswould give an approximate maximum of

Zinner = (ZA+ZL+ZB)/(2x1.73)

= 0.288(ZA+ZL+ZB) pri. ohms.

(3/92) 50


Zinner = 0.288(ZA+ZL+ZB)RC/RV sec. ohms. (2)

Where ZB is the max. equivalent source impedance at the end of the line away from ZA.

An inner blinder setting between the extreme of equations (1) and (2) may be used. Thisprovides operation for any 3-phase fault with arc resistance, and restraint for any stableswing. Except in those cases where very fast out-of-step swings are expected, the largersetting can be used.It will usually be possible to use the minimum inner blinder setting of1.5 ohms.

Set MDAR RT = 1.50

(7b) Setting the Outer Blinder (for OSB function):

For slow out-of-step swings, a reasonably close placement of the outer to the inner blindercharacteristic is possible. The separation must, however, be based on the fastest out-of-step swing expected. A 50 ms interval is inherent in the out-of-step sensing logic, and theouter blinder must operate 50ms or more ahead of the inner blinder.

Since the rate of change of the ohmic value manifested to the blinder elements is depen-dent upon accelerating power and system WR2, it is impossible to generalize. However,based on an inertia constant (H) equal to 3 and the severe assumption of full load rejection,a machine will experience, assuming a uniform acceleration, an angular change in positionof no more than 20° per cycle on the first half slip cycle.

If the inner blinder were set for (0.104ZT), and the very severe 20° per cycle swing ratewere used, the outer blinder should be set for approximately:

Zouter = 0.5 ZT primary ohms (3)

where ZT = ZA + ZL + ZB.

This is the minimum setting of the outer blinder for a 20o per cycle swing rate.

For this example, if Zinner = 0.104 ZT, Zouter = 0.5 ZT,

Set MDAR RU = 7.20

(8) Overcurrent ground backup unit GB

The overcurrent ground backup unit GB provides the following time curves, which aresimilar to the CO and MCO relays, for backing up the distance ground on high resistanceground fault.

CO-2 Short time curve

Zouter

Zinner-------------- 0.500

0.104------------- 4.8= =

Zouter

Zinner--------------

RU

RT------- 4.8= =

RU 4.8 1.5× 7.2= =

51 (3/92)


CO-5 Long time curve CO-6 Definite time curve CO-7 Moderately inverse time curve CO-8 Inverse time curve CO-9 Very inverse time curve CO-11 Extremely inverse time curve

Four settings, GBCV, GBPU, GCT and GDIR need to be determined for applyingthis unit.

a) GBCV is the setting for the selection of the time-current curve. In general, the selec-tion is based on the application and the coordination. A selection of “OUT” disablesthe ground back up function. In general, CO-8, CO-9 and CO-11 are normally beused for line protection, except CO-6 may be used for short line application.

b) GBPU is the current level setting. Its range is 0.5 to 4.0 amperes in 0.5 steps. In gen-eral, the current level setting criteria is(IFmin /2) > Setting Level > 2 x (Max. residual load, 3Io)

where IFmin = Minimum ground fault current for a fault two buses away.

For better sensitivity, GBPU should be set at 0.5 amp. This would be adequate formost of the applications.

c) GCT is the time delay setting of the GB unit. As shown in the relay time-current per-formance curves (not included in this write-up, please refer to I.L.), There are 63 set-ting selection, from 1 to 63 in 1.0 steps. In general, the time delay setting should becoordinated with any protective device downstream of the line section.

d) GDIR is the setting for directional control selection. The GB unit will become adirectional torque control overcurrent ground unit if GDIR is set at YES.

e) The polarizing approach for the directional ground overcurrent unit is controlled bythe setting of DIRU. It has 2 selections for Version 2.50:ZSEQ — Zero sequence voltage polarization only.

NSEQ — Negative sequence voltage and current operated.

For example, assuming that the application needs ZSEQ directional control, and aCO-8 curve is required, the maximum 3Io of unbalanced load is 0.2 amperes, theminimum ground fault current for a fault two buses away is 10 amperes and 0.7 sec-onds is required for coordination with current of 20 times GBPU setting, then thesettings of the GB function should be as shown below:

10/2 > GBPU > 2 x 0.2 Set GBPU = 0.5

From time-current performance curves, for 0.7 seconds at 20 times of GBPU setting,GTC should be set to 24. Select CO-8 from GBCV. Set GDIR = YES if directionalcontrol is required.

Set MDAR DIRU = ZSEQGBCV = CO-8GBPU = 0.5GCT = 24GDIR = YES

(3/92) 52


(9) Timer settings:

a) Zone 1 trip delay timer T1 is normally set to NO, unless it is needed. For example,using MDAR as a non-pilot 3PT backup with another system operated as primary,then set MDAR T1 to the desirable time delay, say 3 cycles.For example, Set MDAR T1 = 3

b) Zone 2 timer T2 setting should be coordinated with the Zone 1 and other high speedtrip units on the adjacent line terminal. Coordination Time Interval, CTI, of 0.3 to0.5 seconds is recommended. For example, if T2 of 0.4 seconds is used, then thephase and ground Zone 2 timers should be set as follow:Set MDAR T2P = 0.40and T2G = 0.40

Note: T2P and T2G are separate timers. They can be set at a different timesetting. Also, either or both Zone 2 phase and ground function(s) canbe disabled by selecting the Z2P and/or Z2G to OUT; or can be dis-abled by selecting the T2P and/or T2G to BLK.

c) Zone 3 timer T3 settings would be similar to the above.For example, if T3 of 0.8 seconds is required, then the phase and ground Zone 3timer should be set as follow:Set MDAR T3P = 0.80and T3G = 0.80

Note: T3P and T3G are separate timers. They can be set at a different timesetting. Also, either or both Zone 3 phase and ground function(s) canbe disabled by selecting the Z3P and/or Z3G to OUT; or can be dis-abled by selecting the T3P and/or T3G to BLK.

d) For the blocking system, the setting of the channel coordination timer, BLKT, isbased on the application criteriaTC > (Slowest remote carrier start time + channel time + margin) - (the fastest

local 21P/21NP pickup time)

where channel time includes the transmitter and receiver times and the times whichoccur between these devices, e.g. wave propagation, interfacing relays, etc.

For MDAR, the fastest 21P/21NP pickup time = 14 ms the slowest carrier starttime = 4 ms and suggested margin time = 2 ms

For example, the MDAR channel coordination timer can be determined as below fora channel time of 3 ms. Tc = (4 + 3 + 2) - 14 = (-)

i.e., Set MDAR BLKT = 0

e) For pilot systems, pilot ground trip is more dependable on high Rf faults by applyingthe FDOG/IoM/FDGT logic. Trip delay of this supplemented function is controlledby the FDGT timer setting. The range of this timer is 0 to 15 cycles in 1 cycle stepsand with BLK step. Recommend to set this timer longer than 3 cycles.Set MDAR FDGT = 3

53 (3/92)


f) For OSB (out-of-step block), if applied, the OSB override timer setting, OSOT, isdetermined by the power system operation. Its range is 400 to 4000 ms in 16 mssteps.For example, Set MDAR OSOT = 0500 if OSB override time of 500 ms is required.

g) For open conductor protection, if applied, the setting of IOST timer is depending onthe application, for example, if 3 seconds delay is desired, theSet MDAR IOST = 3

(B) Selection of MDAR settings

The following settings are determined by the application. They do not require calculation.

(1) The FDAT setting is for selecting the one of the 3 ways,

TRIP/Z2TR/Z2Z3, to initiate the fault data taken. Where:

TRIP — start to store fault data only if trip action occurs.

Z2TR — start to store fault data if Zone 2 units picks up or any trip action occurs.

Z2Z3 — start to store fault data if Zone 2 or Zone 3 units picks up or any trip actionoccurs.

For example, Set MDAR FDAT = Z2Z3

(2) The frequency setting, FREQ, should be selected to match the power system operating fre-quency. For example, select FREQ = 60 if the power system operating frequency is 60hertz.

For this example,Set MDAR FREQ = 60

(3) The current transformer type setting, CTYP, provides the flexibility for 5 ampere or 1ampere rated current transformer selection. For example, select and set the CTYP = 5 if a5 ampere current transformer is used.

For this example,Set MDAR CTYP = 5

The setting of CTYP affects all the distance unit and overcurrent unit setting ranges. Theranges will be automatically changed as listed below:

MDAR UNITS At CTYP = 5 At CTYP = 1

Z1P/Z1G/Z2P/Z2G 0.01-50.00, 0.05-250,Z3P/Z3G/PLTP/PLTG in 0.01 ohms steps in 0.05 ohms steps

ITP/ITG 2.0-150.00, 0.4-30.0,in 0.5 amp steps in 0.1 amp steps

IL/IOS/IOM 0.5-10.0, 0.1-2.0,in 0.1 amp steps in 0.02 amp steps

(4) The read primary setting, RP, should be set at NO unless the monitoring ac voltages andcurrents are desired to be displayed in primary values.

For example, Set MDAR RP = NO

(3/92) 54


(5) The ohms per unit distance of the line reactance setting, XPUD, is the multiplier for faultdistance display. It has a range of 0.3 to 1.5 in 0.001 steps. For this example, the line reac-tance is 0.5 ohms/KM, thenSet MDAR XPUD = 0.500

The fault distance calculation is as follows:

Where Zs is secondary impedance magnitude, and FANG is fault angle.

(6) The setting of TTYP is for selecting the reclosing mode on single pole trip applications (ifapplied). It has six selecting positions, OFF, 1PR, 2PR, 3PR, SPR and SR3R. Refer to theguidances for reclosing mode programming for the TTYP setting selection.

For example, Set MDAR TTYP = 3PR.

(7) The settings of Z1RI, Z2RI and Z3RI provide the selectivity for the Zone 1 RI (reclosinginitiation), Zone 2 RI and Zone 3 RI, respectively. On pilot system applications, the Z1RIshould be set to YES if reclosing initiation is required. On non-pilot system application,set Z1RI, Z2RI and/or Z3RI to YES if RI is required when the particular distance zoneoperates.

For example,Set MDAR Z1RI = YESZ2RI = NOZ3RI = NO

(8) For pilot systems, set BFRB to YES if “RB on breaker failure squelch” feature is required.

For example,Set MDAR BFRB = YES

(9) The setting of PLT (pilot) combines with the external input signal of Pilot Enable (onbackplane panel) controls the operation of pilot and reclosing initiation. The absence ofeither signal will:

(a) disable the pilot system,(b) block the 3RI output, and the PLT can be set either locally from the front panel, or

For example,Set MDAR PLT = YES

(10) The STYP (system type) selects the desired relaying system in application. It has twoselections, 3ZNP (3 zone non-pilot) and Z1E (Zone 1 extension) in non-pilot MDAR.There are five selections, 3ZNP, Z1E, POTT (permissive overreach transfer trip orunblocking), PUTT (permissive underreach transfer trip) and BLK (blocking) in pilotMDAR. It should be selected and set to the one which is desired.

For example,Set MDAR STYP = BLK

(11) The LV-units are used in CIFT and weakfeed logic in the MDAR. It should normally be setto 40 volts unless a higher setting is required for more sensitive application.

For example,Set MDAR LV = 40

Dis cetanVTRCTR-----------

ZS FANG∠sin×XPUD

-----------------------------------------×=

55 (3/92)


(12) Based on the requirements, set the CIF (close-into-fault) and stub bus protection functions,select the value field CIFT/STUB/BOTH/NO of CIF. Where:

CIFT — CIF trip but not stub bus protection has been selected.

STUB — Stub bus protection but not CIF trip has been selected.

BOTH — Both CIF trip and stub bus protection have been selected.

NO — Neither CIF nor stub bus protection has been selected.

For example, Set MDAR CIF = BOTH

(13) Set the LLT (loss-of-load trip) to YES, FDOG or NO. Where:

YES — LLT trip with Z2 supervision.

FDOG — LLT trip with both Z2 and FDOG supervision.

NO — LLT trip function is not used.

For example,Set MDAR LLT = FDOG

(14) Set the LOPB to YES if loss-of-potential block trip function is required.

For example,Set MDAR LOPB = YES

(15) Set the LOIB to YES if loss-of-current block trip function is required.

For example,Set MDAR LOIB = YES

(16) Set the AL2S to YES if trip alarm seal-in is required.

For example,Set MDAR AL2S = NO

(17) Set the SETR to YES if remote setting is required.

For example,Set MDAR SETR = YES

(18) Procedure to set the real time clock:

With MDAR at the setting mode, scroll the function field to TIME, and set the value toYES. Depress function pushbutton RAISE to display YEAR, MNTH (month), DAY,WDAY (week day), HOUR, and MIN (minute), and set the corresponding number via thevalue field. The MDAR clock will start at the time when the minute value is selected andthe ENTER button is depressed.

(3/92)58

( Prelim

inary) I.L. 40-385.2

Figure 5. MDAR System External Connection

Sub 11503B36

59(3/92)

(Prelim

inary) I.L. 40-385.2

Figure 6. MDAR Backplane Board Terminals

Sub 11503B37

67(3/92)

(Prelim

inary) I.L. 40-385.2

Figure 17. MDAR Version 2.50 Zone 2 Trip Logic

Sub 11503B41

(3/92)68

( Prelim

inary) I.L. 40-385.2

Figure 18. MDAR Version 2.50 Zone 3 Trip Logic

Sub 11503B42

(3/92)70

( Prelim

inary) I.L. 40-385.2

Figure 20. MDAR Version 2.50 Blocking System Logic

Sub 11613C65

(3/92) 76


Schematic 1608C92-5PC Boards 1609C22-8, 1498B69-8Parts Lists 1609C23-5, 1498B70-2

All external electrical connections pass thru the Backplate (see Figure 4-1) of the outer chassis. If theMDAR is used without the FT-14 switch, six 14-terminal connectors on the Backplane module (TB1thru TB6) are used. If the FT-14 switch (option) is included (using the two peripheral areas of theMDAR cabinet), then only four of the 14-terminal connectors (TB2 thru TB5) are used. Three DINconnectors, (J11, J12, J13) allow for the removal of the outer chassis (Backplane module) from the in-ner chassis (Interconnect module).

Electrical inputs to the Backplane module, which are routed either directly thru the Backplate orthrough the FT-14 switch to the Backplate, include:

• VA, VB, VC, and VN (70 VAN)

• IA/IAR, IB/IBR, IC/ICR, and IP/In

• BP(48, 125 or 250 Vdc) and BN (common)

The Backplane module, (see Figure A-1 and Schematic) contains three voltage-type transformers,(TX1, TX2, TX3) for VA/VN (VAN), VB/VN (VBN), VC/VN (VCN) inputs.

A Transformer module (see Figure A-2 and Schematic) is piggybacked onto the Backplane module,consisting of four current-type transformers (IA, IB, IC and IN) with four 0.1% resistors. The primarywindings of all seven transformers are directly-connected to the input terminal (TB6/1 through 12); thesecondary windings are connected thru the Interconnect module to the Filter module. The currenttransformers (IA, IB, IC and IN) are not gapped; dc offset attenuation is done with a digital filteringalgorithm. They drive resistive burdens to develop a proportional voltage. Surge suppression is includ-ed where the signals enter and exit the case.

The Backplane module also includes:

• 2 chokes (L1 and L2) for dc power supply filter

• 48 surge-suppressor type capacitors

The D-connector, with 9 terminals on the Backplane module, is used for the INCOM®/PONI (Product

Operated Network Interface) communications box. INCOM®/PONI is supplied in two versions:

• INCOM®/PONI to RS232 computer interface (supplied as standard).

• INCOM®/PONI to INCOM® network interface (supplied as option).

NOTE: “INCOM” ® stands for INTegrated COMmunications.The “PONI” acronym stands for Product Operated Network Interface

Appendix A. BACKPLANE MODULE

(3/92) 80


Appendix B. INTERCONNECT MODULE

Schematic 1608C91-3Component Location Diagram 1611C30-3Parts List 1611C30-3

The Interconnect module (see Figure B-1 and Schematic) becomes the floor of the MDAR chassis andprovides electrical connectors for all other modules; it connects (through J11, J12 and J13) from theBackplane module (at the rear), to the Filter and Power Supply modules (at the left and right sides,respectively), to the Option (single-pole trip) module (at the center if used), and to the Microprocessorand Display modules at the front of the chassis. The components on the Interconnect module include:

• 2 dc power fuses

• 7 optical isolators

• 2 alarm relays

The seven optical isolators are identical in design. Each input jumper (JMP1 thru JMP6 and JMP 13)can be placed in one of three positions, depending on the input voltage:

• Position 1 (220 or 250 Vdc)



NOTE: Position 2 is the factory setting.

Voltage inputs are fed from the Backplane module to the Interconnect module; voltage outputs are fedfrom the Interconnect module to the Microprocessor module. Resistors, zener diodes, and capacitorsare used as input buffers to protect the opto-coupler circuits (IC1 thru IC7) which provide 3500 Vdcisolation.

Two telephone-type relays are used as alarm 1 (K1) and alarm 2 (K2). The inputs are fed by the Mi-croprocessor module; the outputs are connected to the output terminals of the Backplane module.

The second set of alarm 2 (AL2-2) is used only when the jumpers 8 and 10 are connected. Since thesame Interconnect pc board terminals (10A and 12A) and Backplane terminals (TB5/13 and TB5/14)are use for either AL2-2 or Stub Bus Protection (SBP). For SBP application, move jumpers 8 and 10to positions 7 and 9.

(3/92) 83


Appendix C. CONTACT MODULE

Schematic 1612C39-1PC Board 9656A77-2

Parts List 1612C40-1

The Contact Module is mounted on the Interconnect Module at terminal J10 and is supported at thetop by a central support bar.

This module is designed for the programmable output contacts (See Figure C-1 and Schematic). Itprovides four heavy duty contacts (OC1 to OC4) for tripping and four normal duty contacts (OC5 toOC8) for signal outputs. The OC5 to OC8 contacts can be set as normally open (NO) or normallyclosed (NC) contacts, depending on the positions of JMP1 to JMP4, respectively.

All eight circuits are independent and similar. Their input signals are from the Microprocessor Mod-ule through the Power Supply and Interconnect Modules. Opto-isolators U1 to U8 isolate the relaylogic common (COMM) from the battery common (COM). Q1 to Q8 are used to drive the outputrelays K1 to K8, respectively. The eight contacts are connected to terminal block (TB2) on the back-plate through the Interconnect and Backplate Modules.

(3/92) 86


Appendix D. FILTER MODULE

Schematic 1608C84-5PC Board 1497B69-8Parts List 1608C38-5

The Filter module (see Figure D-1 and Schematic) consists of seven active lowpass Butterworth fil-ters, which tend to band-limit the ac input signal prior to sampling and digitization. The filters arethird-order Butterworth, with a cutoff frequency of 235 Hz (at -3 db). They coordinate with theNyquist limit frequency of 240 Hz, determined by the 480 Hz sampling rate (8 samples per cycle) ofthe MDAR A/D converter.

Integrated circuits (IC1, IC2, IC3) are used for the inputs (VAN, VBN, VCN); ICs (IC4, IC5, IC6,IC7) are used for input currents (IA, IB, IC and IN, respectively). All seven input signals are from theInterconnect module; the filter outputs are connected to the inputs of the analog signal multiplexer onthe Microprocessor module.

87(3/92)

(Prelim

inary) I.L. 40-385.2

Sub 81497B69

Figure D-1. MDAR Filter Module Board.

(3/92)88

( Prelim

inary) I.L. 40-385.2

Sub 51608C84

Figure D-2. MDAR Filter Module Schematic.

(3/92) 89


Appendix E. MICROPROCESSOR MODULE

Schematic 1356D41-1

Component Location Diagram 1611C14-1

Parts List 1611C14-1

The Microprocessor module controls the MDAR system (see Figures E-1 and E-2). A 16-bit address-able Microcontroller (INTEL 80C196) is used as the Microprocessor (U100), operating at 10 MHz fre-quency (See Schematic, Sheet 1). There are two programmable memories in separate, easily-replaceable EPROMs (U103, U104) and one Programmable Array Logic unit (PAL,U105). There aretwo read-write memories (RAMs, U200, and U201) for working storage, and one non-volatile RAM(NOVRAM, U202) for storing settings and targets (fault data) when the relay is deenergized.

Alarms 1 and 2 are located on the Interconnect module. The relays are both normally-open. Alarm 1is used to signal a variety of failures; alarm 2 signals the detection of a (trip) breaker circuit. Alarm 1normally is energized (relay contact opens) when dc power is turned “ON”. It “drops out” (contactcloses) when the Microprocessor module detects a failure in any of the following circuits:

• Microprocessor

• EPROM

• PROM

• RAM

• NOVRAM

• A/D Converter

• Digital I/O Circuitry

• DC Voltage Self-Check

Alarm 2 “picks up” (relay closes) when the breaker trip current is detected. Alarm 2 relay can besealed-in if the setting of AL2S is “YES”.

A real-time clock (U501, see Schematic, Sheet 2), with back-up battery, can be set and synchronized

externally through the INCOM®/PONI card communication channel (see Backplane module), thruMicroprocessor (U100).The time at fault is recorded on the fault data in memory. A program whichinterfaces the PONI card is included as part of the Microprocessor module.

An auto-ranging analog-to-digital conversion system includes an 8-channel multiplexer (MUX,U401). Three voltage inputs (VA, VB, VC) and four current inputs (IA, IB, IC, IP)...(See Schematic,Sheet 2), are fed from the Filter module to the multiplexer. The eighth channel (I7) of the MUX (G23)allows for dc voltage self-check; it is monitored (by U300) for +5V or -6.8V. The control signals(MUX1, MUX2, and MUX4) select the channel input to be measured (via binary selection).

A sample-and-hold chip (U404) holds every input sample (sampled 8 times per power cycle) from theMUX for 80 microseconds. An analog switch (U300), used as an auto-ranging circuit, selects either aninput sample (at TP1), or the output from op-amp (U308, pin 6). The op-amp output has a gain of 8 ascompared to the sample at TP1.

90 (3/92)


The signal selection is determined by an evaluation of the magnitude of the sample at TP1. The samplecompares with reference voltages from U307 pin 1 (+0.6V) and U307 pin 7 (-0.6V). If the sample iswithin “0.6V, the output voltages at U310 pins 1 and 7 will be athigh voltage states; the signal with again of 8 will be identified by U311, and U300 will make the actual signal selection. If the sample isoutside the 0.6V limits, the output voltages at U310 pins 1 and 7 will be atlow voltage states, causingU311/U300 to select the signal from TP1. The signal is then converted by the analog-to-digital con-verter (U303), which is accurate to 12 bits. (The 12-bit A/D converter, plus sign bit and auto-ranging,yields 15 bits resolution of sample values.)

The conversion (at U303) takes place when the signal “CONV” is generated from the Microprocessor(U100) and received at U306. The signal, at U306 pin 13, generates a 1µs pulse which activates theA/D conversion.

Data from the A/D converter is read by buffers (U304, U305), which are enabled by ProgrammableArray Logic (PAL, U105) signal “SEL6*”. (see Schematic, Sheet 1). PAL decodes the address busfrom the Microprocessor (U100) through buffers (U101, U102). (The double lines on Schematic, Sheet1 means 16 lines in parallel.)

NOTE: The asterisk (*) shown in this segment, as in SEL6*, means that the line (logic) is nor-mally high (logic 1 state).

For normal program executions, PAL signal SEL0* islow to fetch the program instructions stored inthe EPROMs (U103, U104). Each EPROM contains up to 32,000 bytes of information.

The Random-Access-Memory (RAM) chips (U200, U201) provide 32K x 8 working space for read,write and data storage by the Microprocessor (U100). If the address lines 13 and 15 arehigh it causesSEL1* to golow); then the RAM chips can be accessed by the PAL chip (U105).

A nonvolatile RAM (NOVRAM) chip (U202) is used for storing settings and targets (fault data) whenthe relay is deenergized. All information is stored in the NOVRAM in three places for reliability andsecurity purposes. If there is a discrepancy between all three information entries, the alarm 1 relay will“drop out”, and the Relay In Service LED (RS2) will be turned “OFF”. If two of three are identical,the information will be displayed, and the third position will be updated. If the third position fails torestore and match the other two positions, the relay continues to operate, and shows self-check (bit 1)in the test mode.

In order to access the NOVRAM, if address lines 12, 13 and 15 (of U105) gohigh it will cause signalSEL2* to golow.

If address lines 14 and 15 gohigh, it will make SEL3* golow. The microprocessor (U100) transfersand updates the information to the Display module LEDs (on the front panel), and vacuum fluorescentdisplay, through buffers (U203, U204).

If address lines 11, 14, and 15 (of U105) gohigh, the signal SEL4* will golow. This enables the buff-ers (U205 and U206) for the Front Panel Switch Inputs; the Microprocessor also acknowledges the sta-tus of the output reed relays which monitor the “trip” current flow.

If address lines 12, 14 and 15 (of U105) gohigh, the signal SEL5* will golow; the selected outputrelays and alarm relays will be addressed. Since buffers (U207, U209), for the Relay Control Signals,

(3/92) 91


are octal three state D type flip flop, the relays will stay “ON” until the Microprocessor resets the out-puts. SEL5* also selects the input channel of the multiplexer, through MUX signals (MUX1, MUX2,and MUX4).

If address lines 11, 12, 14, and 15 (of U105) gohigh, the signal SEL6* will golow; the digital numbersfrom analog measurement are transferred to memory (EPROM) thru buffers (U304, U305)...(see Sche-matic, Sheet 2).

If address lines 13, 14, and 15 (of U105) gohigh, the signal SEL7* will golow; the clock setting andclock reading are enabled.

The Microprocessor (U100) performs logic operations, calculates data from the A/D converter, andmakes decisions (e.g., when to energize the output relays). It also receives the following digital I/Osignals directly from the opto coupler (on the Interconnect module):

• Ext. Reset • RCVR #1 (CR1) • SPB (89B)

• 52b • RCVR #2 (DCB)

• 52a • PLT ENA

Microprocessor port #1 (P1) is used for INCOM® communications. Five lines (DATA, SCK, R/W*,

INT, and BUSY*) are compatible with any INCOM®/PONI boxes (see Interconnect Module).

A series voltage regulator (U500), see Schematic, Sheet 2) regulates +5V for all power supply logic.Input power failure is detected by Q501 and Q502 thru Z500. Signal PFAIL* (from Q501) is normallyhigh. If the 8.5V power supply drops to 7V, Q502 will turn “OFF”; Q501 will turn “ON” and thePFAIL* signal drops from high to low. This action resets the Microprocessor and blocks all output re-lays contingent upon U106 (pin 11 and Q100).

The Microprocessor module includes the following jumpers:

JUMPER POSITION FUNCTION

JMP1 1-2 EEPROM (8K x 8)JMP2 1-2 Programmable Output ContactsJMP3 -- SpareJMP4 IN Dropout Time Delay (0/50) For Trip

OUT No Dropout Time DelayJMP5 IN Enable Output Contact Test

OUT Disable Output Contact TestJMP6 IN A/D Calibration Mode

OUT NormalJMP7 Not usedJMP8,9 1-2 RAM (32K x 8)JMP 10,11, Spare and 12

NOTE: When the MDAR is being calibrated, move the jumper from JMP3 to JMP6 position.After calibration, replace the jumper back at the JMP3 position.

92 (3/92)


Three trimpots (R301, R303, R405) are used to calibrate the A/D converter; a variable capacitor(C504) is used for clock adjustment (see Schematic, Sheet 2). The MDAR relay has been properly ad-justed at the factory; adjustments by the customer are not required. The following Factory calibrationprocedure is for reference only.

1. Turn “OFF” all Vac and Vdc power.

2. Remove the inner chassis from the outer chassis, by using a screw driver at the front panel.

3. Connect together all terminals on J11 (from J11-1A to J11-7A, and J11-1C to J11-7C) thru an ex-ternal mating connector.

4. Move jumper from JMP3 to JMP6.

5. Remove U404 (Sample/Hold device) from its socket (see Schematic Sheet 2).

6. Connect a digital voltmeter (with at least 5 digits) to TP3, and TP2 (common).

7. Using a battery and potentiometer, connect the adjustable voltage to TP1, and common to TP2.(Apply voltage per steps 11 and 12.)

8. Apply a rated dc voltage across the two fuses of the Interconnect PC Board, and turn “ON” the dcpower source (see Power Supply module).

9. On the front panel, depress the Display Select push-button until the TEST LED is illuminated.

10. Raise the Function field display to “ADC’ mode. The Value field display shows the average Hexvalue of the analog input over one cycle.

11. Set the Voltmeter input to - 4.99878 Vdc. Adjust Pot R303 until the Value display reads C009 (seeA/D Converter offset adjustment).

12. Set the voltmeter input to +4.99634 Vdc. Adjust pot R301 until the Value display reads 3FF4. (seeA/D Converter Gain adjustment.)

13. Turn “OFF” the dc Power Supply.

14. Remove the battery voltage from TP1 and TP2.

15. Remove the digital voltmeter.

16. Replace U404 into its socket.

17. Turn “ON” the dc power supply and adjust pot R405 until the Value display reads 0 or FFFF. (SeeSample/Hold, U404 offset adjustment.)

NOTE: The value “FFFF” is a hexadecimal number.

18. Connect a precision period/counter instrument to TP4 and TP2 (common). Adjust variable capac-itor (C504) to read the period of pulses at TP4. It should be1 .000000 second(±0.000002).

19. Turn “OFF” the dc power supply.

20. Remove the power leads and external connector (J11).

21. Move jumper from JMP6 to JMP3 position.

22. Slide the inner chassis into the outer chassis and lock the outer chassis with a screw driver.

(3/92) 96


APPENDIX F. DISPLAY MODULE

Schematic 1608C93-1PC Board 1498B40-1Parts List 1609C01-3

The Display module contains a blue vacuum fluorescent alphanumeric display, with 4 characters in thefunction field and 4 characters in the value field; it also includes 7 LEDs, 7 push-button switches and5 test points (See Figures 1-1, F-1, and Schematic). The 7 push-button switches (SW1 thru SW7) areused to activate the following functions on the front panel:

• Display Select (the LEDs, to the right of this push-button, indicate the selected func-tion)

• Reset (the targets selected)

• Function Raise (move to the following function)

• Function Lower (move to the previous function)

• Value Raise (move to the next higher value)

• Value Lower (move to the next lower value)

• Enter (the value that has been selected for upper contact testing)

The Microprocessor module scans these switches once every cycle while in the “background” mode,where it looks for phase current or phase voltage disturbances. When a phase disturbance is detected,the relay enters the “fault” mode. While scanning, the Microprocessor module updates the Displaymodule via the ICs (U1, U2, U3, and U4). The display will be blocked momentarily once every minutedue to the self-check function. This is for readout check and will not interrupt the relay protection func-tion. The Microprocessor also illuminates some LEDs when the Display Select Switch is depressed.IC (U5) controls the LEDs, which are as follows (see 1.3.6):

• Relay In Service (DS2)

• Settings (DS3)

• V/I/Angle (DS4)

• Last Fault (DS5)

• Previous Fault (DS6)

• Value Accepted (DS7)

• Test (DS8)

Test points (TP1 thru TP5) are used to monitor dc voltages; these voltages can be measured from thefront panel, as follows:

• -24V (TP1)

• + 5V (TP2)

• -12V (TP3)

• +12V (TP4)

• Common (TP5)

(3/92) 99


Schematic 1355D07-7PC Board 1497B66-7Parts List 1608C35-11

The Power Supply Module (see Figure G-1 and Schematic) is available in three ranges:

• 38 - 70 Vdc

• 88 - 145 Vdc

• 176 - 290 Vdc

It operates with an isolated dc/dc converter. The secondary windings of the step-down transformer(T1) supply the following voltages to MDAR modules:

• +12 Vdc

• -12 Vdc

• -24 Vdc

• +24 Vdc

• +8.5 Vdc

• 6.5 Vac (square wave)

The analog amplifiers, A/D converter and alarm relays use 13 Vdc. The vacuum fluorescent display

uses -24 Vdc and 6.5 Vac. The 24 Vdc is for the INCOM® power supply. All logic and microprocessorrelated circuits use +5 Vdc which is generated from the +8.5 Vdc supply.

Twelve relays are used for the pilot system. The relay functions are as follows:

• Reed relays for monitoring 2 different breaker currents

• Telephone relays for phase A tripping

• 1 Telephone relay for single pole reclose initiate

• 1 Telephone relay for three pole reclose initiate

• 1 Telephone relay for reclose block

• 1 Telephone relay for breaker failure initiate

• 1 Telephone relay for system test

• 1 Mercury relay for general start

• 1 Mercury relay for carrier send

• 1 Mercury relay for carrier stop

The dc power supply on terminal J8 (22A, 22C) is fed from the Interconnect module (terminals 13 and14 of 1FT-14, thru two fuses).The full-wave rectifier (CR15) provides a positive voltage at C10, re-gardless of the input voltage polarity. Transistor (Q1) supplies the initial start voltage to the pulse-width modulated regulator (U1), which is oscillated at approximately 20 kHz (as determined by thevalues of R4 and C3).

APPENDIX G. POWER SUPPLY MODULE

100 (3/92)


A signal from U1 pin 3 pulses the dual flip-flop (U2), driving Q5 and Q6 to provide a square wave attransformer (T1).This transformer has a ferrite pot core that provides the output voltages: 13 Vdc, -24Vdc, +8.5 Vdc, and 6.5 Vac square wave. The amplitudes of the output voltages can be adjusted bytrimpot (R13).The regulator (U1) pins 1 and 2 are used as a comparator to determine the pulse-widthat pin 13; this controls the conducting time of series regulator (Q4).Overcurrent shutdown is preventedby R16, R17, R23 connected in parallel. A voltage drop >200mV across these resistors starts the cur-rent-limiting circuitry of U1.

Output relays (K1 thru K10 and K14) are logically energized by the microprocessor (U100) throughan optical-isolated coupler (e.g. U8 for K1, K2). All relay driver circuits are similar in design. The fol-lowing discussion gives an example of the trip circuit (TRIPA-1). A 5 Vdc input from the micropro-cessor (U100) will turn on U8 and Q12 (for TRIPA-1) which energizes trip relays (K1, K2).The pickuptime of K1, K2 is improved by components R28, R29, C20, C21.Two reed relays (K8, K9) are usedfor monitoring the breaker trip current. As soon as the trip current is detected, the contacts of K8 and/or K9 will close to send a message to the Microprocessor to begin storing fault data into its memory.The telephone type relay (K13) has two normally-open contacts. For normal operation, VBFI is short-ed to B+ through the external jumper between terminals 13 and 14 of 2FT-14, (behind the relay);hence, K13 is energized. Power supply source +43V will be applied to K5 and K6, through one set ofcontacts (K-13, 3/4); the signal thru the second set of contacts (K-13, 7/8) is fed to the microprocessor.Regardless of whether Q11 or Q13 is “ON” or “OFF” when switch 13 of 2FT-14 is opened, K13 willdeenergize; then the single pole and three pole reclose contacts are blocked. The microprocessor(U100) will recognize the dropout of K13 as the system function test condition, and will store the faultdata without detecting the breaker trip current flow.

Mercury-type relays are used as follows:

• K4(carrier stop)

• K10 (carrier send)

• K14 (general start)

The pick-up time is approximately 1.5 ms.

Due to the wet mercury inside the relays, the power supply module must be testedwhile in a vertical position.

CAUTION

(3/92) 102


APPENDIX H. ACCEPTANCE TESTS (V2.50)

The following kinds and quantities of test equipment are used for the MDAR Acceptance Tests:

• Voltmeter (1)

• Ammeter (1)

• Phase Angle Meter (1)

• Load Bank (2)

• Variac (3)

• Phase Shifter (1)

• Optional Doble or Multi-Amp Test System

NOTE: Before turning on the dc power supply, check jumper positions on the Interconnect andMicroprocessor modules as shown in Table H-5. Also, refer to this table for relay systemoperation.

Refer to the NOTE under Tables H-1 and H-3 for 1 amp ct application.

H-I. FULL PERFORMANCE TESTS

Full performance tests explore MDAR responses and characteristics for engineering evaluation. Theyare in two parts: Non-Pilot and Pilot Acceptance Tests.

NOTE: Customers who are familiar with the MDAR performance and characteristics shoulddisregard this section and proceed directly to Section 2 “Maintenance Tests”.

A. Non-Pilot Performance Tests

To prepare the MDAR relay assembly for Non-Pilot Acceptance Tests, connect the MDAR perFigure H-1, Configuration 1.

1. Front Panel Check

Step 1. Turn on rated battery voltage. Check the FREQ setting to match the line frequencyand ct type CTYP. Apply a balanced 3-phase voltage (70 Vac); the Alarm-1 relayshould be energized. (Terminals TB4-7 and -8 should be zero ohms.)

Step 2. Check “RELAY-IN-SERVICE” LED; it should be “ON”.

Step 3. Press “RESET TARGETS” push-button; the green LED (Volts/Amps/Angle)should be “ON”.

Step 4. Using a dc voltmeter, measure the dc voltages on the front panel display with re-spect to common (± 5 %).

Step 5. Press the DISPLAY SELECT pushbutton, and note that the mode LED cycles thruthe five display modes. Release the pushbutton so that the SETTINGS mode LEDis “ON”.

Step 6. Set the MDAR relay in accordance with Table H-1. For Negative Sequence Direc-tional Unit, change DIRU from ZSEQ to NSEQ.

103 (3/92)


Step 7. Press the DISPLAY SELECT pushbutton to obtain the METERING mode(VOLTS/ AMPS/ANGLE).

2. Angle Current and Voltage Input Check

Step 8. Using Figure H-1, Configuration 1, apply three ac voltages of 70 VLN and an ac

current of 1A. Adjust phase A current to lag phase A voltage (VAN) by 75°.

Step 9. Press FUNCTION RAISE or FUNCTION LOWER pushbutton. Read input cur-rent (IA), input voltage (VAG), and angle (ANG). All values within 5%.

NOTE: Be sure that the RP setting is “NO”. If the RP setting is “YES”, the readingswill be the primary side values.

The angle measurement is for reference only. For I<0.5A, the display of anglewill be blocked and show zero degrees.

3. Zone 1 Test/Single-Phase-To-Ground

Step 10. Using Figure H-1, Configuration 1,adjust:

V1N = 30V

V2N = 70V

V3N = 70V

MDAR goes into fault mode processing only after the current detector is enabled. MDARperforms the test:

• Phase current (∆IA, ∆IB, or ∆IC) >1.0A peak and 12.5% change

• Ground current (∆I0)>0.5 A peak

• Voltage (∆Van, ∆Vbn, or ∆Vcn) >7V and 12.5% change with a current change of∆I>0.5A.

When one of the above is true, MDAR starts fault processing. In order to perform theabove, apply a certain value of current suddenly. If MDAR does not trip, turn the currentoff, readjust to a higher value, and then suddenly reapply current.

The current required to trip without mutual compensation can be calculated using the fol-lowing equation:

IVLN

Z1GCOS PANG X–( ) 1ZR 1–( )

3--------------------+

-----------------------------------------------------------------------------------------=

(3/92) 104


From Table H-1:

• Z1G =4.5Ω• PANG=75°• ZR =3.0

using an X = 75° (lagging)

The current required to trip = 4.00A±5 % for fault current lagging fault voltage by 75°.This is the maximum torque angle test. For other points on the MHO circle, change X to avalue between 0° and 150°, and calculate the value of I. The OC4 contacts should also beclosed for any ground faults only.

See Table 4-3, for a description of the following displayed fault data for:

• Fault Type (FTYP)

• Targets (BK1, Z1G)

• Fault Voltages (VA, VB, VC, 3V0) and Currents (IA, IB, IC, 3I0)

With the external jumper connected between TB1-13 and TB1-14, the BFIA-1, BFIA-2should be closed. The GS contact will be ON for approximately 50 ms. when the fault isapplied. Alarm 2 relay will be picked-up, which can be reset by the RESET button afterthe fault is removed. Change TTYP to 1PR; the RI2-1 and RI2-2 should be CLOSED.Change TTYP to 2PR (or 3PR). Repeat test; RI2-1 and RI2-2 should be closed. ChangeTTYP to “OFF”. Repeat test. RI2-1, RI2-2 should not be picked-up.

Repeat AG fault and measure the trip time, which should be <2 cycles. Change the settingof T1 from 0 to 2. Repeat the test; the trip time should extend for an additional 2 cycles.Reset T1 to zero.

The following formula can be used when PANG≠ GANG:

Vxg = (IX + K0 I0) Zcg

or Vxg =

or IX=

where

K0 =

=

IX =

I x K0I x/3+( )Zcg

Vxg

Zcg 1K0

3------+

------------------------------

ZoL Z1L–( )Z1L

----------------------------

ZR GANG PANG–( ) 1–( )∠

Vxg

Zcg ejPANG 1 Zr ej GANG PANG–( ) 1–3

---------------------------------------------------------+

-----------------------------------------------------------------------------------------------------

105 (3/92)


or IX =

Example:

Vag = 30 Z1g = 4.5PANG = 85 GANG = 40

Zr = 3

Ia =

=

=

This is the trip current (4.3A) at the maximum torque angle of -57.76° (current lags volt-age by 57.76°).

The following equation should be used for the angle of x on the MHO circle:

Iax=

Using Figure H-1, Configurations 2 and 3, repeat (preceding) Step 10 for BG and CGfaults. Note Targets.

Step 11. Assume that the mutual compensation current (lp) from the parallel line is shownas:

lp = 3I0‘= 3kI0 = kla

where k is less than 0.8. The trip current Ia can be expressed as follows:

Vag - (Ia + k0I0 +ZMR x I0‘) Z1G = 0 or

Vag - (Ia + k0Ia/3 + ZMRx k x Ia/3)Z1G = 0 or

Vxg

23--- Zcg ejPANG 1

3--- Zcg Zr ejGANG+

------------------------------------------------------------------------------------

3023--- 4.5( )ej85 1

3--- 4.5( ) 3( )ej40+

------------------------------------------------------------------

303 85( )+ j 3 sin (85) + 4.5 cos (40) + j4.5 sin (40)cos-----------------------------------------------------------------------------------------------------------------------------

4.31 57.76–( )∠

306.96 57.76 x–( )cos-----------------------------------------------

I a

Vag

Z1G----------- 1

1 ZR 1–3

---------------- ZMR k×3

---------------------+ +------------------------------------------------------×=

(3/92) 106


For the settings of Z1G = 4.5, ZR = 3, ZMR = 1, k = 0.5, PANG = GANG = 75°, and theinput voltages Va =30 , Vb = 70 , Vc = 70 , the trip current Ia shouldbe:

and Ip = 0.5Ia = 1.818 amps .

Refer to the test circuit Figure H-4. The relay should trip at the input currents of Ia = 3.8

,Ip = 1.9 and should not trip at the currents of Ia = 3.46 and Ip =

1.73 .

Connect a jumper between terminals 11 and 12 of 1FT14 switch if Ip is not used.

4. Zone 1 Test/Three-Phase

Step 12. Using Figure H-2, connect current and voltage circuits and apply:

• VAN = 30V∠0° IA = 6.67∠-75°

• VBN = 30V∠-120° IB = 6.67∠-195°

• VCN = 30V∠120° IC = 6.67∠+45°

Using a value of x = 75° (lagging), the current required to trip is calculated as follows(Note Targets):

Figure H-2 gives a concept of the test. If a Doble or Multi-Amp test set is used, be sure tosynchronize the 3-phase currents. If possible, use a multi-trace storage scope to verify the

waveforms of IA, IB and IC, or use the WRELCOM® software OSC to monitor the inputwaveforms.

In order to plot the MHO circle for different input angle (X), the setting of RT (and RU, ifOSB option is included) should be at maximum (15 ohms). The RT setting is used for loadrestriction. (Refer to OSB test for detailed information.) Set TTYP = 3PR. Repeat test;RI2-1 and RI2-2 should be closed. For TTYP = OFF, or 1PR, or 2PR repeat the test. RI2-1and RI2-2 should be open. The OC2 contacts should also be closed for any phase faultsonly.

5. Zone 1 Test/Phase-To-Phase

Step 13. Two methods can be used for this test.

a. Using T-connection (with Doble or Multi-Amp Test Unit; refer to Figure H-3 for externalterminal connection and configuration 1.

0°∠ 120°–∠ 120°∠

I a304.5------- 3

3 3 1– 0.5+ +-----------------------------------× 3.636 amps 75°–∠= =

75°–∠

75°–∠ 75°–∠ 75°–∠75°–∠

IVLN

Z1P PANG X–( )cos-------------------------------------------------- = 6.67A 5%±=

107 (3/92)


• VA = 1/2 VF @ 0°

• VB = 1/2 VF @ 180°

• VC = 3/2 (70) = 105V @ 90° lead

Using VF = VA-VB = 30V

• VA = 15V @ 0°

• VB = 15V @ 180°

NOTE: Current (IA) required to trip = 3.33A ± 5%, with an angle of -75 degrees.

b. Using Y-connection

NOTE: This test is actually for φφG testing (see Figure H-3, configuration 1).

VAN= VF

VBN= VF

VCN=

or

VAN= 17.3

VBN= 17.3

VCN= 96.4

For either T or Y connection, using a value of x = 75° (lagging), current required to trip:

12--- 2

3------- 0°∠

12--- 2

3------- 120°–∠

32--- 70 VAN

2 12---VF

2––×

120°∠

0°∠

120°–∠

120°∠

IVF

2Z1P PANG X–( )cos------------------------------------------------------=

BC CA

VAN = 105 ∠90° VAN = 15 ∠180°VBN = 15 ∠0° VBN = 105 ∠90°VCN = 15 ∠180° VCN = 15 ∠0°IF = 3.33∠-75° IF = 3.33∠−75°

The following table is for BC and CA fault tests when the T-connection is used:

(3/92) 108


From Table H-1:

• Z1P = 4.5Ω• PANG = 75°

For Y-connection only, current (IA) required to trip = 3.33A±5%, with an angle of -45°,because Ian has already lagged VF (Vab) by 30°. Review all targets. The OC2 contactsshould be closed for phase faults only.

NOTE: The accuracy of the voltage reading in the metering mode is between 1 and77 Vrms. The inaccurate reading on VCN will not affect the results of the test.

Set IM = 5A. Repeat the test. The relay should trip at 5A±5%. Reset IM = 0.5A.

The reclose contacts (RI2-1 and RI2-2) should be closed for setting of TTYP = 2PR or3PR, and should be open for TTYP = OFF or 1PR.

Step 14. Repeat Step 13 for both BC and CA faults. Use the following voltages for eachfault type:

BC CA

V V

V V

V V

7. Zone 2 Tests

Step 15. Press the DISPLAY SELECT pushbutton until the SETTINGS mode LED is dis-played. Change the setting values to:

• Z1P = “OUT” (Zone 1 phase value)

• Z1G = “OUT” (Zone 1 ground distance)

• Z2P = 4.5Ω (Zone 2 phase value)

• T2P = 1.0 sec (Zone 2 phase timer)

• Z2G = 4.5Ω (Zone 2 ground value)

• T2G = 1.5 sec (Zone 2 ground timer)

• Z2RI = “YES” (Zone 2 reclosing)

• TTYP= “3PR” (Reclosing mode)

VAN 96.4 120°∠= VAN 17.3 120°–∠=

VBN 17.3 0°∠= VBN 96.4 120°∠=

VCN 17.3 120°–∠= VCN 17.3 0°∠=

I F 3.33 45°–∠= I F 3.33 45°–∠=

109 (3/92)


Step 16. Perform Steps 10, 12, 13, and 14 (above) for Zone 2 only, using delayed trip timesaccording to the zone 2 phase timer (T2P), and the Zone 2 ground timer (T2G).Tolerances for T2P and T2G are 5% for an input current that is 10% above the cal-culated value.

Repeat Step 10.The RI2 contacts 1 and 2 should be closed, and the RB contacts 1 and 2should be open. Reset Z2RI to “NO”.

Repeat Step 10 again. The RI2 contacts 1 and 2 should be open and the RB contacts 1 and2 should be closed.

Change the settings of T2G and T2P to BLK. Zone 2 should not be tripped for any type offault.

7. Zone 3 Tests

Step 17. Press the DISPLAY SELECT pushbutton until the SETTINGS mode LED is dis-played. Change the setting values to:

• Z2P = “OUT” (Zone 2 phase value)

• Z2G = “OUT” (Zone 2 ground distance)

• Z3P = 4.5Ω (Zone 3 phase value)

• T3P = 2.0 sec (Zone 3 phase timer)

• Z3G = 4.5Ω (Zone 3 ground value)

• T3G = 2.5 sec (Zone 3 ground timer)

• Z3RI = “YES” (RI = Z3T)

• TTYP= “3PR” (Reclosing Mode)

Step 18. Perform preceding steps 10, 12, 13, and 14 for Zone 3 only, using delayed triptimes according to the Zone 3 phase timer (T3P), and the Zone 3 ground timer(T3G). Tolerances for T3P and T3G are±5% for an input current that is 10%above the calculated value.

Repeat Step 10. The RI2 contacts 1 and 2 should be closed, and the RB contacts1 and 2 should be open. Reset Z3RI to “NO”.

Repeat Step 10 again. The RI2 contacts 1 and 2 should be open and the RB con-tacts 1 and 2 should be closed.

Step 19. This test is not for general purpose. It is for a reference for computer control.

NOTE: For customers who use a computer to test the relays, or use their own settingsfor maintenance, refer to the following example to calculate and determinetrip currents; set the relay as follows:

Z1P = ZIG = 4.5 T1 = 0

Z2P = Z2G = 6.0 T2P = T2G = 0.2

Z3P = Z3G = 9.0 T3P = T3G = 0.3

(3/92) 110


PANG = GANG = 75° ZR=3

a. Single-Phase-to-Ground Fault

Use the equation in Step 10, and the following input voltages:

The single-phase trip currents for Zone 1, Zone 2, and Zone 3 at the maximum torqueangle are 6.0A, 4.5A and 3.0A, respectively.

b. Phase-to-Phase Fault

Use the T-connection and the equation in step 13. Apply the following input voltages:

The single-phase trip currents for Zone 1, Zone 2 and Zone 3 at the maximum torqueangle are 4A, 3A and 2A, respectively.

c. Three-Phase Fault

Use the equation in Step 12 with the following input voltages:

The three-phase trip currents for Zone 1, Zone 2 and Zone 3 at the maximum torqueangles

should be 6.0A, 4.5A and 3.0A, respectively.

8. Instantaneous Overcurrent (High-Set Trip)

Step 20. Using the SETTINGS mode, change the following settings:

ITP = 10A LOPB = “NO”

ITG = 5A Z3G = “OUT”

Z3P = “OUT”

VAN 45 0°∠ VLN= =

VBN 70 120°–∠=

VCN 70 120°∠=

I A 75°∠( )

VAN 18 0°∠ 12---VF= =

VBN 18 180°–∠ 12---VF= =

VCN 105 90°∠=

I AB 75°–∠( )

VAN 27 0°∠ VLN= =

VBN 27 120°–∠=

VCN 27 120°∠=

I A 75°, I B 195°, I C +45°∠–∠–∠( )

111 (3/92)


NOTE: The High-Set ground overcurrent (ITG) and phase overcurrent (ITP) are su-pervised by Forward Directional Ground unit (FDOG) and Forward Direc-tional Phase unit (FDOP), respectively. In order to test the High-Set trip, the3φ voltages are necessary as directional reference. The ITG and ITP will au-tomatically become non-directional overcurrent units if the setting of LOPBis YES and at least one input voltage is zero volts (e.g., LOPB = YES in themetering mode).

Step 21. Using Figure H-1, configuration #1, to connect currents and voltages, apply AGfault as shown in Step 10. The MDAR should trip at Ia = 5 Amps±5 % with a tar-get of ITG-AG. For reversed fault, apply 8A reversed fault current (i.e., Ia leads

Vanby 135° for Y-connection, or 105° for T-connection). The relay should not trip.

Step 22. Using Figure H-3, to connect currents and voltages, apply AB fault as shown inStep 13. The MDAR should trip at Iab = 10 Amps ±5%, with a target of ITP - AB.

Apply a 15A reversed fault current (i.e., Ia leads Vab by 135° for Y-connection or

105° for T-connection). The relay should not trip.

9. Ground Backup (GB) Test

Step 23. Use the SETTINGS mode and change the following settings:

• ITP = “OUT”

• ITG = “OUT”

• GBCV = CO-8

• GBPU = .5

• GDIR = “NO”

• GTC = 24

NOTE: The note in Step 20 applies to the GB test. The GB can be set to directionalground overcurrent. For loss-of-potential condition, GB will be converted tonon-directional, automatically, regardless of the GDIR=YES setting.

Using Figure H-1, apply A-G fault of 4.1A to MDAR. Trip time is determined as follows:

(Tmsec) =

where

(3IOF is zero sequence fault current.)

(Tmsec) =

Tmsec = 1073 msec

478 41223I 0 1.27–------------------------+

GTC24

------------

3I 0

3I OF

GBPU-----------------=

478 41224.1/0.5 -1.27------------------------------+

2424------

(3/92) 112


= 1.073 sec±5 % to tripFor values of 3I0 between 1.0 and 1.5, the following equation would apply:

(Tmsec) =

The following equation can be used to calculate the trip time for all CO curves from CO-2to CO-11:

T(sec) =

T(sec) =

where

GBPU= Pickup current setting (0.5 to 4.0A).GTC= Time curve dial setting (1 to 63).To, K, C, P and R are constants, and are shown in Table H-2.

Step 24. For a Zero Sequence Directional unit (DIRU = ZSEQ), the tripping direction ofMDAR is: the angle of 3I0 leads 3V0 between +30° and +210°. Change the set-ting of GDIR to “YES”. Apply AG fault as shown in preceding Step 10, FigureH-1. The relay should trip at the following angles:

• +28°• -60° (± 88°)• -148°

The relay should not trip at the angles of:

• +32°• +120° (± 88°)• -152°

For a Negative Sequence Directional Unit (DIRU = NSEQ), the tripping direc-tion of MDAR is: I2 leads V2 by a value between +8° and +188°. The relayshould trip at the following angles:

• +3°• -82° (± 85°)• -167°

The relay should not trip at the angles of:

9200( )3I 0 1–----------------- GTC

24------------× CO 8 only–( )

T0K

3I 0 C–( )p--------------------------+

GTC24 000,------------------ for 3I 0 1.5≥( )×

R3I 0 1–( )

---------------------- GTC24 000,------------------× for 1 3I 0 1.5< <( )

3I 0

3I OF

GBPU-----------------=

113 (3/92)


• +13°• +98° (± 85°)• +183°

Reset GBCV = NO

Step 25. IOSD (OC-5) trip test. Set IOST = 1. apply 3 balanced voltages of 70 volts. Turnon Ia with 1 amp suddenly. The OC-5 contacts should close in 1.0 sec. Repeat thetest for IOST = 2, 3, 4, 5 and measure the trip time accordingly.

10. CIF, STUB, Iom, IL and LV Tests

Step 26. Set the relay per Table H-1. Change the following settings: Iom = 3, IL = 2, CIF= CIFT, and connect a rated dc voltage to 52b, between TB5/3 (+) and TB5/4 (-).Apply an AG fault as shown in Step 10 (Figure H-1). The relay should trip at Ia =2A (IL) with CIF target. Change IL setting from 2 to 3.5A and repeat the testshown in Step 26. The relay should trip at Ia = 3A (Iom) with CIF target.

Step 27. LV setting test. Set LV = 60 and with IAN = 4A, apply AG fault as shown in Step10. The CIF trip should be for VAN <60 Vrms± 5%.

Step 28. For STUB Bus Protection (SBP), check the blue jumpers on the Interconnectmodule. JMP7 and 9 should be IN; JMP13 should be at the rated voltage position.Select CIF = STUB. Disconnect the voltage from 52b and connect it to terminalsTB5/13(+) and TB5/14(-).

NOTE: Make sure the jumpers (JMP8 and JMP10) are not IN before applying thevoltage to TB5/13(+) and TB5/14(-).

Apply IA = 4A. The STUB bus trips for any VAN voltage with a target of CIF.Disconnect the voltage from SBP and reset Iom = IL = 0.5 and CIF = NO.

11. LLT and Loss-of-Potential (LOP) Test

Step 29. For Load Loss Trip (LLT), set:

LLT = Yes

Z2P = Z2G = 4.5 ohms

T2P = T2G = 2.99 sec (or BLK)

Apply:

Va = 30

Vb = 70

Vc = 70

Ia = 3.5

Ib = 1

Ic = 1

0°∠

120°–∠

120°∠

75°–∠

120°–∠

+120°∠

(3/92) 114


Suddenly increase Ia from 3.5 to 4.5A and then turn Ib OFF immediately. The relay shouldtrip with LLT target. The trip is accelerated due to the pickup of Zone 2 and the setting ofLLT = YES.

Change the setting of LLT = FDOG and suddenly increase the input current Ia from 1.0Ato 2.0A; then turn Ib OFF immediately. The relay should trip with a target of LLT. The tripis due to the pickup of FDOG and setting of LLT = FDOG.

Reset: LLT = NO

Z2P = Z2G = OUT

T2P = T2G = BLK

Step 30. Disconnect all current inputs. Connect 3 balanced voltages of 70 Vac to Van, Vbn,

and Vcn. Using the SETTINGS mode, change the setting: LOPB = YES.

NOTE: The “RELAY IN SERVICE” LED will not be turned “OFF” for the condi-tion of setting LOPB = Yes, but Zone 1, 2, 3 and pilot distance units will beblocked and all overcurrent units (GB, ITP, and ITG) will be converted tonon-directional operation.

LOPB will be set if the following logic is satisfied:

• one (or more) input voltages (VAN, VBN or VCN) are detected (as <7 Vrms) without∆Ichange, or

• a 3Vo (> 7Vrms) is detected with 3Io <Ios

Apply VAN, VBN and VCN rated voltage to MDAR. Scroll the LED to metering mode; thedisplay shows LOPB = NO. Reduce VAN to 62 Vrms (e.g., 3V0 = 8V). After approxi-mately 0.5 seconds, the display shows LOPB = YES and the form C failure alarm (AL1)contact is also deenergized.

Step 31. Set the relay as follows:

Z1P = 4.5 GBCV = CO-8

Z1G= 4.5 GBPU = 0.5

ITP = 10 GDIR = YES

ITG = 5 GTC = 24

Repeat Step 10 (AG Fault) with IAN = 4.5A. While in the metering mode, be sure thatLOPB = YES before the fault current is applied. The relay should be tripped with a targetof GB. Apply 5.5A; the relay should be tripped with a target of ITG. Repeat the test with areversed AG Fault; the relay will trip. Reset LOPB = NO; the relay should not trip for thereversed fault. Set LOPB = YES.

Step 32. Apply a balanced three-phase voltage (70 Vrms) and current (3A). Turn off Va;the relay should not trip. Reset LOPB to NO.

115 (3/92)


12. Loss-Of-Current (LOI) Test

Step 33. Set LOIB to YES and IOM = 1.0A. Apply a balanced three-phase voltage (70Vrms). Connect the current inputs per Figure H-1, and apply a single phase cur-rent of 1.1A to IA. After approximately 0.5 seconds, the “Relay In Service” LEDwill be turned off, and the Form C failure alarm (AL1) contact will be dropped out(deenergized) indicating a failure condition.

Step 34. Increase IA to 1.5A. Depress the DISPLAY SELECT pushbutton and change tothe metering (VOLTS/AMPS/ANGLE) mode. Press FUNCTION RAISE push-button until the LOI display is shown. The value should indicate “YES”. Suddenlyturn OFF Va voltage; the relay should not be tripped within 500 ms. It may operateafter 500 ms if a delta I is detected by the relay. Change the setting of LOIB fromYES to NO.

13. Output Contact Test

Step 35. The purpose of this test is to check the hardware connections and relay contacts.It is designed for a bench test only. Remove JMP3 (spare on the MicroprocessorPC Board) and place it in the JMP5 position. Open the red-handled FT switch(Trip and Breaker Failure Initiate) in order to avoid the undesired trip.

NOTE: The red-handled FT switch (#13) controls the dc supply of BFI, RI2 and theoptional RI1 relays. In order to test these relays in the system, the externalwiring should be disconnected to avoid undesired reclosing or trip. For relayswithout FT switches,DO NOT perform the Output Contact tests using the re-lay system.

Change the LED mode to “TEST” and select the tripping function field and thedesired contact in the value field. Push the ENTER button; the ENTER LEDshould be “ON”. The corresponding relay should operate when the ENTER but-ton is pressed. The following contacts can be tested:

• TRIP

• BFI (Breaker Failure Initiation)

• RI1 (Carrier Receive)

• RI2 (Reclosing Initiation

• RB (Reclosing Block)

• AL1 (Self-Check & LOP alarm; with three balanced voltages ap-plied)

• AL2 (Trip Alarm)

• GS (General Start)

• SEND (Pilot Carrier Send)

• STOP(Pilot Carrier Stop)

• OC (Output Contacts; OC1 to OC8)

Remove JMP5 and replace it on JMP3.

(3/92) 116


Step 36. This completes the basic Acceptance Test for the MDAR Non-Pilot system. (Seesubsequent segment for optional Single Pole Trip and Out-of-Step Block tests.)

B. PILOT PERFORMANCE TESTS

To prepare the MDAR relay assembly for Pilot Acceptance Tests, connect the MDAR per Fig-ure H-1, Configuration 1.

1. Front Panel Check

Step 1. Repeat steps 1 thru 6 in Non-Pilot Acceptance Tests, except that in step 6, set val-ues are in accordance with Table H-3.

Step 2. Change the value settings, in Table H-3, as follows:

• PLT YES • CRSR 4.5

• FDGT BLK • Z3P 6.0

• ZIP OUT • Z3G 6.0

• ZIG OUT • T3P BLK

• CRSF9.0 • T3G BLK

NOTE: When the dc voltage is applied to TB5 terminals, check jumper position onInterconnect module for the appropriate selection.

Connect a rated dc voltage to PLT/ENA terminals TB5/9(+) and TB5/10(-).

2. Blocking (BLK) Scheme

Step 3. Change the STYP setting to BLK. Apply a rated dc voltage to RCVR #1 terminalsTB5/7(+) and TB5/8(-). The contacts RI-1 and OC-7 should be closed for RCVR#1 presented. Check the metering mode for RX1 = YES. Apply an AG fault asshown in Step 10 of the Non-Pilot Acceptance Test (i.e., Va = 30 volts and Ia = 4Amps). The trip A contacts should not be closed. The Carrier Stop should beclosed.

Step 4. Remove the dc voltage from RCVR #1 and apply AG fault. Trip A contacts shouldbe “closed” and the target should show “PLTG AG”. The OC-3 contact should beclosed.

Change the LED mode to “TEST” and select the “RS1” function. Push theENTER button; the ENTER LED should be “ON”. Repeat Step 4 with theENTER button depressed. The relay should not trip.

Step 5. Apply AG reversed fault (i.e., Ia leads Va by 105 degrees). The relay should nottrip with or without RCVR #1 voltage.

Step 6. In order to determine setting accuracy (6 ohms), the forward directional groundunit must be disabled. Set FDGT = BLK. Repeat preceding Step 4 of the Pilot Ac-ceptance Test, with a trip input current (Ia) of 3 Amps (±5%).

Step 7. Set the Forward Directional Ground Timer (FDGT) from 0 to 15 cycles. RepeatStep 4 with Ia = 1.5 A. The relay should be tripped after the delay time of FDGT.Reset FDGT = BLK.

117 (3/92)


NOTE: The FDOG trip is determined by the IOM setting. It trips if 3I0 >Iom and theforward ground directional unit picks up.

Step 8. In order to perform the Breaker Failure Reclose Block Test, change the setting ofFDGT = 0 and BFRB = NO. Repeat test Step 4; RB contacts (TB3/1 and TB3/2)should not close. Change BFRB to YES and repeat the test. The RB contactsshould be closed with a time delay between 150 ms and 200 ms.

Step 9. Repeat Step 4 for AB fault as shown in Step 13 of the Non-Pilot Test. The relayshould trip with “PLTP AB”. The OC-1 should also be closed.

3. Carrier SEND/STOP

Step 10. V2 keying check. The SEND contact should be closed if 3V2 > 25 volts. Applythree balanced voltages (70V) and currents (1A). The SEND contacts (TB4/1 &2) should be open. Reduce Va from 70 volts to 45V±5%. The SEND contact

should be closed. The OC-6 contacts should also be closed for the SEND signal.Return Va to 70 volts.

Step 11. Change the LED mode to TEST and select the function “SEND”. Push the EN-TER button; the ENTER LED should be on and the SEND contacts should beclosed. Repeat this test for selecting the function “STOP”. The STOP contactsshould be closed.

Step 12. Apply a forward fault as follows:Va = 60∠0°, VB = 70∠−120°, VC = 70∠120°, AND Ia = 6.0∠-75° ±5%.

The TRIP and STOP contacts should be closed and the SEND contacts should beopen because of the pickup of Z3G (6 ohms).

Step 13. Apply a reverse fault as follows:Va = 60∠0°, Vb = 70∠-120°, Vc = 70∠120°, and Ia = 2.0∠105°The Carrier SEND contacts should be closed and the STOP contacts should beopen because 3I0 >I0s (0.5a).

Step 14. Change the settings as follows:Z3P = Z3G = OUT, I0m = I0s = 10 amps

Repeat the test of Step 13 except Ia = 4.0∠105° ±5% for the closure of the SEND

contacts because of the setting of CRSF (9 ohms).

Step 15. Repeat the test of Step 12 exceptIa = 8.0∠-75°±5% for the closure of the SEND contacts because of the setting of

CRSR (4.5 ohms).

C. MDAR WITH OUT-OF-STEP BLOCK

Refer to Figure H-5. The RT setting (21BI) is for the inner blinder and it is also used for three-phase fault load restriction. The RU setting (21BO) is for the outer blinder. If the setting of OSBis “YES”, and the power swing stays inside the two parallel lines (RT and RU) for more thanOST1 setting, the three-phase fault trip will be blocked until the timer (OSOT) times out.

(3/92) 118


Connect the test circuit as shown in Figure H-2.

1. Condition OSB = NO, OST = NO

Step 1. Set the relay per Table H-1, except for the following settings:

OSB1 = OSB2 = OSB3 = NO

Z1P = 10 Z3P = 20

Z1G = 10 T2P = 0.1 Z3G = 20

Z2P = 20 T2G = 0.1 T3P = 0.2

Z2G = 20 T3G = 0.2

(Check: PANG = GANG = 75; RT = RU = 15; OSOT = 240)

Step 2. Adjust the inputs as follows:

Va = 40 ∠0° Ia = IF ∠-45°Vb = 40 ∠-120° Ib = IF ∠−165°Vc = 40∠120° Ic = IF ∠75°

Step 3. Apply current IF of 2.35A±5% suddenly. The relay should trip with a display ofZ2P = ABC.

Step 4. Apply IF of 4.7A±5% suddenly. The relay should trip with a display of Z1P =ABC.

Step 5. Change the RT setting from 15 to 4. Repeat Steps 3 and 4 (above). The relayshould not trip because the RT restricts the 3-phase fault current.

NOTE: The trip current (IF) can be obtained from the equation in test Step 12 (1.1.4Zone 1 Test/Three-Phase), with the parameters:

VLN = 40 PANG = 75

Z1P = 10 (or Z2P = 20) X= 45

2. Condition OSB = YES, OST = NO

A computer controlled test unit is required for the following tests from Step 6 toStep 10.

Step 6. Change the OSB1 to YES and RT = 4, RU = 8, and OST = NO. Change the LEDto metering mode with the display of OSB = NO. apply a current If = 2.7 A±5%

suddenly. The display should show OSB = YES for four (4) seconds. This meansthe input power swing is inside the outer blinders (21BO). Repeat this test for If= 4 A and 4.75 A. The display should show OSB = YES because the power swingis within two blinders (21BO and 21BI).

Step 7. Use a computer to set the test sequence as follows:

State 1: Va = 70 ∠0° Ia = 1∠0°Vb = 70∠-120° Ib = 1∠-120°Vc = 70∠120° Ic = 1∠120°

for 100 cycles.

119 (3/92)


State 2: Va = 40 ∠0° Ia = 3.5∠−45°Vb = 40∠-120° Ib = 3.5∠-165°Vc = 40∠120° Ic = 3.5∠75°

for 2 cycles.

State 3: Va = 40 ∠0° Ia =5.5∠−45°Vb = 40∠-120° Ib = 5.5∠-165°Vc = 40∠120° Ic = 5.5∠75°

for 30 cycles.

The relay should trip with Z1P = ABC. This means that the OSB has not beenestablished.

Step 8. Repeat Step 7 except change State 2 from 2 cycles to 4 cycles. The relay shouldtrip with Z2P = ABC after the T2P timer times out because of OSB1 = YES andOSB2 = NO.

Step 9. Repeat Step 8 except change the setting to OSB2 = YES. The relay should tripwith Z3P = ABC after the T3P timer times out because of the settings of OSB1 =OSB2 = YES and OSB3 = NO.

Step 10. Repeat Step 9 except change the setting to OSB3 = YES. The relay should tripwith OST after OSOT (240 cycles) times out. The OST can be blocked by the set-ting of OSOT = OUT.

3. Condition OSB = YES, OST = YES

A computer controlled test unit is required for the following tests from Step11 toStep 15.

Maintain the settings of OSB1 = OSB2 = OSB3 = YES and change OST fromNO to WAY1.

Step 11. Use a computer to set the test sequence as shown in Step 7 except change the State2 from 2 cycles to 4 cycles. The relay should trip with OST after OST2 timer timesout.

Step 12. Repeat Step 11 except change State 3 from 30 cycles to 2 cycles. The relay shouldnot trip.

Step 13. Change the settings to OST = WAYO. Repeat Step 11. The relay should not trip.

Step 14. Repeat Step 11 except add State 4 as follows:

State 4: Va = 40 ∠0° Ia =1 ∠−45°Vb = 40∠-120° Ib = 1∠-165°Vc = 40∠120° Ic = 1∠75°

for 10 cycles.

The relay should not trip.

(3/92) 120


Step 15. Change the States 1 to 4 and add state 5 as follows:

State 1: Va = 70 ∠0° Ia =1 ∠0°Vb = 70∠-120° Ib =1 ∠-120°Vc = 70∠120° Ic =1 ∠120°

for 100 cycles.

State 2: Va = 40 ∠0° Ia = 3.5∠−45°Vb = 40∠-120° Ib = 3.5∠-165°Vc = 40∠120° Ic = 3.5∠75°

for 5 cycles.

State 3: Va = 40 ∠0° Ia =5.5∠−45°Vb = 40∠-120° Ib =5.5∠-165°Vc = 40∠120° Ic =5.5∠75°

for 20 cycles

State 4: Va = 40 ∠0° Ia =3.5∠−45°Vb = 40∠-120° Ib =3.5∠-165°Vc = 40∠120° Ic =3.5∠75°

for 5 cycles.

State 5: Va = 40 ∠0° Ia =1 ∠−45°Vb = 40∠-120° Ib =1 ∠-165°Vc = 40∠120° Ic =1 ∠75°

for 10 cycles.

The relay should trip after OST3 and 20/500 timers out.

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H-II. MAINTENANCE QUALIFICATION TESTS

Maintenance qualification tests will determine if a particular MDAR unit is working correctly.

A. Non-Pilot Maintenance Tests

It is recommended that either Doble or Multi-Amp test equipment should be used for this test. Referto Figure H-1 for the input voltage and current terminal connection per configuration 1. Check alljumper positions on the Interconnect module for rated dc voltage.

1. Front Panel and Metering Check

Step 1. Turn on rated dc voltage. Check the FREQ setting; it should match the line fre-quency and ct type (CTYP). Apply a balanced 3-phase voltage (70 Vac); theAlarm 1 relay should be energized. (Terminal TB4/7 and TB4/8 should be zeroohms.) The “Relay-in-Service” LED should be “ON”.

Step 2. Press RESET pushbutton; the green LED (Volts/Amps/Angle) should be “ON”.Press the FUNCTION RAISE or FUNCTION LOWER pushbutton. Read the in-put voltages and their angles:

VAG = 70∠0°VBG = 70∠-120°VCG = 70∠120°with an error of± 1 volt and± 2°

Step 3. Press the DISPLAY SELECT pushbutton, and note that the mode LED cycles thruthe five display modes. Release the pushbutton so that the SETTINGS mode LEDis “ON”. Press the RAISE button to scroll thru the FUNCTION FIELD to checkthe settings per Table H-1 (non-pilot) or Table H-3 (pilot). Change the setting, ifnecessary, by depressing the RAISE button in the VALUE FIELD to the desiredvalue and then pressing the ENTER button.

Step 4. Press the RESET pushbutton (LED jumps to Metering mode). Apply 3.0 A to IAwith an angle of -75°. Read IA from the front display; it should be 3.0∠-75° withan error of 5% and± 2°. Move the input current from IA to IB or IC terminal.Read IB or IC to verify the transformer’s accuracy.

2. Impedance Accuracy Check

Step 5. Apply voltages to MDAR as follows:

VAG = 30∠0°VBG = 70∠-120°VCG = 70∠120

Apply forward fault current IA∠-75° suddenly. The relay should trip for IA =4A ± 5%. The display should show “Z1G AG”.

Repeat for B and C phases per the following table:

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Phase B Phase C

VA = 70∠120° VA = 70∠-120°VB = 30∠0° VB = 70∠120°VC = 70∠-120° VC = 30∠0°IB = 4 ∠-75° IC = 4 ∠-75°

3. Input Opto-Coupler Check

Step 6. External ResetApply an AG fault as shown in Step 5. The LAST FAULT LED should be flashing.Press the front RESET pushbutton. The green LED (Volts/Amps/Angle) shouldbe “ON”. Press the DISPLAY SELECT pushbutton and move the LED back toLAST FAULT. The fault information “Z1G AG” should be displayed again. Ap-ply a rated dc voltage to terminals TB5/5 (+) and TB5/6(-). The target data shouldbe erased and the display should show “FTYP”. Remove the external reset volt-age.

Step 7. 52b TerminalsChange the CIF setting from “NO” to “CIFT”. Apply an AG fault as shown inStep 5, with IA = 2∠-75°. The relay should not trip. Apply a rated dc voltage toterminals TB5/3 (+) and TB5/4 (-). Repeat the test. The relay should trip with atarget of CIF. Remove the 52b voltage and set CIF to STUB for the next test.

Step 8. Stub Bus Protection (SBP)Check the blue jumpers on the Interconnect module. Jumpers (JMP 7 and JMP 9)should be “IN”. JMP 13 should be at the rated voltage position. Apply a balanced3-phase voltage (70 Vac and IA = 2A) using any angle. The relay should not trip.Apply a rated voltage to the SBP terminals: TB5/13(+) and TB5/14(-). The relayshould trip with a target of SBP. Change jumpers from JMP 7 and 9 back to JMP8 and 10; if the Stub Bus Protection is not used. Reset CIF to “NO”.

4. Input Transformer (IP) Check

Step 9. Change the settings per Table H-1. Refer to Step 11 shown in Section I.A. Set theinput voltages:Va = 30∠ 0°, Vb = 70 ∠-120°, Vc = 70 ∠120°.Apply Ia = 3.8 ∠-75° and Ip = 1.9 ∠-75° suddenly. The relay should trip.Apply Ia = 3.46 ∠-75° and Ip = 1.73 ∠-75° suddenly. The relay should not trip.

5. Output Contact Test

Step 10. The purpose of this test is to check the hardware connections and relay contacts.It is designed for a bench test only. Remove JMP 3 (spare on the MicroprocessorPC Board) and place it in the JMP 5 position.

Change the LED mode to “TEST” and select the tripping function field and thedesired contact in the value field. Push the ENTER button; the ENTER LEDshould be “ON”. The corresponding relay should operate when the ENTER but-

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ton is pressed. The following contacts can be tested:

• TRIP

• BFI

• RI1

• RI2

• RB

• AL1 (with 3 balanced voltages)

• AL2

• GS

• SEND

• STOP

Remove JMP 5 and place it on JMP3.

B. Pilot Maintenance Test

Connect the MDAR per Figure H-1, Configuration 1.

1. Basic Function Test

Step 1. Repeat Step 1 thru 10 in the Non-Pilot Maintenance Test.

2. Input Opto-Coupler Check

Step 2. PLT ENA TerminalsChange the following settings from Table H-3:

• PLT YES

• Z1P 0UT

• Z1G OUT

• Z3P OUT

• Z3G 6.0

• T3P BLK

• T3G BLK

Change the STYP setting to BLK. Apply a forward fault, as shown in the Non-Pilot Maintenance Test, step 5. The relay should not trip.

Apply a rated dc voltage to PLT ENA terminals TB 5/9(+) and TB 5/10(-).Repeat the test. The relay should trip.

Step 3. Receiver 1 (CR1)Apply a dc voltage to PLT ENA terminals TB 5/9(+) and TB5/10(-). Repeat thetest shown in Step 2. The relay should trip.

Apply a rated dc voltage to RCVR-1 terminals TB 5/7 (+) and TB 5/8(-).Repeat the test. The relay should not trip.

Step 4. Receiver 2 (DCB)Apply a 3-balanced voltages (70V) and currents (1A). apply a rated voltage to

124 (3/92)


PLT ENA terminals TB5/9(+) and TB5/10(-) with the setting of PLT = YES. Apply a ratedvoltage to RCVR2 terminals TB5/11(+) and TB5/12(-). The SEND Contactsshould change from “OPEN” to “CLOSE”. This test can be simplified by Vac = 0

& I ac = 0, but the voltage on terminals 52b should be zero volts.

Step 5. Programmable Output ContactsUse WRELCOM® software to check the 8 additional output contacts are pro-grammed correctly.OC1 — PLTPOC2 — Z1P/Z2P/Z3P/ITPOC3 — PLTGOC4 — Z1G/Z2G/Z3G/ITG/GBOC5 — IOSDOC6 — SENDOC7 — RCVR #1 (CR1)OC8 — (Spare)

130 (3/92)


TABLE H-1. MDAR SETTINGS (NON-PILOT SYSTEM)

TABLE H-2. TRIP TIME CONSTANTS FOR CO CURVES

Curve # To K C P R

CO2 111.99 735.00 0.675 1 501CO5 8196.67 13768.94 1.13 1 22705CO6 784.52 671.01 1.19 1 1475CO7 524.84 3120.56 0.8 1 2491CO8 477.84 4122.08 1.27 1 9200CO9 310.01 2756.06 1.35 1 9342CO11 110. 17640.00 0.5 2 8875

VERS 2.xxOSC TRIPFDAT TRIPCTR 1000VTR 2000FREQ 60CTYP 5RP NOXPUD .5DTYP KMTTYP OFFZ1RI YESZ2RI NOZ3RI NOBFRB NOPLT NOSTYP 3ZNPFDGT BLKBLKT 0CRSF 9.0CRSR 4.5Z1P 4.5Z1G 4.5T1 0Z2P OUTT2P 1.00Z2G OUTT2G 1.50Z3P OUTT3P 2.00

Z3G OUTT3G 2.50PANG 75GANG 75ZR 3.0ZMR 1.00LV 60IL .5IM .5IOS .5IOST 1.0IOM .5ITP OUTITG OUTOSB1 NOOSB2 NOOSB3 NOOSOT 240RT 15.00RU 15.00DIRU ZSEQGBCV OUTGBPU .5GTC 24GDIR YESCIF NOLLT NOLOPB NOSETR YESTIME NO

NOTE: This MDAR settings table is for 60 Hz and 5A ct systems. For 1A ct, change Z1P, Z1G, Z2P, Z2G, Z3P,Z3G, RT, RU by multiplying a factor of 5, and all current values mentioned in the text should be multi-plied by a factor of 0.02.

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TABLE H-3. PRESENT MDAR SETTINGS (PILOT SYSTEM)

VERS 2.xxOSC TRIPFDAT TRIPCTR 1000VTR 2000FREQ 60CTYP 5RP NOXPUD .5DTYP KMTTYP OFFZ1RI YESZ2RI NOZ3RI NOBFRB NOPLT YESSTYP BLKFDGT BLKBLKT 0CRSF 9.0CRSR 4.5Z1P OUTZ1G OUTT1 0Z2P OUTT2P 1.00Z2G OUTT2G 1.50Z3P OUTT3P 2.00Z3G OUTT3G 2.50PANG 75

GANG 75ZR 3.00ZMR 1.00LV 60IL .5IM .5IOS .5IOST 1.0IOM .5ITP OUTITG OUTOSB1 NOOSB2 NOOSB3 NOOST NOOST1 3OST2 3OST3 3OSOT 240RT 15RU 15DIRU YESGBCV OUTGBPU .5GTC 24GDIR ZSEQCIF NOLLT NOLOPB NOLOIB NOAL2S NOSETR YESTIME NO

NOTE: This MDAR settings table is for 60 Hz and 5A ct systems. For 1A ct, change PLT, PLG, Z1P, Z1G,Z2P, Z2G, Z3P, Z3G, RT, RU by multiplying a factor of 5, and all current values mentioned in thetext should be multiplied by a factor of 0.02.

132 (3/92)


TABLE H-4. FAULT TYPES APPLIED TO MDAR

SETTING FAULT TYPE OUT CONTACTSTTYP APPLIED RI TRIP BFI

OFF AG NO A,B,C A,B,CBG NO A,B,C A,B,CCG NO A,B,C A,B,CABC NO A,B,C A,B,C

1PR AG RI2 A,B,C A,B,CAB NO A,B,C A,B,CABC NO A,B,C A,B,C

2PR AG RI2 A,B,C A,B,CAB RI2 A,B,C A,B,CABC NO A,B,C A,B,C

3PR AG RI2 A,B,C A,B,CBG RI2 A,B,C A,B,CCG RI2 A,B,C A,B,CAB RI2 A,B,C A,B,CABC RI2 A,B,C A,B,C

INTERCONNECT ModuleJMP 1 to 6, & 13 For the rated input dc voltageJMP 7 & 9 For Stub Bus ProtectionJMP 8 & 10 For the trip alarm (AL2-2)JMP 11 & 12 For MDAR with FT switches only

MICROPROCESSOR ModuleJUMPER POSITION FUNCTIONJMP 1 1-2 EEPROM (8kx8)JMP 2 1-2 Programmable Output ContactsJMP 3 IN Spare jumperJMP 4 OUT No dropout time delay for trip contactsJMP 5 OUT Disable output contact testJMP 6 OUT Normal operationJMP 8 & 9 1-2 RAM (32kx8)JMP 10 IN Spare jumperJMP 11 & 12 OUT Spare positions

OUTER CHASSISExt. JMP 13-14 (2FT14) Enable BFI & RI Contacts

TABLE H-5. RECOMMENDED JUMPER POSITIONS (V2.5X)

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Section I. SPECIFICATIONS

1. TECHNICAL

Operating Speed(from fault detection 12-14 ms (minimum)to trip contact close 22 ms (typical)-60 Hz) 32 ms (maximum)

ac Voltage (VLN) at 60 Hz 70 Vrms(VLN) at 50 Hz 63.5 Vrms

ac Current (In) 1 or 5 A

Rated Frequency 50 or 60 Hz

Maximum Permissible ac Voltage

. • Continuous 1.5 x nominal voltage

. • 10 Second 2.5 x nominal voltage

Maximum Permissible ac Current

Continuous 3 x Nominal Current

1 Second 100 x Nominal Current

Typical Operating Current 0.5 A

dc Battery Voltages

Nominal Operating Range48/60 Vdc 38 - 70 Vdc110/125 Vdc 88- 145 Vdc220/250 Vdc 176 - 290 Vdc

dc Burdens: Battery 7 W normal30 W tripping

ac Burdens:

Volts per Phase 0.02VA at 70 Vac

Current per Phase 0.15VA at 5 A

2. CONTACT DATA

Trip Contacts - make & carry 30 A for 1 second, 10 A continuous capability, break 50 watts resistive or 25watts with L/R =.045 seconds

• Non-Trip Contacts

1A Continuous0.1A Resistive Interrupt Capability

Supports 1000 Vac across open contactsContacts also meet IEC - 255-6A, IEC - 255-12, IEC -255-16, BS142-1982.

3. ENVIRONMENTAL DATA

Ambient Temperature Range• For Operation -20°C to +60°C• For Storage -40°C to +80°C

Dielectric Test Voltage 2.8 kV, dc, 1 minute (ANSI C37.90.0, IEC 255-5)Impulse Withstand Level 5 kV peak, 1.2/50 microsecond, 0.5 joule (IEC 255-5)Fast Transient Surge Withstand Capability 4 kV, 5/50 nanosecond (IEC 801-4); 5kV 10/150 nanosecond(ANSI C37.90.1)Oscillatory Surge Withstand Capability 2.5 kV, 1 MHz (ANSI C37.90.1, IEC 255-6)EMI Volts/Meter Withstand 25 MHz-1GHz, 10V/m Withstand (Proposed ANSI C37.90.2).

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Appendix J. System Diagrams

Drawing Title Page No.

MDAR Block Diagram ..................................1611C12 ................................................................... 142

MDAR System Logic Diagram .....................2677F21 (sheet 1 of 2).............................................. 143

MDAR System Logic Diagram .....................2677F21 (sheet 2 of 2).............................................. 144

effective: march, 1992 preliminary numerical distance ... automation, inc. substation automation...

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