design and implementation of raid load shedding scheme … (no.27... · rls scheme for southern...

Design and Implementation ofDesign and Implementation ofRLS SchemeRLS Scheme for Southern Thailand Network

byM Y i B tMr.Yossawin Bureetan

Engineering Level 4Control and Protection System Department

Electricity Generating Authority of Thailand

Outline

1. Introduction1. Introduction

2. Previous Protection Scheme

3. Power System Analysis

4. Transient Stability Studies

5. Installation of the Protection Scheme

6 Post Event Analysis6. Post Event Analysis

7. Conclusion

Network Configuration of Southern Thailand

To PKK

- Network configuration before 2011

BSPBSP2

CP

500 kV

230 kV

115 kV Power Flow From Central RegionCP

LSNRN

KNSRT

RPB

TPPN

PP BDN

KN

NT

KAPK1

PK2

TS

LRPU RA

Main Load

SKLHY2

HY1

STU SDO KNEPTN

YL1 NW

CHN

BLG

BSTSUK

GURUN

YL2

Problem Solving Method

To PKK

- The previous RLS Scheme System Information- Tie-Lines Power Flow

BSPBSP2

CP

500 kV230 kV115 kV Areva

- Generation in Southern system- HVDC Status

CP

LSNRN

KNControlTrip

L d Sh ddi

HVDCRun Up/Back

SRTRPB

TPPN

PP BDN

KN

NT

BoxSignal Load Shedding(81 Cases Table)

KAPK1

PK2

TS

LRPU RA

SKLHY2

HY1

STU SDO KNEPTN

YL1 NW

CHN

BLG

BSTSUK

GURUN

YL2

Current Network Configuration

Changing in Southern Thailand Network after 2011To PKK Network after 2011 Network configuretaion Load Increament

BSPBSP2To PKK

CP

LSNRN

KNSRTRPB

TP PP BDN

KN

NTPN

KAPK1

PK2

TS

LRPU RA

NPK3

PN2

500 kV230 kV

SKLHY2HY1

STU SDO KNEPTN

YL1 NW

CHN

115 kV BLG

BSTSUK

NW

GURUN

YL2

Power System Analysis

C diti fCondition forSteady State Study

System Disturbance :Only largeLoad Condition is divided into 3 condition

System Disturbance :Only large disturbance will be investigated, Ex.- CHN Power Plant Full Block Trip (700 MW)

- Evening Peak Load- Day Peak Load- Light Load

- CHN Power Plant Half Block Trip (350 MW)- KA Power Plant Trip- HVDC Trip while importing 300 MWHVDC Trip while importing 300 MW- Central to Southern Tie-Line Trip 2 Circuits- Tie-Transformer 500/230 kV BSP2 Trip

Part of study

Part 1 Part 2 Part 3

Aft th tAfter the system disturbance, the System can

After the system disturbance, the system can remain stable with

After the system disturbance, the system can remain stable with

remain stable without any protection Scheme

can remain stable with only the action of HVDC Run Up/Run Back

can remain stable with HVDC Run Up/Run Back and Rapid Load Sheddingp

response Back Shedding

Studies Result from Part 1

Part 1 : Maximum Pre-condition Tie-Line Power Flow which, After the system disturbance, the System can remain stable without any protection Scheme response.protection Scheme response.

( ) ( ) ( ) ( ) ( )HVDC (+300) CHN (700) KA (300) CHN (350) Tie Line (N-2) KN-CC Bus

Evening 800 400 800 800 700 700

Day 800 350 800 750 650 700

Light 800 300 750 700 650 700


Part 2 : Maximum Pre-condition Tie-Line Power Flow which, After Part 2 : Maximum Pre condition Tie Line Power Flow which, After the system disturbance, the system can remain stable with only the action of HVDC Run Up/Run Back

CHN (700) KA (300) CHN (350)

Evening 700 1100 1100

Day 750 1100 1100

Light 650 1100 1000

Load Shedding Point Selection

The appropriate load shedding point are selected using V-P Ch t i tiCharacteristics.

The slope of V-P Characteristic of each load points indicate the weakness of that load points at that condition.

V

Stable

V critical

Unstable

P

Weak point in the system

500 kV BSPBSP2To PKK

230 kV115 kV

BSP

CP

Weak Load point

LSNRN

SRTRPB

KNSelected Load Shedding Point

TP

KA

PP BDNNT

TSPN

PK3PN2

PK1PK2 LR

PU RA

SKLHY

HY1 PTNCHN

2HY1STU SDO KNE

PTN

YL1

BLGSUK

NWYL2

BSTSUK

GURUN


Part 3 : Amount of load shedding which, After the system disturbance, the system can remain stable with action of HVDC Run Up/Run Back and Load Shedding

Load Shedding (MW)Tie Line Flow

Light Day Evening

700 28.10 - -

800 116.92 93.17 67.01

900 216 18 156 39 134 31900 216.18 156.39 134.31

1000 284.42 241.92 295.99

Transient Stability Studies

In studies result from transient stability studies 2 example cases are In studies result from transient stability studies, 2-example cases are shown Case 1: CHN full block trip (700 MW) at tie-line flow 400 MW Case 2: CHN full block trip (700 MW) at tie-line flow 700 MW

Transient Stability Result : Case 1

Case 1 : CHN Full Block Trip ( 700 MW) : Tie-Line Flow 400 MW

T = 1 s : Fault

T ≈ 1.4 s : HVDC Run up

T = 1.1 s : Clear Fault

Transient Stability Result : Case 2

Case 2 : CHN Full Block Trip ( 700 MW) : Tie-Line Flow 700 MW

T = 1 s : Fault

T ≈ 1.4 s : HVDC Run up

T = 1.2 s : Shed Load @ HY2 = 143.60 MW

T = 1.1 s : Clear Fault

Special Protection Scheme Operation

To PKK- The Scheme Operation to prevent system instability after large disturbance

BSPBSP2

ArevaTie-line Flow

CP

LSNRN

KNControlTrip

Load1Shedding

U/V @ Load(200 ms)

If Tie-line Flow > 700 MWand CHN full block trip

SRTRPB

TP PP BDN

KN

NTPN

BoxSignalLoad2

Shedding

500 ms

U/V @ Load

500 kV

230 kV

KAPK1

PK2

TS

LRPU RA

PK3PN2 HVDC

Run Up/Back

115 kVSKLHY2

HY1STU SDO KNE

PTN

YL1NW

CHN

BLG

BSTSUK

NW

GURUN

YL2

Special Protection Scheme Installation

To PKK500 kV

230 kV115 kV

BSPBSP2

Areva

U/V @ L d

Tie-line Flow

CP

LSNRN

KNControlTrip

Load1Shedding

U/V @ Load(200 ms)

If Tie-line Flow > 700 MWand CHN full block trip

SRTRPB

TP PP BDN

KN

NTPN

BoxSignal

Load2Shedding

500 ms

U/V @ Load

KAPK1

PK2

TS

LRPU RA

PK3PN2 HVDC

Run Up/Back

NCCSKL

HY2HY1

STU SDO KNEPTN

YL1NW

CHNNCC

Monitor and ControlSignal

BLG

BSTSUK

NW

GURUN

YL2

Challenge and Suggestion

The delay of the construction cause delay of scheme The delay of the construction cause delay of scheme installation.

Number and location of the communication device have to Number and location of the communication device have to be consider to minimize the scheme installation cost while remaining effective scheme operation.g p

Changing of load point impact amount of load shedding when the scheme operate.

In the scheme installation, the previous scheme was removed then the new scheme was installed. The function of scheme operation during that period had to be able to protect the system from black/brown out.

Example Event

On 5th March 2012 : Transmission Line 230 kV SKL2 On 5th March 2012 : Transmission Line 230 kV SKL2 –HY2 – KNE cct. 1 and 230 kV HY2 – KNE cct. 2 trip while central to southern tie-line flow 442 MW from Central tocentral to southern tie line flow 442 MW from Central to Southern System and HVDC was importing power 30 MW from Gurun to KNE

Special Protection Scheme OperationTie-Line Flow

442 MWThe event occur in the evening

RPB-H:232.5 KN-CC:645.6KK-T :74.3

CHN Full Block

710 MW

No KA

HVDC Ex.30 MW

BLG-H:73.3

Measurement Value from Post EventTie-Line Flow

763 MWAng(TPR)-Ang(KNE)

34.14 degree

SRT 1.00

PN 0.98

NT 0 98

No CHN

PK3 0.98

PN2 0.98KA 0.98

TS 0.99NT 0.98

PK3 0.98

PK2 0.99 PK1 0.97

HY2 0.99

KNE 1.00

HVDC Im.245 MW

Study ResultTie-Line Flow

929 MWAng(TPR)-Ang(KNE)

44.27 degree

SRT 0.98

PN 0.93

NT 0.97

No CHNPK3 0.93

PN2 0.93KA 0.95

TS 0.96

PK2 0.90 PK1 0.90

HY2 0.98

HVDC Im

KNE 1.00

HVDC Im.245 MW

Study ResultActual Value

Conclusion

In Southern Thailand Network a special protection In Southern Thailand Network, a special protection scheme was installed to prevent black out after large disturbance.disturbance.

When the scheme is trig, the scheme will send run up/back command to HVDC and load shedding command to load gpoint simultaneously.

After getting the shedding command, load at each will be shedded only when the voltage at that bus is low.

Post event analysis show that the scheme can prevent the system black out when large disturbance occur.

The load shedding, after the scheme action, can be avoided by controlling of the tie line flowby controlling of the tie-line flow.

Thank you

design and implementation of raid load shedding scheme … (no.27... · rls scheme for southern...

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