cowgd725 75 gen 301(design basis)rev.0

7/21/2019 Cowgd725 75 Gen 301(Design Basis)Rev.0

1/39

PAGE No.: 1 OF 39

L&T-VALDEL ENGINEERING LTD

19 PRIMROSE ROAD BANGALORE-560025

INDIA

PROJECT : MHS RE-DEVELOPMENT PROJECT PHASE II

CLIENT/OWNER : ONGC

CONTRACT No. : COWGD725

DOCUMENT No. : COWGD725-75-GEN-301

DOCUMENT TITLE : ELECTRICAL DESIGN BASIS

LTV L&T-OGSP ONGC OD ONGC OW

LARSEN AND TOUBRO LIMITED OIL AND NATURAL GAS

OIL & GAS SPECIAL PROJECTS CORPORATION LIMITED

0 15..04.08 APPROVED FOR DESIGN KV NKS NKS MK

C1 17.03.08 ISSUED FOR CLIENTS COMMENTS KV NKS NKS MK

REV. DATE REVISION DESCRIPTION PREPD. CHKD. APPD. P.M.

LTV5001-1/COWGD725


2/39

PAGE No. 2L&T-VALDEL ENGINEERING

LTDREVISION STATUS SHEET

CONTRACT No. COWGD725

DOCUMENT No.: COWGD725-75-GEN-301 REV. 0 DATE 15.04.08

SIGN. :DOCUMENT TITLE: ELECTRICAL DESIGN BASIS

SHEET 1 OF 1

PAGE

NO.REV.

ADDL.

PAGE NO.

REV.

PAGE

NO. REV.

ADDL.

PAGE NO.

REV.PAGE

NO.

REV. ADDL.

PAGE NO.

REV.

1 0 51 101

2 0 52 102

3 0 53 103

4 0 54 104

5 0 55 105

6 0 56 106

7 0 57 107

8 0 58 108

9 0 59 109

10 0 60 110

11 0 61 111

12 0 62 112

13 0 63 113

14 0 64 114

15 0 65 115

16 0 66 116

17 0 67 117

18 0 68 118

19 0 69 119

20 0 70 120

21 0 71 121

22 0 72 122

23 0 73 123

24 0 74 124

25 0 75 125

26 0 76 126

27 0 77 127

28 0 78 128

29 0 79 129

30 0 80 130

31 0 81 131

32 0 82 132

33 0 83 133

34 0 84 134

35 0 85 135

36 0 86 136

37 0 87 137

38 0 88 138

39 0 89 139

40 90 140

41 91 141

42 92 142

43 93 143

44 94 144

45 95 145

46 96 146

47 97 147

48 98 148

49 99 149

50 100 150

NOTE: IF REVISION REQUIRES ADDITIONAL PAGES TO BE INSERTED IN BETWEEN THE DOCUMENT, THE NUMBER OF THE PAGE ATINSERTION SHALL BE NUMBERED WITH DECIMAL (e.g. INSERTION BETWEEN PAGE 10 AND 11 SHALL BE NUMBERED AS 10.1, 10.2 ........)

LTV5046-1/0


3/39

L&T-Valdel Engineering

Ltd.

Project: MHS

Redevelopment ProjectPhase-II

ELECTRICAL

DESIGN BASIS

Page No : 3

Contract No :COWGD725

Revision No : 0

Doc. No : COWGD725-75-

GEN-301Date : 15.04.08

LTV5062/0

TABLE OF CONTENTS

1.0 INTRODUCTION..................................................................... ............................................................... .........4

2.0 REFERENCES ...................................................................... ................................................................... .........4

3.0 CODES, STANDARDS AND ABBREVIATION.................................................................... .......................5

4.0 GENERAL REQUIREMENTS........................................................................................................................7

5.0 ELECTRICAL SYSTEM DESIGN.................................................................................................................9

6.0 POWER SYSTEM...........................................................................................................................................15

7.0 SPECIFIC REQUIREMENTS FOR EQUIPMENT AND ASSOCIATED COMPONENTS..................17

8.0 ELECTRICAL EQUIPMENT/PRODUCT/MATERIAL SELECTION PHILOSOPHY........................27

9.0 ELECTRICAL EQUIPMENT CALCULATIONS.................................................................. ....................28

10.0 REVIEW AND APPROVAL..........................................................................................................................28

11.0 TAGGING AND NAMEPLATES ................................................................. ................................................ 29

12.0 ELECTRICAL EQUIPMENT INSPECTION & TESTING PHILOSOPHY........................................... 29

13.0 ELECTRICAL EQUIPMENT SPARES PHILOSOPHY ................................................................... ........30

14.0 TRANSPORT AND SHIPMENT ............................................................... ................................................... 30

15.0 WARRANTY...................................................................................................................................................30

16.0 DOCUMENTATION.............................................................. ................................................................ ........31

17.0 MODIFICATIONS ............................................................. ..................................................................... .......33


4/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 4


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

1.0 INTRODUCTION

Oil and Natural Gas Corporation Limited, is engaged in exploration & exploitation of

Mumbai High Field located about 165 km. West-North-West of Mumbai located in the

Arabian Sea on the continental shelf of Western India. The field is well developed, with an

extensive infrastructure of wellhead platforms, process platforms and pipelines.

Under this project, ONGC Ltd plans to add 3 nos. unmanned platforms along with

associated pipelines and modification works at SQ well platform and BHS, ICP and SH

process platforms. The works include installation of 3 nos. well platforms namely RS-15,

RS-16 & RS-17. In addition, the associated works include laying of sub-sea pipelines,

sub-sea cables, modifications on existing platforms and miscellaneous works.

2.0 REFERENCES

This document is prepared based on the following provided along with the bid package.

Background and general (Basic Bid Work) MHS Re-Development (Phase-II) Project,

Rev.0

Description of work (Basic Bid work) for MHS Re-Development (Phase-II) Project (RS-15, RS-16 & RS-17), Rev.1, Volume- II

Design Criteria for Well Platform (Submarine Cable), Rev.0

Addendum I

Addendum to Volume -1

Annexure X of Instrumentation design criteria Vol-II Rev 2

COMPANY Reply to Bidders Queries

Further, these documents describe the brief scope of work and design criteria to be followed

for the electrical works for the MHS Re-development Project Phase-II covered in the bid

package. The electrical work shall consist of design, detailed engineering, supply, erection,

testing and commissioning of the complete electrical facilities for the project as per theDesign Criteria, Equipment Specifications, Data sheets, Drawings and Standards included in

the bid package.


5/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 5


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

3.0 CODES, STANDARDS AND ABBREVIATION

Design of the electrical systems shall be based upon the requirements of the latest versions

of all applicable International Standards, Codes, Regulations and Code of Practice being

followed by the Industries world-wide. Some of them are listed below

CODE DESCRIPTION

API RP 500 (1997)

Recommended Practice for Classification of Locations for

Electrical Installations at Petroleum Facilities Classified as ClassI, Division I and Division 2

API RP 14C (2001)

Recommended Practice for Analysis, Design, Installation, and

Testing of Basic Surface Safety Systems for Offshore Production

Platforms

API RP 14F (1999)Recommended Practice for Design and Installation of Electrical

Systems for Offshore Production Platforms

IEC 60079-1(2005)Electrical apparatus for explosive gas atmospheres.

IALA (1984) International Association of Light House Authorities

IEC-60228 (2004) Conductors of insulated cables.

IEC 60332-1-2

(2004)

Tests on electric and optical fibre cables under fire conditions -

Part 1-2: Test for vertical flame propagation for a single insulated

wire or cable - Procedure for 1 kW pre-mixed flame.

IEC 60332-3

Category A (2000)

Tests on cables under fire condition-Part3: Tests for Vertical flame

spread of vertically mounted bunched wire of cables Category

A.

IEC 60079-10

(2002)

Electrical apparatus for explosive gas atmospheresPart 10:

Classification for hazardous area.

IEC 60331-11

(1999)

Tests for electric cables under fire conditions - Circuit integrity -

Part 11: Apparatus - Fire alone at a flame temperature of at least750 C

IEC 60079-14

(2007)

Electrical Apparatus for explosive gas atmospheres Part 14:

electrical installation in hazardous area (Other than Mines)

IEC 60947-3

(2005)

Low-voltage Switchgear and Control gear - Part 3: Switches,

Disconnectors, Switch-Disconnectors and fuse-combination units.

NEMA FG 1

(1994)Fiberglas Cable Tray Systems (Revision to FG1-1993)

SOLAS (IMO 110E

2004)

International Convention for Safety of Life at Sea 1947, and its

protocol of 1988. Articles, annexes.

33 CFR 67(2004) Navigation and Navigable Aids.


6/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 6


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

DNV-RPB-401

(2005)Recommended practice for Cathodic protection design

IS 2026 Part -1

1977Power Transformers: Part 1 : General

IS 11171 - 1985 Specification for Dry-Type Power Transformers

ABBREVIATIONS

CCE Chief Control of Explosive

CCTV Closed Circuit TelevisionCP Cathodic Protection

ESP Electrical Submersible Pumps

LV Low Voltage

HV High Voltage

LCS Local Control Station

kV Kilo Volts

kW Kilo Watt

HMI Human Machine Interface

IMCS Integrated Motor Control SystemP&ID Piping and Instrumentation Diagram

MCT Multi Cables Transit

ONGC Oil and Natural Gas Corporation

API American Petroleum Institute

BIS Bureau of Indian Standards

ASTM American Society for Testing of Material

NFPA National Fire Protection Agency

IALA International Association of Marine Aids to Navigational and

Lighthouse Authorities

ANSI American National Standards InstituteSOLAS Safety of Life at Sea

NESC National Electric Safety Code

DNV Det Norske Veritas

NACE National Association of Corrosion Engineers

IEC International Electrotechnical Commission

NEMA National Electrical Manufacturers Association

IEEE Institute of Electrical and Electronics Engineers

NEC National Electric Code

BSI British Standards Institution


7/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 7


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

BASEEFA British Approvals Service for Electrical Equipment for Flammable

Atmospheres

UL Underwriters Laboratories Inc.

FM Factory Mutual Research Corporation

SLD Single Line Diagram

VFD Variable Frequency drive

HMI Human Machine Interface

HPMV High Pressure Mercury Vapour

In the event of conflict between codes being used, the most stringent one shall be

followed.

4.0 GENERAL REQUIREMENTS

4.1 Well platforms do not have their own generating source of electrical power to meet the

requirements of electrical drive, communication and instrumentation equipments, platform

illumination, fire and gas system etc. Well platforms shall be connected to a nearby process

platform or well platform already connected to cable for electrical power. This designbasisbroadly outlines the minimum requirements for the design, selection, sizing on the well

platforms connected to process platform by submarine power/composite cable and also the

process platform for the modification purpose .

The electrical systems on well platform shall be designed to provide safety to personnel,

equipments, safety to personnel, equipments, reliability of service, minimal fire risk, ease of

maintenance, remote operation of electrical breakers, automatic protection of all electrical

equipment through selective relaying system, adequate provision for future expansion and

modification, fail safe features.

4.2 Site Conditions

All electrical equipment and accessories / material shall be suitable for installation and

operation under extremely saline, humid, corrosive and hostile marine environment with

specified degree of hazard.

In general, all outdoor electrical equipment shall be designed for 40 deg C temperature

and maximum 90% relative humidity while the indoor equipment shall be designed for 45

deg C and maximum relative humidity of 90%.


8/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 8


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

4.3 Fire Integrity

All cable penetrations through firewalls, switchgear room walls and between safe and

hazardous area shall be sealed using Multi Cable Transits to maintain fire integrity of the

system and prevent gas migration. Multi Cable Transit shall be fitted where cables pass

through:

a) Decks and walls to open air

b) Fire walls

c) From safe to hazardous area

Such cable transit frames shall be designed to include 25% spare capacity for future use .

Cable transit frames are to be supplied with test certificates from an accredited

independent test authority to confirm a fire and blast adequate for the deck or wall in

which they are to be installed.

4.4 Design Life

The electrical system including CP System shall be designed for reliable and trouble freeperformance for 25 years of design life.

4.5 Material, Workmanship & Suitability

All material to be used in the construction of electrical equipment, cables, mounting and

fastening devices, etc., shall be of latest specifications, new and in manufacturers current

production. Should any material proves unsatisfactory it is to be rejected notwithstanding

any previous satisfactory examination on test of similar material or of equipment.

4.6 Units and Information

All quantities shall be expressed in SI / metric units. All information, manuals,

certificates, data and inscriptions shall be in English language.


9/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 9


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

5.0 ELECTRICAL SYSTEM DESIGN

5.1 Electrical Loads

5.1.1 Utilization Category

Loads shall be divided into following three classes according to usage.

Continuous - Loads which draw power at continuous rate.

Intermittent - Loads which draw power for a fraction of time given by the duty

cycle of the load.

Standby - Loads which are connected with power supply and ready to act as

and when required.

5.1.2 Load Assessment

An electrical load list shall be developed by contractor based on estimated load as

identified in mechanical equipment list and the electrical loads envisaged. This data shall

be used to design the capacity of the power transformers and the switchgear configuration.

In evaluating load summary, utilization category is applied as follows:

a) Continuously operating equipment- 100% of operating load

b) Intermittent load - 50% of the total intermittent load or the largest

intermittent load, whichever is greater

c) Standby equipment - 10% of total standby load or largest standby

load, whichever is greater

d) Margin for future load growth - 10% of sum of (a), (b), (c) above

The total load shall be sum of (a), (b), (c) and (d)

5.2 Generation and Utilization Voltage Levels

5.2.1 Voltage Level Classification

a) Low Voltage (LV) - Up to 1000 Volts

b) High Voltage (HV) - Above 1 KV and up to 33 KV


10/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 10


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

5.2.2 Generation Voltage Level

The generation voltage on a process platform in ICP is 6.6 KV and in MSP 11KV.

5.2.3 Utilization Voltage Levels (Nominal)

Sl.No Voltage Description

a) 6.6 / 11KV AC, 3 , 50 Hz For motors rated 150 KW and above

b) 440 V AC, 3 , 50 Hz For motors rated at 0.37 KW up to 150KW,

Pressurization and ventilation system,

battery chargers, Heat tracing, etc.

c) 250 V AC, 1 , 50 Hz For motors rated below 0.37 KW, Anti-

condensation space heaters, Convenience

outlets, etc.

d) 240 V AC, Phase to Phase Platform Illumination System (Normal

Lighting)

d) 110 V DC, 2 wire Critical lighting, Switchgear Controls,

Telephone System etc.

e) 24 V DC, 2 wire Instrument supply, Fire & Gas detection

system, Video Monitoring (CCTV) system,

Communication system, etc.

f) 12 V DC, 2 wire Navigational Aids system

5.3 Calculation Methods

5.3.1 Faults levels

As part of detailed engineering, initial fault current calculation shall be carried out based

on typical vendor data for machine parameters, cable parameters of the sub-sea cables,

taking account of design tolerances. However, minimum fault current of HV bus bar shall

be 25 KA for 1 sec. The calculations should identify the maximum expected values of

switchgear making and breaking fault currents. Calculations are to be done as per IEC

60909. Switchgear are to be designed such that actual fault levels are at least 20% below

the switchgear ratings, considering transient, fault break, fault make and peak fault levels.


11/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 11


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

Calculations shall be checked by:

a) Preliminary hand calculations to test the order of magnitude of results

b) Computer modeling of the power system using internationally recognized software

Final calculations shall incorporate actual equipment data.

5.3.2 Cable Sizing

During the detailed engineering, all power and control cables shall be identified and sized

according to the requirement of Indian and International standards. All main power cables

on the platform, including feeders to switchboards and MCCs, tie cables between

switchboards and all HV motor cables shall be individually calculated and sized.

The sizing calculations shall take into account the following design criteria:

Connected load

Current carrying capacity

Voltage drop

Short circuit temperature rise for HV and main feeder cables. Laying conditions

Wherever possible, power cables and control cables should be run separately or with

adequate spacing.

Conductor current rating shall be established on the basis of 125% of design load current

at an ambient temperature of 40oC and de-rated for grouping and method of installation.

The voltage rating of cables shall be as per the standard international practice for the

utilization voltages defined.


12/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 12


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

5.3.3 Voltage Drop

a) The maximum allowable voltage drop in any feederload on the same platformunder

steady state condition is to be maintained as follows:

Description Allowable Voltage drop

Motors 3%

Switch Boards / Distribution

Boards, Lighting / Power Panels

1%

Lighting Points 2%

DC System 3%

b) The voltage available at motor terminals during start-up shall be sufficient to ensure

positive starting and acceleration to full speed by the motor (even in fully loaded

condition of motor, if required) without causing any damage to the motor. However,under no circumstances, the voltage at motor terminals during starting is allowed to

fall below 80% of the nominal voltage.

5.3.4 Lighting Levels

Lighting levels shall be designed to meet Indian standards supplemented by the

requirements of API RP 14F and shall include a further 10% design allowance to cover

lamp deterioration and dirt accumulation on the fixture lens over a period of time.

The minimum illumination levels recommended by IES (illumination Engineering

Society) as per API-RP-14F, is as tabulated below:

Area Minimum Lighting level

for Normal Lighting (Lux)

Staircase/ Walkways 20

Open deck area 50

Open process area 50

Electrical Switchgear room/

battery Room/ VFD room 300


13/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 13


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

AreaMinimum Lighting level

for Critical Lighting (Lux)

Staircase/ Walkways 20

Open deck area 5

Electrical Switchgear room/

battery Room/ VFD room50

5.4 Earthing

Power System earthing shall be as given below:

LV (AC) - Neutral solidly grounded

HV (AC) - Neutral grounded through low resistance

Plant earthing shall be as per API-RP-14F. Double earthing (two independent earth

connections to earth grid) for all electrical equipments shall be used. Double earth bonding

shall be required for all metal equipments and structures. However, the lighting fixtures

shall be wired with 3 core cables (2 phases and earth). Where cables are not used,separate earthing wire of same size as phase and neutral shall be run for earthing the

lighting fixtures.

The minimum size of earth bonding conductors on local control station enclosures shall be

6 mm2. The minimum size of earth conductors for electrical panels shall be 16 mm2.

Vessels, tanks, and mechanical packages not directly welded to the structure shall be

bonded to structural earth pad or boss using at least two independent 70 mm2 conductors.

Items such as pipes and duct work that have insulating material (i.e. gasket) betweenconnected sections shall be made electrically continuous by bonding with a 6 mm2

earthing cable or equivalent earthing strip.

All electrical panels shall be provided with a tinned copper earth bar.

5.5 Plant Layout

Switchgear room shall be located in safe, non-hazardous and well-ventilated area.

Ventilation and pressurization system as described in the basic bid work shall be provided

in these switchgear rooms. All electrical equipment in the switchgear room shall be

designed considering inadequate ventilation in the room.


14/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 14


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

All batteries shall be located in battery room. The battery room shall be located in safe

area. Batteries shall be designed considering inadequate ventilation in the room.

The Contractor shall install electrical equipments only in approved locations, with due

consideration of the following:

Lighting fixtures shall be fitted so that they can be serviced and removed by a single

person.

Cables and cable ladders shall not be fixed to gratings or handrails.

Cables shall be properly tied in FRP cable trays at 600/800 mm interval.

Stainless steel tags shall be provided at each bend, near terminations and while passing

through wall/MCTs or one deck to another.

Cable tray height must be minimum 2.5 meters for safety and convenience.

The minimum clearance between electrical equipment or between other items and

electrical equipment shall be as tabulated below:

SI

No.

Description Clearance

A Floor Mounted Equipment

1 Front clearance for HV, Switchboards 2000 mm

2 Front clearance for all other switchboards / panels 1500 mm

3 Rear clearance for panels having only front access Maximum 50 mm

4 Rear clearance for panels 1000 mm

5 Side clearance between two switchboards (but not less

twice the width of each panel)

1500 mm

6 Side clearance between switchboard and nearest

obstruction

1500 mm

7 All around clearance for transformers 1000 mm

B Wall Mounted Equipment

1 Front clearance 1000 mm


15/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 15


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

C Battery Bank

1 Battery rack to wall clearance for following arrangements:

1.1 Single row, single/double tier 100 mm

1.2 Double row, single tier 100 mm

1.3 Double row, double tier 750 mm

2 Rack to rack front clearance 750 mm

3 Rack to rack side clearance < 150 or >

750mm

D General

1 Head room clearance for all above equipments excepting

transformer

800 mm

2 Head room clearance for transformer in transformer room 2000 mm

6.0 POWER SYSTEM

6.1 Main Power

6.1.1 Main Power requirement for the platform shall be sourced from process platform to well

platform by submarine composite cable. Power transmission shall be at 6.6 / 11 KV. This

shall be stepped down by two identical HV/440 V 3 phase cast resin copper wound indoor

distribution transformers. Each transformer shall be designed to supply the whole

electrical power of the well platform independently with of 10% for future load growth.

However, minimum power rating of each transformer shall be 100 KVA. The transformers

shall be complete with all accessories, marshalling box, off load tap changer (OLTC). The

OLTC shall be able to compensate for voltage variations in all conditions ranging fromfull load to no load. The Transformer tapping shall be of range 5% in 2.5% steps in RS

15 & RS 16 platform and 10% in 2.5% steps in RS 17 platform.

6.1.2 The project specific requirements are as follows

6.6 KV, 3 core 400 sq.mm with 24 Core fiber optic composite cable shall be connected

from ICP process platform to unmanned SMART well platform RS17.

11 KV, 3 core 70 sq.mm with 24 Core fiber optic composite cable shall be connected from

MSP process platform to unmanned SMART well platform RS16.


16/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 16


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

11 KV, 3 core 50 sq.mm with 24 Core fiber optic composite cable shall be connected from

unmanned SMART well platform RS16 to unmanned SMART well platform RS15.

6.1.3 The Transformer shall be connected to 440V, 50 Hz, 3 phase & neutral LV switchboard

with two incoming, one bus coupler and required number of outgoing circuits.

6.1.4 A parallel redundant 24 V DC Battery Charger system for Video Monitoring System

(CCTV) / platform surveillance system, instrumentation loads and communication with

Ni- Cd battery banks with a backup time of 24 hrs shall be provided.

6.1.5 A parallel redundant 110V DC Battery charger system for Switchgear control, Telephone

system & Critical Lighting with back up of 24 hrs shall be provided.

6.1.6 A parallel redundant for 12 V DC Nav-aid system (considering an operation of 14 hrs/ day

with 7 days backup) shall be provided.

6.1.7 Two nos. Lighting Transformer with 440 V/ 240 V phase to phase shall be provided and

connected to a lighting distribution board for lighting purpose.

6.1.8 Small Power and Space Heaters Distribution panel shall be fed from LV switchgear and

shall be 440 V 3phase 4 wire 50 Hz.

6.2 ESP Power

A separate switchgear room having pressurization and ventilation system with space

requirements for future transformers and VFD panels for supply to ESP in RS17 well

platform, shall be considered.

6.3 Critical Power

Critical supply for the platform shall be met by various DC Systems to be provided on the

platform.

6.4 Power Distribution System

Overall power distribution of the platform shall generally be as per the indicative power

distribution scheme described in the scope of work. The power distribution system for RS

15, RS16 & RS17 platform shall be as per Overall Single Line Diagrams COWGD725-75-

1-RS15-1001, COWGD725-75-RS16-1001 and COWGD725-75-1-RS17-1001.


17/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 17


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

6.5 D.C. System

6.5.1 Separate battery banks with battery chargers shall be provided at RS15, RS16 & RS17

platform for 110V, 24V and 12V DC System to meet the DC power requirement. All

battery banks shall have 10% spare capacity to meet future load growth requirements. The

DC systems where 2 nos of Battery chargers are provided shall be of dual redundant

configuration.

6.5.2 DC power system for communication and instrumentation loads such as telemetry &data

transmission system, video monitoring system, gas detection, well shutdown control, well

testing , critical lighting, Telephone system, Switch gear controls,etc., consisting of Ni-Cd

batteries with battery rack, battery chargers shall be designed as per FS 4023. Back up

time for this system shall be 24 hours.

6.5.3 The navigational aid along with associated Ni-Cd Batteries with battery rack, battery

charger shall be provided on the platform as per FS 4023. Battery for Navigational Aids

shall have backup time of 7 days

6.5.4 The video monitoring system shall be designed as per specification. The video data shallbe sent to process platform through fiber optic cables as described elsewhere in the bid

package.

7.0 SPECIFIC REQUIREMENTS FOR EQUIPMENT AND ASSOCIATED COMPONENTS

7.1 Corrosion

For outdoor locations, corrosion resistant material shall be considered for electrical

equipment. As a minimum material / equipment requirements shall be as follows:

Cable ladders and trays shall be of fiberglass reinforced plastic and UV protected.

Explosion proof junction boxes, light fittings, control stations, etc., shall be

manufactured from cast stainless steel or copper-free aluminum with an epoxy finish.

Cable glands shall be nickel plated brass or equivalent.

All electrical panels shall be epoxy coated.


18/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 18


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

7.2 Degree of Protection

The degree of protection against dust and water ingress, necessary for individual electrical

items will be determined by the equipment duty, its environment, its location and the

hazardous area classification. The equipment located outside or those subject to deluge

from fire water system shall be of weather proof construction and protected against the

most adverse conditions that are anticipated. These enclosures are to be classified to IP-56

as a minimum degree of protection, increased as necessary where the location/situation

demands. Indoor equipment will be a minimum of IP-42 protection and accessible

equipment within enclosures will be a minimum of IP-20 degree of protection. Where

indoor has specific ventilation requirement lower ingress protection rating may be

considered subject to approval by the company. The degree of protection for Transformer

indoor shall be IP 23 and for outdoor IP45.

7.3 Hazardous Area Classification and Equipment Requirements

7.3.1 The hazardous areas Classification shall be in accordance with API-RP-500 (1997)

Contractor needs to follow any one standard throughout the project.

7.3.2 Hazardous area classification drawings of the platform shall be prepared by the Contractor.

All equipments on the platform shall be designed for the respective area in which it shall be

installed as shown in the approved area classification drawing.

Selection of Electrical Equipment shall be done

a) As per Section 4 of API RP 14 F if area classification is as per API-RP-500.

b) As per API RP 14FZ / IEC 60079-14 if area classification is done as per IEC 60079-10.

c) Increased safety (Ex e) equipment shall not be used in class 1 Division 1 or Zone 1

areas.

7.3.3 All the equipment selected for use in Hazardous area shall have surface temperature limited

to 200C (T3). All equipment meant to be used in hazardous area shall be certified by

BASEEFA, UL, FM, CMRI or an internationally Recognized Certification Agency for the

area and service in which they could be used.

7.3.4 Outdoor equipment which are required to be powered during an emergency shall be suitable

for Class1 Division 1 or Zone - 1 irrespective of their location.


19/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 19


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

7.4 Allowance for future / spare capacity:

In general a spare capacity of 20% shall be provided in switchboards and distribution

boards.

7.5 LV Switchgear

Feeders for 400 ampere rating or more shall be provided with ACBs. Feeders for more

than 63 ampere rating and up to 400 ampere rating shall be provided with MCCBs.Feeders up to 63 ampere rating shall be provided with MCBs. However, all motor feeders

below 63 amps shall have only MCCBs regardless of ampere rating. Bus bar and isolating

devices shall be rated at 125% of design load. Bus bars are generally identified as R, Y &

B with phase colored as red, Yellow and blue. All the switchgears shall be industrial

grade equipment installed in freestanding sheet metal cubicles of modular design.

Protection relays for main incomer circuit breakers shall be intelligent relays with serial

communication to the process platform. It shall be possible to remotely operate and

control the main incomers from process platform.

Electrical Switchgear shall be installed in non air conditioned room and hence shall bedesigned for high humid and corrosive atmosphere. The panels shall be EPOXY painted.

7.6 HV Switchgear:

6.6/11 KV, 50 Hz, 3 phase, sheet steel enclosed floor, mounted switchboard as per

functional specifications shall be installed. All HV switchboards shall be complete with

VCB/SF6 Circuit breakers, intelligent numerical relays, meters, components etc. for

power distribution to various switchboards / panels etc. All feeder panels shall be digitally

communicable. It shall be possible to remotely operate the circuit breakers from the

associated process platform. Communication interface for this is described in the basic

bid work. All protection relays shall be numerical relays capable of communicating

digitally with network equipment (network switches). For details, refer to basic bid work

of communication and Instrumentation lt. shall be possible to reset and configure all

relays remotely through this digital communication interface from the process platform.

All upstream and downstream relays shall be properly coordinated so that faults are

discriminated. A well designed relay co- ordination scheme shall be implemented as per

international standards for proper discrimination of fault. The protection schemes shall be

approved by ONGC before procurement of any related items. The panels shall be EPOXY

painted.


20/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 20


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

7.7 HMI

A communication and control network along with an HMI system between the Process

platform and well platform through fiber optic shall be designed and Installed by the

contractor. The detailed network architecture shall be designed by the contractor and the

same shall be got approved from ONGC before procuring of the items.

The following functionalities are envisaged as minimum.

It shall be possible to open, close all HV and main incoming LV breakers at the well

platform remotely from the process platform.

It shall also be possible to monitor breaker status (such as opened / closed / trip) from

the process platform for all HV feeders and incoming LV feeders.

lt shall be possible to monitor and configure the relays of HV and main incoming L V

breakers at the Well platform remotely from the process platform.

lt shall be possible to monitor voltage, current, power factor, power and energy

consumption for the main incoming HV feeder remotely from the process platform.

It shall be possible to monitor trip circuit healthy and DC failure for HV Switchgear

and incomers of LV Switchgear.

In addition, the following functions of well platform shall also be monitored from process

platform

Video monitoring system

Monitoring and control Pressurisation and ventilation system of all platforms

Monitoring and control of ESP system for RS17 Well platform.

o ESP controls: Pump start, stop (normal), speed raise/lower, emergency stop,

fault reset.

o ESP indications: Motor current, Motor frequency, Drive ready to run & Drive

running, Drive alarm, Fault / Drive tripped, Pump alarm and pump tripped.

The monitoring and controlling system shall have 20 % spare capacity for future addition

of feeders. This HMI shall be located at process platform. Laptop for trouble shooting at

well platform shall be provided.

7.8 Power Transformers

7.8.1 The main LV switchgear is supplied from two transformers enabling either transformer to

accept the entire LV load. The transformers shall be sized, using the natural air-cooled

rating. Each shall be rated for 110% of the predicted distribution design load.

Transformers shall normally be Dy connected, natural air cooled, cast resin dry type


21/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 21


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

vector group Dyn-11. Minimum power rating of each transformer shall be 11 KV or 6.6

KV /440 V, 100 KVA.

7.8.2 The power transformers shall be located in a transformer room in RS15, RS16, RS17 with

suitable ventilation (Grilled rolling shutter shall be provided). However in RS17 the VFD

transformers for ESP shall be located in a completely enclosed room with pressurization

and ventilation.

7.8.3 Two lighting transformer of 3-phase, 440 V /240 V AC 50Hz, AN, Dy11, cast resin dry

type shall also be provided upstream of Lighting, and shall be located in the Switchgear

room with pressurization and ventilation.

7.9 Electric Motors

Continuous output rating of motors shall be at least 110% of the maximum shaft KW

demand of the driven equipment.

7.9.1 LV Motor

All LV motors shall be totally enclosed fan cooled (TEFC) motors with class F insulation,

temperature rise limited to class B. Selection of motors for Hazardous area shall be as per

section 7.3 above (Hazardous area requirements).

Any motor rated 75 kW and above, shall be fitted with positive temperature co-efficient

thermistors. If motors are used with variable speed drives, they shall also be fitted with

positive temperature coefficient thermistors. Motors rated 3.7 KW or above are to be

fitted with anti-consideration space heaters which will be energized when the motor is not

running.

7.10 Lighting

7.10.1 The lighting fixture shall be as per area classification. Lighting system shall consist of

normal lighting and critical lighting. Critical lighting shall have backup of 24 hours.

7.10.2 Voltage level shall be 240 V AC line to line for normal lighting and 110 V DC for critical

lighting. Power for the lighting shall be drawn through two lighting transformer

(secondary voltage is 240 V between lines) installed in the switchgear room (refer 7.8.3

above). Each lighting transformer shall be rated to supply the complete lighting power

independently.


22/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 22


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

7.10.3 Normal and critical lighting system for Electrical/ Instrumentation room, Battery room,

bunk house, pig launching/receiving area shall be provided. Lighting levels shall be

designed to meet Indian standards supplemented by the requirements of API RP 14 F and

shall include a further 10% design allowance to cover lamp deterioration and dirt

accumulation on the fixture lens over a period of time.

7.10.4 Critical lighting shall provide a minimum horizontal level of illumination as per API RP

14 F (standby lighting). Critical lights shall be fed through the chargers. All Critical

lighting fixtures shall be suitable for class1 Division 1 Gas Group D Temp class T3 (as per

API RP 500) or for Zone 1, Gas Group IIA and IIB, Temp Class T3 (as per IEC 60079-10)

7.10.5 Type of lighting fixtures shall be restricted to minimum and shall preferably be supplied

from one vendor. Lighting fixtures shall not be based over rotating equipment. Indoor non

hazardous area shall be provided with industrial fluorescent luminaries. External areas of

platform shall be provided with fluorescent luminaries suitable for the area classified but

as a minimum shall be for class 1 division 2. Critical lighting shall be provided by 100 W

Incandescent Well glass lighting fixtures. Ingress rating of these fittings shall be

minimum IP 56.

7.10.6 Total 6 Nos flood lights (flame proof HPMV of minimum 400 W) shall be provided in

Main deck (2 Nos), cellar deck (2 Nos) and boat landing (2 Nos). Proper access platforms

with vertical caged ladders shall be provided for the same.

7.11 Protection Equipment

7.11.1 Transformer Protection

The following protections shall be provided for transformers as a minimum.

Earth fault and Over current protection

Over temperature protection

7.11.2 Motor Protection

LV motor starters incorporate the following protective devices:

MCCB for short circuit

Single phasing prevention

Earth fault protection for motors above 37.5 KW

Overload


23/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 23


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

7.11.3 LV Feeders

ACBs/ MCCBs used for LV feeders shall have short circuit and over load protective

devices. MCCBs / MCBs used for DC incomer feeders and DC distribution feeders are to

be provided with short circuit and overload protections as a minimum.

7.12 Socket Outlets

7.12.1 Two types of socket outlets are provided on the platform.

440 V, 50Hz, 3 wire plus earth 63 amp, 4 pin for welding sets

250 V, 50Hz, 2 wire plus earth, 15 A, 3 pin

They shall generally be industrial type, metal clad and surface mounted construction,

however, the sockets provided in control rooms and building areas shall be decorative

type. These outlets provided outdoors shall be as per clause 7.3. The number of socket

outlet for 15 Amp shall be such that at least one outlet is available for every 15 meters

distance. 63 Amps welding outlets shall be such that any point on the platform can be

reached using a 50 meters cable. Socket outlets shall be provided with earth leakage

protection, 30mA for 250 V, outlets and 300mA for 440 V, welding outlets via dedicateddistribution board.

7.12.2 250 V socket outlets shall be considered indoor and not for outdoor areas for the well

platforms and the indoor sockets shall be connected from a dedicated distribution board.

The 440 V socket outlet shall be considered only for outdoor and shall be fed from the LV

Switchgear.

7.13 Junction Boxes and Start/Stop Control stations (Push button stations)

Junction boxes and Start/Stop Control stations shall be provided as per clause 7.3 and

fabricated from the following material.

SS-316

Epoxy coated copper free aluminum

They shall be suitable for service during the entire life of the platform.

The cable entry glands are nickel plated brass material and of double compression type

with Ex (d) protection.


24/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 24


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

7.14 Cables

Cable shall be heat and oil resistant, flame retardant (HOFR) type suitable for service in

environmental conditions described for the platform. All (normal and emergency) cables

have flame retardant characteristics to IEC 60332-3 category A.

Cables for safety systems like critical lighting system, navigational aids, F&G system and

Communication system shall be fire resistant type to the requirement of IEC 60331.

Cable joints via cast resin kit or other type are not permitted on the offshore installations.

Special care shall be taken to the routing and separation of cables to minimize the effect of

fire on emergency and essential supplies and production operations.

All cables are identified with SS316 Tags.

In addition, the minimum distance between power/control wiring and electronic signal

wiring on prolonged cable route will be as follows:

Power / Control Cable Minimum distance from electronic /

signal cable

Up to 125 V 150 mm

Up to 300 V 150 mm

Up to 1000 V 300 mm

Above 1000 V 450 mm

7.15 Earth Conductor

Earth cable shall be 6 mm2, 16 mm2, 70 mm2, or 240 mm2, stranded copper conductor with

CSP or EVA insulated with green / yellow insulation sheath.(Also refer section 5.4)

7.16 Cable support System

The cable system comprises cable installed on cable tray or ladder with 25% spare

capacity for future extension.

HV cables shall be installed on dedicated trays/ladders.


25/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 25


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

Intrinsically safe circuit cables shall be separated from other cables by 50 mm spacing or

metallic barrier.

Cable straps or ties shall be of SS-316.

7.17 Cable Tray/Ladder

Fourprimary cable tray / ladder system shall be installed on the platform wherever

possible. However, in case of space restriction low voltage power and control cable shall

be considered in the same tray with adequate spacing.

High voltage

Low voltage power

Control cable

Instrumentation, communication and ESD

The cable trays / ladders shall be heavy duty type capable of being loaded to 120 kg/m

with 6 m support spans to NEMA 20B. Cable ladders/trays are to be manufactured from

FRP material with UV protection features.

Cable ladders are fitted with removable, ventilated covers where there is exposure to

chemical spillage, falling object or direct sunlight. The covers are suitable for cyclone /

monsoon conditions.

Cable trays shall be installed in accordance with manufacturers recommendations and

specifically supported each elbow. The overhead cable trays shall be installed a minimum

of 2.5 meter above deck.

7.18 Cable Glands

Suitable size double compression type glands shall be supplied for all cables. For entries

into Ex (d) enclosures, barrier type (or compound filled) glands shall be provided. All

cable glands and adaptors will be made up of nickel plated brass and shall be fitted with

soft sealing nylon washer. Fiber washers shall not be used. Lock nuts shall be used for

entry into sheet steel boxes and enclosures. Cable termination shall be made with Tinned-

copper lugs.

Industrial cable glands are not used on offshore platforms. All cable glands are to be type

tested and certified of use in specified hazardous area.


26/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 26


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

7.19 Cathodic Protection

Cathodic Protection for Structures and J-tubes shall be designed in accordance with the

functional specifications enclosed in the bid package.

7.20 Navigational Aids

4 Nos. Nav-aid lanterns (1 at each corner of the platform) shall be provided in each well

platform.

The Navigational Aids and its Junction box shall be suitable for a hazardous area of Class

1 Division 2.

7.21 Video Monitoring system

Four new cameras shall be located in each well platform and shall be integrated to the new

console located in the existing process platform through the fibre optic cable.

7.22 Electrical Heat Tracing for RS15 & RS16

7.22.1 The process and piping documents specify the operating temperature range for each

piping. For electrical heat tracing design/calculations, the maximum operating temperature

specified shall be considered as maintenance temperature i.e. for operating temperature

35- 75C, maintenance temperature shall be 75C.

7.22.2 The minimum temperature for heat tracing design/calculations shall be considered as

30C as per process requirement.

7.22.3 Hot insulation compatible with the electrical tracing shall be used. Insulation details i.e.

type of insulation and thickness shall be as indicated in the piping documents.

7.22.4 The fluid data to be considered for heat tracing design shall be as per the Process input.

7.22.5 Thermostats shall have adjustable settings and shall be mounted at accessible

positions/places. Heat tracing system shall be designed in such a way that the temperature

of pipeline at any stage shall not exceed the temperature indicated in the Process

documents.

7.22.6 The tracer for instruments, valves, flanges and vessels shall be provided with adequate

looping of heat tracer tape, in order to facilitate removal of heater tracer tape for

maintenance.

7.22.7 The heat tracer and accessories shall be certified for use in Class 1, Division 2, Gas Group

D (Zone 2 Gas Group IIA, IIB) Temperature Class T3 hazardous area.


27/39


28/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 28


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

Functional specifications and electrical design basis in respect of each individual

equipment

Applicable Standards, Codes & Recommended Practice

Reliable & trouble free performance for 25 years of design life

Safety

General Operating / Site conditions

Hazardous area classification

Suitability for the specified requirement for use in outside pressurized rooms and

inside pressurized rooms

Suitability for the corrosive effects of the saline and humid marine atmosphere,

galvanic action, etc.

9.0 ELECTRICAL EQUIPMENT CALCULATIONS

Certified calculations, as listed below, for electrical equipments of well head platform in

respect of size / rating / power / capacity, etc., are to be provided by the contractor for

approval of ONGC during Detailed Engineering:

Transformers (Load List)

Electric Motors (SLD, Load list)

Switchgear and control gear(SLD)

Power and control cable (Cable sizing)

MCTs (MCT schedule)

Area lighting fixtures (Lighting Calculation)

Cable trays (Cable tray layout)

Battery & Battery Charges for various system (by Battery system Vendor)

Earthing cable/conductor (Legend and Notes for Earthing)

Lighting transformer (Load list)

Cathodic protection system (by CP system Package Vendor)

These calculations form part of the relevant Purchase Specification to be submitted during

detailed engineering.

10.0 REVIEW AND APPROVAL

All Purchase Specifications along with list of deviations calculation sheets, offers of the

vendor and all relevant documents are to be furnished for ONGCs approval during

detailed engineering. Contractor is advised not to place order for purchase of any item

without obtaining prior approval from ONGC in writing.


29/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 29


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

Contractor prepares and furnishes the list of all drawings / documents enlisted in the bid

document for document for ONGCs review. The category of drawings / documents (i.e.

whether to be reviewed / approved by ONGC is generally decided in consultation with

contractor and ONGCs consultant after award of Contract.

All vendor drawings are to be submitted for ONGCs review after the contractors

engineering consultant approves them.

11.0 TAGGING AND NAMEPLATES

All equipment (Motors, push buttons, motor control centers, push button stations, pull

boxes etc.) are provided with SS tag or nameplate of a permanent type with identification

number and service description.

The Contractor assigns individual tag numbers in accordance with ONGCs established

system to all electrical equipment. The tag number that pertains to a electrical equipment

appears invariably on all drawings and documents.

Nameplates and identification tags are to be provided to properly identify each equipmentand / or their component.

All panel electrical equipment nameplates are to be made up of white laminated plastic

plates with black engraved lettering and securely fastened with SS-316 screws.

All front panel mounted equipment are to be identified with a metal or plastic nameplate

attached to the rear of the device and easily device and easily visible via the rear access

doors.

All wiring, power and control cables, junction boxes and auxiliary equipment are to be

suitably identified as per applicable codes and practices. Plastic adhesive tapes are notused for identification. All wirings are to be tagged with slip on or clip on wire marker at

both ends with the wire number specified on the drawing.

12.0 ELECTRICAL EQUIPMENT INSPECTION & TESTING PHILOSOPHY

The contractors quality plan includes a comprehensive fully documented inspection and

testing plan specific to the project and it is to be submitted to ONGC for review and

approval. The inspection procedures include inspection specifically for compliance with

hazardous area requirements. The Contractor is also required to provide suitable

workshop, equipment and all necessary tests for electrical equipment.


30/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 30


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

ONGC reserves the right to reject any or all test work, if found unsatisfactory/not up to the

mark.

In addition to yard testing of loop checking and setting for safety devices like overload

relays etc. and simulation testing of all interlock and shutdown systems, they are required

to be carried out in offshore also.

All testing and pre-commissioning activities are required to be done by the Contractor.

The Contractor is also required to provide assistance for ONGCs commissioning

activities.

The Contractor is required to provide written results of all above tests, it so required by

ONGC. Also, the contractor is required to furnish reasonable evidence of the satisfactory

condition of test equipments.

13.0 ELECTRICAL EQUIPMENT SPARES PHILOSOPHY

For all major equipment, the Contractor is required to include normal commissioning

spares as a part of the equipment. The Contractor is also required to furnish separately,list of recommended spares for two years trouble free operation along with the prices for

purchasers review.

The spares requirement of individual systems shall be as per the relevant functional

specification.

14.0 TRANSPORT AND SHIPMENT

All electrical equipment, cables and trays etc. are required to be securely anchored to the

skid. All equipments that could be damaged in shipment shall be removed, tagged and

crated in weather proof box. Weather proof box shall protect the equipment from dynamicforces.

All openings, flange thread connections and cables exposed as a result of cable removal

are required to be protected in a manner to prevent damage during shipment.

15.0 WARRANTY

All equipments and systems supplied by the contractor / his vendor is required to perform

satisfactorily and meeting all criteria as per specification. The warranty / guarantee from

the contractors side to this effect shall be governed by the warranty / guarantee clause


31/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 31


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

mentioned in the general terms and conditions of contract and special conditions of

contract.

16.0 DOCUMENTATION

The contractor shall provide hard copies plus electronic copies on CD for all the

documents.

16.1 Equipment Documentation

The contractor shall provide the following documents as a minimum:

Engineering, Design and calculation books

Operating philosophy of the system and proposed maintenance schedule of all major

components, for the design life of the system including replacement requirements of

parts

Specifications, test certificates and data sheets for all items

Deviation schedule for items if any

Anode location drawings

Single line diagram, schematic diagram and functional wiring diagram of LV

Switchgear and all DC panels

Bill of materials

Cable and tray routing drawings and cable schedule

Earthing layout

Lighting fixtures and obstruction light layout drawings

Interconnection and hook up drawings

MCT frame drawing

Equipment layout drawing in electric room and as build drawings

Battery / Battery rack layout

Minimum 3 (three) sets of Dossier shall be provided to the Company.

The contractor shall be responsible for the authenticity of the drawings & data provided by

the vendor as well as sub-vendor(s).

Each vendor data items requested above must be identified by the Purchase Order number

and equipment tag number located on the cover sheet or first page of said item and in the

case of engineering drawings on each and every drawing.


32/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 32


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

Any additional data/drawings required, as a result of issuing supplements to a purchase

order or during detailed engineering, shall be furnished by Vendor and handled in the

same manner as the original order.

All drawings and literatures shall be in English language and in the Metric Measurement

System.

The reproducible drawings, 279mm x 432mm (11 x 17) size and full size are to be of

such quality that clear legible prints can be made.

16.2 Electrical Equipment Index

The contractor shall provide an electrical equipment Index.

The index shall include the information listed below:

Electrical Tag Number

Service Description

Rating/type

Electrical drawing (single line, schematic and wiring Drawing)

Data Sheet Number

The electrical index shall form the basis for documenting all electrical drawing and shall

be listed in alphanumeric order of electrical tag number and shall contain all relevant

information for each electrical item. The index shall be based on Microsoft Access.

16.3 Electrical Equipment Data Sheet

A duly data sheet shall be provided by contractor for every item of electrical equipment,

including those which are part of packaged plant. The data sheet shall include but notlimited to the following:

Manufacturer name

Model/type

Standard and code reference

Electrical parameter details

Construction materials details

Performance details

Mechanical/physical details

General arrangement drawing showing electrical equipment and details of interface


33/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 33


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

Test certificate

Hazardous area classification and certificate details (type of protection, certifying

authority)

17.0 MODIFICATIONS

In addition to the above the following shall also be applicable for modification in Process

Platform.

17.1 General Requirements

The offshore platforms generally have their own generating source of electrical power to

meet the requirements of process utilities and other electrical drives, living quarters,

platform illumination system, communication and annunciation system, fire and gas etc.

17.1.1 General Safety

The electrical system shall employ safety margins to ensure that platform is safe under all

operating conditions, including those associated with the start up and shutdown ofequipment and throughout intervening shutdown periods. The emphasis in equipment

selection is on operability, prevention of accident / fault and functionality for the intended

design life.

17.1.2 Evacuation

All services required for safe evacuation of the facility shall be designed to operate for

sufficient time after loss of both main and emergency power at the platform. The support

duration is in line with the risk assessment study.

17.2 Electrical loads

17.2.1 Voltage Level Classification

a) Low Voltage (LV) - Up to 1000 Volts

b) High Voltage (HV) - Above 1 KV and up to 33 KV


34/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 34


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

17.2.2 Generation Voltage Level

The generation voltage on a process platform is usually 6.6 KV and in some cases 11KV.

Emergency power generation is generally at 415V.

17.2.3 Utilization Voltage Levels (Nominal)

Sl.No Voltage Descriptiona) 6.6 / 11KV AC, 3 ,

50 Hz

For motors rated 150 KW and above

b) 415 V AC, 3 , 50

Hz

For motors rated at 0.37 KW up to 150KW,

battery chargers, HVAC, bulk AC loads (like

Process heaters)

c) 240 V AC, 1 , 50

Hz

For motors rated below 0.37 KW, Platform

communication system, Anti-condensation

space heaters, Convenience outlets, Platform

Illumination system ( Normal Lighting etc.,)

d) 110 V DC, 2 wire Critical lighting, Switchgear Controls, DC

motors for Emergency lube oil pumps,

compressors UCP, etc

e) 24 V DC, 2 wire Instrument supply, Fire & Gas detection

system, etc

f) 12 V DC, 2 wire Navigational Aids system

g) 110 V AC, UPS Distributed Control System, ESD, FGS

h) 240 V AC, UPS Telephone Exchange, CCTV system, Radio

system, Paging & Intercom system, Telemetry,

telecom and computer system

17.2.4 Cable Sizing

LV Motor cables shall be selected from a standard Motor Cable Selection chart. . For

branch circuits and feeders, conductor current rating shall be established on the basis of

125% of design load current at an ambient temperature of 40oC and de-rated for grouping

and method of installation. Final sub-circuits shall be sized from standard cable selection

charts based on circuit breaker rating, and voltage drop limits.


35/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 35


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

17.2.5 Lighting

The lighting system shall be designed in accordance with recommendations of

Illumination Engineering Society (IES) and to achieve minimum levels of illumination as

per API RP 14F. Power for the lighting shall drawn through a lighting transformer

(secondary voltage is 240 V single phase installed in the switchgear room.

Luminaries shall be circuited such that illumination in any area shall not be lost if one sub

circuit fails.

Type of lighting fixtures shall be restricted to minimum and shall preferably be supplied

from one vendor.

Mounting height and location of lighting fixtures shall permit ease of maintenance and

lamp replacement. Lighting fixtures shall not be located over rotating equipment.

Indoor non hazardous area shall be provided with industrial fluorescent luminaries.

External areas of platform shall be provided with fluorescent luminaries suitable for the

area classified but as a minimum should be for class 1 division 2. Ingress rating of these

fittings shall be minimum IP 56.

Floodlighting shall be provided for large and open areas such as main deck, jacket

walkways and boat landing etc. Proper access platforms with vertical caged ladders shall

be provided for the same.

Lighting for gauges shall be provided with local On/Off switch.

Lighting on the platform is divided into 4 categories, Normal lighting, Emergencylighting, Critical lighting and Special lighting. Each category is defined in the following

sections.

Normal illumination level is the total illumination provided by normal and emergency

lighting. DC lighting and Special lighting shall no be considered for this.

Critical illumination level is the total illumination provided by DC lighting only.

Emergency lighting shall not be considered for this.

All light fittings are to be secured and fastened using SS-316 fasteners and accessories.

The highest point on the platform is fitted with omni directional red obstruction light.


36/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 36


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

17.2.5.1 Normal Lighting

Normal lighting on the platform shall provide safety to operating personnel and also

ensure effective and efficient job performance.

17.2.5.2 Emergency Lighting

Emergency lighting fixtures of fluorescent type with self contained battery / inverter

having duration of ninety (90) minutes shall be located near exit points, in buildings,

near rotating equipment and other areas.

Outdoor emergency lighting shall also be provided by using similar type of fixtures as

above. Ingress protection shall be minimum of IP56.

All emergency lighting fixtures will be suitable for Class 1 Division 1/ Zone-1, Gas

Group D.

Emergency light fittings shall be in accordance with IEC 60598-2-22 and hence shall

have battery autonomy of 90 minutes after 4 years of continuous operation.

17.2.5.3 Critical Lighting

DC critical lighting fixtures shall be provided in all areas to provide safe access for

personnel evacuation points and in the control and other building areas to permit

emergency operation for safe shutdown of the platform in the event of mains failure.

Critical lighting shall provide a minimum horizontal level of illumination as per API RP

14F (standby lighting).

Critical lights shall normally be kept ON and fed through the charger and beautomatically switched over to battery banks in case of AC failure.

All critical lighting fixtures shall be suitable for class 1 Division 1 Gas Group D Temp

class T3 (as per API RP 500) or for Zone 1, Gas Group IIA and IIB, Temp class T3 (as

per IEC 60079-10).

Lighting fixtures provided in each EXIT leading to walkways and life boat stations

shall be fitted with green lens.


37/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 37


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

17.2.5.4 Special Lighting

In addition to the normal lighting, incandescent lamp AC fixtures shall be provided in

operational areas and these shall be powered by the output of a dimmer stat to vary the

voltage to the fixtures and consequently the illumination level which may be required in

a special situation. The dimmer stat shall be installed in the switchgear room and there

shall be provision to control the dimmer stat from remote. These incandescent fixtures

shall not be considered for calculations of normal lighting illumination level.

17.3 Power System

17.3.1 Main Power

Main Power requirement for the platform shall be source form one of the following:

a) Main generators installed on the new platform

b) Additional power, if available, from the existing bridge connected platform

Basic Bid Work (Electrical) enclosed in the Bid Package shall be referred for project

specified requirements.

17.3.2 Emergency Power

Emergency power requirement for the platform shall be sourced from one of the

following:

a) Emergency generator installed on the new platform

b) Additional emergency power, if available form the existing platform bridge

connected to the new platform

Basic Bid Work (Electrical) enclosed in the Bid Package shall be referred for project

specified requirements.

17.3.3 Critical Power

Critical supply for the platform shall be met by various DC Systems and UPS system to

be provided on the platform.


38/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 38


Revision No : 0


GEN-301Date : 15.04.08

LTV5062/0

17.3.4 Power Distribution System

Overall power distribution of the platform shall generally be as per the indicative power

distribution scheme enclosed with the basic bid work (Electrical).

17.3.5 Operating Philosophy

Please refer to the basic bid work (Electrical) for the operating philosophy for electricalequipment installed on the platform.

17.4 Protection Equipment

The equipment defined provides adequate safeguards against the effect of any fault

occurring on the system or component parts.

All protective devices, including relays and current transformers (CTs) etc. are to be

adequately rated to withstand the prospective short circuit current, which can flow or be

induced.

Unrestricted over current relays provided shall have IDMT characteristics of the

standardized type A, B or C in accordance with IEC 60255-4.

The relay protection devices are such that a clear indication is given of the fault which

caused at trip. Circuit breakers should not be able to re-close without first resetting the

appropriate master trip relay.

17.4.1 Modification of Existing Switchgear

The existing 11kV AC, 3Ph, 50Hz, 2200A, 50kA (1sec) HV Switchgear (M-5300 -ABB

Unigear make) Feeder number B05 in Switchgear Room at MSP Platform, spare motorfeeder shall be used to feed the new SMART Well Platforms RS-16 and RS-15.

The existing 6.6kV AC, 3Ph, 50Hz, 1200A, 40kA (1sec) HV Switchgear (201-Westing

House make) feeder number VS#10 in Switchgear Room at ICP Platform, spare motor

feeder shall be used to feed the new SMART Well Platform RS-17. For more details

please refer Pre-engineering Survey report COWGD725-30-GEN-105).


39/39


Ltd.

Project: MHS


ELECTRICAL

DESIGN BASIS

Page No : 39


Revision No : 0


GEN-301Date : 15.04.08

17.5 Navigational Aids

If the platform is bridge-connected to an existing platform, Navigation Aid System of new

platform shall be synchronized to the Navigation Aid System of the existing platform. In

this project the MSP platform is bridge-connected to existing SA platform

17.6 Video Monitoring System

The location of the CCTV system at existing process platform control room of BHS and

ICP platform shall be as per pre-engineering survey report.

17.7 Telephone System

A new telephone system in the well platform shall be interfaced with the existing

exchange in the process platform.

cowgd725 75 gen 301(design basis)rev.0

Documents