electrical design basis_rev 0

7/23/2019 Electrical Design Basis_Rev 0

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DOCUMENT No.

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ENGINEERING DESIGN BASISELECTRICAL

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0 10.02.05IOCL Comments incorporated and issued forimplementation

SA RCS AAN

A 02.11.04 Issued for clients comments/Approval SA RCS AAN

Rev.No

Date PurposePrepared

byChecked

byApproved

by

Format No. EIL 1641-1924 Rev. 1 Copyright EIL All rights

ENGINEERING DESIGN BASIS

DESIGN PHILOSOPHY5.7 ELECTRICAL

THIS DOCUMENT HAS BEEN APPROVED BY IOCL


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Format No. EIL 1641-1924 Rev. 1 Copyright EIL All rightsreserved

1.0 Site conditions

2.0 Power Source Details

3.0 Power Supply Distribution System

4.0 Protection - Metering Control

5.0 Substation Design

6.0 Equipment Design

7.0 Cabling System

8.0 Earthing System

9.0 Lighting System

10.0 Electric Heat Tracing System

11.0 Electrical Equipment For Hazardous Areas

12.0 Statutory Approval

13.0 Cable Sizes for MV Motors

14.0 Specific requirements

15.0 Attachments

16.0 Deviation to design philosophy


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The electrical design data defines the design requirements agreed by owner/clients in addition toDesign philosophy for electrical facilities no: 6-51-0099 Rev 4 (Any additional deviation must berecorded as part of this document)

1.0 SITE CONDITIONS

A. 1Equipment design temperature (IS 9676) : 45C

B. Soil Resistivity : Later (after the soil Resistivity test)

C. Minimum temperature. for battery sizing : 10C

D. per IS-1893)

E. Altitude above mean sea level :


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3.1 Voltage and frequency variation

AC System

i. Voltage : + 6 %ii. Frequency : + 3 %

B. DC System (at system output terminals)

i. Electrical Control, Lighting etc. : + 10%ii. Instrumentation Power Supplies2 : + %

3.2 Utilisation voltage and operating philosophy

A. Primary HV distribution voltage : 33KV

B. Secondary HV distribution voltage : 6.6 KV

C. Primary HV distribution system neutral earthing : Solidly earthed

D. Secondary HV distribution system Neutral : Resistance earthed

E. HV motor voltage3 : 6.6KVabove 160KW &


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H. Annunciation panel power supply6 : V AC Normal/AC UPS

V DC (No separate Pnl)

4.0 PROTECTION - METERING CONTROL

4.1 Metering for external power supply incomers7

Not applicableA. Summation metering : Yes/No

B. Trivector meter : Yes/No

4.2 Control Philosophy

A. Protection relays for HV switchgear : On Switchgear panel

B. HV Switchgear control : Local/ Remote/ ECS

C. Hard wired annunciation panel : No (Part of substation HMI)

D. Numerical Protection/Monitoring system for

i. EHV system : Yes / No (Not applicable)ii. HV Switchboard : Yes

iii. 415V PMCC/PCC : Yesiv. 415V MCC : Yes

E. Microprocessor based system for control interlocks : Yes

and monitoring of electrical power system

i. Human machine interface system-HMI : Yes Operator console : Yes

Engineering console : No, use LAP TOP instead

ii. Data concentrator for each substation (Separate for HV and MV system): Yes/ No

8

iii. Interface with higher level control system: Yes

F. Limiting Conditions for Motor start up

(e.g. starting current limitation or method of Starting)

i. HV Motors9 : 550% (No tolerance allowed)ii. MV Motors : 600% up to 75KW, 550% above

75KW

iii. Method of starting for large HV motors : Direct on line (refer foot note forF(i)

iv. Method of starting for large MV motors : Direct on line

G. Type of power isolation for remote transformers10

i. Load break switch in switchgear room : Noii. Push button in transformer bay for tripping: for all transformers

Remote breaker

6

Hard wired annunciation panel is not proposed. Annunciation will be part of substation HMI7No grid backup is envisaged as per CPP design basis.8Separate data concentrators for HV and MV are not required for same make and type of relays

9For motors greater than 2.5MW, maximum starting current shall be based on motor startup study

10 As 33KV switchboards are of rating 31.5KA and available in GIS, instead of local isolating panel, it is

suggested to provide push button station with lamp indication for trip of sending end breaker and requiresapproval with CEA for implementation.


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4.3 Relay protection system11

Protection devices for power distribution system shall be as indicated belowRelaynumber

Relay description Transformer

Feeder

Motorfeeder

Outgoing feeder Incomer

(Secondarywindingvoltage

> 3.3 KV)

(Secondarywindingvoltage

< 0.433 KV)

HV HV MVPCC/

PMCC

HV MV PCC/

PMCC

51 IDMTL over-current relay Yes Yes - Yes Yes

(4)

Yes

(13)

Yes (4)

51N IDMTL earth-fault relay Yes (7) No - Yes Yes

(4)

Yes

(13)

Yes

51G 51G backup earth-fault relay(secondary neutral)

Yes Yes - No No No No

99 Motor protection relay with lockedrotor feature

(50, 50N,46, 49, 50L/R)No No Yes No Yes (8) No No

64R Instantaneous restricted earth-faultrelay (secondary side)

Yes No - No No No No

50 Instantaneous over-current relay Yes Yes - No No No No

50N Instantaneous earth-fault relay Yes (6) Yes - No No No No

87 Differential protection relay Yes (1) No Yes (2) Yes (3) No No No

86 High speed tripping relay Yes Yes Yes Yes Yes Yes Yes

95 Trip circuit supervision relay Yes Yes Yes Yes No Yes No

63 Transformer auxiliary relay Yes Yes - No No No No

27/2 Under-voltage relay with timer - - No

(14)

- - Yes(5)

Yes (5)

25 Check synchronisation relay - - - - - Yes(9)

Yes(9)

NOTES:1. For transformers rated 5 MVA and above.2. For motors rated 1500 kW and above.3. For critical/long feeders and plant feeders connected to main power generation and

distribution bus.4. These relay functions can be substituted by inherent releases. At remote substationswhere

DC supply is not envisaged, 415V switchboard shall have inherent releases instead ofrelays.

5. Wherever auto-transfer feature is provided.6. Instantaneous earth fault 50N shall be provided only for transformer with delta primary.7. Directional IDMTL earth fault 67N shall be provided for transformer with star primary.8. For motor feeders rated 55 kW and above.9. For switchgears having bus transfer scheme, where continuous or momentary paralleling is

envisaged, check synchronising relay shall be integrated with overall paralleling scheme.10. The bus tie feeders in HV switchboards shall be provided with 51, 51N, 86 and 95 relays.

However MV bus tie shall not have any protective relays.11. HV capacitor bank feeders shall be provided with 51, 51N, 59 (over voltage), 60 (Neutral

displacement), 86 and 95 relays.12. In case of HV switchboards with parallel operation of incomers, following additional relays

shall be provided:a. One set of 87B (Bus differential) and 95 B (Bus wire supervision) for each bus

section.b. 67 and 67N (Directional IDMTL over current & earth fault) relays for the incomers.

13. The following feeders shall be provided with timers for delayed tripping on bus undervoltage while the under voltage relay shall be common for the bus

a. HV and MV capacitor feeders

11Generator protection requirement shall be covered separately in respective EPCC document.


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b. HV and MV breaker controlled motor feeders or contactor feeders with DC controlsupply.

c. One no. DC supply supervision relay (80) shall be provided for each incoming DCsupply to the switchboard.

14. One set of bus differential relays (87B) and bus wire supervision relay (95 B) for each bussection shall be provided for HV switchboards connected directly to generation buses andthose used as extension buses at remote substation.

15. In case of numerical relays, all relays shall be comprehensive units including all protection,metering and control unless other wise specified.

16. Breaker control switch shall be hardwired type in addition to control switch as a part ofnumerical relay.

17. Transformer trouble 63TX relay shall be provided for all transformers and relay shall belocated on MV side in case of remotely located transformers. This function shall be realizedpart of numerical relays.

4.4 Metering

The metering devices in EHV, HV and MV switchboards shall be as below :

Feeder Type A V Hz PF MW MWH

Hour

Run MVAR MVAH MVA

EHV Incomers

EHV Bus Tie

EHV Transformer

EHV Bus P.T.

HV Incomer X X X X X

(2)

X - X

(2)

X

(2)

X

(1,2)

HV Bus Tie X - - - - - - - - -

HV Transformer X - - - X - - - -

HV Bus P.T. - X - - - - - - - -

HV Plant Feeder X - - - - X - - - -

HV Motor X - - - - XkWh

X - - -

HV Capacitor X X - - - - - - -

PCC/PMCC Incomer X X - X - X

kWh

- - - -

PCC/PMCC Bus Tie X - - - - - - - - -

PCC Bus P.T. - X - - - - - - - -

ACB Outgoing X - - - - X

kWh

- - - -

MV Motor (>55kW) - - - - - - - - - -

MCC/ASB Incomer X X - - - - - - - -

MCCB/SFU

O/G(250A)

X - - - - X

kWh

- - - -

LDB Incomer X X - - - - - - - -

DG Set X X X X X

kW

X

kWh

X - - -

NOTE :1. MVA meter in Grid Incomers shall include maximum demand indication also.2. MW, MVAR, MVA, MVAH meters shall be provided for only Grid Incomer feeders.3. Field Ammeters are to be provided for all motors rated above 3.7kW.4. All metering shall be part of numerical relay in case of electrical system having numerical

relays. Energy meter where provided separately shall be digital type.5. Indicating lamps in switchboards shall be cluster type LED lamps as per EIL specifications.


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5.0 SUBSTATION DESIGN

5.1 EHV Switchyard Not applicable

A. Type : String bus / Tubular bus

B. Structure : Galvanised / Painted / RCC

C. Bus material : Aluminium / Copper

5.2 HV/MV Substation

Description HV * MV

Elevated with trays in cable cellar Yes No

Raised with internal trenches Yes12

Yes

All top cable entry with trays below ceiling No No

Pressurisation against ingress of dust Yes Yes13

Air-conditioned room for operator Yes No

Roof slab for

Power transformer

Distribution transformer

No

No

No

No

Note:1. * Substation with long high voltage switchboards having substantial amount of cabling work2. Battery room shall be preferably located in corner side at first floor of the substation

building.

5.3 Specific Equipment Locations

A. Batteries

Electrical switchgear batteries : Separate room in sub-station

UPS batteries : Separate room in control room

B. Battery charger for electrical system : In substation air conditioned room

Battery charger for instrumentation : In Control room along with UPS.C. Variable speed drive panels/Thyristor control panel : Air-conditioned room in substation

D. UPS System : Air conditioned room in control room

E. Lead-Acid and Nickel-Cadmium : In separate rooms

F. Annunciation panel : Not envisaged/ HMI to haveannunciation Operator room insubstation

6.0 EQUIPMENT DESIGN

6.1 EHV Switchyard NOT APPLICABLE

A. Bus bar system : Single/Double

B. Circuit breaker type : Minimum oil/SF6

C. Isolator type : Pantograph/ Semi pantograph/ Centre rotating/ Centre break

6.2 HV Switch-board

A. Execution : Drawout (Fixed for GIS-33KV)

B. Bus bar system : Single/(Double bus for GIS)

C. Circuit breaker typ : SF6/Vacuum

D. Motor Control : Breaker/ Vacuum contactor

6.3 Current Transformer (CT)/potential Transformer (PT)

A. CT Secondary

Protection14

: 1/5A

12HV cables in cable cellar shall be laid in trenches filled with sand

13Pressurization not required for remote MCC room located in safe area

141A Protection CT for differential, REF protection; Separate CT for differential/ REF protection


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Metering : 1A (No separate metering CTexcept Metering CT for motorPB stn

B. PT Secondary : 110 V AC

6.4 Transformers (Power/distribution)15

Transformer Vectorgroup

Tap changer Soak pit Preferred rating(kVA)

Main power transformer Yyo/Dy1 OLTC Yes

Generator unit transformer Ynd 11 Off-circuit Yes

Intermediate power transformer Dyn 11 OLTC/Off-circuit Yes / No

Dedicated (e.g. for VFD)16

As Reqd. Off-circuit Yes / No

Distribution transformer

(< 2000 KVA)

Dyn 11 Off-circuit No

6.5 MV Switchboard

A. Execution

i. PCC / PMCC Breaker panels :Draw out/Single front

Contactor feeders :Drawout, single / Double front

ii. MCC :Drawout, single / Double frontiii. ASB :Drawout /Fixed, single/Double Frontiv. LDB :Drawout /Fixed: single/Double Frontv. Motors

PMCC : Above 55KW Upto&Including 160kW

MCC : Upto and including 55 kW

vi. Type of switchboard for package17 : Compartmentalised/Fixed type

B. Motor Starter Type

i. Contactor and switch fuse with overload relay: Up to 22 kWii. Contactor, switch fuse and overload relay with: Above 22 up to 55 KW

CBCT for earth fault protection

iii. Contactor and switch fuse with motor protection relay: Above 55 up to 160KW

iv. Air circuit breaker with motor protection : Nov. Contactor and MCCB with overload relay: Novi. Contactor, MCCB and overload relay with CBCT:No

for earth fault protection

vii. CT for remote metering : Motor rated above 5.5KW

C. Motor Controls18

i. Auto / Manual switch : Near motor/Switchgear/control roomii. Local/remote switch : Near motor/Switchgear/control roomiii. Normal / Standby switch : Near motor/Switchgear/control roomiv. Process interlock : PLC /relay panel/switchgearv. Reacceleration equipment : PLC /relay panel/switchgearvi. Control voltage for Contactor Starter : 240V ACvii. Control supply for contactor starter : Control transformer.viii. Separate transformer for each bus section: Yes/No

15 Rating of Power and intermediate transformers, OLTC requirement including vector grouping of alltransformersshall be decided during basic engineering based on KSLD attached with FEED.16

To be finalized based on licensors recommendation17

Package like AC plant MCC, Bagging plant MCC etc18

6.5C(i to iv): Operating philosophy and location of controls shall be as per process and instrumentationdesign basis.


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6.6 Motors

Motors High voltage 415 volts

Enclosure:

Indoor

Outdoor

IP55/IP54

IP55

IP55/IP54

IP55

Insulation class F (Temp. Rise limited to B) B

Terminal box Phase segregated/ Phase separated /Phase insulated

-

Anti-condensation heater Yes 30 kW and Above

Additional canopy (outdoor motors) Yes Yes

Design voltage / frequencyvariation

6 % / 3% 6 % / 3%

Note: Motors for MOV actuator shall have F class of insulation with temperature rise limited toclass-B.

6.7 UPS SystemA. Redundancy : 50% /100%

B. Type of redundancy : Parallel redundant/Hot standby

C. Back-up time : 120 minutes

D. Inverter bypass transformer : Static /servo controlled

E. Bypass transfer control : Auto / Manual

F. Separate fault diagnostic unit : Yes/No

G. Battery type : Lead acid/Ni-Cd/VRLA

H. Type of UPS : IGBT/Transistorised

I. Battery execution : Single bank up to 600 Ah/Parallel bank above 600 Ah

6.8 Communication System

A. Plant Communication System : Yes

B. Telephone System19 : Yes

C. Telephone system and plant communication system : Separate/Integrated

D. No. of intercom and external P&T lines : Later By IOCL

E. Battery type for telephone system : Sealed Lead acid (SMF)/ VRLA

F. Battery type for plant communication system : Sealed Lead acid battery/ VRLA

G. Battery backup time : 120min for both systems

H. Interface of Communication system with fire alarm system: Yes

I. Interface of PA and telephone system : YesJ. Type of communication system : Digital microprocessor based

6.9 Fire Detection and Alarm System

A. Type : Conventional/Analogue addressable

B. Name of buildings to be provided with detectors : All buildings except watch tower

C. Battery type :Sealed Lead acid (SMF)/Ni-Cd/VRLA

D. Battery backup time :48hrs. (Normal) + 120 minutes. (Alarm)

E. Detection System : Break Glass/ Smoke, Heat, linear beam

F. Type of manual call point : With/Without call back facility

G. Number of Sirens and location20 : 1 Number at Main control room

19Plant wide Telephone and LAN system shall be common. Refer design basis for LAN system for details.

20 Siren shall be electronic type with 5 tones (as per IOCL comment clause 2.3.10 (9) on fire and safety

document no. 6556-00-16-47-DB-01), Number and range shall be modified as per the availability.


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H. Power supply for Siren : 415 V AC/DC normal supply

I. Any specific requirement of range : 10 Km diametrical

6.10 DC System

A. Battery typei. Switchgear Protection, control : Lead acid/Ni-Cd/VRLA

Control and critical lighting

ii. Instrumentation System : Lead acid/Ni-Cd/VRLAiii. Diesel Engine Starting : Lead acid/Ni-Cd/VRLA(automotive type)iv. DC Motors21 : Lead acid/Ni-Cd/VRLA

B. Battery back up time

i. Switchgear Protection :120 minute when no DG back up andControl, Lighting 30 minutes where DG set is available

ii. Instrumentation : 30 /60/120minutesiii. Diesel Engine Starting : 10Starts (FW pumps)& 6 Starts othersiv. DC Motors : refer foot note

6.11 Variable frequency drive

i. Type of inverter22 : See foot noteii. Number of pulse 23 : 6/12iii. By pass feature required : Yesiv. VFD rated output voltage : As per licensor/FEED reqt.

6.12 Cables

The power and control cables shall have the following minimum cross sectional areas:

A. Medium voltage power cable24 : 25mm (Al)/2.5 mm (Cu)

B. Control cables : 2.5 mm (Cu)

C. Lighting25 : 2.5 mm (Cu)

D. Communication system26 : 0.9 mm dia (Cu)

E. Fire alarm system : 1.5 mm (Cu)

7.0 CABLING SYSTEM

7.1 Cable details

Design Criteria High voltage27

415 volts

Loads located beyond 1 km 1Core/ 3 Core Cable Cable

Loads located 200-1000 m 1-Core/ 3 Core cable 1-core cable/ 3-core cable

Load located up to 200 m 3 Core Cable Cable / Bus trunking

Loads beyond 1 kA rating Bus duct / cable Bus duct /1 core cable

Recommended limiting size of multi-core

cable (mm)

300 300

Short-circuit withstand time (seconds) 0.2 (Outgoing)/0.60 (Plant)/1.0(Incomer)

N.A.

Insulation voltage grade Earthed for both 33KV and6.6KV system

Earthed

Type of cable insulation XLPE PVC

21DC motor application is not envisaged

22Licensors recommendation/ EIL equipment specification shall apply

23 6 or 12 pulse rectifier as per manufacturers standard and as required for meeting EIL equipment

specification requirement.24Cable for motor above 110KW shall be sized considering copper cable.25

1.5 mm Cu conductor PVC Insulated wire shall be used in conduit with proper colour coding for buildinglighting.26

Cable sizes for PA and FA systems are indicative. These shall be finalised later as per the manufacturersrecommendation27

1Core or 3 Core HV cable shall be decided during basic engineering based on load and distance


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Design Criteria High voltage27

415 volts

Fire survival (Resistant) cable28

Fire pump

Plant communication

Yes/No

-

Yes/No

Yes/No

Armour for cables inside the substation Yes/No Yes/No

7.2 Cable laying philosophy

A. Process area29 :Overheadcable tray /RCC trench-sand filled

B. Offsite paved area30 :Above Ground cable tray on sleeper/overhead rack/ RCC trench

C. Offsite unpaved area :Above Ground cable tray (on sleeper/ overhead rack) / directlyburied. (see footnote against point 7.2 above)

D. Type of cable trays :Galvanized prefabricated / Site fabricated and painted

E. Special requirements :Cables for fire water system shall be taken on exclusive routethrough underground trench starting from main substation in caseapplicable

F. Road Crossings for under ground cables31

:PVC Pipes /Cable culvertG. Road Crossings for above ground cables :Overhead cable bridge/culvert/ERC

8.0 EARTHING SYSTEM

A. Earth electrode : GI pipe

B. Main earth loop material : GI strip

C. Substation earth loop : GI strip

D. EHV switchyard earth grid : Not applicable

E. Lightning system : As per IS2309

9.0 LIGHTING SYSTEM

9.1 Supply SystemA. Centralised with separate transformer32 : Yes/No

B. At each substation with separate transformer : Yes /No

C. Separate metering required : Yes/No

9.2 Control Philosophy

A. Outdoor yard : Auto/Manual/centralised (ECS)/Local

B. Street lighting33 :Auto/Manual/centralised(ECS)/Local

C. Outdoor process area : Auto/Manual/Centralised (ECS)/ Local34

D. Process building : Auto/Manual/centralised/Local

E. Auto control : Yes-Synchronous timer/photocell/ No

F. Lamp type for outdoor lighting : HPMV-Process area/HPSV-Street light,FLM/ (Incandescent type forDC/emergency Critical lighting)

G. Panel execution : Lighting transformer fed LDB with OGfeeders for lighting panels

28Where fire proof MOVs are provided cables shall be fire survival type as per IEC331 or mica insulated

29Cables for FA/PA shall be laid in instrument duct where available and shall be in separate trays where ducts

are not available in ISBL.30

FA and PA cables in offsite area shall be laid in road berm (opposite to berm used for lighting cable). Wherechemical handled are hazardous for PVC insulation, cables shall be laid above ground.In such cases. Cablesshall be laid overhead on pipe rack or above ground on sleeper level depending on availability of pipe rack/

sleeper. Where there is no rack/ sleeper, cable shall be laid in trenches if cables are large and directly buried ifcables are few.31

Road crossing through PVC pipe or culvert shall be decided based on number of cables.32

The secondary voltage for lighting transformer shall be 380V.33

Lighting shall normally be done using 30m flood light mast as per IOCL philosophy. Street light shall beconsidered only where considered absolutely necessary.34

Local control shall be through FLP lighting panel in process area.


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H. ELCB at Incomer of lighting and Power panels35 : Yes/No

9.3 AC Emergency Lighting

A. Name of process plants : All process Unit except U&O Pump stn

B. Name of buildings : All buildings- Plant and non plantC. Power supply : As per CPP design basis

9.4 DC Critical Lighting For Escape

A. Name of process units : All process units

B. Name of building36 : All buildings (see footnote)

C. Power supply : 220V DC

D. DC lighting for remote substation : (See foot note)

9.5 Wiring Type

A. Process plant / Building / Shed : Armoured cable

B. Large service building : Concealed/ surfaceconduit

C. Buildings with false ceiling : cables/Surface conduit above falseCeiling

D. Substation (Switchgear Room) : METSEC channel

E. Substation (Cable Cellar) : Surface Conduit/armoured cable

F. Other buildings : Concealed/Surface, conduit/cable(armoured/ unarmoured).

9.6 Specific Lighting Requirements

A. Aviation lighting : Yes /No

B. Navigation lighting : Yes/No

C. Security lighting for peripheral road at boundary wall37: Yes/No

D. Type of control gear for HPMV/HPSV Lamps : Separate/Integral

E. Control gear box location : Accessible level if separate

F. Type of flood light mast : 30 m Telescopic fitted tubular

10.0 ELECTRIC HEAT TRACING SYSTEM

A. System Design Basis : Product Classification /System approach

35ELCB shall be provided at sub distribution feeder at LDB for lighting panels for AC as well as DC lighting.

36All buildings except remote buildings not having DC supply shall be provided with DC lighting for escape.

For buildings where DC supply is not available, portable DC light for escape to be provided.37

To be provided on watch towers through search light


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11.0 ELECTRICAL EQUIPMENT FOR HAZARDOUS AREAS

The electrical equipment for hazardous areas shall be selected as per IS-5571 and petroleum rulesThe minimum requirement is summarised below:

Zone-1 Zone-2Equipment

Gas Group IIA, IIB Gas Group IIC Gas Group IIA, IIB Gas Group IIC

MV Motors Ex-d Ex-d Ex-e/Ex-n Ex-e/Ex-n

HV Motors Ex-d / Ex-p Ex-d/ Ex-p Ex-p/Ex-e/Ex-n/ Ex-e/Ex-n

Push Button Station Ex-d Ex-d Ex-d Ex-d

Motor Starters Ex-d Ex-d Ex-d Ex-d

Plug & Socket Ex-d Ex-d Ex-d Ex-d

Welding Receptacle Ex-d Ex-d Ex-d Ex-d

Lighting Fixtures

i. Lighting fitting

ii. Control Gear Box

Ex-d

Ex-d

Ex-d

Ex-d

Div.2 Ltg.

(IS-8224)

Ex-e/Ex-d

Div.2 Ltg.

(IS-8224)

Ex-e/Ex-d

Junction Boxes Ex-d Ex-d Ex-e/Ex-n Ex-e/Ex-n

Hand Lamps

i. Light fitting

ii. Transformer Unit

iii. Plug & Socket

Ex-d

Ex-d

Ex-d

Ex-d

Ex-d

Ex-d

Ex-d

Ex-d

Ex-d

Ex-d

Ex-d

Ex-d

Break Glass Unit

(Fire Alarm System)

Ex-d Ex-d Ex-d Ex-d

Lighting Panel/Power Panel

Ex-d Ex-d Ex-d Ex-d

Transformers Hermetically sealed with surface temperature not exceeding 200C

Notes:1. The electrical equipment for hazardous areas shall generally be suitable for gas group IIB

and temperature classification T3 as applicable to the selected type of explosion protection.In case of hydrogen or hydrocarbon mixtures having more than 30% hydrogen, the gasgroup to be considered shall be IIC.

2. As additional safety features, the following requirements for electrical equipment shall befollowed

a. All electric motors for vertical oil sump pumps including ETP area shall beflameproof type.

b. Irrespective of the area classification (whether zone-1 or zone-2), all lightingfixtures within the storage areas shall be flameproof type.

c. All emergency/critical lighting fixtures and associated junction boxes in hazardousareas (whether zone-1 & zone-2) shall be flameproof type.

3. Even though fired heaters in process units are not considered for area classification, allelectrical equipments associated with fired heaters in process units shall as a minimum be

suitable for installation in Zone-2 area.4. Where air conditioning system is designed considering ammonia as refrigerant, the roomhousing air conditioning equipment shall be adequately ventilated to classify it as safearea. For additional safety the following shall be considered:

a. 100% standby system for ventilationb. Location of MCC/local panels in adjacent separate room.c. Instrumentation to be flameproofs type or hermetically sealed.d. AC plant room motors with type`e' protection.e. Lighting in AC plant room suitable for zone-2 area.

5. Compressor sheds in hazardous area shall be designed to allow adequate ventilation toallow area classification as Zone-2 Lighting equipment, EOT crane etc. in the shed shall beflameproof type. All other electrical equipment shall be suitable for Zone-1 or Zone-2 areadepending on extent of hazard.

6. Motors fed from variable frequency drive in hazardous area application shall be type testedas unit with the VFD panel in case of Ex(e) type of motors and provision for tripping themotor in case temperature rise exceeds the permissible limits ,shall be considered forflameproof motors as per relevant standards.


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12.0 STATUTORY APPROVAL

Statutory Authority for Electrical Installation : Central Electrical Inspectorate

Hazardous area equipment : CCE

13.0 CABLE SIZES FOR MV MOTORS

i. Direct on line (D.O.L) start motors (2/4 pole motors)38Cable DetailsMotor Rating

Number of runs No. of coresper run

Conductor material Conductor sizemm

Below 3.7 KW 1 3 Cu 2.5

3.7 KW 1 3 Cu 4

5.5 KW 1 3 Cu 6

7.5 KW 1 3 Cu 10

9.3 KW 1 3 Cu 16

11 KW 1 3 Cu 16

15 KW 1 3 Cu 16

18.5KW 1 3 Al 3522 KW 1 3 Al 35

30 KW 1 3 Al 50

37 KW 1 3 Al 70

45 KW 1 3 Al 95

55 KW 1 3 Al 120

75 KW 1 3 Al 185

90 KW 2 3 Al 95

110 KW 2 3 Al 120

125/132 KW 2 3 Cu 120

160 KW 2 3 Cu 120

ii. Cable sizes for motors not confirming to above table e.g. for 2/4 poles motors, extended distance,reduced voltage starting, low speed motors, shall be worked out on case to case basis.

iii. Cables sizes as indicated above are applicable for a distance up to 350m maximum and for 2/4poles motors fed from MCCs located near PCCs and PMCCs.

iv. Cables for lighting shall be used to allow the following voltage dips

Street lighting :10%

DC critical lighting :5%

14.0 SPECIFIC REQUIREMENTS

i. Canopy shall be provided for all out door equipment.ii. Substation shall be sized to ensure 2 nos panel extension on each bus section

for all HV/ MV switchboards except GIS.iii. Dummy panel shall be provided in switchboards wherever there is expansion

joint in the building.

iv. If signal cables for DCS interface with substations are envisaged, these shall belaid in separate trays/ trench. However in exceptional cases signal cables maybe laid in electrical trench, properly cleated on trench wall allowing 300mm gapwith other power cables in the trench.

v. For building engineering, each office room, in addition to switch/ socket forlighting design, shall be provided with minimum 2 nos telephone sockets and 2number LAN socket at two different location as duly approved during detailedengineering.

vi. Modular type switches/sockets in main control room and all non plant buildings

shall be modular type.vii. Lamps shall be standardized for the purpose of inventory in hazardous arealighting as below.

38Cable sizes given in the table are indicative and standardized for inventory and are the minimum sizes. The

cable size as required to meet voltage drop criteria shall be provided.


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Well glass normal Lighting : 70W HPMV lamps for well glass fittings

Flood Lighting : 250W HPMV lamps for flood lighting

Critical lighting : 100W GLS lamps

15.0 ATTACHMENTSDesign philosophy for Electrical Facilities 6-51-0099 Rev 4

16.0 DEVIATION TO DESIGN PHILOSOPHY

Document number 6-51-0099 rev 4

The requirement given under engineering design basis document shall be overriding. Howeverfollowing job specific requirement are highlighted as deviation to Design Philosophy of Electricalfacilities document number 6-51-0099.

16.1 Clause 4.6.1 Voltage drop

i. b(ii) MCC/Aux switchboard situated remote from PCC/PMCC 2%ii. d - Cable between PCC/PMCC to motor- 5% during normal running

16.2 Clause 4.11 DC Power supply

i. DC power supply system for electrical controls and for critical lighting shall beseparate. For electrical controls and instrumentation, DC system shall be dualredundant with single set of battery and for critical lighting, DC system shall benon redundant.

16.3 Clause 4.15.3 Plant communication system-capacity for future expansion

i. Exchange supplied shall be fully wired for hardware, power supply, software etcfor the capacity as required with spare capacity of 20% field call stations with nofuture modification in exchange hardware/ software.

ii. Exchange shall have required hardware for communication between twoexchange of the same make

16.4 Clause 4.16 Fire detection and alarm system

i. Cl 4.16.5 : Spare fire alarm loop for future shall be 20% or 1number whichever ismaximum. Each loop shall be engineered to provide the flexibility to add 20%additional detectors in future, if required.

ii. Cl 4.16.6 : The status for actuation of fire suppression system shall also be wiredto fire alarm panel to annunciate at central fire alarm monitor.

16.5 Clause 5.3 Switchgear

i. Cl 5.3.4 : Each HV Switchboard (above 415V and except 33KV) shall haveminimum 2 numbers spares of each type. (i.e. type like transformer feeder, motorfeeder, plant feeders etc)

ii. Cl 5.3.4 : Each MV Switchboard (Up to 415V) shall have 20% spares of eachtype ( Spares in each MCC shall however be 20% subject to 1 number of eachmotor feeder module )

16.6 Clause 5.7 Battery charger and Distribution board

i. Cl 5.7.3 : Each DCDB shall have 20% spare feeder for future use.ii. DCDB outgoing feeders for critical lighting shall be provided with ELCB.

16.7 Clause 5.8 Uninterrupted power supply system

i. Cl 5.8.4: Spare feeders in ACDB shall be 20% for future use with minimum of 1number of each rating.

ii. Cl 5.8.5 : UPS shall be sized to have 20% spare capacity on calculated load forfuture loads.

16.8 Clause 5.13 Cable and Wiresi. Cl 5.13.6 : No unarmored cable shall be used.ii. Cl 5.13.10 : Control cables shall have 1core spare upto 6core requirement and

20% or 2 core whichever is maximum for cables having requirement above 6cores.


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iii. For 4-20mA signal interface between switchboards and DCS, screened cableshall be used.

iv. Cl 5.13.7 : Cables laid for hazardous area shall not have any joints.

16.9 Clause 5.14 Control stations

i. Cl 5.14.1 : Each motor shall be provided with local control station. If specified perprocess or equipment control requirement, local control station can be part oflocal control panel.

16.10 Clause 5.16 Actuators for motor operated valves

i. MOV shall have separately mounted actuator in area of high vibrations. Inparticular the MOVs for Cooling water application shall have separate actuatorlocated near the valve for local actuation.

16.11 Clause 7.2 Cabling System

i. Clause 7.2.5: Cable trays shall be sized to allow 20% additional space for futurecables.

ii.Clause 7.2.14: MCTs shall be provided wherever the entry is above ground. Andwhere entry is below ground, sleeves (Laid in outward slope to avoid water entry)shall be provided for electrical cables.

16.12 Clause 7.4 Lighting system

i. Non-plant buildings such as administrative building, gatehouses etc should beprovided with energy efficient CFL lamp fixtures.

ii. In plant buildings, control rooms should be provided with energy efficient CFLlamp fixtures.

electrical design basis_rev 0

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