Electrical Design

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CHAPTER 1 ELECTRICAL SCOPE OF WORK

FOR

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OFFSITE AUTOMATION – Electrical Scope of Work

1. The scope of work of the contractor for the Offsite Automation System comprises of Design, Detailed Engineering, Supply, Erection/Installation, Testing and Commissioning of all Electrical equipment and systems required to meet the functional needs of the Offsite Automation Project.

2. The list of Electrical equipment and systems covered in the scope shall include, but not limited to the

following:-i) All electrical drive motors

ii) Local Push Button Stations for each motor iii) Transformer as per requirement

iv) Power cables, cable installation equipment’s & accessories and conduits for routing cables required

v) Motor operated Valves

vi) 415V MCC / power distribution boards / Local control panels required to feed electrical power loads

vii) Uninterrupted Power Supply Systems for Control Systems, Analyser and Motor Operated Valves.

viii) Earthing system consisting of provision of required earth pits at suitable location and connection of earth lead from all bidder supplied equipment’s

ix) Lighting System inclusive of lighting fixtures, fitting and switches. x) Air conditioning systems for control rooms and other locations where

instrumentation systems that require air conditioning are installed. xi) Building electrification works

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3. All civil and mechanical works, such as foundations, structural works, false ceiling works, ducting etc., related to the completion of the electrical scope of work is included in the scope of the contractor.

4. All equipment and components shall be procured from the manufacturers listed in the enclosed approved vendor list.

5. Bidder shall be provided suitable feeders in the substation nearer to the load center by CPCL subjected to the availability of spare feeder. PURCHASER reserves the right to reserve spare feeders for future maintenance purposes. In case, required number of feeders could not be spared by CPCL, the Bidder shall erect a separate distribution board for the purpose inside the substation / extend the existing panels if load conditions permit. In case of extension, extension panels shall be of same standards as that of existing panels and preferably of same make.

6. Bidder shall note that his scope of work includes supply of all material and resource. CPCL will not provide any material or resource.

7. The bidder shall design, supply, erect , test and commission a centralised air conditioning and ventilation system for the following –

(a) Control Room (b) Rack room

(c) Shift In-Charge room (d) Computer room (e) Operator room (f) UPS Room (g) Operator Room (h) Dining Room

The sizes of the rooms shall be as per the drawings enclosed.

8. The bidder shall design, supply, erect, test and commission the Uninterrupted power supply (110 V) system for providing power supply to DCS system and analysers shall be considered. The UPS shall be parallel redundant with by-pass facility having three independent incomers. The batteries shall be Ni-Cd type and shall provide a minimum back up of 30 minutes in event of mains failure. Suitable power distribution board shall be provided for feeding to various devices. UPS in the control room shall be for control room instrumentation and other requirements only. UPS requirements of analyser sheds shall be met through separate UPS’s in those locations.

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9. The bidder shall design, supply, erect, test and commission the DC power supply (110 V) system for providing power supply to Critical lighting, etc. The battery charger shall be of dual float cum boost type and the batteries shall be Ni-Cd type or Plante lead acid and shall be designed to provide a minimum back up of 2 hours in event of mains failure. Alternatively, the vendor can source DC from OMS/Ref-I substation by laying suitable cables. For analyser shelters only portable emergency lights shall be provided.

10. Additional outdoor lighting shall be provided wherever operation of equipments are envisaged.

11. HT motor feeders will be made available in OMS/REF-I HT substation by CPCL. One LT (415V) feeder of required capacity will be provided by CPCL in each of the SS4, SS5, Ref-I substations. Further power distribution, including that for inputs to UPS, Airconditioning plant MCC, shall be carried out by the contractor through separate switchboards.

12. Vacant space with floor opening available in the above mentioned substations can be used by the contractor for erection of his panels. However, if the space is not sufficient the contractor has to extend the substations/ floor openings, as required.

13. Ten number telephones of premier model of tatafone make shall be provided and installed in the control room. All required cabling from the junction boxes shall be laid and connected by the contractor.

14. Bidder shall involve CPCL’s Engineers at each and every stage of the project and shall proceed only after obtaining the necessary approval from CPCL.

15. The scope includes supply of miscellaneous items as per specifications.

16. The scope includes supply of Special tools and test equipment, calibration and maintenance of the system.

17. The vendor shall supply all final drawings, documents. Operating / maintenance manuals, test reports, commissioning reports, etc in following form :- 6 nos. of hardcopies including tracing & prints for drawing. One set in digitized form in floppy and one set in CD.

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18. Supply of two years Operational, Mandatory & Commissioning Spares as per spare philosophy Warranty and Post-Warranty Maintenance etc. mentioned in the specifications of equipment.

19. BIDDER IS ADVISED TO CAREFULLY SCRUTINIZE THE TENDER

DOCUMENT, SPECIFICATIONS, AND INSTRUCTIONS. ETC AS CONTAINED HEREIN AND TO UNDER TAKE A SITE VISIT BEFORE SUBMITTING THEIR OFFER FOR CPCL’S REVIEW AND ACCEPTANCE. ANY ADDITIONS, WHICH SHALL BE REQUIRED DURING THE EXECUTION OF THE PROJECT TO MEET THE FUNCTIONAL REQUIREMENT, SHALL BE PROVIDED BY BIDDER AT NO EXTRA COST.

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CHAPTER 2 STANDARD SPECIFICATION

FOR

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1.1 This specification along with specific job requirements. Standard specifications, etc. defines the requirements for design, engineering, supply and, where included in job requirements, installation, testing and commissioning of electrical equipment and facilities for the OFFSITE AUTOMATION PROJECT.

1.2 For the purpose of this specification, the term `package equipment' or `package' denotes the all equipment to be supplied or work to be carried out by the vendor. 1.3 It is not intended to cover all aspects of design but to indicate the basic requirements

only. Vendor shall ensure that the design and installation of the equipment is carried out as per good engineering practice to meet the requirements of safety, reliability, ease of maintenance and operating, aesthetics, scope of further expansion and maximum interchangeability of equipment. Vendor shall acquaint himself with CPCL standards, specification and field testing procedures as deemed necessary for proper execution of the work.

1.4 Compliance with this specification and /or review of any of the vendor documents shall not relieve the vendor of his responsibility and his contractual obligations with regard to the completeness and satisfactory operation of the project.

2.0 CODES AND STANDARDS

2.1 All electrical equipment and the complete package shall meet the requirements of this specification and enclosed data sheets in addition to the relevant Publications and Codes and Practice of Bureau of Indian Standards, , statutory regulations and good engineering practices. Complete system must be also conform to the latest revisions of the following:

a) Indian Electricity Act and Rules framed thereunder b) Fire Insurance Regulations

c) Petroleum Rules and any other regulations laid down by Chief Controller of Explosives

d) The Factory Act and regulations laid down by Factory Inspectorate

e) Regulations laid down by local statutory authorities and Electrical Inspectorate f) Oil Mines Regulations (For Projects under DGMS jurisdiction).

g) OISD Standards –

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2.2. Vendor shall obtain all necessary approvals from statutory authorities (Central Electricity Authority) for materials, plant design/drawings and complete installation. The statutory approval from CEA shall be obtained by the vendor prior to energising the electrical installations.

2.3 Where Indian Standards do not exist, the relevant IEC/British/ German (VDE) standards shall apply. Any other international standard may also be followed provides it is equivalent to or more stringent than the standards specified above. 2.4. In case of any discrepancy/conflict between this specification and the specified codes

and standards, the following order of decreasing precedence shall govern: i) Statutory Regulations

ii) Electrical Design basis and Equipment Data Sheets iii) Job specifications

iv) CPCL Standard Specifications and Installation Standards etc. iv) Codes and Standards

In case of any discrepancy/conflict between the specification of the same level [2.4 i) to iv) ] mentioned above, the better standard among them shall be adopted.

CPCL's concurrence shall, however, be sought and obtained before taking a decision in the matter.

3.0 SITE CONDITIONS

Provided in design basis.

4.0 AREA CLASSIFICATION AND EQUIPMENT SELECTION

4.1 In case of storage handling or processing of flammable materials within the battery limits of the package, area classification shall be carried out in line with IS : 5572, Petroleum Rules and DGMS guidelines where applicable. Where specified, the vendor shall furnish an `Area Classification Drawing' indicating the zones of hazardous area and the applicable gas groups. A list of flammable materials handled alongwith their properties like flash point, ignition temperature, explosive limits etc. shall also be furnished.

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4.2. Selection of the type of all equipment for use in hazardous areas shall be done in accordance with IS : 5571 and DGMS regulations where applicable. The electrical equipment shall meet the requirements of relevant IS, IEC or NEC standards. Increased safety type Ex (e) equipment shall not be permitted for use in Zone -1 areas. For Zone-2 areas, Increased safety type Ex(e) or Non sparking Type Ex(n) equipment shall be provided as a minimum, subject to the same being acceptable to statutory authorities. Ordinary safe type electrical equipment shall not be used in Zone -2 areas (even though this may be permitted by NEC for Div.2 areas).

4.3. Electrical equipment for hazardous areas shall be certified by CMRI and approved by CCE/DGMS as applicable (or equivalent recognised testing agency and statutory approval authority) for installation and use in the specified hazardous area. Flameproof equipment of indigenous origin shall be `BIS' market. Vendor shall furnish the necessary certificate indicating such approvals.

4.4. Unless otherwise specified, electrical equipment for hazardous areas shall generally be suitable for gas IIA and IIB and Temperature Class - T3 applicable to the selected type of explosion protection. In case hydrogen is handled, the gas group to be considered shall be IIC.

4.5. Unless otherwise agreed, electric motors for agitators/mixers, metering pumps and oil sump pumps handling flammable materials shall be flameproof Ex(d) type, irrespective of the area being classified as Zone-2 or Zone-1.

4.6. In case the Package or part of the package /equipment is to be located in a classified hazardous area, the same shall be indicated in the data sheet. In such a case, the offered equipment/ package shall conform to whichever are the more stringent requirement i.e. either due to materials being handled in the package or hazardous location in which package is installed.

5.0 EQUIPMENT SPECIFICATION

5.1. Specifications of each system and equipment shall be furnished by the vendor for review by CPCL. However, certain minimum requirements for the major equipment are highlighted in this section.

5.2. All equipment and components shall be new and supplied by CPCL approved manufactures. Equipment requiring specialized maintenance or operation shall be

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equipment shall be complete with all necessary weather and anticorrosion protection including tropicalization to prevent damage due to climate, sline atmosphere, dust and corrosive vapours.

5.3. All equipment /material shall be protected for inland / marine transport,. carriage at site and outdoor storage during transit and at site. Vendor shall be responsible for any damage to the equipment during transit. All packages shall be clearly, legibly and durably marked with uniform block letters giving the relevant equipment/mutable details . Each package shall contain a packing list in a waterproof envelope.

5.4. All electrical components and equipment shall be sized to suit the maximum load under the most severe operating conditions. Rated voltage and frequency for the equipment shall be as indicated in enclosed date sheet.

5.5. All spares required for testing and commissioning the package shall be included alongwith any special tools and tackles required for operation and maintenance.

6.0 STANDARD SPECIFICATIONS

Standard Specifications have been enclosed for Induction motors, Cables, UPS, MCC, Transformer and MOV. All of the above equipment supplied by the vendor shall meet the requirements specified therein.

7.0 EARTHING SYSTEM

7.1 Earthing system design and installation shall generally be as per IS:3043. One or

more number of G.I. earth plates shall be provided for the equipment in package depending upon in size. All metallic non-current carrying parts of electrical apparatus, control stations, current and potential transformer secondaries, structural steel, vessels etc. shall be connected by at least two distinct separate earth conductors to an earth plate. All earth plates shall be bonded together and shall have the provision for interconnection to owner's main earth grid at two points. Earth plates shall be of 3060x80x10mm size and shall be provided with adequate number of tapped holes. Earth continuity bonding shall be provided across all pipe flange joints.

7.2 The resistance value of earthing system to the general mass of the earth shall

ensure the operation of the protective device and in any case should not exceed 5 ohms. Normally earthing system shall comprise of main earth grid along with

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suitably located disconnecting plates to provide multiple earth connections between earth grid and equipment and for connections between main earth grid and electrodes. Connections between earth electrodes and the disconnecting plates shall be done by GI strip. Connection between disconnecting plate and various equipment shall be done by GI strip, GI wire or GI rope. Earth electrodes and conductors shall be designed to cope with the conditions imposed. The earth conductor shall be adequately sized to carry the applicable maximum earth fault current without undue temperature rise. All joints shall be protected to prevent corrosion.

7.3 Design calculations and for earthing layout has to be submitted for approval.

7.4 All hardware used for earthing installation shall be hot dip galvanized for zinc passivated. Thickness of hot dip galvanizing shall be minimum 700gm/m2. Specifically provided bolts, lugs and spring washers shall be used for all earthing connections of equipment.

Following sizes of earth conductors shall be used for motors: Upto 3.7 KW85WG GI wire

5.5 to 30 KW3/8" GI fine wire rope or 35mm2 AI insulated conductor 37 to 75 KW 5/8" GI fine wire rope or 70mm2_{AI insulated conductor}

Above 75 KW 40 x 5mm2_{GI strip.}

Earthing connections to equipment shall be made by means of bolts and lugs provided specifically for this purpose.

8.0 LIGHTING SYSTEM

8.1 General lighting for areas in which equipment supplied in the package is to be installed shall be provided by vendor. Normal lighting system shall be fed by 415/240 VAC supply.

8.2 HPMV lamps or MLL lamps shall be used for outdoor plant lighting, however to overcome the re strike time lag in case of voltage dip/ blackout incandescent lamps may be judiciously distributed throughout the plant area. All chemical handling facilities shall be provided with chemical resistant fixtures. Control gear boxes shall be located at accessible level, which should not exceed 2m above operating level.

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8.4 All outdoor lighting shall be automatically controlled by synchronous timers with manual overriding control. Lighting panels shall be used for distribution and these panels shall be provided with MCB + ELCB as incomer and MCB’s for outgoing feeders control and protection. Only 8 -10 fixtures shall be wired in each circuit. MCB’s shall not be loaded beyond 80% rated capacity. A minimum of 25% of MCB ‘s shall be left as spares. The lighting distribution shall not combined with power distribution and separate panels have to be used for power distibution.

8.5 The minimum illumination levels for the following areas shall be: Process areas - 60 LUX

MCC room - 200LUX Control room - 500LUX

8.6 Design calculations and for lighting system lighting layout has to be submitted for approval.

8.7 Lighting fixtures mounted on plat forms, walkways, stairs, High bays etc shall be installed in such a way that relamping can be done without the use of ladders.

8.8 Any other lighting requirements such as Local panel lighting shall be provided by vendor. Power for such local lighting shall be obtained from a suitable feeder in PDB/Local Panel.

8.9 All lighting circuits shall have provision for isolation in both phases and neutral for packages to be installed in hazardous areas. For packages under DGMS jurisdiction, power supply voltage shall be limited to 240V between phases by the use a suitable transformer.

9. Facilities Inside Control Room Building

9.1 Concealed conduit wiring shall be used below the false ceiling and surface conduit wiring above the false ceiling.

9.2 Adequate number of combined 5/15 Amps power sockets shall be provided.

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10.1 Each motor shall be provided with a control station in the field. The control station shall have suitable protection for site conditions (such as flameproof, weatherproof , dust proof, corrosion resistant etc.). and minimum acceptable IP class is 55. Canopy shall be provided to protect outdoor control station against direct rain. The control station shall include start & stayput type stop pushbuttons and Ammeters (for motors rated > 18.5 KW)

11.0 INSPECTION, TESTING AND COMMISSIONING

All equipment shall be tested and inspected at vendor's works before dispatch to ensure compliance with the relevant specifications and agreed quality assurance/testing plan. Precommissioning and Commissioning tests have to be carried out by the vendor on all the electrical equipment.

The owner or his authorized representative may visit the works during manufacture or various electrical equipment/materials to assets the progress of work as well as to ascertain that only quality raw materials are used for the same. He shall be given full assistance to carry out the inspection. Owner's representative shall be given minimum two weeks' advance notice for witnessing the final testing. The minimum testing/inspection requirements for all components/equipment shall conform to the requirements stipulated in applicable codes and standards. Test certificates including test records and performance curves etc. shall be furnished by the vendor.

Vendor shall submit the field testing procedures for CPCL's approval. Field tests as per the approved procedures shall be performed on the electrical system/ equipment before its being put into service. All test equipment required for this purpose shall be arranged by the vendor, in case testing and commissioning at site is included in his scope, and test reports shall be approved by the size-in-charge before acceptance of the complete package.

12.0 SPARES

Vendor shall separately quote for 2 years' operation and maintenance spares for all electrical equipment in the package, including but not limited to the following. Vendor shall indicate unit rates and recommended quantity for each item in his offer. All spares required for commissioning the equipment is included in the scope of the contractor.

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- Terminal cover with screws etc. - Fans for critical motors.

- DE, NDE end Shield

Power Distribution Board/Local Panel

- Switches and fuses of all ratings

- Set of main contacts and coils of all contactors - Bimetal relays

- Indicating lamps assemblies/lamps - Push buttons and auxiliary devices.

13.0 DRAWINGS AND DOCUMENTS

All drawings, SLD ‘s design calculations and data sheets has to be approved by CPCL before issuing for construction. Four copies ofAs-built documents/vendor drawings shall be provided by the vendor as per contract. Additionally, one set of all as-built documents/ vendor drawings in bound volumes and/or in the form of electronic files on specified media shall be submitted to CPCL alongwith certified and updated drawing schedule. The following shall also be included.

a. Design and installation instruction manual including design documents, certificates relating to type/acceptance/special tests, description of procedures and description of field testing procedures after installation.

b. Operating instruction including description of start-up procedure and description of conditions of use.

c. Maintenance instructions including precautionary maintenance instructions/periodic inspection programmes, setting instructions, procedures for removing and replacing all parts and accessories included in the spare parts list, and list of spare parts and consumables together with all information required for ordering them from manufacturers.

Sub-suppliers of individual components shall be clearly identified. Communication address shall be indicated for each reference.

14. OTHERS :

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14.2 All equipments supplied (except fuses and bulbs) shall have warranty for 12 months from the date of commissioning.

14.3 Any deviation from the specifications is not acceptable, unless it is specifically approved by CPCL. Deviations to Electrical specifications, if any envisaged by the vendor shall be submitted clause wise, as a separate Annexure to the technical bid, for consideration of CPCL.

14.4 Any discrepancies between different specifications provided in this document shall be notified clause wise in a separate Annexure to the technical bid and the specification to be adopted shall be indicated there in. However CPCL decision on the standard to be adopted shall be final.

14.5 If some of the Specification specified anywhere in the document is not part of the document the same shall be provided by CPCL on request.

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CHAPTER 3 ENGINEERING DESIGN BASIS

FOR

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1. SITECONDITIONS

A. Equipment design temperature (IS 9676) : 40.0 DEG C B. Soil Resistively : * ohm – m C. Min. temps. for battery sizing : 10 DEGC D. Min. Temp. For Electric heat tracing : 10 DEGC E. Seismic zone(IS – 1893) : *

F. Altitude above mean sea level : 3.5 m

G. Design wind velocity : 150 km/hr. or as per IS 875,

Which ever is higher.

2.0 POWER SOURCE DETAILS

2.1 General

Independent system or extension of existing system : Extension of existing system.

2.2.Grid Supply:

A. Name of grid sub station : To be decided later.

B. Number of feeders : Later C. Length of feeder / conductor size : Later

D. Voltage : 6.6.KV or 415 V + 10% E. Frequency : 50 Hz + - 3%

F. Min / max fault level / BIL : 40 kA / 60 kV G. Design fault level / BIL : 40 kA / 60 kV H. System neutral earthling : Resistance Earthed I. Minimum load p.f. stipulated by

Supply authority : 0.9

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3.0. POWER SUPPLY DISTRIBUTION SYSTEM

3.1. Voltage and frequency variation

(Refer cl.6.6.for design voltage / frequency variation for motors)

A. AC System

Voltage : 6.6.kv + - 10% (motors rated above 160KW) 415 V + - 10% (motors rated less 161KW)

Frequency : 50Hz + - 10%

B. DC System (at system output terminals)

Electrical Control, Lighting etc. : 110V + - 10% 3.2 Utilisation voltage & operating philosophy

A. Primary HV distribution voltage : 6.6kv B. Secondary HV distribution voltage : 6.6kv

C. Primary HV distribution system neutral : Resistance earthed D. Secondary HV distribution system neutral : Resistance earthed E. HV motor voltage : 6.6kv (above 160 kW) F. Auto transfer at 6.6KV Bus : Not Applicable G. Auto transfer at MV (At PCC Level) : Yes

H. Continuous Parallel operation of Incomers

- HV : No - MV : No

I. Load shedding : Provision for wiring of trip contact in HV SW. Gr.

J. MV motor voltage (415 VAC) : : 0.37 kW to 160 kW K. Power factor improvement capacitors : NA

L. Battery charges : 415 V AC M. UPS System : 415 V AC N. AC Lighting / Power Panels and

Auxiliary Boards : 415 VAC O. Welding Receptacles : 415 V AC P. Bulk loads like Process Heaters etc. : 415 VAC Q. Normal Lighting / Emergency Lighting : 240V AC R. Motors rated below 0.37 kW : 240 V AC S. Convenience outlets : 240 V AC

T. DC Motor : DC motors not envisaged in hazardous areas.

( e.g. emergency lube oil pump motor etc.)

U. MOVs : 415V AC

3.3 Utilisation voltage for critical supplies

A. Normal Instrumentation power supply : # V AC B. Critical instrumentation power supply : # V AC/ DC

C. Shut down system power supply : V, AC (UPS) /DC D. Switchegear protection and critical

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E. DC supply for instrumentation #

Refer Instrument design basis : Independent system F. Fire alarm system power supply : 240 V. AC Normal

4.0 Metering for grid incomers ( If applicable)

A. I) protection relays for 11 or 33kv switch gear : NA

II) Protection relays for 6.6kv switch gear : On switch gear B. 11kv or 33KV Switch gear control : NA

i) ON/ OFF for testing purpose : NA ii) Normal operation : NA C. 6.6KV Switch gear control

i) ON / OFF for testing purpose : From switch gear ii) Normal operation for Incomers/

Bus Tie/ Transformers feeders : From switch gear

iii) 6.6KV motors feeders : Field / DCS control room D. Annunciation panel

i) For each substation in operation room : NA ii) For Power Plant control room : NA

iii) UPS and DC trouble : shall be provided in control room DCS E. Numerical Protection / Monitoring system

(MMI/ SMS for each substation)

i) EHV system : NA ii) HV Switch board : Yes iii) 415V MCC : No iv) 415 V MCC : No F. MMI / SMS system separate for

EHV / HV system relays : NA G. Centralised Lighting control

From operator room. : NA

H.. Microprocessor based system for control : interface I/ O requirement etc. shall be Interlocking and monitoring of electric MR. furnished by CPCL for inclusion in switch

Power system. Gear. I. Limiting Conditions for Motor start up

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

i) HV Motors : Motors starting current as per standard

specification for motor rated upto 2500KW and Motor starting current limited to 400% of normal Current for KW more than 2500kw.

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ii) MV Motors : As per standard specification unless other wise specifically mentioned.

iii) Method of starting : Direct on line (DOL) For large HV motors

iv) Method of starting for large MV Motors

(Above details shall be forwarded by CPCL to CPP Contractor to decide machine parameters and system design)

G. Isolation for remote transformers : Push button near transformer bay for tripping remote Breaker.

4.3 Protection devices for power distribution system shall be as indicated below. Requirements for switchyard, power generation and D.G (If required) shall be as per cl. 14.0 of this document or as shown on the single line diagram and data sheets

Transformer feeder Motor

feeder Out goingFeeder Incomer Relay number _(L.V winding > 3.3kv ) (L.V winding < 3.3kv) HV&M V above 55 kW) HV MV /PCC/ PMCC HV MV / PCC/ PMCC

51 IDMTL over current relay

Yes Yes - Yes Yes (4) Yes

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Yes (4) 51 N IDMTL earth fault

relay

Yes (7) No - Yes No Yes(

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Yes (4) 51G back up earth fault

relay (secondary neutral)

Yes Yes - No No No No

Motor protection relay with locked rotor feature (50, 50N, 46,49, 50L /R)

No No Yes No Yes (8) No No

64 R instantaneous restricted earth fault relay (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 Yes No

86 tripping relay Yes Yes Yes Yes Yes Yes Yes

95 trip circuit supervision relay.

Yes Yes Yes Yes No Yes No

63 auxiliary relay(transformer)

Yes Yes - No No No No

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Transformer feeder Motor feeder Out going Feeder Incomer Relay number _(L.V winding > 3.3kv ) (L.V winding < 3.3kv) HV&M V above 55 kW) HV MV /PCC/ PMCC HV MV / PCC/ PMCC with timer. (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

&distribution bus.

4. _______.

5. Where ever auto transfer feature is provided.

6. Instantaneous earth fault 50 N shall be provided only for transformer with delta

primary.

7. Directional IDMTL earth fault 67N shall be provided only for transformer with

star primary.

8. For motor feeders rated 75 kW & above.

9. For switch gears having bus transformer scheme, where continuous or momentary

Paralleling in envisaged, check synchronising relay shall be integrated with overall paralleling scheme.

10. The bus tie feeders in HV switch boards shall be provided with 51, 51N, 86 and

95 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 switch board with parallel operation if incomers, following additional relays shall be provided.

i) One set of 87B (Bus differential) and 95 B( Bus wire supervision) for each bus section.

ii) 67 and 67N (Directional IDMTL over current & earth fault) relays for the

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

i) HV & MV capacitor feeders

ii) HV and MV breaker controlled motor feeders or contractor feeders with

DC- control supply.

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

15. One set of bus differential relays (87B) and bus wire supervision relay (95B) for each bus section shall be provided for HV switch boards connected directly to generation buses and those used as extension buses at remote substation.

4.4.The metering devices in HV and MV switchboard shall be as below.

Feeder type A V Hz PF MW MWH Hour

Run MVAR MVAH MVA

HV Incomer X X X X - X - - - -HV Bus Tie X - - - -HV Transformer X - - - X - - - -HV Bus P.T - X - - - -HV Plant Feeder X - - - - X - - - -HV Motor X - - - - X (kWh) X - - -HV Capaciter X X - - - -PCC/ PMCC Incomer X X - X - X(kW h) - - - -PCC/ PMCC Bus Tie. X - - - -- -PCC Bus Tie - X - - -

-ACB Out going X - - - - X(kW

h) - - - -MV Motor(>- 75 kW) X - - - -MCC/ ASB Incomer X X - - - -MCCB/SFU Out going (>- 250A) X - - - - X(kW h) - - - -LDB Incomer X X - - - -DG Set X X X X X(kW h) X (kWh) X - - -5. Substation Design

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5.1. EHV Switchyard (IF applicable) NA

A. Type : String bus / Tubular bus B. Structure : Galvanised

C. Bus material : Aluminium / Copper

5.2. HV / MV Substation

HV MV

Elevated with trays in cable cellar Yes Yes

Raised with internal trenches No Yes(for MCC room)

All top cable entry with trays below ceiling

No No

Pressurisation against ingress of dust Yes Yes Air conditioned room for operator /

Variable speed drives / Annunciator panel / MMI system/ Exiter panel etc

Yes Yes

Final paint shade for switchboard / Busduct / Pressurisation duct / all elect, equipment, Panels, JB etc.

Shade –631

as per IS -5 Shade – 631as per IS – 5

5.3. Specific Equipment Locations

A. Batteries : Separate room in sub station / control room for electrical and

instrumentation system respectively. B. Battery charger : Air – conditioned room

C. Variable speed drive panels/ Thyristor : Air- conditioned room Controlled panels.

D. UPS System : Air- conditioned room in control room E. Lead- Acid and Nickel- Cadmium

Batteries in separate rooms. : Yes

F. Annunciation panel : Operator room in substation.

6. EQUIPMENT DESIGN

6.1. EHV Switchyard (if applicable)* : NA

A. Bus bar system : Single B. Circuit breaker type : SF6

C. Isolator type : Center break

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A. Execution : Drawout B. Bus bar : Single C. Circuit breaker type : Vacuum D. Motor Control : Breaker E. Separate : No

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

A. CT Secondary

- Protection : 1A - Metering : 1A B. PT Secondary : 110 V AC

6.4.Transformers (Power / distribution)

Transformer Vector group Tap changer Soak pit Preferred rating (MVA)

Main power transformer NA

Generator unit transformer NA Intermediate power transformer NA

Dedicated (eg for VSD) As Reqd Off –circuit Later

Distribution transformer

(< - 2000 KVA) Dyn 11 Off- circuit No 2MVA Later

6.5.MV Switchboard A. Execution

i).PCC / PMCC Breaker panels : Drawout / Single front

contractor feeders : Drawout, Single / Double front ii). MCC : Drawout : Single / Double front iii). ASB : Fixed : Single

iv). LDB : Fixed : Single

v) .Motors PMCC : Above 55KW Upto 160 kW MCC : Upto 55 kW

B. Motor Starter Type

i). Contactor and switch fuse with over load relay : Upto 22 kW

ii). Contactor, switch fuse & CBCT for : Sw. fuse 250 A & for motor

feeders above 22 KW up to 55 KW with earth fault protection

iii) Contactor and switch fuse with motor

protection relay : More than 55 KW and up to 75 KW. iv) Air circuit breaker with motor protection relay : Above 75 KW upto 160 KW

v). Contactor and MCCB with over load relay : Not applicable vi) Contactor, MCCB & over load relay

with CBCT for earth fault protection : Not applicable

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i). Auto/ Manual switch : : DCS in control room @ ii). Local/ remove switch : DCS in control Room @ iii). Normal / Standby switch : DCS in Control Room @ iv). Sequence interlock : PLC in control room @ v). Process interlock : PLC in control room @ vi) Reacceleration equipment : Switch gear in substation

@ To be provided as per process package / operating philosophy. vii) Control voltage for contractor Starter : 220 V AC viii) Control supply for contractor starter : Control transformer.

6.6.Motors

Motors High voltage 415 volts

Enclosure : Indoor Outdoor IP55 IP55 IP55 IP55

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

Anti- condensation heater Yes Above 30kW

Additional canopy (out door

motors) Yes Yes

Design voltage / frequency

variation + - 10% / + - 3% + - 10%/ + - 3%

6.7. UPS System

A. Redundancy : 100%

B. Type of redundancy : Parallel redundant for UPS for DCS power

Non redundant for Analyser shelter UPS’s

C. Back – up –time : 30 minutes D. Inverter by pass transformer : Static

E. By pass transfer control : Auto / Manual

F. Battery type : Ni- Cd for capacities above 5 KVA SMF for lesser capacities

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

6.8.Communication System

A. Plant Communication System : NA

B. Telephone System :Yes C. Telephone System & plant communication system: Separate D. No. of intercom & P&T lines : Later E. Battery type :

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F. Battery back up time : 2 Hrs.

6.9. Fire Detection &Alarm System

A. Type : Analogue addressable B. Name of buildings to be Provided with detectors : Substation / Control room

building etc. C. Battery type : VRLA

D. Battery back up time : 48 hrs. (Normal) + 30 minutes. (Alarm) E. Detection System : Break Glass/ Smoke and Temp. Detector. F. Siren for the plant : Not Attended

6.10. DC System

If DC Supply is required the same shall be sourced from a separate dual float cum boost charger and DCDB.

A. Battery type

i) Switch gear Protection ,Control & critical lighting. : Ni -cd ii) Instrumentation System : Ni – cd iii) Diesel Engine Starting : NA iv) DC Motors : B. Battery back up time

i) Switch gear Protection & Control : 2 Hours ii) Critical lighting : 2 Hours iii) Instrumentation : 30minutes iv) Diesel Engine Starting : NA v) DC Motors : NA

6.11. Cables

The power and control cables shall have the following minimum cross sectional areas: a). Medium voltage power cable : 25 mm2 (Aluminum) / 2.5. mm2 (Copper) b). Controls cables : 2.5 mm2 (Copper)

c). Lighting : 2.5 mm2 (Copper)

d) Communication system : 0.9 mm dia (Copper) jelly filled

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Note : 1) For lighting inside the building, minimum 1.5 mm2 copper conductor, PVC

insulated wire shall be used in conduit system (for circuit and point wiring), with proper colour coding.

2) All power cables up to 16mm2 shall be of copper conductor.

3) Cable size are indicative only and same shall be finalized as per equipment / Manufacturer’s recommendation.

7. Cabling System

7.1. Cable details

Design Criteria High Voltage 415 volts

Loads located beyond 1 km Cable

-Loads located 200 – 1000 m 3 -core cable 3 ½ - core cable

Load located upto 200m Cable Cable / Bus trunking

Loads beyond 1 kA ratting Bus duct/ Cable Bus duct Recommended limiting size of

multi core cable (mm2)

300 300

Short – circuit with stand time (seconds)

0.2 (Out going ) / 0.06 (Plant)/ 1.0 (Incomer)

N.A Insulation voltage grade Unearthed for 6.6KV Earthed

Type of cable insulation XLPE PVC

7.2. Cable laying philosophy

A. Process area : Above ground in overhead cable tray/ directly buried B. Off site paved area : Above Ground cable tray (on sleeper / Overhead rack) or

RCC trench/ directly buried

C. Offsite unpaved area : Above Ground cable tray (on sleeper / Overhead rack) or RCC trench or directly buried type.

D. Cables for non hazardous area : Armoured.

E. Type of cable trays : Galvanized prefabricated

F. Special requirements : Cables for fire water system shall be taken on exclusive route through underground trench starting from main substation G. Road Crossings for under ground cables : Cable culvert.

H. Road Crossings for above ground cables : Over head cable bridge / Cable culvert

8.0. Earthing System

A. Earth electrode : GI Pipe B. Main earth loop : GI strip C. Substation earth loop : GI strip

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E. Lightning conductor : As per IS: 2309.

9.0. Lighting System 9.1. Supply System

A. Centralised with separate transformer : No B. At each substation with separate transformer : Yes C. Separate metering required : Yes

9.2. Control Philosophy

A. Out door yard : Auto / Manual ; Centralised / Local

B. Street lighting : Auto / Manual ; Centralised / Local C. Out door process area : Auto / Manual ; Centralised / Local D. Process building : Auto / Manual ; Centralised/ Local E. Auto control : Synchronous timer.

F. Lamp type for Outdoor lighting : HPSV / MLL/ Metal Halide lamp /HPMV G. Panel execution : LDB connected to MCB panels.

H. ELCB at incomer of : Yes lighting & Power Panels

9.3. AC Emergency Lighting:

A. Name of process plants : NA

B. Name of buildings : Control room – to be provided C. Power supply : NA

9.4. DC Critical Lighting For Escape

A. Name of process unit : As per OISD guidelines

B. Name of building : Substation, control room Buildings, ACplant etc. C. Power supply : 110 V DC

9.5.Wiring Type:

A. Process plant / Building / Shed : Armoured cable B. Large service building : Concealed conduit

C. Buildings with false ceilling : Cables / surface conduit above false ceiling. D. Substation (Switch gear Room) : METSEC channel

E. Substation(Cable Cellar) : Armoured cable

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9.6 Specific Lighting Requirements

A. Aviation lighting : NA B. Navigation lighting : No C. Security lighting for peripheral road

Boundary wall : NA D. Type of control gear for HPMV/ HPSV lamps for Process units, Plant / non plant building : Separate

E. Control gear box location : Accessible level(Not more than 2 meters above operating level) for separate control gear.

F. Type of flood light mast : Telescopic tubular (30m High lighting mast) with integral power control.

10. Electric Heat Tracing System

A. System Design Basis : Product Classification approach.

11. Electrical Equipment for Hazardous Areas

11.1 The electrical equipment for hazardous areas shall be selected as per IS – 5571 and petroleum rules. The minimum requirement is summarised below.

Zone-I Zone-II Equipment

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

MV Motors Ex –d Ex-d Ex-e Ex-e

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

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

Motors 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-dEx-d Div.2 Ltg.(IS –8224) Ex-d / Ex-e

Div.2 Ltg. (IS – 8224) Ex-d/ Ex-e

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Hand Lamps i)Light fitting ii)Transformer 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

(FireAlarm 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 200 0C Notes :

1. The electrical equipment for hazardous areas shall generally be suitable for gas group IIB and temp classification T3 as applicable to the selected type of explosion protection. In case of hydrogen of hydrogen or hydrocarbon mixtures having more than 30% volume hydrogen, the gas group to be considered shall be IIC.

11.2.As additional safety features, the following requirements for electrical equipment shall be followed.

A. All electric motors for agitators / mixers and metering pumps handling flammable material shall be flame proof type irrespective of the area being classified as zone -2 or zone -1.

B. All electric motors for vertical oil sump pump shall be flame proof type.

C. Irrespective of the area classification (whether zone -1 or zone –2 ) all lighting fittings with in the storage areas shall be flameproof type.

D. Irrespective of the area classification (whether zone –1 or zone-2 ) , all motors and lighting fittings within the pump house (station) associated within the loading / unloading gantries shall be of flame proof type.

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

F. Even though fired heaters in process units are not considered ammonia as refrigerant, the room housing air conditioning equipments associated with fired heaters in process units shall as a minimum be suitable for installation in Zone -2 area.

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G. Where air conditioning system is designed considering ammonia as refrigerant, the room housing air conditioning equipment shall be adequately ventilated to classify it is a safe area. For additional safety the following shall be considered:

! 100% standby system for ventilation

! Location of MCC / local panels in adjacent separate room. ! Instrumentation to be flameproof type or hermatically sealed. ! AC plant room motors suitable for zone –2 area.

! Lighting in AC plant room suitable for zone -2 area.

H. All electrical equipment installed in Analyser room shall be flameproof type suitable for gas group IIA, IIB , IIC irrespective of the area being classified as Zone –1 or Zone -2. 12. Statutory Approval

Statutory Authority for

Electrical Installation : Central Electrical Inspectorate Statutory approval / License

For hazardous area equipment : For indigenous equipment

CMRI Test certificates, CCE, DGF ASLI approval certificates and BIS License (for flameproof equipment)

13. Cable Sizes for MV Motors

13.1 Direct on line (D.O.L) start motors

Cable Details Motor Rating Number

of runs No. of cores per run Conductor material Conductor size mm2 Below 3.7 kW 1 4 Cu 4 3.7kW 1 4 Cu 6 5.5kW 1 4 Cu 10 7.5kW 1 4 cu 16 9.3 kW 1 3 ½ Al 25 11K 1 3 ½ Al 35 15W 1 3 ½ Al 50 22kW 1 3 ½ Al 70 30kW 1 3 ½ Al 70 37kW 1 3 ½ Al 95 45kW 1 3 ½ Al 120 55kW 1 3 ½ Al 150 75kW 1 3 ½ Al 185 90kW 2 3 ½ Al 120 110Kw 2 3 ½ Al 120 125/ 132 kW 2 3 ½ Al 185 160kW 2 3 ½ Al 185

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180kW 3 3 ½ Al 185

13.2 Cable sizes for motors not conforming to above table (e.g Extended distances, Reduced voltage starting) shall be as below.

13.3 Cable sizes mentioned above are applicable for a distance of maximum 350 m and for 2/4/6 pole motors. Cables sizes for other distances and low speed motors shall be worked out by the engineering contractor.

CHAPTER 4 JOB SPECIFICATION

FOR

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4.2.3 All electrical equipment installed in hazardous areas shall be selected as per IS- 5571 and shall meet the requirements of relevant IS, IEC or NEC Standards. However, electrical equipments for Zone – 2 areas as a minimum shall be ex (e)/ Ex (n) type as per IS/IEC codes. Increased safety {Type Ex(e)} equipment shall not be used in Zone-1 areas. Ordinary industrial electrical equipment (even though permitted for use in Div.2 area as per NEC) shall not be used in Zone –2 areas. Type of explosion protection to be used for individual equipment shall be as specified in the job design data.

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4.2.4 For pressurised electrical equipment {Type Ex(p)}, on failure of pressurisation system , the following minimum actions shall be provided:

Area classification Enclosure does not Enclosure contains ignition Contain ignition capable apparatus. Capable apparatus

Zone 1 Alarm Alarm and Switch- off. Zone-2 No action reqd. Alarm.

4.2.5 All electrical equipments for hazardous areas shall be certified by CMRI, PTB, BASEEFA, UL or FM or equivalent independent testing agency for the service and the area in which it could be used and shall be approved by CCE/DGFASLI/DGMS (as applicable). All indigenous flameproof equipment {Type Ex (d)} shall be under BIS license.

4.2.6 Motors fed by frequency converters/variable frequency power supplies shall be tested and certified along with the converter by an a appropriate agency.

4.3 Power System Design

The distribution system shall be designed in accordance with project specification taking into account all possible factors affecting the choice of the system to be adopted such as required continuity of supply, flexibility of operation, operational costs, reliability of supply from available power sources, total load and the concentration of individual loads.

Special attention is drawn to chapter X of IE rules which includes requirements for design of electrical system as applicable to oil mine installation under the jurisdiction of DGMS.

4.4 Capacity of Electrical System

All the components of the electrical system shall be sized to suit the maximum load, under the most severe operating conditions. Accordingly, the maximum simultaneous consumption of power, required by continuously operating loads shall be considered and an additional margin shall be taken into account for intermittent service loads, if any. System design shall permit direct- on- line starting of all motors unless specified otherwise.

The amount of electrical power consumed by each process unit shall be calculated for its operation at the design capacity. As far as practicable, a switchboard for essential services required for plant maintenance during extended period of shut –down, shall be provided.

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4.5 System Voltages

Voltage selection shall be based upon the following factors: a) Size and location of loads.

b) Provision of future extension c) Short circuit level

d) Availability of switch gear with suitable current rating and rupturing capacity e) Possibility of keeping the number of different voltage levels to a minimum f) Utilisation voltages for various equipment

g) Economics

The choice of voltages may also be affected by local regulations, standards, as well as, the voltages of existing installations.

4.6 Voltage Drops

4.6.1 The maximum voltage drops in various sections of the electrical system under steady state conditions at full load shall be within the limits stated in the following table:

S.NO SYSTEM ELEMENT MAXIMUMPERMISSIBLE VOLTAGE DROP

a) Busduct or cable between transformer secondary and HV Switchboard or PCC/PMCC

0.5% b) Cable between PCC/PMCC and MCC or auxillary

switchboard.

i)MCC / Auxillary Switch board near PCC/PMCC

ii) MCC / Auxillary Switchboard situated remote from PCC / PMCC.

0.5% 2 to 2.5% c) Cables between HV Switchboard and HV Motor 3%

d) Cable between PCC/ PMCC and motor. 5.5%

e) Cable between MCC (situated near PCC/PMCC) and motors.

5%

f) Cable between MCC (situated remote from

PCC/PMCC) and motors

3% g) Cable between Auxillary Switchboard & Lighting

Panel.

1 to 1.5% h) Circuit between lighting panels and lighting points. 4%

i) DC Supply Circuit (Electrical Controls) 5%

j) DCDB to Control Room 2% (Note – 1)

k) UPS outgoing circuit 5% ( Note- 1)

Note – 1 Minimum voltage available across any instrument in the field shall be as per Instrumentation design basis. Distribution system for instrumentation supplies shall be

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designed accordingly. In case of any conflict between electrical design basis and instrumentation design basis, the later shall govern regarding instrumentation power supplies. 4.6.2 The maximum voltage drop at various buses during start up of large motor and / or

motor reacceleration conditions shall be with in the limits stated below:

S.NO SYSTEM ELEMENT OPERATING

CONDITION MAX.PERMISSABLE

VOLTAGE DROP a) At the busbars of the worst

affected Switch board.

Start up of the large HV motor with other loads on the bus or reacceleration of a group of HV motors(Simultaneous start up or group reacceleration of MV motors is not envisaged) 15%

b) At the busbars of the worst affected MV Switchboard. (PCC/PMCC/MCC)

Start up of large MV motor with other loads on the bus, or reacceleration of a group of MV motors.

10%

c) Cables between HV Switch board & motor.

Motors start up or reacceleration. 5% d) Cables between MV switchboard (PCC/PMCC/MCC) & motor. Motor start- up or reacceleration. 15% NOTES:

a) The voltage available at the motor terminals during start –up must be sufficient to ensure positive starting or reacceleration of the motor (even with the motor fully loaded, if required), without causing any damage to the motor.

b) For medium voltage motors, the voltage available at the motor terminals must not be less than 75% of the rated value during start- up or reacceleration.

c) For high voltage motors, the voltage available at the motor terminals must not be less than 80% of the rated value during start –up or reacceleration.

4.7 System Earthing

4.7.1 System earthing for incoming supply & primary / secondary / HV distribution system shall be as per design data. The 415 V system neutral shall be solidly earthed.

4.7.2 For resistance earthed system, the resistance value shall be chosen to limit the earth fault current to a value which shall be sufficient for selective and reliable operation of

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earth fault. However, the value of limited earth fault current shall generally not exceed 50% of transformer or generator full load current.

4.8 Short Circuit Capacities

Each short circuit interrupting device shall be designed to have rated service-breaking capacity (Ics) equal to or higher than the maximum value of short circuit current calculated, at is location. The related switchgear and busduct shall withstand the above maximum available fault current for a minimum period of one second. The sizing of high voltage cables shall be based on the short circuit withstand capacity for a minimum time period as dictated by the protection system in addition to the maximum anticipated load current.

4.9. Insulation System

The insulation of electrical facilities shall be designed considering the system voltage, the system neutral earthling and the over voltages resulting due to system fault, switching or lighting surges. The insulation coordination between the electrical equipment and the protective devices shall be done in line with IS: 3716.

Lighting arresters ad surge absorbers shall be provided where necessary.

4.10 Protection and Metering Schemes

4.10.1 The protective system shall be selected and coordinated to ensure the following:

a) Protection of equipment against damage which can occur due to internal or external short circuits or atmospheric discharges.

b) Uninterrupted operation of those parts of the system which are not affected by the fault.

c) Personal and plant safety.

4.10.2 In general, quick acting relays (with time delays, if necessary) shall be used and all fault tripping shall be done through high speed tripping relays. All relays, excepting auxiliary relays and timers, shall be draw out type.

4.10.3 Metering instrument shall be provided to keep a record of power consumption and supervision of all instrument shall be flush mounted back connected type.

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4.11. DC Power Supply

Independent DC Power supply systems shall be provided for the following: - Plant shutdown system and DC instrumentation.

- Electrical switch gear controls and critical lighting. - PLCC equipment.

- Emergency DC motors (if applicable) - Telephone system

- Fire alarm system.

- Diesel engine starting (for each engine) - Communication system (if applicable) - Telecom & SCADA ( if applicable)

Each DC power supply system shall include charger -cum –rectifier, dual float cum boost type, batteries and DC distribution board.

4.12. Emergency Power Supply

The emergency power supply system, where ever envisaged, shall feed the following: - Electrical loads essential for the safe shutdown of the plant.

- Emergency lighting.

- Process plant instrument as required. - Communication equipment.

- Fire alarm system. - D.C Supply system. - UPS Systems.

- Fire fighting equipment excluding main fire water pump. - Loads critical for process, plant and personnel safety.

- Emergency power supply shall be made available within a time period of 30 seconds, from the instant of failure of normal supply.

- The emergency generator shall, generally, not be required to run continuously in parallel with the normal power supply system.

4.13 Uninterrupted Power Supply

Uninterrupted power supply system shall be provided, (if required) for meeting critical loads that cannot withstand a momentary interruption in voltage. A separate battery shall be provided for UPS system. Following loads shall be connected to the UPS system.

- Critical instruments and control. - Critical communication equipment. - Critical security equipment.

- Computers.

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4.15 Plant Communication System

4.15.1 It shall consist of the following:

- Micro – processor based central exchange installed in the control room. - Power supply system.

- Master station along with external loudspeaker, microphone etc.

- Desk type call stations along with microphone and external loudspeaker for installation in buildings.

- Wall / column mounting type call stations for hazardous / safe areas with external loudspeaker.

4.15.2. Paging speakers provided in areas having high ambient noise levels shall produce a paging level at least 6dB above the anticipated ambient level. Field stations shall be capable of operating in areas of high noise without any interference. Separate battery and battery charger shall be provided for each exchange.

4.15.3. System shall have provision for addition of10% field call stations/ loud speakers in future.

4.16 Fire Detection & Alarm System:

4.16.1 The Fire Detection & Alarm System shall be an independent system comprising of individual break glass type manual call points, automatic sensors e.g. smoke and heat detectors, main panel, zonal panel, hooter, battery charger & other hardware. The system shall be designed to provide audio – visual indication at the main panel to be located in fire station and zonal panel, in control room. Repeater panels shall be provided as applicable.\

4.16.2. The manual call points shall be provided at strategic locations with access of 60mtrs. Along all exit routes & roads.

4.16.3. Battery and battery charger shall be provided for each panel separately. 4.16.4 Electrical sirens shall be provided at stragegic points to cover entire plant area. 4.16.5 Response indicators, hooters & exit lights shall be provided at required locations. 4.16.6 System shall have provision for addition of 10% detectors, manual call points in future. 4.16.7 The fire detection system shall be interfaced with fire suppression system; wherever required.

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5.0 EQUIPMENT DESIGN PHILOSOPHY

5.1 General

The equipment shall in generation conform to Standard specifications. Equipments shall be designed as per philosophy given below.

5.2 Transformers

5.2.1 All Transformers except lighting transformers shall be three phases, oil immersed, double wound type suitable for outdoor use. Lighting transformers shall be dry type. 5.2.2 The rating of transformers shall be decided based on the following

criteria:-ONAN transformers:- The rating shall be equal to or higher than 110% of maximum simulations demand envisaged.

ONAN/ONAF transformers:- The ONAN rating shall be equal to or higher than the maximum simulations demand envisaged. The ONAF rating shall be equal or higher than 125% Of ONAN rating.

5.2.3 The percentage impedance of each transformer shall generally be as per Indian Standards.

5.2.4 100% standby transformers shall be provided in all unit, offsite & utility substations, unless otherwise specified.

5.3 Switchgear

5.3.1 All switchgear and associated equipment fed from generators and transformers shall have rating equal to the rating of respective generators and transformers feeding it, under any circuit configuration. However, generator incomer shall be rated at least equal to 110% of the continuous rating of generator and transformer incomer shall be rated atleast equal to forced cooled rating of transformer or 110% of ONAN rating as applicable.

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5.3.2 Bus tie circuit breakers shall have rating higher of the following: a) Largest incoming circuit breaker.

b) Maximum running load on either side of bus section.

In no case shall the tiebreaker rating be less than the bus- bar current rating.

5.3.3 All other switchgears not directly fed from generator and transformers shall have rating atleast equal to the maximum demand under any circuit configuration plus a provision for 10% future load growth. Incomers of these switchgears shall be designed to cater to the complete load including 10% margin for future load growth.

5.3.4 Spare outgoing feeders shall be provided in all switchgear. At least one number of each rating and type or 20% whichever is more, shall be provided as spare.

5.3.5 Circuit breakers/ contactors controlling motor feeders shall have a rating of at least 125% of the maximum continuous rating of the connected motors.

5.3.6 Separate feeders shall be provided in the switch board for each load/ motor. However, as an exception maximum two numbers welding receptacles may be connected to one power feeder.

5.3.7 All circuit breakers shall be of single break type having one pole per phase. Circuit breakers for MV generator incomer shall be with four poles. Alternatively three pole breaker with adequately rated air break contactor for neutral isolation may be provided.

5.3.8 In case of HV vacuum circuit breaker, adequate provision shall be made for motor switching to limit the over voltage to 2.2 per unit of rated peak line to earth voltage. 5.3.9 Service breaking capacities (i.e. Ics) for all breakers & MCCB s shall be equal to or

higher than the maximum value of the short circuit at the point of installation. MCBB s with back up fuses shall not be acceptable.

Electrical Design

CONTENTS

CHAPTER 1

ELECTRICAL SCOPE OF WORK

FOR

OFFSITE AUTOMATION – Electrical Scope of Work

CHAPTER 2

STANDARD SPECIFICATION

FOR

CONTENTS

CHAPTER 3

ENGINEERING DESIGN BASIS

FOR

CHAPTER 4

JOB SPECIFICATION

FOR

CONTENTS