Design basis report.pdf

8/9/2019 Design basis report.pdf

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(ELECTRICAL)

DOC NO: DALIANEAST-CCE-20006-DBR-XXX-800

JULY 2013

EE PP CC CCOO NN TTR R AACCTT OO R R

M/s. DALIAN EAST NEW ENERGY DEVELOPMENT CO., LTD.

DALIAN, CHINA .

EENN GG II NN EE EER R II NN GG CCOO NN SS UU LLTT AANN TT

CETHAR CONSULTING ENGINEERS LIMITED .

( 100% Owned by TRACTEBEL Engineering Pvt. Ltd)No.672/476, Ground FLOOR, TEMPLE TOWER

NANDANAM, CHENNAI- 600 035,INDIA.


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M/s DALIAN EAST NEW ENERGY DEVELOPMENTCO.LTD

1X23.5 MW WASTE HEAT RECOVERY POWER PLANT

FOR SHREE CEMENTS LIMITED, RAS, RAJASTHAN

DALIANEAST-CCE-20006-DBR-XXX-800 / REV 00

DESIGN BASIS REPORT(ELECTRICAL ) Page

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DALIANEAST-CCE-20006-DBR-XXX-800 /REV 00

26.07.13 00 C.Sudarmathi P.Manivannan S.Manivel

Document No. IssueDateRevNo. Prepared By Reviewed By Approved By


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1.00.00. INTRODUCTION

This Design basis report covers the features of Electrical system/

equipment and design philosophy to be adopted for 1 x 23.5MW WHRB

Power Plant at Shree Cement Limited, Ras, and Pali District- Rajasthan

State. Detail engineering works would be carried out in accordance with

the concepts developed in this report. This report covers the major

features and design philosophy proposed to be adopted for the following Power Generation System and Evacuation (Via Tie feeder) Generator

AVR Panel LAVT Panel NGR Panel Generator relay and control panel Synchronizing Panel segregated phase bus duct 11kV Switchgear Auxiliary distribution transformers Non- segregated phase bus duct

LT PCC / MCC / APFC/DBs DC System Cabling system Plant lighting system Plant earthing and Lightning protection system

2.00.00. PROJECT SITE DATA:

Location : BangurCity, RAS Pali District,Rajasthan

Altitude : 378.0 m above MSLAmbient air temperature : (Dry)

- Minimum: 9C

- Maximum: 48C

Design temperature for : 50C electrical equipment

Design relative humidity : 40%

Basic wind velocity : 4.7 m/s


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Average annual rain fall : 368.34 mm

Seismic zone : Zone III

3.00.00. CODES & STANDARDS

All the electrical equipment and materials shall generally conform to

Indian Standards and CBIP recommendations for power station design.

Statutory guidelines of the following will also be observed in

implementation of Power plant.

Indian Factories act Indian Electricity Act Indian Electricity rules TAC (Fire protection) Regulations for electrical equipment Indian Standard Code. CBIP Recommendations. IEC. IEEE.

3.01.00. Standards in below to be followed for the Respective equipment asper contract.

Transformer : IS 2026 Circuit Breaker : IEC - 56 / IS 13118 LT Switchgear : IS 4237 / IS 4047 LT Cables : IS 1554 / IS 7098 Part I Current Transformer : IS 2705 Potential Transformer : IS 3156

Earthing : IS 3043 Lightning Protection : IS 2309 Motors : IS 325 / IS 4029 Insulation Rubber mates : IS15652-2006


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4.00.00. DESIGN CONSIDERATIONS

The Electrical system will be designed based on the requirements for the

safe, reliable performance, easy operation and maintenance of all

equipments covered in this report and the associated electrical system.

4.01.00. Basic Design Basis Data:

Proposed Capacity : 23.5 MW Configuration & rating : 1 x 23.5 MW

System Frequency : 50 Hz 5% Generation voltage : 11kV CPP Auxiliary Voltage : 11000V & 415V ( 10% ) DC System Voltage : 110V Control Supply Voltage : 110 V 10% for AC,

110 V, - 15% for DC Design Max. ambient temp : 50 deg C Design life : At least 30 years Periodic maintenance interval: Greater than 4 years

Environment : Tropical,dusty,chemical,laden,atmosphere

VFD selection : VFD power selection shall be

considered after derating at

max. ambient temp

4.01.01. Following fault levels will be considered for design of all electrical

equipment at various voltage levels. Fault levels shall be restricted

to the same.

System Fault Level Duration

11 KV System 40KA 1 seconds

415 V System 50KA 1 seconds

110 V DC System 10 KA 1 seconds


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4.01.02. The system details at various utilization equipment voltages will

be as given below

S.No. Service Voltage PhaseSystem Neutral

Earthing

01. Generation 11 KV AC, 3Ph Low Resistance

02.HV

Distribution11 KV AC, 3Ph

Non Effectively

Earthed

04. LV Panels 415V AC, 3Ph

Solidly earth at

transformer starpoint

05. LV Motors 415V AC, 3Ph Earthed

06.

Lighting /

Space

heater

Circuits

230V AC,1Ph&N Earthed

07. UPS 230V AC, 1Ph&N Earthed

08. DC System 110V DC DC (2 Wires) Unearthed

4.01.03. The system details at various utilization equipment

Auxiliary/Control voltages will be as given below

Sl.

No.Service Voltage Remarks

01. Control Voltage(HT Panel)

110V DC Protection, Breaker controland indication

02.Aux. Voltage

(HT Panel)230 V UPS Metering

03.Control Voltage

(PCC)

110V DC /

AC

Protection, Breaker control

and indication


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04.Aux. Voltage

(PCC)110 V AC Metering

05.Control Voltage

(MCC)230V AC

Breaker control and its

indication

06.Aux. Voltage

(MCC)

110V AC (2

Wire)

Feeder Control and its

indication

07.Aux.Voltage

(MCC)

240 V

AC (2 Wire)

Space heater/cubicle lamp,

etc.

5.00.00. System Configuration

5.01.00. Power Generation & Evacuation

One no rated 25 MW, 11kV at 0.8 pf and synchronous generator with

brush less excitation system will generate power for the plant with

excitation transformer.

One number Evacuation feeder in HT panel will be used for evacuation of

power.

The Plant auxiliary supply will be taken through 2 nos of 2.5 MVA 11/0.433kV auxiliary distribution transformers.

5.02.00. Plant start up power & Normal Running

The plant start up power is fed through customer 11 KV Cement plant

panel in Evacuation feeder. The plant auxiliaries are started through by

closing evacuation feeder breaker which is connected to customer 11kV

cement plant panel.

Once the STG is started, the incomer breaker of the generator feeder

connecting to the 11 kV switchgear at CPP can be closed i.e. the generator

will be synchronized with the start-up supply source. When the STG is in

service it will feed its own auxiliary loads and excess power will be

evacuated through evacuation breaker.


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6.00.00. Equipment Design

6.01.00. Generator:

The generator will be 2 poles, 50Hz, star connected, 3 phase type and it is

designed for continuous operation at its rated output of 25 MW at 0.8pf.

The cooling system will be closed air circuit water cooled (CACW) type.

The generator will be capable of continuous operation at rated MVA &

power factor at any voltage from 90% to 110% of rated voltage and within

a frequency range of 45 to 55 Hz.

The generator will be of cylindrical rotor design, degree of protection

conforming to IP 54 for alternator & IP 54 for exciter. The generator will

be provided with brushless digital excitation system. The generator is resin

rich type with class F insulation and class B temp rise.

6.02.00. AVR panel:

The excitation system shall be with Microprocessor based Digital AVR with2 nos auto channel and 2 nos manual channel. The digital Auto excitation

regulator will be fed through excitation transformer.

6.03.00. LASCPT PANEL

11 KV HT LASCPT panel shall include Surge Capacitor, Lightning arrestor

Excitation transformers, and Potential transformers. Degree of protection

for LASCPT Panel shall be IP55.

Surge Capacitor : 12kV, 0.25F Lightening arrestor : 12kV, 10kA Excitation Transformer : 11KV / 220V, YD11 Potential transformers : 11 kV/3 /110V/3/110V/3/110V/3


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The following table illustrates the Potential Transformers considered in

LASCPT Panel.

Sl.No PTs CORE 1 CORE 2 CORE 3

1 PT 1

CL 0.2, 100VA

(For AVR Panel

metering)

CL 3P, 100VA

(For GPR -2)

CL 3P , 100VA

(For GPR-2)

2 PT 2

CL 0.2, 100VA

(For Generator

Metering cum Syn

Panel)

CL 3P , 100VA

(For GPR -1)

CL 3P , 100VA

(For GPR-1)

3PT 3

(Spare PT)

CL 0.2, 100VA

(Spare)

CL 3P , 100VA

(Spare)

CL 3P , 100VA

(Spare)

6.04.00. NGR Panel :

11 KV HT NGR panel having Current transformers for phase and standby

E/F,63.51 Ohm Resistance , 100 Amps , for 30 sec, max limit up totemperature rise 375 deg C and Motorized neutral isolator with vacuum

contactor. Degree of protection for NGR Panel shall be IP55 for enclosure

and IP42 for resistance.

Resistance : 11kV, 63.51 Ohm, 100A for 30 sec Vacuum contactor : 12kV, 400A


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The following table illustrates the Current Transformers considered in NGR

Panel.

CTs RATIO CORE 1 CORE 2 CORE 3

CT-1 100 / 1A

CL : 0. 2, 10VA

(Generator

Metering Cum

Syn Panel)

CL:5P20,10VA

(GPR-1)

CL:5P20,10VA

( For GPR-2)

CT - 2 2500 / 1A

CL : 0. 2, 30VA ,

Imag 15 (ForAVR Metering)

CL : PS , KPV

250 ( For GPR-2)

-

CT - 3 2500 / 1A

CL : 0. 2, 30VA ,

Imag 15

(Spare)

CL : PS , KPV

250 (For GPR-1)-

CT - 4 2500 / 1A

CL : 0. 2, 30VA ,

Imag 15

(Spare)

CL : PS , KPV

250 (For

Generator

Metering cum

Syn Panel)

-

6.05.00. Generator Relay panel.

Protection of the generator shall be achieved through microprocessor

based, 2 Nos Numerical relay (P-343), one as primary and the other as

back up. This panel shall be of free standing, floor mounting, sheet steel

enclosed type. Degree of protection shall be of IP55. The panel mainlyconsists of:

Metering for Generator. Generator protection relay. Auxiliary relays for protection.


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6.05.01. The following protections are envisaged in protection relay of

generator-

Generator Differential Relay (87G) Over Fluxing (24) Negative Phase Sequence (46) Non directional phase over current ( 50) Inadvertent Energisation (Dead machine) (50/27) Neutral voltage displacement / Residual over voltage (59N) Voltage restrained over current (51V)

Non directional earth fault (51) Loss of Excitation (40) Generator VT fuse failure protection (60) Reverse power Relay (32 ) Low Forward Power protection (37) Under & over Frequency Relay (81U / 81O) Thermal over load relay ( 49) Rotor earth fault Relay (I & II stage) (64R) Stator earth fault Relay(51N)

Circuit breaker failure protection Relay (CBFP) AC control Supply Failure Relay DC control supply Failure Relay 100% stator earth fault relay (27TN) Under Voltage Relay(27) Over voltage relay (59) Earth fault relay (64F) Master trip relay (86-T A&B, 86-G A&B, 86C) Trip circuit supervision relays (95)

Check synchronizing relay(25C) Guard relay (25G) No volt relay (27 I) Auto synchronizer (25A) PT protection & supervision relay (60) CT protection & supervision relay MRU -4 relay far sensing HT Bus PT for df/dt


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6.06.00. Generator Control , Metering cum Synchronizing Panel

Considering various operating conditions of power plant Synchronizing

facility will be provided as under:

Auto, Manual synchronizing facility shall be provided for Generator

breaker, evacuation feeder breaker, Spare Power Evacuation Feeder

breaker and Generator incomer breaker will be provided through

Auto/Manual selector switch in Generator Control, metering &

synchronizing panel (GCMSP). Degree of protection shall be of IP55.

To facilitate auto synchronizing one number Auto synchronizer shall be

provided.

To facilitate manual synchronizing of breakers, double voltmeter, double

frequency meter, Synchroscope with cutoff switch, Synchro check relay,

Live/ Dead bus synchronizing switch and necessary lamps will be provided.

2 Nos 24 window annunciator shall be considered foe alarm and indication

purpose. Emergency push button for Generator and turbine trip shall beprovided. All the meters shall be digital with 0.5 accuracy class.

Transducers for 3P-4Wire MW (4 output), MVAr (2 Output), 3 Nos Voltage

(Two output), Frequency (Two Output), 3 Nos Current (2 Output) shall

be provided. It shall be programmable type with accuracy class 0.5%,

4-20 milli Amps output & auxiliary supply shall be 230V AC.

6.07.00. GENERATOR BUS DUCT ( SPBD)

11 KV, 3 Phase 3200 Amps, Segregated Phase Bus dud (SPBD) shall be

provided for generator Phase terminal to LASCPT Panel and Generator

Neutral terminal lo NGR panel. Maximum allowable temperature rise on

bus duct shall be 40 deg C and enclosure shall be 25 deg C. The degree of

protection for enclosure shall be IP55.


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6.08.00. High Voltage Switchgear:

The following High Voltage switchgear is envisaged. The design basis of

High Voltage switchgear will be as follows.

Type : Metal clad, draw out Service : Indoor Rated voltage : 11kV rated current : 3200A Bus Bar Material : Copper

Degree of protection : IP4X for enclosure Type of circuit breaker : VCB Duty cycle of breaker : O-0.3sec-CO-3min-CO Closing mechanism at CB : Spring charged stored energy Short Circuit Rating : 40kA for 1 sec

6.08.01. FEEDER DETAILS

Generator Feeder with PT 1 No. + 1 SPARE

Transformer feeder (2.5 MVA) 2 Nos + 1 SPARE Power Evacuation feeder with PT 1 No. + 1 SPARE Bus PT 1 NO

6.08.02. Protection & Metering Envisaged:

The protections envisaged for different feeders are listed below. Main

protective relays will be Numerical fixed type. However auxiliary relays will

be electromechanical type only .

A) 11 KV Incomer feeders:

Instantaneous and definite time over current protection. (50/51) Directional over current and earth fault protection. (67/67N) Under voltage protection with timer (27+2) Trip circuit supervision relay(74)


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Master trip relay(86)

Anti pumping relay(94) DC Fail relay(27D)

B) 11 KV Power evacuation feeder:

Instantaneous and IDMT over current protection.(50/51) Directional over current and earth fault protection. ((67/67N) Cable differential protection (87C) Under voltage protection with timer (27+2)

Trip circuit supervision relay(74) Master trip relay(86) Anti pumping relay(94) Neutral voltage displacement (59N) DC Fail relay(27 D)

C) Auxiliary transformer feeder:

Instantaneous and definite time over current protection.

Instantaneous and definite time earth fault protection. Winding temperature protection (49 WT) Oil temperature protection (49 OT) Bucholz relay (63). Trip circuit supervision relay(74) Master trip relay(86) Anti pumping relay(94) DC Fail relay(27 D)

D) Bus PT feeder

Under voltage relay with timer (27+2) DC Fail relay(27 D) Voltage balance relay 60)


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6.08.03. Metering:

Incoming feeder shall be provided with energy meters of class 0.5

accuracy, Digital Ammeter & Digital voltmeter. Auxiliary transformer

feeder shall be provided with Energy meter and Ammeter. However

evacuation feeder shall be provided with 0.2 accuracy class Trivector

meter & Digital ammeter.

6.09.00. LV Transformers:

6.09.01. LV Auxiliary Transformers

Auxiliary Transformers are Oil impressed type, 2.5 MVA rated ,2 x 100%

capacity, 11/ 0.433kV, ONAN cooled, Dyn11 vector group, 8.25 %

impedance, 99.5% efficiency at 50% load, 99.0% efficiency at 100% load,

outdoor type. This transformer will be provided with off load tap switch

having +5 to -5 % taps in steps of 2.5% on HV side. The LV side neutral

of this transformer will be solidly grounded.

The following assumptions as per normal power plant practice had beenmade in sizing the transformer

Load factor = 0.8 for continuous load, 0.2 for intermittent load

Coincidence factor = 0.05 for motorized valves, 0.5 for AC & heater

unit, 1 for continuous load

General:

The flux density considered is 1.67 T for the core and yoke at the rated

MVA, voltage & frequency. The transformer & all its accessories includingCTs shall be designed to withstand without any injury the thermal &

mechanical effects caused due to short circuit fault. Transformers shall

withstand, without injurious heating, the combined voltage & frequency

fluctuations.


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The transformer will be provided with following accessories and fittings:

Double float type buchholz relay having alarm and trip contacts Dial type (150 mm) oil temperature indicator with alarm and trip

contacts. Dial type (150 mm) winding temperature indicator (WTI) with

alarm and trip contacts. Magnetic oil level gauge, with low level alarm contact. Tap position indicator (Local ) Jacking pads.

Bi-directional flange wheels with suitable locking arrangement. LV neutral CT for LV REF protection and standby earth fault

protection. Rating & Diagram Plate Earthing Terminals Lifting Lugs Radiators Silica Gel Breather Explosion Vent with Diaphragm

Bottom drain cum Filter Valve Top Filter Valve Pressure relief valve.

6.09.02. Lighting Transformers:

Two no 2X100% dry type lighting transformer of 100 KVA, 415/415,

Dyn11, AN, 8.25 % impedance, greater than 99.5% efficiency at 50%

load, 99.0% efficiency at 100% load, 10% variations on secondary side

in 2.5% steps shall be provided. Lighting transformer shall be of class Hinsulation with temperature rise limited to class F.

6.10.00. NSPBD:

415 V, 3 Phase + Neutral 4000 Amps TPN Sand witch type Non

Segregated Phase Bus duct (NSPBD) shall be considered for connecting


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between auxiliary distribution transformer and 415V PCC. Maximum

allowable temperature rise on bus duct is 40 deg C and enclosure is 25deg C. The degree of protection for enclosure shall be IP54.Bus conductor

& Bus enclosure shall be Electrolytic grade Aluminum & MS respectively.

Bus bar material shall be of Aluminum flats grade 83401 WP, IS 5082

6.11.00. Low Voltage Switchgear - 415V

6.11.01. LTPCC:

Type : Fixed type Service : Indoor Current Rating : 4000 A Short circuit Rating : 50kA for 1 Sec. Protection : IP4X Busbar material : Aluminium Maximum current density : 0.8A/mm2 Incomers : Two with 4000 A ACB breaker Closing/tripping of ACB : 110 V DC / AC

The protections envisaged for different feeders were listed below.

a) LTPCC Incomers:

Instantaneous and IDMT over current protection (50/51) Instantaneous and IDMT earth fault protection (50/51N) Restricted earth fault relay (64R) Standby earth fault Relay (51N)

Under voltage protection with timer(27+2) DC failure relay (27 D)

b) LTPCC outgoing feeders

Thermal & magnetic releases for overcurrent & short circuit

protection shall be provided.


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c) LTPCC Bus PT feeders

Under voltage relay (27)

Metering:

Energy meter shall be provided in the all incoming and outgoing feeders of

PCC. Analog type ammeter and voltmeter with selector switch shall be

provided on the incoming feeders. For Bus PT feeders voltmeter with

selector switch will be provided

6.11.02. MCC

MCC shall be double front as per the contract. MCC shall have uniform

height placed side by side.

Type : Free standing fixed type Service : Indoor Short circuit Rating : 50kA for 1 Sec.

Current Rating : as per requirement Enclosure : IP 52 Rated voltage : 415V Maximum current density : 0.8A/mm2 Bus bar Material : Aluminum Incomers : Two

The CPP shall have following MCCs:

TG MCC

Boiler MCC (1 No for each PH + 1 No for each AQC) A/C, P&V MCC ACC & CWS MCC WTP MCC ACDB, MLDB, DCDB APFC MCC Emergency MCC


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6.12.00. 415V Motors

Motors are of TEFC IP55 enclosure with Class `F insulation with a

temperature rise limited to Class `B. LT motors shall have premium

efficiency (IE-3 type). Protection class shall be IP65. All the S1 Duty Cycle

(continuous running) motors shall be compatible with VFD (Inverter grade

for VFD application).

Local Push Button Station (LPBS) shall be provided for all the motors and

MOV's (for VFD LPBS shall have RPM meter and raise lower push buttons).

For motors 3.7 kW and above ,LPBS shall be equipped with Ammeter.

All motors below 75 kW: 415V rated, 3 phase/SFU+110 V (from MCC) AC

control contactor + O/L relay with single phase preventer

From 75 kW and above : 415 V rated, 3 phase contactor/ circuit controlled

from MCC through Digital motor protection relay with bearing temp.

For above 22kW motors ammeters shall be provided. For above 30kW

motors Space heaters shall be provided. For 75kW and above motorsbearing & winding temperature monitoring shall be provided.

7.00.00. DC system

One no 800AH 1X100% (2V X 55), 110 Volts , 2 wire ungrounded system ,

four (4) hours back up Vented type Plante Lead acid Battery of adequate

capacity with their Float cum Boost charger shall be considered for DC

loads with associated FRP battery racks etc..

110 V DC power supply is the most reliable source of power supply for

control, protection, interlock and annunciation requirements of the power

station.


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The rating of charger will be calculated as below:

Float charger:

Continuous DC load + trickle charging current of battery +15 % margin.

Boost charger

Boost charging current of battery+ continuous DC load.

Float cum Boost charger:

Boost charging current of battery.

Battery Charger

Type - One float and float cum Boost charger Voltage regulation - 110V 1% Service - Indoor Enclosure - Sheet steel Degree of protection - IP 42 AC input - 415V, 3ph, 3W, 50Hz, 50kA

Busbar Material Aluminum

7.00.01. DC Distribution Board

DC Distribution Board constructional features will be given below

Type - Fixed type NON-Compartmentalized Service - Indoor Enclosure - Sheet steel

Degree of protection - IP 42 Short circuit rating - 10kA for 1 sec (Tentative) Bus bar Material Aluminium


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8.00.00. Auto Power Factor Correction Panel

2 Nos x 500 WAR , 113 STEPS (50 KVAR OF -10 Nos ) capacitor units shall

be hermetically sealed type, with two bushings and shall be designed to

carry a minimum of 1 .5 times the rated current at 110% of rated voltage

and 1.35 times rated reactive power, continuously. The capacitors should

be of non PCB type, suitable for operation in tropical areas

9.00.00. Cabling System:

9.01.00. Cables:

9.01.01. HT Power cable

HT power cable used for 11 kV systems will be 12.7/22kV (E) grade.

The cable will be heavy-duty, stranded Aluminum conductor with FRLS,

conductor screened with semiconductor, extruded XLPE insulation and

insulation screen (semiconductor +copper tape), extruded PVC inner

sheath, G.S flat (for multi-core)/aluminium wire (for single core) armoured

and extruded PVC (ST-2) outer sheathed conforming to IS7098 part-II.Maximum operating temperature under normal condition for XLPE

insulation cables will be 90C. Trefoil Clamps for HT Cable shall be

provided.

The following rating of HT cable XLPE (UE) insulated shall be

envisaged for the Plant

LASCPT panel to HT switch gear panel - 4RX 1C X 630 Sq.mm/ph

GPP-4 HT panel to Existing HT Panel for power evacuation - 4R X1C X 630 Sq.mm/ph

GPP-4 HT Panel to Auxiliary transformer 1 & 2 - 1R X 3C X 300

Sq.mm


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9.01.02. LT Power cable

LT power cable used for 415V AC, 230VAC, 110V AC & 110 V DC system

will be 1.1kV (E) grade, stranded aluminum conductor with FRLS, XLPE

insulated, not extruded PVC inner sheath, G.S. Flat/round wire with

armoured, extruded PVC (ST-2) outer sheath conforming to IS 7098 part-

I. Maximum operating temperature under normal condition for XLPE

insulation cables will be 90C. Cables less than 10 sq.mm shall be of

copper conductor. DC Power cables for EOP will be UNINYVIN CABLE &

Cable for UPS will be Copper armour cable. Separate earthing cable shall

be laid from each VFD to respective Motor.

9.01.03. Control cable

Control cables will be 1100V (E) grade, multi-core with stranded 1.5 mm

and copper conductor with FRLS, PVC insulated, extruded PVC inner

sheath, G.S. flat / round wire armoured and extruded sheath of PVC (ST-

1) with numbering of all cores, conforming to IS 1554 part-I/IS 5831.

9.02.00. Cable Tagging

Cable tagging shall be at both end & at every 20 meter considered for all

cable. Anodised type tagging plate will be provided.

9.03.00. Cable Trays

Cables laid in overhead racks shall be GI ladder/perforated type trays for

electrical/instruments with proper prefabricated bends respectively in

outdoor areas and supports shall be MS (painted). The top cable tray shallbe covered with GI sheet canopy/GI sheet covering in outdoor cable racks.

All outdoor cable racks shall be vertically oriented. Galvanized cable trays

for Boiler, Turbine, ACC and BOP area shall be supplied. For WTP area all

cable tray shall be FRP type only.


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Separate cable tray for HT Power, LT Power, Control Cable, Instt. Analog

Input/output cable each, Instt. Digital Input/output cables each &Compensating Cable shall be considered.

No. Of Cable layers per Cable tray shall be as follows:

HT Power Cable & LT Power(up to 120 mm2) Cable - One Layer LT Power Cable (below 120mm2) - Two Layer Control Cable - Three Layer Instt. Cables - Three Layer

10.00.00. llumination System:

10.01.00. Basic Concept

The system provides lighting and service power at 240V, single phase 50

Hz to receptacles and single phase feeders in plant areas. The plant

illumination system includes normal cum Emergency lighting and critical

DC lighting.

10.02.00. 100 % Normal cum Emergency A.C lighting

Normal cum Emergency A.C. lighting will be provided by lighting fixtures

distributed throughout the plant. Separate circuits with timers will be

provided where round the clock lighting is not required. Lighting fixtures

will be fed from respective area lighting panels, which in turn receive

supply from lighting distribution board. MLDB shall be provided with Dual

incomer. LDBs shall be equipped with 30 mA ELCB. In Normal condition

the Main lighting distribution board will be fed from 415V PCC &Emergency MCC through 2 x 100%, lighting transformer. In blackout

condition then the supply for MLDB shall be fed from Emergency MCC

(which is connected to Customer DG set) through lighting transformer .


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10.03.00. Emergency DC Lighting

Critical DC lighting will be provided with bulk head lamps at Cable Cellar

MCC room, CCR, TG house, stair cases, steam drums on all boilers & Start

up vents. This DC lighting will remain OFF normally and will be switched

ON automatically when main AC supply fails. The power supply for lighting

will be fed from 110V DCDB. FL DC lamp with integral battery shall be

provided for Boiler area MCC room.

10.04.00. Power Receptacles / Welding Sockets

1 Phase & 3 Phase power receptacles will be provided for alternative floors

of Boiler area, each floor ACC areas and at least 3 Nos in TG building, MCC

room, cable cellar area. 3 Phase Welding Sockets will be provided at each

stage of boiler, TG Floor & as required in ACC area etc. 24 Volt AC power

receptacles with transformers and proper distribution at all location of

boilers, ACC floors will be provided.

10.05.00. The type of fixtures & type of luminaries for different areas is

listed below:

Area Description Type of Fixture Type of LuminariesCable gallery,Transformer AreaCompressor room,Battery charger room,P&V room & Storeroom

Industrial Trough Type 2x28 W FluorescentLamp

MCC Switchgear roomIndustrial Trough typewith ReflectorArrangement

2x36 W FluorescentLamp

Battery rooms Corrosion Proof 2x36 W FluorescentLampControl Rooms & Officerooms

Industrial Trough typewith mirror optics


Turbine houses Integral Well glassIndustrial type 1 X 80W HPMV

TG Building Operatingfloor

Industrial type highbay 1x400 W MH Lamp

TG Building Staircases Industrial Trough Type 2x36 W FluorescentLamp


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Boiler area, Boilerplatforms ACC, & WTP

Integral Well glassIndustrial type

1x70 W MH Lamp

Toilet areas Integral Well glassIndustrial type1 X 36 W Fluorescent

Lamp

Street Lights & Outdoorlights

Integral Well glassIndustrial type withtimer arrangement

1 x 150 W MH Lamp

DC lights in TG Building Bulk head type 1X 100W GLSDC lights in Boiler areaMCC room

FL with integral batterytype


11.00.00. Earthing & Lightning Protection System

11.01.00. Plant Earthing:

System earthing will be adopted to facilitate earth fault relaying and to

reduce the magnitude of transient over-voltage. The system earthing

involves earthing of the neutrals of generator. Low impedance earthing is

used for 11 KV system to limit the earth fault current to about 100 A by

grounding generator neutral by means of Neutral Grounding Resistor

(NGR).

A ground grid of 32mm MS Rod will be provided encircling the plantthrough a system of grounding electrodes and pits to keep ground

resistance less than one ohm. Earth mat shall be laid below 500mm below

absolute ground level and earth pits shall be 1.5 meter away from nearby

building walls. Every electrical system will have dual earthing.

Treated earth pits will be considered for generator NGR, Aux. Transformer

Neutral, lightning arrestor & equipments. All Earthing electrodes shall be

of Gel type maintenance free (homogeneous readymade mixture).

All instrument earth pits shall be maintenance free and configuring delta

spaced by 6 meter with redundant copper cable connection.The underground grid shall be connected with lightning protection earth

electrodes below ground at average depth of 500 mm.


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11.01.01. Equipment Earthing:

Electrical equipment shall be provided with two separate and distinct

grounding pads, each complete with tapped hole, galvanized bolt and

spring washer for connection to station ground conductors.

The neutral of generator and transformer shall be earthed through two

dedicated earth pits.

Flat from the main earthing grid to local network and electrical equipment

will be GI flats of suitable size, except for smaller items, which will beconnected using steel wire. However, for portable equipment, if one of the

conductors of the connecting cable/plug socket is earthed, no other earth

connection is required.

An earthing conductor will be installed along the entire length of top most

power cable trays. The tray earth will be connected at various locations to

the station earth grid. The offsite areas will be connected through the

earth flats running along the cable trays. Earth continuity will be provided

for all cable trays & conduits. The following aspects will be addressedduring design, of the equipment earthing system to be adopted.

Availability of sufficient earth current for effective relaying. Stabilization of circuit potential with respect to earth.

The size of earth conductor used for individual equipment earthing

Main Ground Conductor: 32 mm MS rod

Earth Electrodes : MS Rod 32 mm dia, 3 m long pipe Generator and Transformer Body: 75 mm x 10 mm GI Flat. Transformer and Generator Neutral: 75 mm x 10 mm GI Flat. HT switchgear Panels: 50 mm x 6 mm GI Flat. 415V PMCC, MCC, DCDB, MLDB Structures, Bus duct, Control

Panel, Cable Trays: 50 mm x 6 mm GI Flat.


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LT AC Motors from 110kW up to 132 KW: 50 mm x 6 mm GI Flat.

LT AC Motors above 30kW up to 90 KW: 25 mm x 6 mm GI Flat. LT AC Motors from 5.5kW up to 30 KW: 25 mm x 3 mm GI Flat. LT AC Motors below 5.5 KW : 8 SWG GI wire Local Panels, LPBS, Switch sockets, LDBs, JB,Receptacles: 8 SWG

GI wire

11.02.00. Lightning Protection:

The main purpose of the lightning protection system is to provide

protection to structures from lightning strokes and provide a lowresistance-conducting path for lightning discharge to earth. For metal

structures, which are continuous down to the ground level, no lightning

protection is required except adequate grounding connections. Air

termination network with down conductor and earthing electrodes will be

provided on the basis of IS-2309 recommendations.

The zone of protection will depend on each structure height, overall shape,

and physical location in relation to other structures.

Documents

Design basis report.pdf