Comments on Volume 07 - Electrical DBR Rev(1)0702[Final]. a

1980MW (3x660) SUPER-CRITICAL THERMAL POWER PLANT AT BANAWALA, DIST: MANSA, PUNJABCOMMENTS ON ELECTRICAL DBR REV-A, DTN-TALW-SEPC1-0018, VOLUME-7

Sr.No Clause No Page TSPL/DCPLComments

1 Design Instruction

2 1

Document/ Drawing Ref

Cover sheet

Volume 12 shall be corrected as Volume-7

1(General Description)

The last paragraph shall be added as "All Electrical equipments shall be designed for full capacity output and capable of operating satisfactory' at ambient air temperature of 50Deg. C and relative humidity of 90%

3 2

4 1.2 2

1.3 (to be added under heading"

System Studies")

A clause shall be added after Clause 1.2 under heading System Studies indicating followings-" AC and DC system analysis studies shall be made during design stage in order to substantiate the satisfactory operation of the electrical systems and the studies shall be subject to Owner's approval prior to the ordering of all equipment. The studies shall include load flow, fault levels, voltage regulation (steady state and motor starting) and stability studies both during start-up and normal running.

For inclusion of String insulator for out going lines, replace 'without' by 'with'.

5 2.1 3 a) Combined variation shall be indicated b)DC control voltage shall be 220V and 24V and DC voltage variation shall be +10% -15%.

c) Terminology 'Peak' shall be replaced by 'Highest System Voltage'.

6 2.2 3---5 Followings shall be indicated/ taken care --- a) 400kV switchyard layout with I type or D type configuration as adopted b)There is a duplication in page 5 regarding mention of 6 diameter, line feeders etc ,which shall be removed as the same is indicated previously c)The complete details of equipment located in Network control building shall be covered for clarity .Please adopt same designation (identification by name) for control room or the room under discussion adjoining switchyard , as "Relay room" has been adopted in Drg 373-F2491C-Z-02, also mention of "NCCS" is there in this document. The room shall also house PLCC ,related 48V battery, Billing & Metering panel ,400kV Switchyard SCADA etc in addition to whatever indicated. Location of Protection panel for GT,ST, Line, centre breaker etc shall be clearly indicated.

7 2.3 a) The wording " ----- within +3% and -5% with temperature rises to increase by up to B+10K approximately " shall be indicated as "------within +3% and -5% with temperature rise limited to Class B+10K as per conditions indicated in IEC 60034-3. b) Correction shall be made "one common spare single phase generator transformer for three units shall be provided

8

9 2.2 6

c) Criteria for sizing of GT,ST & UT as per contract specification shall be indicated in the Cl 2.3 of this Design Instruction. The rating for GT, UT and ST as specified shall be substantiated with calculation and subject to approval by TSPL/DCPL . d) As per CEA guideline, the tap range for OLTC shall be(+)10 to (-) 10% for UT and ST e)Please confirm that the Vector group YNyn0-yn0,(+d) signifies provision of tertiary delta

Replace synchronism with grid voltage '+10%' by '±10%' and frequency '+5%' by '±5%'.

10 2.4 7 a) In parameters of Generator Winding insulation/temperature rise of stator shall be "Class F insulation but temperature rise limited to Class B for continuous operation at rated out put at rated voltage and frequency and at rated power factor. Please note that +10K additional rise is allowed at certain parts of boundary of operation over ranges of Voltage (+/-5% ) and Frequency (+/-2%) variation as per IEC60034-3. Please submit the Voltage and frequency variation Curve for continuous rated operation at rated power factor for the generator offered. b)Over speed withstand capability for 2 minutes - 120%.

11 7 d) Please submit Printed catalogue for DFEM make generator of Model No. QFSN-660-2-22A indicating various parameters including Rated Hydrogen pressure

12 9 e) Please confirm the provision of 3No. 2500kVA single phase epoxy moulded dry type transformer with class F insulation for excitation system for each unit. The temperature rise over ambient shall be 70 Deg C for winding f) Please confirm the capacity 70% during outage of one cooler section of generator also covers simultaneously 5% tube plugging in each cooler section

13 10 d) The sizing of GT, ST and UT shall be submitted as per criteria indicated in contract e) The rated short time thermal current indicated as 40kA for 3 sec for CB, Isolator, CT, PT etc shall be confirmed if the same as manufactured are actually rated for 50kA for 3 sec

14 11 f) Name of manufacturer of 400kV switchyard equipments shall be indicated and catalogue shall be submitted

15 13 g) SEPCO shall confirm compliance of technical parameters, CT & PT accuracy class etc as indicated in the Contract specification.

16 14 h) The rated short time thermal current for IPBD main and Tap-off run shall be confirmed in line with short circuit current calculation result sheet( 373-F2491C-D_04)

17 2.4 11

18 3.1 15

Please include Full wave impulse with stand voltage (1.2/50 microsecond), switching impulse withstand voltage, one minute power frequency with stand voltage (dry and wet) for various EHV equipment shall be specified.

The consideration of 40kA as short circuit current for 400kV system shall be discussed .

19 3.1 16 The short circuit level at 400KV is near 40KA so margin for design 400 KV equipment is required. This will be discussed in DBR review meeting.

3.2

20 17 Correction shall be made for Station Transformer rated for ONAF cooling

21 17 Regarding sizing of ST ,please clarify 16 MW motor driven Feed Water pump has been considered for start-up load as connected to UT. Accordingly please clarify the additional statement made by you as " The ST shall be considered to feed the common load and the start up load of one unit .When the ST feed the unit load, the FW pump shall not be considered." It shall be noted that motor driven FW pump load shall be considered in ST sizing during start up of the plant. Also the same motor driven FW load shall be considered for UT sizing, as failure of any FW pump will need running of motor driven FW pump. The ST rating 76/50-50 MVA shall be revised accordingly. Detailed load compilation and ST,UT sizing with break up of load details shall be submitted covering a) Unit load b) Station load c) Load of a Unit under HP-LP by pass mode of protection

22 18 A brief feature of 11kV switchgear shall be added as under " The switchgear shall be indoor, metal clad, floor mounted, draw out type and suitable for locating in a clean but hot, humid and tropical atmosphere. Degree of protection shall be IP4X."

23 18 A paragraph shall be added under 11kV Switchboard regarding sizing criteria mentioned as under " The continuous current rating for incomers,bus section and bus bar shall be based on total running load plus highest load during change over of equipment/stream (one at a time) as applicable plus 20% overall margin. A 20% spare feeder (at least one in each bus section of each size and type) shall be kept for future use and shall be considered for rating selection. The continuous current rating of the outgoing breaker shall cater for the rated load with a margin of 20%.

24 4.2 19 Please add a paragraph indicating a)" All motors located indoor shall have enclosure degree of protection class as IP-54 where as all outdoor motors will be weather proof IP 55XW as per IEC 60529" b) All motors (11kV & 415V) will have Class F insulation but temperature rise limited to as per Class-B

25 4.3 19 The first paragraph under LV auxiliary system regading sizing criteria of LT aux transformer shall be corrected as under "-------- is fed by 2x100% transformers/feeders and these are rated to carry connected load without any diversity , Due consideration shall be given for motor starting/voltage drop etc during planned changeoverof largested motor load . " The continuous current rating for 2x100% incomers,bus section and bus bar shall be based on total running load plus highest load during change over of equipment/s

26 19 Design criteria for 415V PCC/MCCshall also include additionally the following at the last para "The continuous current rating for incomers, bus coupler and bus bar shall be based on total running load plus highest load during change over of equipment/stream (one at a time) as applicable plus 25% of total connected intermittent loads like valves, damperswhere ever applicable plus 20% overall margin."

27 5.1 22 a)Last para under this clause shall read as under"--------------- between the GT and UT and spare single phase transformer as necessary." b) Please mention that transformer oil soak pit and burnt oil pit shall be sized as per Indian Regulation and Code c) 31 mm /kV minimum creepage shall be considered d) Generator transformer shall be provided with 2x60% cooling radiator banks. Each radiator bank shall be provided with suitable number of working fans plus one stand-by fan and 2x100% oil pumps.

6

7

28 8.1 26 a) Please indicate that all the Batteries shall be located in air conditioned room.Each set shall have 110 batteries. Battery sizing calculation shall be submitted and selection shall be based on approval.

b) Please clarify type of charger meant by "charger/float charger" whether the same is Float cum Boost and Float charger provided for each battery set.

8.2

8.3

29 9 28 UPS sizing calculation shall be submitted and selection shall be based on approval.

30 10 28 Excitation equipment particularly Regulating cubicle( AVR) shall be located in air conditioned room

31 11.1.1 30 - 31 a) Instead of important motor ,first and last para shall be corrected as "------- emergency sections, ALL 11kV and 415 V motor of unit/station" b) Please note that for motor/feeder control shall be hardwired directly to DCS.c) synchronisation, change over etc, all signals shall be hardwired directly to DCS. d) CB and Isolators of 400kV GT and ST feeders including centre breakers control from DCS shall be mentioned e) Control function from ESCADA as mentioned shall be discussed

32 11.1.2 32

33 11.1.2.2 33

Considering control requirement of 400kV central breakers with associated isolators from CCR as well as Switchyard Control room for Generator &Start up Transformer feeders, DCS in CCR shall have same provision. Generator & Start-up transformer bus side breaker and associated isolators shall also be controlled from DCS in CCR. Line side breaker and isolators will be controlled from switchyard control room ( NCCS)

Isolators and CB for GT and ST including centre breakers and adjoining isolators will be controlled from DCS

34 35 Provision of ABT meter for Export/Import measurement by Electricity board in NCCS shall be confirmed.

35 11.1.3 36 Please clarify provision of control function in ESCADA and communication interface whether the same is through serial link. If the system resolution is not fast , --- control , synchronisation , change over, sequence of event recording etc will not be proper.

11.2

36 11.2.1 40

37 11.2.1.1 41

All the protective relays used for the project shall be micro processed based numerical communicable type relays. Please furnish main facilities details.

Please explain accidental electrify protection, non electric quantity, I&C start protection.

38 11.2.1.3 46

39 60 6.6 KV shall be corrected to 11kV.

Kindly classify with details of motors load in I, II & III.

12.1

12.2

12.2.1, 12.2.1.1, 12.2.1.2, 12.2.1.3

40 15.1 & 15.3 62 a) Voltage rating of lighting transformer shall be 2x100% transformer 415/433V for nornal as well as emergency with OCTC b) 24 V maintenance pug/socket shall be provided.

41 16.1 66 a) LV power cable details shall include features as "galvanised steel strip/wire armoured for twin and multi core cables and non magnetic hard drawn aluminium wire armoured for sibngle core cable, extruded PVC ( ST-2) FRLS outer sheathed conforming to IEC.for construction and test. " Armoured cable shall also be provided "for the cable laid from the building to outside for field equipment in addition to area as specified. Unarmoured cable shall be used for cables laid within the building (where both end of the cable with in the same building) and terminated. the minimum size of aluminium power cable shall be 6 sq. mm. b) Feature of provision of armouring for Control cableshall be as per LV power cable

Cable specification shall be in line with the contract to be followed.

Please clarify DJYPVP, KBVP type.

42 18.2 76 a) The Billing & metering Equipment quantity partcularly for ABT meters, shall be rechecked as there are 6 out going lines. Total number of ABT meter for main and check shall be 12. b) The location of ABT main meter for lines shall decided by PGCIL/PSEB . ABT check meter for line may be in NCCS with RS 485 port for connectivity to CCR. Genertor Main and Check meters and other metering shall be located in CCR

43 16.3 68

44 16.3 68

a) All instrunentation cables shall be separate and dedicated trays. Electric control and instrumentation cables shall not be mixed up. Perforated galvanised tray shall be used for Electrical control and Instrumentation trays.

b) Minimum 300mm space shall be kept between bottom of upper tray to top of lower tray

c) Solid bottom tray shall be provided for all special noise sensitive circuit and analogue instrumentation circuit.

Cables shall be provided with cable terminations on both ends with double compression glands. Pl. incorporate in DBR.

45 16.3 68

46 18.4 78

Cable trays shall be separate for MV and LV cables and shall not have sag more than 10 mm when loaded.

Note is not clear and shall be discussed. Only PLCC at PGCIL/PSEB substation end are in the scope of Owner but PLCC at plant end is in the scope of this contract.The model number and make of equipments to be supplied by SEPCO shall match with the requirement of PGCIL/PSEB.

47 9 28

48 11.1.1 30

Please mention the no. of UPS envisaged in the plant application wise.

The backup panel should include electrical system mimics panel.

49 11.1.1 30 We understood ESCADA system envisaged is only for monitoring of Intelligent Protection devices while control of the Electrical aux. system in totality upto 415 V breaker feeder will be implemented in DCS. Please confirm.

50 11.1.4 39 Separate PLC & OS/ES is required for ESP control.

51 11.1.4 39 There is no mention of the controls envisaged for the CHP sub systems like Wagon tippler, stacker-reclaimer, etc.

Hence Kindly mention the same and a clause as follows may be added.- “Coal Handling System is controlled from PLC. PLC have hot standby redundancy in all level i.e. controller, memory, power supply, I/O bus and communication. Two no. OWS and One no. OWS/EWS will be provided. Wagon tipplers, Stacker reclaimer Will each have separate hot standby redundant PLC. One OS/ES will be provided for each system.Local control panel for magnetic separator, belt scale, metal detector, paddle feeder, bunker level indication etc. will be provided.”

52 17.1 68

53 75

Communication schemes , Scheme 1 & 2 (Drg. No. 373-F2419C-D-51, Drg. No. 373-F2419C-D-52, Drg. No. 373-F2419C-D-54 & Drg. No. 373-F2419C-D-55) to be discussed.

17.3.2(17.1.2)

No. of stations & their locations to be mentioned.

54 Drive Control Interface: Control philosophy for interfacing of MCC/ SWGR/ Actuator with PLC/ DCS shall be mentioned as per vol.II.-Sec. XIXA- Annexure-I. To be discussed in DBR meeting

55 Current indication for important motors below 30KW also will be required in DCS/PLC.

56 GENERAL COMMENT

1) Please note that all the drawings attached with the DBR need not be considered as approved and final. Final system drawing and layout will be approved during detail engineering. 2) Manufacture, Equipment details, credential of manufacture & Equipment supply report from customers etc. to be provided to owner for Major Equipments like Generator, GT, UT, ST, 11kV & 415V switchgear, HT motor & 400KV switch yard equipments. 3) 400KV Circuit breaker - Manufacture should be ABB, Areva, Siemens4) Detailed calculation for fault level considered for different voltage level shall be submitted with DBR.

57 Please furnish brief technical details of electric motors (AC & DC), motor actuators indicating type, class of insulation, temperature rise, temperature indicator, degree of protection etc. All the motor shall be energy efficient type and with enclosure (indoor, out door) in DBR.

58 Excitation System


TSPL / DCPL Comments of DBR / Drawing Rev A

SEPCO noted. OK, Point closed.

OK, Point closed.

Resolution dated. 3th Feb. 2010

SEPCO agreed as per Contract Section VII/S-XVIII, Cl. No. 1.13.00.

OK, Point closed.

SEPCO agreed to provide calculation result for short circuit level. SEPCO also confirmed that calculation shall be done with ETAP software.

Calculation for voltage regulation refer Sr. No. 21 below.

SEPCO shall submit calculation result with details of considerations/factors considered in ETAP. SEPCO shall note that relay setting shall be performed considering actual fault level at 400 KV grid and subsequent downstream level.

TSPL agreed that as per scope line side insulators may not be supplied.

a) SEPCO confirmed that combined variation of voltage and frequency shall be 10%.b) SEPCO confirmed DC coils/equipment can operate at -15% voltage variation.c) SEPCO will correct the DBR.

DC voltage variation-indicated is +10% -12.5%, it should be +10% -15%.

48 V DC supply system required for the PLCC to be indicated.

a) SEPCO confirmed that I type configuration will be used.b) SEPCO will revise the DBR.c) SEPCO confirmed that protection & metering panel of GT, ST & UT shall be in main CCR and protection & metering panel of 400kV lines & centre breaker shall be in NCCS building.

a) OK, Point Closedb) OK, Point Closedc) OK, Point Closed

a) SEPCO confirmed.b) SEPCO confirmed.

a) OK, Point Closedb) OK, Point Closed

SEPCO confirmed. OK, Point closed.

c) SEPCO confirmed sizing criteria as per Contract. SEPCO give the supporting calculation.d) SEPCO confirmed as per Contract.e) SEPCO confirmed (+d) signifies the tertiary delta.

c) GT/ST & UT sizing calculation as per contract to be submitted by SEPCO, sizing of these transformer can only be freezed after receipt & approval of same by TSPL / DCPL. Transformer vendor specification, technical requirement shall take care of contract specification (4.02.00) and to be submitted to TSPL/DCPL before finalisation. d) OK, Point closed.e) OK, Point closed.

a) SEPCO confirmed as per IEC 60034-3, Cl. No. 4.6, Figure-1.b) SEPCO confirmed.

a) OK, Point closed.b) Over speed withstand capability for 2 minutes - 120%. Shall be included in DBR

Configuration details for the following generator auxiliary system shall be provided in DBR. - Generator Seal Oil System- Stator Cooling Water System- Generator Gas System

d) SEPCO will submit the detailed data sheet and catalogue during detailed engineering.

Printed catalogue of appropriate model need to be submitted earlier as the same is readily available

e) SEPCO confirmed.f) SEPCO confirmed that the capacity 67% during outage of one cooler section of generator also covers simultaneously 5% tube plugging in each cooler section.

e)SEPCO shall indicate in the DBR class -F insulation and temperature rise as per class-Bf) SEPCO shall indicate in the DBR 67% availability during outage of one cooler with 5% tube plugging.

d) SEPCO will submit the calculation for approval.e) TSPL shall inform the value of fault level of grid later. After which SEPCO will revert with recommendation.

d) SEPCO yet to submit Sizing calculations for GT, ST and UT as per serial 21 below, only after review of the same by TSPL / DCPL sizing of transformer can be freezed. Also during detail engg. & procurement SEPCO to submit technical specification, data sheet, GTP, FQP, all the drawings for TSPL / DCPL approval.e) OK, As per DBR fault level for switchyard equipment 50 KA.

f) SEPCO will furnish the data/catalogue during detailed engineering.

The details shall be submitted urgently. SEPCO shall submit detailed Technical Specification, Data sheet, GTP, Vendors for all the 400 KV Switchyard equipments before finalisation.

g) SEPCO confirmed that accuracy class shall be as indicated in drawing.

OK, Point closed. SEPCO to submit data as per point 14 during detail engineering & procurement.

h) SEPCO will revised the rating as per final calculation result.

SEPCO shall submit the IPBD sizing calculation as per contract specs. Also submit ETAP detailed results and including considerations for calculation for our review.

Refer Sr. No. 13 above.

SEPCO will include the parameter in DBR as per Contract.

SEPCO yet to include the parameter in DBR as per Contract.

OK, 50kA as short circuit current for 400kV switchyard has been considered. It shall be clearly mentioned in this clause also.

Refer Sr. No. 13 above. 50kA as short circuit current for 400kV system has been considered and hence OK.

SEPCO confirmed.

Please refer Drawing No-373-F2491C-D-04 Rev-A regarding short circuit rating of 11kV switchgear. It is noted that short circuit rating 50 kA ,as considered earlier has now been revised to 40kA. The same shall be revised back to 50 kA,as the safety margin is not at all available in both UT&ST 11KV switchgear as per final result tabulated by SEPCO. Regarding the 11 KV fault level selection, following points are also noted- 1) Total kW contribution for 11kV Motor in different bus sections of UT &ST has been reduced as compare to previous revision. Also please confirm whether 16 MW FW pump ( electrical driven) has been included as motor contribution for short circuit current calculation.2 )Percentage impedance of ST has been increased.Please confirm the basis for the above two points and provide us the details. Also we would request you to provide us the ETAP data/considerations & detailed calculation sheets for our reference for review of short circuit calculation Doc No-373-F2491C-D-04 Rev-A at our end ".

SEPCO confirmed to submit the calculation.

SEPCO yet to submit the calculation in line with the considerations as indicated and as per contract condition. Also under condition "a" power requirement of the auxiliaries being fed by a UT shall include motor driven Feed Water Pump.

OK, Point closed.SEPCO agreed to add this clause in revised DBR.


OK, Point closed.a) SEPCO agreed to add this clause in revised DBR.

b) SEPCO agreed to add this clause in revised DBR.


OK, Point closed.SEPCO agreed to add design criteria as per Contract.

a) SEPCO agreed to provide firewall between GT/ST/UT, if required as per TAC/IE Rules & NFPA 850. b) SEPCO agreed to provide oil soak pit for GT/ST/UT, as per TAC/IE Rules & NFPA 850.c) SEPCO confirmed.d) SEPCO agreed to provide one standby cooling unit for GT.

SEPCO shall indicate the features as per agreed resolution in DBR as well as in layout of transformer yard 373-F2491C-D-06.

Transformer specifications in the layout drawing as above are not matching with DBR, please correct.

SEPCO shall submit sizing calculation to the proposed DG set of capacity 1200KW. As indicated in the DBR interconnection between the DG switchgear of different unit to be shown in the SLD, also failure to start of the particular unit DG should initiate starting and picking up load by the other unit DG.

Size of the underground condutor shall be selected based on unrestricted groundfault current of 50kA for the complete palnt as mentioned earlier in the DBR Rev 0. Regarding this please note that as per this DBR switchyard and 415 V system is designed as per 50 KA, whereas 11 KV system also needs to be reinstalled to 50 KA as mentioned in DBR Rev 0.

a) SEPCO offers 104 cells but TSPL requested to provide 110 Nos of cells for 220 V DC system. SEPCO agreed to provide as per TSPL request. SEPCO agreed to submit the calculation for battery as per IEEE 485.

b) SEPCO agreed to provide battery charger as per Contract.

SEPCO yet to submit the sizing calculation as per the specification for all the batteries & battery chargers.a) Please indicate in DBR that all the Batteries shall be located in air conditioned room. Battery sizing calculation shall be submitted and selection shall be based on approval.

b) Please clarify and indicate in DBR type of charger meant by "charger/float charger" please confirm whether the same is separate Float cum Boost and Float charger for each battery set as indicated in specification.

c) Separate 2*100 % station battery and 2*100 % station float and float cum boost charger shall be provided for the main plant common systems as per the specification, preferably station DC system capacity shall be same as the unit battery system. Also Station DC system shall have ties with each Unit DC system to ensure reliability.

d) N+2 modules shall be provided in all the battery chargers.

e) CHP, water sytem and other auxiliary area DC system shall be designed on same philophy as above (as per contract specification) consisting of the two independent DC bus section, bus-coupler, 2*100% Battery, 2*100% float & float cum boost charger etc.

Refer Sr. No. 13 of Resolution of DBR Drawings.

SEPCO yet to submit the sizing calculation for the UPS & UPS battery system.

SEPCO agreed. a) SEPCO yet to indicate in DBRExcitation equipment particularly Regulating cubicle( AVR) shall be located in air conditioned room AND LAYOUT DRAWING.b)Please clarify excitation system shall be of ABB make, not based on the ABB technology.

a) SEPCO agreed to provide control of all 11kV and all process related 415V motor of unit/station from DCS/PLC.b) SEPCO agreed.c) SEPCO agreed.d) SEPCO agreed.e) Refer C&I discussion.

a) SEPCO to clearly indicate in the DBR that all 11KV and all 415 V process related motors are controlled from DCS/PLC and which other type of motors not controlled from DCS/PLC. b) please indicate clearly in DBR.c) please indicate clearly in DBR.d) OKe) OK

SEPCO agreed. OK, Point closed.

SEPCO agreed. OK, Point closed.

SEPCO to confirm after checking back with their metering expert.

SEPCO shall indicate as per below in DBR.This is a mandatory requirement and shall be complied.Every line shall have dedicated main and check ABT meters of 0.2S accuracy and located in respective line out going side or switchyard control room as per PSEB/PGCIL technical requirement / location.

Refer C&I discussion. Please note that clause :11.1.3.2 under the heading monitoring and control range of ESCADA neede to be inline with minutes (ESCADA system envisaged is only for monitoring of Intelligent Protection devices while control of the Electrical aux. system in totality upto 415 V breakers, feeders shall be implemented in DCS. )as covered under C&I section.As discuss ESCADA will have only monitoring function taking input from intellegent devices (Through port of numerical relay ) for 11kv ,415 V power feeder etc.Please modify and indicate in the DBR claus 11.1.3.2 accordingly.Correction shall be made inthe paragraph to delete "control function" and "Imoptant 11 kv & 415 V motor of unit".

Please ensure that minimum protetion for the various type of the 11 KV switchgear, 415 PCC, MCC & DB modules are as per the contract specification and to be incorporated in DBR accordingly.

Noted, point closed.

Noted, point closed.

SEPCO confirmed to provide micro processor based digital relay. Catalogues & technical details shall be detailed engineeirng.

SEPCO clarified. TSPL noted.

OK, Point closed.

SEPCO agreed to provide the list during detailed deisgn stage.

SEPCO shall indicate in general regarding the classification in DBR with example of details of motor loads.

SEPCO noted & corrected.

SEPCO shall provide Manual Synchronisation system along with the Auto Synchronisation System as per the contract specs.

SEPCO shall submit all the 11KV / 415 V auxilliary system detailed logics / scheme for our approvel before finalisation during detail engineering.

SEPCO shall clarify fast changeover by synchronism blocking, facility shall check synchronism of the two sources before initiation of the fast changeover and shall close the standby source breaker before synchronism is lost due to decaying voltage of earlier source. Also fast changeover between UT &ST shall be initiated in two distinct bay for the following two different condition - 1. Class A trip - ST source tie breaker closes moment after opeing of the UT source breaker.2. Turbine trip - ST source tie breaker closes moment after before opeing of the UT source breaker.

a) SEPCO confirmed voltage regulator shall be provided for incomer of lighting PCC. b) SEPCO confirmed that emergency lighting shall be provide in all auxiliary area.

a) Mention of OCTC in ligthing transformer in DBR shall be madeb) clause 15.3 (ii), some part is missing from DBR Rev 0, same should be included.C) Provision for the 24V maintenance plug / socket shall be included in DBR.

a) SEPCO agreed to provide cables as per Contract. Minimum size of power cable shall be 6 sq.mm Aluminium.

b) SEPCO agreed.

a) Same wording as mentioned for cable specification shall be incorporated in DBR.b) DBR shall mention that construction of cables with armour shall be as per LV power cable for control cables also.

Cable specification shall be in line with the contract to be followed.

a) SEPCO agreed & DBR shall be revised accordingly.

b) SEPCO confirmed that the switchyard parameter including ABT check metering shall be monitored from NCS operating station located in CCR.

a) SEPCO shall revise DBR, "Billing & metering Equipment quantity partcularly for ABT meters, shall be re-checked as there are 6 out going lines. Total number of ABT meter for main and check shall be 12".B)SEPCO shall revise DBR & indicate clearly.

OK, Point closed.

a) SEPCO agreed that separate cable tray shall be used for (1) Power, (2) Control (Electrical & C&I), (3) Signals cables. DBR shall be revised accordingly.

b) SPECO agreed to provide minimum 300mm space between bottom of upper tray to bottom of lower tray.

c) SPECO agreed as per Contract.

a) SEPCO shall indicate in DBR "Perforated galvanised tray shall be used for Electrical control and Instrumentation".

b) SEPCO yet to indicate as "Minimum 300mm space shall be kept between bottom of upper tray to top of lower tray" in revised DBRc) SEPCO shall indicate in the DBR "Solid bottom tray shall be provided for all special noise sensitive circuit and analogue instrumentation circuit."

SPECO agreed and shall be indicated in revised DBR.

Noted, to be taken care during detail engg.Shall be decided during detailed engineering.

SEPCO agreed to provide PLCC equipments at the TSPL Plant side. TSPL shall provide the make and model number of PLCC used in PGCIL/PSEB sub-station during detailed design.

SEPCO shall clearly indicated this in the revised DBR.

OK, Noted.

SEPCO confirmed that 2x100% UPS for each unit as per Contract. SEPCO also confirmed that PLC for auxiliary system shall be provided with 1x100% UPS with manual bypass.

Each unit UPS has been indicated with 2X100% system along with 2X100% battery.SEPCO shall confirm that inaddition to dedicated Unit UPS, seperate UPS shall be provided for common system load. Details of common and unit system load shall be indicated.All UPS shall be backedup by 2X100% battery & 2X100% UPS system for main plant as well as for off site PLC requirementPlease also mention the no. of UPS envisaged in the plant & auxiliary system, application wise in the DBR.

SEPCO confirmed that there is no back up panel. TSPL noted.

SEPCO confirmed. SEPCO shall revise DBR clause no11.1.3.2 as following."ESCADA system envisaged is only for monitoring of Intelligent Protection devices while control of the Electrical aux. system in totality upto 415 V breaker feeder will be implemented in DCS. "

Separate PLC will be provided with one OS/ES for each ESP . SEPCO agreed. Also refer AHP resolution.

SEPCO shall clearly indicate in DBR that separate PLC, OS & ES shall be provided for each unit ESP, as already indicated in C&I DBR.

Refer C&I DBR resolution.

Please mention the resolution as finalised for C&I in the Electrical DBR

SEPCO describe the Scheme-1 with DADX system in place of PA System. SEPCO should follow Scheme-2 with PA system as per Contract.

a) AS per revised DBR Scheme-1 2 selected, Noted.b)EPABX capacity is reduced from "priliminary 600 Lines and expandable to 1024 lines" of DBR REv 0 to "priliminary 200 lines and expandable to 400 lines" in revised DBR, same shall be restored back.

SEPCO will include in DBR number of stations envisaged.

SEPCO shall mention no. of stations & their locations in Electrical DBR, this shall cover all the plant indoor & outdoor areas.


SEPCO to confirm incorporation in Electrical DBR


SEPCO to confirm incorporation in Electrical DBR

1) SEPCO agreed.2) SEPCO agreed supply the equipments as per approved Vendor List. SEPCO will furnish the equipment details & data sheet ordering of equipment. 3) SEPCO agreed as per Contract.4) Discussed earlier.

SEPCO shall indicate the schedule for submission of detail engineering drawings and finalisation of vendor list.

4)Detailed calculation for fault level considered for different voltage level shall be submitted with DBR.

SPECO agreed as per Contract.

Please confirm use of energy efficient motors in DBR

Noted.SEPCO confirmed that If one cubicle is out of operation, the remaining cubicles can satisfy with the requirement of all operation conditions including 1.1 times rated excitation current and field forcing. If two cubicles are out of operation, it shall ensure that the generator operates continuously at 110% rated excitation current (without field forcing).TSPL noted.


SEPCO REPLY TSPL/DCPL RESPONSE TO SEPCO REPLY

SEPCO has submit calculation report done with ETAP.

SEPCO has not submitted ETAP calculation officially till date. TSPL is in receipt of advance unofficial copy of ETAP calculation but the SLD identifying different Bus number is not attached and also the report is not complete as only BUS 3 & 5 has been tabulated for 11kV bus .The generated drawing in ETAP showing fault contribution and power flow through each branch shall be submitted.

Please note the following points1) The revised figure for ST,UT capacity as per updated calculation shall be considered 2) Lump load shall be modified as per our document regarding ST & UT sizing (enclosed)3)Load flow and voltage drop study by ETAP also shall be submitted4) Relay setting shall be a part of study at later stage before commissioning.5) Detailed comment on ETAP will be forwarded later.The ETAP result shall be submitted officially

voltage variation of DC system +10% -12.5%, DC coils/equipment can operate at -15% voltage variation.

48V DC shall be provided for PLCC, and this has been indicated in DBR 17.1.4.

OK. Noted..

OK. Noted.

SEPCO shall submit sizing calculation later.

SEPCO shall submit sizing calculations based on sizing reference document enclosed with these comments. THE SAME SHALL BE SUBMITTED URGENTLY ALONG WITH ALL OTHER CALCULATIONS FOR TSPL/DCPL APPROVAL BEFORE PROCEEDING FOR FURTHER ENGINEERING & PROCUREMENT. ANY IMPLECATION AT LATER STAGE IN ABSENCE OF THE REQUIRED SIZING DOCUMENT AND APPROVAL BY TSPL, LIES WITH SEPCO.

a) closeb)included in DBR clause 2.4

b) Over speed withstand capability has not been indicated in the DBR. SEPCO to please note and indicate in the revised DBR.

all necessary information for electrical design has been indicated in electrical DBR, the seal oil system, cooling water system and gas system are provided by mechanical .

The Generator catalogue and all related details as indicated shall be briefly covered in Electrical DBR even if already covered in details elsewhere. (Details asked are not included in Mechanical DBR)

SEPCO has submitted the document, refer to the letter LE-TALW-SEPC1-TSPLX-10-0018.

Required document has not been received by us ,SEPCO shall submit once again to Engineering/Project group.

e) f)included in DBR clause 2.4 e) SEPCO shall confirm and clearly indicate in revised DBR "dry type transformer with class F insulation for excitation system for each unit". The temperature rise over ambient shall be 70 Deg C for winding of excitation transformer.F) SEPCO shall indicate in the revised DBR 67% availability during outage of one cooler with 5% tube plugging.

d)SEPCO shall submit sizing calculation later.e)close

SEPCO shall submit ST & UT sizing calculation based on TSPL/DCPL comments as per the Sr. No. 8 as above.

SEPCO shall submit the documents as per EPC contract.

SEPCO SHALL SUBMIT DETAILS URGENTLY.

SEPCO shall submit sizing calculation later.

SEPCO SHALL SUBMIT SIZING CALCULATION & OTHER DETAILS URGENTLY FOR TSPL/DCPL APPROVAL BEFORE PROCEEDING FOR FURTHER ENGINEERING & PROCUREMENT. ANY IMPLECATION AT LATER STAGE IN ABSENCE OF THE REQUIRED SIZING DOCUMENT AND APPROVAL BY TSPL, LIES WITH SEPCO.

included in DBR clause 2.1 OK, Noted.

included in DBR clause 3.1 OK, Noted.

a) after the DBR review meeting, some loads have changed, according to the result of ETAP, short circuit rating 40kA can be considered for UT&ST 11kV switchgear.

B) FW pump has been included as motor contribution for short circuit current calculation of unit 11kV switchgear. when UT is shutdown, ST will feed the load of UT except FW pump. so FW pump has not been included as motor contribution for short circuit current calculation of common 11kV switchgear.

c) when the unit start, FW pump is fed by ST, but the capacity of FW pump is 50% during start. so the impedance of ST has been increased.

a) SEPCO shall adopt 50kA rated 11kV switchgear as we have to consider adequate design margin, extra contribution due to addition of fourth unit, spare motor feeder etc.

B) FW pump shall be included as during start-up of station, all motor connected to both 11kV UT as well as 11kV ST bus will contribute in the event of fault. During the period, electric motor driven FW pump will come into scenario as power will flow from 11kV ST to UT bus. Hence to calculate short circuit current, all motors connected to 11kV ST and UT bus need to be considered for both 11kV unit as well as Station switchgearc) If percentage impedance is increased to control fault contribution, then simultaneously Voltage drop situation also need to be checked during running and starting of largest motor ( FW pump) as the same will be critical.

usually feed water pump is driven by turbine, when the turbine fail, the motor will driven the FW pump, and the motor is fed by UT, when UT is shutdown, the unit loads will be fed by ST, and in this condition the FW pump driven by turbine is considered, and the FW pump driven by motor is not considered.

During start up , no steam is available and hence please consider motor driven pump fed by ST. Also in all condition availability of motor driven Feed pump shall be ensured. Accordingly ST sizing calculation shall consider FW pump.

Last para under this clause has been revised as under"Fire Wall will be set between the GT and UT and spare single phase transformer if necessary."we have checked the distance between the transformers, according to the distance, fire wall will be set between GT and UT as indicated in 373-F2491C-D-06.

SEPCO shall submit revised DBR & drawings.

For each unit one DG will be provided, and each DG only provided power for one UNIT emergency loads. DG will start in 30 seconds, so it is not considered that failure to start of the particular unit DG should initiate starting and picking up load by the other unit DG

SEPCO shall provide interconnections for flexibility and avialability of DG Power for a particular unit in case of failure or non-availability or maintenance of unit's own DG. Alternatly a separate common DG bus may be created to feed emeregency PC section of each unit individualy through separte standby feeders.

By adopting either of the suggested scheme reliability and availability of the emergency power will greatly enhance.

Also as mentioned in DBR Clause no. 6 "DG Switchgear will have interconnection among themselves for reliability purpose", SEPCO shall change the Emergency Power Supply Arrangement Layout accordingly.

Size of the underground condutor shall be selected based on unrestricted groundfault current of 50kA for the complete palnt .

OK. SPECO shall revise the clause as follows "Size of the underground condutor shall be selected based on unrestricted ground fault current of 50kA and maximum fault clearing time shall be 1 sec. for the complete palnt

SEPCO shall submit sizing calclation later.

A) Battery room shall be air conditioned, and it has been indicated in the drawing.

B) charger/float charger is the same with separate Float cum Boost and Float charger. DBR has been modified.

SEPCO SHALL SUBMIT SIZING CALCULATION URGENTLY FOR TSPL/DCPL APPROVAL BEFORE PROCEEDING FOR FURTHER ENGINEERING & FINAL PROCUREMENT. ANY IMPLECATION AT LATER STAGE IN ABSENCE OF THE REQUIRED SIZING DOCUMENT AND APPROVAL BY TSPL, LIES WITH SEPCO.A) OK, NotedB) SEPCO shall modify the wording accordingly , float and float cum boost charger instead of charger/float charger in DBR .

Noted.

SEPCO shall provided 2*100% station battery and 2*100 % station float and float cum boost charger . The capacity of station DC system shall meet the requirement. Station DC system is separate form unit DC system.

SEPCO shall confirm and clearly indicate in the revised DBR and Drawings that Station DC system is separate from Unit DC system with dedicated 2x100% battery with dual float cum boost charger,

SEPCO shall provided N+2 modules for unit DC system, and N +1 modules for others .

For auxiliary workshop will have one 100% 200Ah VRLA battery and one 100% charger/floating chargers. Civil has complete design, so there is no space for 2*100% battery. 1*100% battary can meet the requirement .

Not acceptable, SEPCO shall provide as per contract. Necessary design changes required elsewhere to be made to accommodate the same.


SEPCO SHALL SUBMIT SIZING CALCULATION URGENTLY FOR TSPL/DCPL APPROVAL BEFORE PROCEEDING FOR FURTHER ENGINEERING & FINAL PROCUREMENT. ANY IMPLECATION AT LATER STAGE IN ABSENCE OF THE REQUIRED SIZING DOCUMENT AND APPROVAL BY TSPL, LIES WITH SEPCO.

a) okb)the components of excitation system is made by ABB. Assembled in DFEM.

a) OK, please include as indicated.b) Noted, details and drawings shall be discussed and to be submitted for TSPL/DCPL approval

a)SEPCO agreeed and modified DBR.B)already in DBR as "SCS and SOE signals of devices supervised by DCS shall be brought into DCS by hard wiring.". C)already in DBR as "(synchronisation, change over etc)ALL above of Electrical devices shall be controled by DCS with hard wire。"

a) Please refer cl 11.1.1 of DBR Rev-A Important motors need to be explained as indicted.

for ABT please refer to 18 Billing and Metering System, here are detail discriptions.

SEPCO shall confirm the number of ABT meters as per contract with break up.

ok, 11.1.3.2 has been modified SEPCO shall submit revised DBR as the same is not covered in Rev-A

ok SEPCO shall submit revised DBR as the same is not covered in Rev-A

the classification in general has been indicated in this clause, and the example will be provided during detailed design stage.

Please classify with details of load and its repercussion in allotment in switchgear such as emergency load or loads that are repeated in both bus section etc.

Manually synchronization can be done on the auto synchronisation panel .

SEPCO shall clearly specify regarding manual synchronization in the revised DBR. Manual synchronising device shall be different from auto synchroniser and also clarify how voltage and frequency adjustment will be made.

OK, Noted.SEPCO shall submit detailed logics/scheme in detailed design stage.

fast changeover by synchronism blocking means facility shall check synchronism of the two sources before initiation of the fast changeover and shall close the standby source breaker before synchronism is lost due to decaying voltage of earlier source. It's used after G-T unit trip, to changer over ST power. the change should be fast befor motors stop, and there is voltage on 11kV, the standby power should be synchronized with the voltage existed on 11kV switchgear.

OK, Noted.

Also, we suggest that fast changeover between UT &ST shall be initiated and executed in following two distinct manner for the following two condition -

1. Class A trip - ST source tie breaker closes moment after opeing of the UT source breaker.

2. Turbine trip - ST source tie breaker closes moment after before opeing of the UT source breaker.

a)added.b)clause 15.3(ii) is same with DBR Rev 0.c)there is no 24V pug/socket, emergency lighting shall be provided in all auxiliary.

a)SEPCO shall submit revised DBR as same is not covered in DBR Rev-A.b)clause 15.3(ii) shall be modified as "The outlet boxes will be supplied for each floor and/or room of various plant building and turbine hall,power will be supplied from 415/240 V MCCs or ACDBs "as specified in DBR Rev 0.c)SEPCO shall provide 24V pug/socket, emergency lighting as per contract.

a)SEPCO agreed to provide cables as per Contract.b)SEPCO indicated this requirement in DBR.

a)SEPCO shall modify DBR accordingly,as same is not covered in DBR Rev-A.b)Ok.noted.

ok DBR will be modified OK, Noted SEPCO shall submit revised DBR,as same is not covered in DBR Rev-A.

a)ok,DBR has been modified。B)SPECO agreed to provide minimum 300mm space between bottom of upper tray to bottom of lower tray.C)ok,DBR has been modified。

OK.noted SEPCO shall submit revised DBR,as same is not covered in DBR Rev-A..

ok DBR will be modified OK.noted SEPCO shall submit revised DBR,as same is not covered in DBR Rev-A..

Number of 80kVA UPS is 2*100% for each unit. The number of UPS For PLC shall be give at the end of DBR.

SEPCO shall provide separate station 2x100 % UPS for feeding load of common DCS panel, common C&I ,Fire protection system etc along with separate dedicated 2x100 % battery.2X100 % UPS system shall be provided for off site PLC along with2x100% dedicate battery.

DBR clause no 11.1.3.2 has been modified.

OK, Noted. SEPCO shall submit revised DBR,as same is not covered in DBR Rev-A.

DBR has been modified. Each Unit have seperated ESP PLC and OS/ES


Coal Handling System is controlled from PLC. PLC have hot standby redundancy in all level i.e. controller, I/O bus and communication. Two no. OWS/EWS will be provided. Wagon tipplers, Stacker reclaimer Will each have separate hot standby redundant PLC. One OS/ES will be provided for each system.


Noted.

Local control panel for magnetic separator, belt scale, metal detector, paddle feeder, bunker level indication etc. will be provided.”

SEPCO reply is not relevant.

SEPCO shall provide system as per the comments on the DBR Rev A.

The final no. and location of stations can only be determined at detailed design.Then they will be clear.

Refer C&I DBR resolution. SEPCO shall mention "Drive Control Interface: Control philosophy for interfacing of MCC/ SWGR/ Actuator with PLC/ DCS shall be mentioned as per vol.II.-Sec. XIXA- Annexure-I." in the Electrical DBR.

Refer C&I DBR resolution. SEPCO shall mention "Current indication for important motors below 30KW will be provided in DCS/PLC." in the Electrical DBR.

1）SEPCO has submitted the schedule for submission of detail engineering drawings by letter early. The vendor list shall be submitted with the monthly report.2）SEPCO shall submit calclation later.

1）SEPCO shall note and confirm that make of componetns form approved vendor list only.2）SEPCO shall submit calclation before further engineering.

SEPCO confirm use of energy efficient motors.

SEPCO shall revise DBR accordingly, as same is not covered in DBR Rev-A.

SEPCO REPLY SEPCO REPLYTSPL/DCPL RESPONSE TO SEPCO REPLY DATED 14.06.2010

SEPCO will submit the etap calculation report and the SLD showing fault contribution and power flow through each branch.

ALL THE LOAD AND CONDITION IN THE SCOPE OF EPC CONTRACT ARE CONSIDERED. THE LOAD EXCEED THE SCOPE OF CONTRACT ARE NOT CONSIDERED.

Noted. Please submit calculation covering all the loads with DBR Rev B for approval. Early submission is requested.

Calculations shall cover all loads fed from Station Switchgear. Accordingly same shall cover HCSD load and additional load of 7.0 MVA for power supply to offsite buildings, like Zero discharge system, Canteen Bldg, Training complex, fire station, work shop, store, Colony and O&M office etc.,

ALL THE LOAD AND CONDITION IN THE

SCOPE OF EPC CONTRACT ARE

CONSIDERED. THE LOAD EXCEED THE SCOPE OF

CONTRACT ARE NOT CONSIDERED.

SEPCO shall submit sizing calculation with DBR Rev B

Noted. Please submit calculation with DBR Rev B for approval. Early submission is requested

ok，

b)included in DBR Rev B clause 2.4

Noted. Please submit incorporating changes in DBR Rev-B.

ok，

the details shall be indicated in manual of generator.

The brief coverage of generator auxiliary system as indicated is requested in Electrical DBR so that electrical details are available in one consolidated document.These details are not available in Mechanical DBR also.Generator contract already finalised, may please submit the drawings for these auxiliary system for reference.

the details of equipment shall be indicated in the documents of manufacturer

SEPCO will submit again. Noted. Early submission is requested.

SEPCO has submitted the document, refer to the letter LE-TALW-SEPC1-TSPLX-10-0121.

included in DBR Rev B clause 2.4

Noted. Please submit incorporating changes in DBR rev-B

ok，


Please submit calculation with DBR Rev B for approval. Early submission is requested

ok，

the vendors of 400kV equipments ordered are ABB, XIDIAN, GUIRONG, RUGAO.

The details of items ordered on ABB shall be mentioned. The credentials of XIDIAN ,GUIRONG and RUGAO are not known . Please indicate the items /components planned to be ordered on these vendors and also confirm whether they have supplied similar equipments in any Indian projects. Selection of subvendor shall be done with prior consultation with owner.

the vendor of 400kV CB is ABB, LIGHTNING ARRESTER is XIDIAN, CVT is GUIRONG, ISOLATOR is RUGAO. XIDIAN and GUIRONG are vender for BALCO etc. project.


SEPCO shall submit calculation for approval before procurement

ok，

a)SEPCO has revised the scheme of electrical auxiliary system, 50kA rated 11kV switchgear will be adopted. B)FW pump has been considered for the sizing of ST and UT. To calculate short circuit current, all motors connected to 11kV ST and UT bus need to be considered for both 11kV unit as well as Station switchgear. Details refer to the sizing calculation and short current level calculation.

Noted. SEPCO shall submit the short circuit current calculation with DBR Rev B for approval.

ok，

during start up the motor driven pump has been considered for sizing of ST.SEPCO has revised the scheme, even in the condition of UT outage, the unit loads are fed by ST include the FW pump.

Noted. Please submit sizing calculation with DBR Rev B for approval.

ok，

SEPCO has revised the DBR and drawing Rev B.

Noted. SEPCO shall submit the revised DBR and drawing Rev B incorporating relavent details.

ok，

DG is used for fault situation, It's no need to consider fault in fault situation in China design standard. it is too complex to interconnect DG bus of different unit, and there are many connection between the DG bus . It will bring more fault in the operation.

SEPCO has revised the layout of emergency switchgear.Bus coupler is provided for emergency MCCA and emergency MCCB.

As mentioned in DBR Clause no. 6 "DG Switchgear will have interconnection among themselves for reliability purpose",the same feature is required to be followed.

This is required as respective DG for the unit, which is only 1x100%, may not be available during emergency due to maintenance of DG or fault on DG.

In case of the DG unavailability, unit may have to be shutdown to protect main equipments due to sudden failure of grid.

DG bus interconnection can avoid these conditions.

“DG Switchgear will have interconnection among themselves for reliability purpose” means there is two emergency MCC for one unit, and there is one bus coupler between the MCCA and MCCB.

SEPCO has revised the DBR Rev B.

Noted. Please submit, incorporating changes in DBR Rev-B.SEPCO shall also submit ground mat design calculation ( under ground main mat) covering conductor sizing, grid spacing ( based on touch -step potential criteria) as per IEEE 80 for approval by TSPL/DCPL. The same is required urgently as civil construction at site is under progress

ok，

ok, calculation will be submitted and DBR will be modified

Noted. Please submit, incorporating changes in DBR Rev-B. Also submit sizing calculation with DBR Rev B.

ok，

ok, DBR will be modified Noted. SEPCO shall submit the revised DBR and drawing Rev B incorporating relavent changes.

ok，

SEPCO has revised the design. 2*100% DC battery will be provided for chemical water system and CHP system.

Noted. SEPCO shall submit the revised DBR and drawing Rev B incorporating relavent changes.

ok，

the caculation will be submited with DBR Rev-B.

Please submit with DBR Rev B for approval. Early submission is requested

ok，

a) SEPCO has indicated in the drawing.

a) A note shall be added in relevant Equipment layout drawing to indicate AVR is located in A/C room. b)QAP for DFEM made(with ABB component) excitation system equipment /AVR shall be submitted

a)the note has been added in relevant Equipment layout drawing to indicate AVR is located in A/C room. b)ITP(QAP) for DFEM made(with ABB component) excitation system equipment /AVR is being compiled and submited later.

ok,DBR will be modified Noted. SEPCO shall submit the revised DBR Rev B incorporating relavent details. Motors covered under"important motors" need to be clearly indicated in DBR.

ok，

Total number of ABT meter for main and check shall be 12 for 6 out going lines.

Noted. SEPCO shall submit the revised DBR Rev B incorporating relavent changes.

Our requirment is that SEPCO shall procure these meters from India as per PSEB / PGCIL / CEA requirment to avoid any mismatch later.

ok,SEPCO shall procure these meters from India

ok Noted. SEPCO shall submit the revised DBR Rev B incorporating relavent details and changes.

ok，

ok. DBR will be modified Noted. SEPCO shall submit the revised DBR Rev B incorporating relavent details and changes.

ok，

the details shall be indicated in detailed drawings.

SEPCO shall generally indicate in DBR identifying systems/subsystems attached to Class I,II &III load .

the exact name and number of all loads shall be confirmed in detailed stage. the details shall be indicated in detailed drawings. The general description of classification refer to clause 11.2.1.3.1.

This is a 600MW unit, it's strongly advised not use manual synchronization. manual synchronization may do serious damage to generator. In China ,no one dare to do manual synchronization on such a huge unit.

Please provide Manual Synchronising System in addition to Auto synchroniser. This is required as back-up system and as per the contract requirment.Please clarify the features as planned to be provided

SEPCO strongly advise not to use manual synchronising system. And Manually synchronization can be done on the auto synchronisation panel .

okok, noted. Please refer to D33 table ARRANGEMENT AND OUTPUT OF ELECTRIC QUANTITY PROTECTION . The trip out put is designed to minimize the fault. Most situation like"all stop"& "step out DEEXCITATION" need to make auto transfer, but some situation like "PARALLEL" do not start the auto transfer.

Noted. Shall be discussed during detail design of control and protection scheme.

a)mention of OCTC has been covered in DBR Rev-B。b)15.3(ii) Rev-A is same with Rev-0, "The outlet boxes will be supplied for each floor and/or room of various plant building and turbine hall,power will be supplied from 415/240 V MCCs or ACDBs " is covered in both Rev-0 and Rev-A.c)SEPCO will provide 24V pug/socket in detailed design.

Noted. SEPCO shall submit the revised DBR Rev B incorporating relavent details and changes.

ok，

a) same has been covered in DBR Rev-B.


ok，

OK. Total number of ABT meter for main and check shall be 12 for 6 out going lines.

Noted. SEPCO shall submit the revised DBR Rev B incorporating relavent changes.

Our requirment is that SEPCO shall procure these meters from India as per PSEB / PGCIL / CEA requirment to avoid any mismatch later.

ok,SEPCO shall procure these meters from India

it has been indicated in DBR rev B.


ok，


ok，

there is no common DCS panel and common I&C, it's a part of Unit2 DCS. Fire protection is also supplied from Unit2 UPS. Unit 2 UPS never stop so no need of common UPS. In the contract only unit UPS requiment is 2*100%. No need of 2*100% UPS for auxiliary PLC. In China 300MW unit all UPS is of one set. UPS is used under fault situation, fault of UPS in fault situation is double fault, which is no consider in China design standard.

Separate station 2x100% UPS shall be considered for DCS system( Ref Drg No 373-F2491C -K-06 ) taking care Air compressor,Fuel oil,Fire protection ESCADA,Common Electrical system.This UPS shall be independent of any unit and shall supply to DCS /system controlling load in general,not related to a particular unit. 2x100% UPS for off site also is necessary and SEPCO shall comply

there is no common DCS. The auxiliary system is fed from different bus, so the power is very safe. SEPCO provide 1*100% UPS for CHP.

ok, DBR will be modified Noted. SEPCO shall submit the revised DBR Rev B incorporating relavent details and changes.

ok，


ok，


ok，

According to EPC contract,EPABX of preliminary 50 lines and expandable 100 lines shall be provided.But SEPCO believes that 50 lines are not enough,but 200 lines will be OK and enough.EPABX of prelimiary 600 lines and expandable 1024 lines are too large to use for this project,or it will be a waste.So DBR-0 is revised.

DBR will be modified Noted. SEPCO shall submit the revised DBR Rev B incorporating relavent details and changes.

ok，

DBR will be modified Noted. SEPCO shall submit the revised DBR Rev B incorporating relavent details and changes.

ok，

1)SEPCO confirm the vendor is included in the vendor list of EPC contract. 2）SEPCO will submit

calculation with DBR Rev-B。

1) As the Vendor list do not cover all equipment ,the same shall be finalised with dueconsultation with owner for all major Equipments like GT, UT, ST, 11kV & 415V switchgear, HT motor & 400KV switch yard equipments.

2)Please submit calculation with DBR Rev B for approval. Early submission is requested

The final vendor shall be submitted with the monthly report.

same is covered in DBR Rev-B 4.1.


ok，

1980MW (3x660) SUPER-CRITICAL THERMAL POWER PLANT AT BANAWALA, DIST: MANSA, PUNJAB

OBSERVATION ON REPLY MADE BY SEPCO ON TSPL/DCPL"S COMMENTS- ELECTRICAL DBR REV-A, LE-TALW-SEPC1-TSPLX-10-0076 ( Dtd 8th April 10)

S.No Clause No PageDocument / Drawing Ref

1 General comments on review of Design document & drawings

Sizing Calculation

2 D02MAIN CIRCUIT SINGLE LINE DIAGRAM (373-F2491C- )

3 D02

4 D02

5 D02

6

7 D02

8

9 D02

10 D02

11 D02

12 D02

13 D02

14 D02

15 D02

16 D03AUXILIARY POWER SYSTEM SINGLE LINE DIAGRAM

17 D03

18 D03

19 D03

20 D03

21 D03

22 D03

23 D03

24 D03

25 D03

26 D03

27 D03

28 D03

29 D03

30 D03

31 D03

32 D03

33 D03

34 D03

35 D04

36 D04

Shorcircuit current calculation result sheet.

37 D04

38 D04

39 D04

40 D05

41 D05

Choice sheet of main electrical equipment.

42 D05

43 D05

44 D05

45 D05

46 D05

47 D05

48 D05

49

50 D06

51 D06

Plan layout drawing of Electrical buildings outside a row of Turbine building

52 D06

53 D06

54 D06

55 D06

56 D06

57 D06

58 D06

59 D06

60 D06

61 D07Plan Layout Drawing of 400 kV Switchyard

62 D07

63 D07

64 D07

65 D07

66 D07

67 D07

68 D07

69 D06, D07

70 D07

71 D07

72 D08, D09

73 D08, D09

Sectional drawing of 400 kV line

74 D08, D09

75 D08, D09

76 D08, D09

77 D08, D09

78 D08, D09

79 D10Plan layout drawing of Isolated Phase Busduct

80 D10

81 D10

82 D10

83 D10

84 D10

85 D10

86 D11Section drawing of Isolated Phase Busduct

87 D11

88 D11

89 D11

90 D11

91 D11

92 D11

93 D12Plan and section layout drawing of segregated Phase Busduct

94 D12

95 D12

96 D12

97 D12

98 D12

99 D12

100 D12

101 D12

102 D13 & D14Plan and sectional layoutdrawing of 11 kV unit & common switchgear room

103 D13 & D14

104 D13 & D14

105 D13 & D14

106 D13 & D14

107 D13 & D14

108 D13 & D14

109 D13 & D14

110 D13 & D14

111 D13 & D14

112 D13 & D14

113 D13 & D14

114 D15, D17

115 D15

0.0m floor plan layout drawing of electrical and control building

116 D15

117 D15

118 D15

119

120 D16 ~ D25

Floor Plan Layout Drawing of Switchgear Room of different area

D16, D17, D22,

121 D16, D17

122 D16, D17, D19

123 D16, D17

124 D16 ~ D25

125 D16 ~ D25

126

127 D16

D16, D17, D24

128 D16

129 D16

130 D16

131

132 D17

D16, D17, D19, D21, D22, D23

133 D18

134

Plan Layout Drawing of 415V Common Swtchgear Room-II

D18, D20, D23, D24,

D25

135 D19, D22

136 D19

Plan Layout Drawing of 415V Lighting & Maintenance Switchgear & Relay Room / ESP & FF Switchgear

137 D20

138 D20

Plan Layout Drawing of CHP Complex House 0.0M Floor

139 D21

140

Plan Layout Drawing of CHP Complex House 4.5M Floor

D20, D21, D22, D23

141 D22 & D21

142 D26

Plan Layout Drawing of 415V ESP & FF Swgr. House

Cable tray Layout diagram of turbine hall

143 D26, D27

144 D26, D27

145 D26, D27

146 D26, D27

147 D27

148 D28

149 D28

150 Switchgear Room & Cable Tray Layout

General Comment

151

152

153

154

155 220 V DC system D29, D30 & D31

156

157

158

159

D29, D30 & D31

D29, D30 & D31

D29, D30 & D31

D29, D30 & D31

160 D29, D30 & D31

161 D29, D30 & D31

162 D29

163 D31

164

165 D32

166 D32

Plan layout drawing of network control building

167 D32

168 D32

169 D32

170 D35Schemetic diagram of 240V AC UPS for Unit

171 D35

172 D33 & 34Schematic diagram of protection and metering of generation system & station transformer

173 D33 & 34

174 D33 & 34

175 D33 & 34

176 D33

177 D33 & 34

178 D33 & 34

179 D33

180 D33

181 D33

182 D33

183 D33

184 D33

185 D33

186 D33

187 D33

188 D33

189 D33 & D34

190 D33 & D34

191 D33 & D34

192 D33 & D34

193 D33 & D34

194 D33 & D34

195 D33 & D34

196 D33 & D34

197 D33 & D34

198 D33 & D34

199 D34

200 D33 & D34

201

202 D33

203 D33

204 D36Schematic diagram of network computer control system (NCCS)

205 D36

206 D36

207 D38

208 D38

Diagram of 400 kV Synchronising System

209 D38

210 D37

211 D37

ESCADA System Diagram

212 D37

213 D37

214 D37

215 D37

216 D37

217

218 D39Diagram of emergency power supply circuit

219 D39

220 Wiring drawing of 11kV Feeders

D40, D41, D42, D43

221

222

223

D40, D41, D42, D43

D40, D41, D42, D43

D41, D42, D43

224 D40

225 D40 & D42

226 D40 & D42

227 D40 & D42

228 D41 & D43

229 D41 & D43

230 D41 & D43

231 D41 & D43

232 D41 & D43

233 D44

234 D45

235 D45

236 D46Wiring drawing of 415V Feeders

237 D46

238 D46

239 D47

240 D47

241 D47

242 D48

243 D49

244 D44 & D49

245

D40 ~ D49

246

D40 ~ D49

Wiring drawings - General Comments

247

D40 ~ D49

248

D40 ~ D49

249

D40 ~ D49

250

D40 ~ D49

251

D50Electrical Main Equipment List

252

D50

253

D51 ~ D55

254 PLCC drawing D56

Communication System & EPABX System



TSPL /DCPL Comments Resolution dtd. 3th Feb. 2010

SEPCO agreed.

a) Generator Transformer sizing

Detailed design calculation supporting the rating/sizes of the following equipments/system shall be furnished for review and approval. The calculation shall be done considering design ambient of 50 deg.C, design margin, temperature correctin factor, aging factor, derating factor etc. as applicable as per contract document, general practice followed in India & other international standards.

SEPCO agreed to provide sizing calculation during detailed design stage.

b) Generator busduct sizing considering continuous current, termperature rise, short circuit current.


c) UT & ST sizing considering voltage regulation not less than 85% at DMBFP motor terminal during starting with all other load.

SEPCO agreed to provide sizing calculation during detailed design stage as per contract.

d) Generator neutral grounding transformer & secondary loading resistor

SEPCO agreed to provide sizing calculation from generator vendor during detailed design stage as per contract.

e) Excitation Transformer capacity (MVA) to be to establish with ceiling voltage level as mentioned in contract

SEPCO agreed to provide sizing calculation from generator vendor during detailed design.

f) 11kV Segregated phase busduct sizing calculation considering continuous current, termperature rise, short circuit current.


g) 11KV switchboard, 415VPCC & MCC busbar sizing calculation

SEPCO agreed to provide sizing calculation from switchgear manufacturer during detailed design stage.

h) LV dry type Transformer capacity sizing calculation with detailed load list considering voltage regulation during starting & running of largest motor with all other load connected.

SEPCO agreed to provide transformer sizing calculation (with out voltage regulation). SEPCO will ensure that voltage regulation shall be maintained as per contract during detailed design.

j) Battery & Battery Charger sizing

i) DG sizing calculation with detailed load list and considering voltage regulation during starting & running of largest motor with all other load connected.

SEPCO agreed to provide sizing calculation to check that the largest motor can be started with other load connected.


k) UPS & UPS battery sizing SEPCO agreed to provide sizing calculation during detailed design stage.

l) Minimum size of 11kV rower cable for fuse-contactor & VCB operated feeder. Similar minimum size of 415V power cable for ACB operated feeder.


m) Auxillary power consumption calculation in details & net output of generator.

SEPCO guranteed auxiliary power comsumption shall be as per Contract.

n) ACSR conductor and tube busbar (for 400kV switchyard) sizing calculation considering continuous currect, short circuit current and permissible temperature rise.


SEPCO agreed.Current rating and fault level of 400kV busbar shall be indicated. Tube bus bar shall be capable to handle 3150A current at design ambient condition (at 50 deg.C ambient temperature with permissible temperature rise of 35 deg.C). SEPCO to size accordingly.

SEPCO agreed.Dedicated CT & PT for Main and Check metering on grid side shall be provided. Class of CT and PT shall be 0.2S & 0.2 respectively.

Please confirm that Diiferential protection CT Class TPY is equivalent to PS class. Please also submit the supporting documents.

SEPCO confirmed. SEPCO also agreed to submit the technical documents in detailed design.

SEPCO agreed to provide LA as per Contract.

Castle Key interlock for all earth switch of 400KV bus, line feeder, outgoing feeder & isolator of Generator earthing transformer shall be provided.

SEPCO agreed except for NGTR. For NGTR locking arrangement shall be provided. TSPL Noted.

Please furnish the basis for selecting Lightning Arrester rating as 360/876 kV for transformer and 390/900kV for Lines. Rating of both LA should be same.

SEPCO agreed as per Contract.

SEPCO agreed.

Shorting links shall be provided on main run, UT tap-off, LAVT & Ex. Transformer tap-off and NGTR neutral tap-off. Please revise the drawing accordingly.

Xd" = 21.47% indicated here, but in write-up it is indicated as 19.76%. SEPCO to check & correct.

SEPCO agreed.Secondary rating of CT used on 400 kV side of GT, ST shall be 1A instead of 5A. Similarly secondary rating of CT used on 400 kV neutral of GT & ST shall also be 1A instead of 5A. Please revise the drawing accordingly.

SEPCO agreed.

SEPCO agreed.

Earth fault current of 11kV system shall be restricted at 300 Amp instead of 100 Amp. Accordingly revise the rating NGR. Calculation for NGR shal be submitted.

Neutral side CT used on 11 kV side of ST & UT shall be 300/5A accordingly.

Rating of neutral side CT of GT shall be 1250/1A same as phase side CT.

SEPCO agreed.

SEPCO agreed.

PT used for metering purpose of Generator & HV side of UT shall be of Class 0.2.

For comments regarding accuracy class, ratio of CT & PT refer comments on Protection & Metering Drawing No. 373-F2491C-D33 & 34 below. This drawing shall be revised accordingly.

SEPCO agreed.

SEPCO agreed.

All the data/parameter/rating of equipments indicated in this drawing shall be supported by detailed calculation as per design criteria specified in Contract, general practice followed in India and relevant standards. The Owner's approval on the calculations shall be taken before finalisation of rating.

Comments marked in this drawing are also applicable to other similar drawings appearing elsewhere.

SEPCO agreed.Numbers, ratio and class of CT on 20kV side of UT & 400 kV side of ST shall corrected as per comment on Drg. No.373-F2491C-D-02, D-33 & D-34.

SEPCO agreed.

SEPCO agreed.

Ratio and class of CT on 11kV neutral side of UT & ST shall corrected as per comment on Drg. No. 373-F2491C-D-02, D-33 & D-34.

Rating of NGR shall be corrected as per your Drg. No. 373-F2491C-D-02.

SEPCO agreed.MCCB-Contactor-Thermal over load relay for motor feeder fed from 415 V PCC is not acceptable. Motor rated above 110 kW shall be fed from PCC and ACB operated.

TSPL agreed for the scheme provided.2 x 100% duplicate incomer feeder with one bus coupler on bus shall be utilised for all MCCs. Chemical dosing and sampling system MCC does not have the same arrangement. Please check and revise.

Refer DBR resolution at Sr. No.40 .

Line PT at incomer to be provided in all incoming feeders of 11KV switchgear & 415V PCC.

a) SEPCO agreed to provide Line PT at incomer of 11kV switchgear.b) For 415V PCC, SEPCO agreed as per Contract.

Please confirm that isolation transformer shall be provided in lighting feeders.

SEPCO agreed.

20% spare feeders covering minimum one feeder of each rating and type to be provided for both 11kV & 415V switchgear as per contract.

SEPCO agreed as per Contract. However, spare feeder for 11kV switchgear shall be decided as per space availability.

Breaker shall be used for incomer from DG to Emergency PC as per Drg. No. 373-F2491C-D-39. Please revise accordingly.

SEPCO agreed.For comments regarding emergency power supply please refer drawing no. 373-F2491C-D-39.

SEPCO agreed.Breaker & CT rating of tie feeders and incomers shall be indicated in the SLD. Tie feeder rating shall be same as incomer rating.

Please clearly indicate the number of Compressor used main plant instrument & service air and the number of compressor used for AHP system. for unit (boiler,turbine system) has not been mentioned.

Separate 11kV Switchgear may be considered for AHP & HCSD System. This switchgear may be located in AHP Compressor Building.

Shall be decided during detailed design.

SEPCO also confiremd that HCSD is not in scope. TSPL noted.

SEPCO confirm to correct as transformer feeder.

Tie feeder between 11kV Unit & 11kV Common switchgear shall be connected by segregated phase bus duct. Cable connection is not acceptable. Please revise accordingly.

SEPCO confirmed that tie connection shall be done by 11/11kV unearthed grade cable.TSPL noted.

Stacker reclaimer feeder is of Tranformer feeder type. Please revise accordingly.

Refer Sr. No.1 above.Busbar rating of CHP switchgear shall be as per calculated downstream load. The calculation along with load list shall be submitted for review and approval.

SEPCO agreed.SEPCO to confirm that SLD for auxiliary power distribution furnished with DBR is a conceptual drawing. Further detailed drawings incoporating all information (i.e. feeder rating, CT rating, etc.) shal be submitted during detailed engineering stage for approval.

SEPCO agreed.SEPCO to note & confirm that the number feeders indicated in the drawings are based on preliminary design. If there is changes in number & rating of feeder in detailed design as per actual load list, the same shall duly incorporated in revised drawing.

SEPCO agreed to provide during detailed design.

Please indicate the location of each switchgear/PCC/MCC in Single Line Diagram.

SEPCO agreed to indicate the loaction of 11kV, 415V PCC and 415V MCC which are already finalised. Location of MCC shall be indicated during detailed design.

SEPCO is requested to furnish the total power distribution system from 22kV generation to 415/240V power supply arrangement in a single drawing.

Fault contribution from station loads through ST shall also be considered for fault level calculation at d1. Please revise the clculation accordingly.

SEPCO will submit the calculation report done in ETAP.

Fault level at d4 shall be sleceted based on fault contribution from unit auxiliary loads in addition to the station auxiliary loads.

SEPCO will submit the calculation report done in ETAP.

Detailed fault level calculation/study, clearly indicating assumption/considerations taken, shall be submitted.

SEPCO will submit the calculation report done in ETAP. SEPCO also confirmed to indicate the assumptions & considerations taken.

a) Detailed computerised system study i.e. fault level study, voltage regualtion considering largest motor (MD BFP) staring & running with all other load connected shall be furnished.

b) Please ensure that for fault level calculation permissible negative tolerance shall be considered for all generator and transformer impedances. Whereas for voltage regulation permissible positive tolerance shall be considered for all transformer impedances.

a) Refer Sr. No. 37 above.

b) SEPCO confirmed to considered the tolerance on impedance as per IEC.

In NOTE 220kV shall be corrected as 400kV. SEPCO agreed.

SEPCO agreed.

Please furnish the current density and maximum tempeture above 50 deg C ambient for the overhead conductor LGKK-600.

SEPCO agreed to indicate temperature rise. Current density shall be furnished during detailed design.

Please check economical cross-section and conductor cross-section of Over Head conductor used for GT incomer.

Refer Sr. No. 1 above.Please ensure that 1688 A is the derated current of 2(LGKK-600) at 50 deg C with tempeture rise limited to 35 deg C. Also please confirm that 884 A and 3582.8 A are derated current of LGKK-600 and LDRE Ø200/184 at 50 deg C with temperature rise limited to 35 deg C. Supporting document/calculation shall be submitted.

11/11kV UE grade cable shall be provided.Minimum size of 11kV cable (Al) shall be 240 sq.mm. for breaker operated feedering considering 50kA fault level for 0.2 sec.

SEPCO confirmed that copper conductor are used for 11kV system. Minimum size of cable shall confirmed by calculation during detailed design.

SEPCO agreed.Please furnish the description/meaning of each letter/number of nomenclature i.e LGKK-600, LDRE-Ø200/184,YZV22, RN4-22/05, LZZBJ9-10 etc. for clarity and better understanding.

Rated current of circuit breaker used for 11kV feeder of UT(ST) shall be equal to UT feeder rating i.e. 3150 Amp.

SEPCO confirmed that rating of tie feeder to Unit Switchgear is 3150A.

SEPCO checked & confirmed.

Rated current of 400kV Isolator should be equal to breaker rating i.e 3150 A.

SEPCO confirmed that isolators of 2500A shall be used for 400kV GT & ST feeder. SEPCO agreed to include isolator of 3150A in the list also.

Maximum voltage of CT used for 11kV feeder of UT(ST) shall be 12 kV. Please indicate.

Thermal time of CT used for 11kV feeder of UT(ST) shall be 3 sec. instead of 1 sec.

SEPCO conveyed that thermal withstand time of 11kV CT may not be provided by Chinese manufacturer. TSPL agreed.

Please furnish the rated current of HV fuse used. SEPCO agreed to indicate in revised DBR.

SEPCO agreed.Minimum one meter clearence shall be provided between transformer and firewall and between GT and ST.

Firewall between two ST s shall be provided if required as per TAC/IE Rules. The same shall be decided during detailed engineering.

SEPCO agreed to provide firewall between transformers, if required as per TAC/IE Rules & NFPA 850.

Centre-to-centere distance of 12 meter between two GT s seem to be less.Please check the transformer dimension and revise the same.

SEPCO will check & revise the drawing during deatiled design.

Bus post insulator (BPI) shall be provided before LA for all the GTs and STs. Vertical dropper from over hesds conductor shall be connected to BPI first and then LA and transformer bushing terminals.

SEPCO confirmed that dropper will taken from the overhead conductor directly to Trnasormer bushing & LA separately. SEPCO will also ensure the adequate distance will be maintained.

Rails in front of LA/BPI shall be provided for maintainance of transformers.

SEPCO mentioned that due to the weight, width and Height of the transformer, it will be difficult to arrange such rail monted arrangement in this project, however they displayed how the transformer can be shifted to and from the location by using slippers and Rail, SEPCO also mentioned in case of any problem faced by the Site they will extend all cooperation to get it solved.TSPL agreed.

Gantry near GT nad ST shall be shifted to the central line of BPI/LA located near the respective transformer.

Shall be discussed & finalised during detailed engineering.

Location of common oil pit in transformer yard shall be indicated.Minimum distance of 15 meter shall be maintained between nearest transformer oil pit and common oil pit as per IE Rule.

SEPCO agreed & shall be indiacted in the revised DBR drawing.

Fencing in transformer yard shall be provided and the same shall be indicated in the drawing.

SEPCO agreed shall be indiacted in the revised DBR drawing.

Please show the CW & ACW pipes in transformer yard layout drawing. It shall be help to avoid fouling the foundation of intermidiate gantry/transformers with CW & ACW pipes.

SEPCO confirmed that same indicated in General Layout drawing. SEPCO will revised the drawing to avoid any fouling with CW & ACW pipes.

Please correct the terminology as Generator Transformer instead of Alternator Transformer in equipment and material list

SEPCO agreed & shall be corrected in revised DBR drawing.

Equipment & material list is not matching with SLD. Please correct and confirm it with respect to Drg. No. 373-F2491C-D-02


Please modify this drawing as per our comments on drawing no. 373-F2491C-D-02.


Minimum electrical clearances for outdoor switchyard such as phase-to-phase, phase-to-earth, safety clearance, ground clearance shall be mentioned in NOTE form and also indicate in respective drawing clearly. Nominal voltage, maximum voltage, BIL, switching impulse withstand voltage, power frequency withstand voltage, creepage distance of insulators, size & type of shield wire, type and size of bus, short circuit level of 400kV system shall also be mentioned.


Minimum clearance between fence and switchyard equipment/structure shall be 5 meter. Please indicate.


CT marshalling box shall be provided and indicated in the drawing.

SEPCO agreed & shall be indicated in detailed design.

Lightning rod or shield wire for lightning protection of switchyard equipments shall be provided and shown in layout drawing. Coverage to be ensured for all equipments and lines also.

SEPCO agreed & shall be indicated in detailed design.

The typical distance of 6.5 meter between Ph-E and 7 meter between Ph-Ph for bus & feeder shall be maintained as minimum. Please add as NOTE here.

SEPCO want to see the Indian standard. Relevant pages of Indian standard will be sent for reference. SEPCO agree to revise DBR drawing accordingly.

Approach road, inside the switchyard, shall be provided between CT and Circuit breaker, whereever appearing.

SEPCO confirmed that roads are provided between phases for accessibility of switchyard equipments.

All structures inside the switchyard shall be made of hot dipped galvanised steel.

SEPCO agreed & shall be indicated in Civil drawing.

Discussed earlier.Switchyard configuration shall be considered as 'D' instead of 'I' type. With 'D' one intermidiate gantry (one for each incoming feeder) may be avoided and the conductor stringing arrangement will be athetically good.

SEPCO agreed.

SEPCO agreed.

The equipment spacings indicated are minimum. The same shall be be revised to ensure minimum clearence required as stipulated.

The space for one spare diameter in the switchyard shall be kept.

Please indicate name of equipments along with central line.


Please clarify the distance B1 indicated in drawing no. 373-F2491C-D-08

SEPCO confirmed that B1 is the minimum clearance required for maintenance. TSPL noted.

Ligtining Protection is not shown in drawing SEPCO confirmed that lightning rods shall be provided for switchyard & transformer area.

Please revise as per comments on SLD and Switchyard plan layout and check the ratings with respect to Drg. No. 373-F2491C-D-02.


Please indicate Post insulator (item - 15) in equipments material list. Also Item-16 of equipment material list.

SEPCO noted & shall be corrected in revised DBR drawing.

The connection to the outgoing line shall be connected to lightning arrestor first.


All 400kV insulator discs shall be of Anti-Fog type. All 400kV string insulators (Tension and suspension) shall have impulse withstand voltage rating of ± 1550KVp with corona rings. Please specify in DBR/drawing.

SEPCO confirmed that the insulators used for 400kV system will have impulse withstand voltage rating of ± 1550KVp with corona rings and so take care of local climatic condition.TSPL agreed.

Please indicate by a sectional drawing the connection arrangement of branch IPB to LAPT cubicle and excitation transformer cubicile shall be indicated.

SEPCO agreed to indicate the sectional view in detailed design.

Location of CT in busduct to be shown. SEPCO confirmed that there is no CT in bus duct. All the CTs are loacted in bushing of respective UT & generator. SEPCO also agreed to indentify the bushing CT with separate symbol/ legend.

Please furnish the routing of DC excitation NPB and AC excitation NPB in this layout.

SEPCO agreed to indicate the routing in detailed design.

Discussed earlier.

Portable hot air blowing equipment shall be provided.

Sizing calculation (diameter and thickness)considering design ambient, permissible tempeture rise, s/c and continuous rating shall be submitted. Temperature rise and s/c rating calculation shall also be furnished.

SEPCO agreed as per Contract & DBR shall be revised accordingly.

Expansion joints shall be provided and indicated in drawing.

SEPCO agreed to indicate the same in revised drawing.

Discussed earlier.

Seal of bushing shall be provided at wall crossing and equipment connection as per contract. Please indicate the same in this drawing.

SEPCO confirmed that seal-off bushing shall be provided at Generator, GT, UT, LAPT & Excitation Transformer ends.

Disconnecting link and short circuit link shall be provided on Main run and Tap-off run and same shall be indicated in drawing.

For other comments refer drawing no. 373-F2491C-D-10

SEPCO agreed to indicate the same in revised drawing.

Please ensure that height and dimension of fire wall shall be as per TAC and IE Rule.

SEPCO agreed to indicate the same in detailed drawing.

Staircase near A row shall be provided for crossing IPBD.

SEPCO will discussed with mechnical counterpart regarding the fouling with water/ steam pipes and revised the drawing accordingly.

Support for IPB shall be indicated. Shall be shown during detailed engineering.

Minimum clearence between any live part and any metalic part shall not be less than 4200 mm. i.e minimum clearence between top most part of HV bushing and IPBD shall not be less than 4200 mm.

SEPCO agreed & shall be indicated in the revised drawing.

Gantry considered shall be shown and removal of transformer shall be considered while deciding the location, footing etc.

SEPCO agreed to indicate the same in detailed design drawing of transformer yard.

Wall seal off bushing shall be provided wherever required.

SEPCO agreed to provide seal off bushing as per Contract.

Flexible and metal bellow shall be provided.

SEPCO agreed.

SEPCO agreed to provide flexible and metal bellow as per Contract.

Phase cross over chamber shall be provided if terminal sequence will not match.


Bottom entry busduct is not acceptable. There is enough clear space above the HT switchgear. Re-routing shall be done for HT busduct for top entry to the HT switchgear.

SEPCO conveyed that because of fouling structures bottom entry busduct has been given. TSPL agreed.

Outdoor portion of SPBD shall have sloped top to prevent accumulation of water.

Discussed earlier.

Please indicate the floor level of Switchgear rooms.

Busduct dimensions are tentative only. Dimensions shall be finalised by supporting calculation considering continuous current rating, S/C rating, permissible temperature rise and reference design ambient temperature of 50 deg. C temperature.

SEPCO agreed & shall be indicated in revised drawing.

Sectional drawing of segregated phase busduct shall be furnished.

SEPCO will furnish the same during detailed design.

Discussed earlier.

Structutral supports for busduct as required shall be provided.

SEPCO will indicate the same during detailed design.

Cable entry provision for outgoing feeder shall be indicated. Tie feeder connection to individual unit through busduct shall be shown and adequate no. of dedicated tie breaker on common switchgear to be considered.



SEPCO agreed.

Panel numbering shall be from left to right direction looking from front of switchgear.

Minimum back and side clearances between panel & any obstruction (like column, any other panel etc.) shall be kept as 1200mm for HT switchgear. Accordingly revised the drawings.

Suitable flanges shall be provided for busduct connection to switchgear.

Discussed earlier.Bottom entry busduct is not acceptable. There is enough clear space above the HT switchgear. Re-routing shall be done for HT busduct for top entry to the HT switchgear.

We understand that vertical steel members (may be vertical bracing) are provided between Grid A7-A8, A15-A16 & A24-A25. Please indicate the actual clearance between steel member & HT panel in Section A-A.

SEPCO agreed to indicate the back clearance from the nearest wall.

Ventalition ducts if any shall be marked or alternatively provision for heat dissipation of switchgrear room shall be ensured.

SEPCO electrical group will discuss with SEPCO HVAC group and confirmed accordingly.

SEPCO agreed.Comments marked in this drawing are also applicable to other switchgear layout drawings appearing elsewhere.

Front of switchgear panel shall be clearly marked in all switchgear layout drawings.

SEPCO agreed & revised the darwings accordingly.

SEPCO agreed.

SEPCO agreed as earlier resolution.

Number of HT switchgear panels are indicatively. The number shall be finalised after approval of feeder list & SLD and the drawing shall be revised accordingly.

Spare feeders shall be as per contract - Present drawing to be revised accordingly.

We assumed that cable cellar is provided below the electrical switchgear rooms. In drawing it is not clearly indicated. Please furnish the sectional view of switchgear room indicating the cable cellar.

SEPCO confirmed that bottom entry cable will considered. SEPCO inform that space not available below switchgear room in TG building due to piping and for that reason cable cellar not provided below 6.9M floor in TG building. TSPL noted..

SEPCO confirmed.

Type of battery shall be indicated. Also please specify the application of 400 Ah and 1800 Ah battery indicated here.

SEPCO confirmed that type of is maintenance free lead acid battery.400Ah - Unit UPS & 1800Ah - Unit DC system. SEPCO agreed to indicate the same in drawing.

Please note and confirm that rating of battery indicated are tentative only. Actual rating shall be indicated after finalisation of battery sizing calculation.

Air conditioning shall be provided if the battery are of VRLA or SMF type. Please confirm and indicate the same in the drawing.

Proper ventilation to be ensured if battery are of Lead Acid Plante type.

SEPCO confirmed to add a NOTE that 'Maintenance free lead acid battery room shall be air conditioned' as per Contract.

Sectional drawing shall be furnished to ensure that sufficient space is available above cells.


Location of battery used for UPS shall be indicated. SEPCO will indicate the same in revised drawing.

SEPCO agreed.

Discussed earlier.

Back clearances of Dry Type Transformers and panel shall be minimum 1000 mm.

Panel numbering shall be from left to right direction looking from front of switchgear.

Sufficient clear space for movement and removable of Dry Type transformer as required shall be provided.

SEPCO agreed. Clearnces shall be indicated in detailed design.

Please show sectional view/elevation of this area separately covering 0.00 M to 6.9 M equipment with cable cellar, cable tray, trenches etc. as considered.

SEPCO agreed & will be indicated in detailed design.

Other MCC in Turbine House (like Boiler MCC, Unit MCC,Air Conditioner MCC, CPP MCC, Bunker Bay MCC, etc.) as indicated in SLD shall also be shown in layout drawings.

SEPCO agreed & will be indicated in detailed design.

Front of switchgear panel shall be clearly marked in all switchgear layout drawings.

SEPCO agreed & the drawings will be revised accordingly.

Please clearly specifiy / indicate whether MCC/PMCC are double front type of single front type. If MCC/PMCC are double front type, minimum 1500 mm clearance shall be provided between wall and panel front.

SEPCO confirmed that all MCC & PCC are single front. SEPCO will indicate the same in drawings.

There is no sufficient space in 415V Unit Switchgear Room for maintanace / removal of dry type transformer. Please rearrange the layout with sufficient clear space accordingly. SEPCO to clarify how the transformer can be took out through the corridor with door opened outside?

SEPCO agreed & confirmed that dry type transformer will be removed after removing of enclosure. The dimension of dry type transformer with out enclosure will be indicated suitably in detailed design drawing.

Please shift the door of Emergency Switchgear Room of Unit-2 & 3 to the middle of MCC-A & MCC-B.

SEPCO agreed & will be indicated in revised drawing.

SEPCO agreed.

Please shift the dry type transformer of 415V Common Switchgear towards opposite side i.e. wall side.

SEPCO agreed & will be indicated in revised drawing.

Please inter change the location of UPS of Unit-3 and DC Equipment of unit-3 to maintain uniform arrangement for both the units.

We note that one column is appearing inside the 415V Emergency Switchgear Room, which is not acceptable. Please rearrange the layout to avoid the column inside the switchgear room. The following option may be adopted for the same.a) Shift the wall appearing between 415V Emergency Switchgear Room & UP Room to Grid-K1.b) Inter change the location of 415V Common Switchgear & DC Equipment of Unit-2.c) DC Equipment of Unit-2 and UPS of Unit-2 shall be located in one room between Grid-D & K1.d) Similar changes/modification need to be done for Unit-3 also.

SEPCO noted & agreed for the scheme proposed by DCPL. Detailed drawing will be prepaared & submitted by SEPCO with revised DBR.

SEPCO noted & agreed.

Please note that UPS Panel/Control Equipments/Electrical Relay Panels shall be located in air conditioned room. Please clearly mentioned in layout drawing which rooms are air conditioned.

SEPCO agreed. For details HVAC DBR shall be referred.

For comments on battery room refer the comments on Drg. No. 373-F2491C-D-15.

Refer Sr. No. 113. above.

Location of 415V Common Switchgear Room-II is not matching with Civil Drg. No. 373-F2491C-T-02, Rev-0 and Mechnical Drg. No. 373-F2491C-J-21, Rev-0. SEPCO to please expalin and confirm the correct location of 415V Common Switchgear Room-II and 11kV Common Switchgear Room.

SEPCO will correct the layout & indicate in revised drawings.

Please expore the provision for cable entry to switchgear panel located in EL. 0.00m.

Discussed earlier.

We assumed that cable cellar is provided below the electrical switchgear & relay rooms. In drawing it is not clearly indicated. Please furnish the sectional view of switchgear / relay room indicating the cable cellar.

SEPCO confirmed that cable cellar is provided below the switchgear room for bottom entry of cable to the panel.

Please indicate the floor level/elevation on each layout drawing.


Back clearances of CHP HT switchgear shall be such that one panel of Section-A shall be took out easily through the double door.

SEPCO agreed & revised the darwings accordingly.

Degree of enclosure protection shall be IP 52 for coal handling area. Please specify the same in remarks column.

Battery & UPS will be indicated in detailed design.

We assumed that false flooring is provided below the CHP Control Room & Office Room. In drawing it is not clearly indicated. Please furnish the sectional view of indicating the false flooring & cable entry provision.

SEPCO confirmed that 300 mm high false floor will be provided below the CHP Control Room & Office Room.

Battery room and UPS for offsite building switchgear room shall be indicated/ located in respective drawings.

Please show the wall for cable cellar room. Refer Sr. No. 151.

SEPCO to expalin the arrangement for unloading/lifting of dry type transformer & switchgear panels at EL. 8.00M & 17.5M. Separate unloading bay with mono rail-hoist arrangement shall be provided.

SEPCO will provide alternative arrangement of wheeled trays in order to carry the transformer to the open balcony/platform without any roof Transformer will be lifted from this platform by crane.

SEPCO agreed as per Contract.Minimum 250mm clearance shall be provided between top of top most cable tray and floor beam. There are some cable trays appearing at EL. 6.3 m level, it seems to be incorrect. Please check and revised the drawing.

Cable tray size design to be ensure that only single layer of power cable & multi layer control & instrumentation cable is on tray and it should not beyond height of cable tray. Hence tray tray width & no of tray layers shall be design accordingly.

AS per Contrct Document the design values being used for standard current ratings, maximum conductor/armour temperatures, ambient and ground temperatures, soil thermal resistivity, depth of burial, cable spacing and grouping etc. shall be subjected to Owner's approval. TSPL conveyed that SEPCO will submit deisgn ducument for cable sizing for approval. SEPCO agreed.

Cable laying / routing drawing to be provide with cable tag number.

SEPCO will provide tag number to each cable. SEPCO will also provide list of cable with tag number to indentify the used of that cable during detailed design.

Provosion for accessibility to cable cellar room of STG & Control Building shall be clarified/explored. Separate layout drawing for cable cellar room shall be furnished.

SEPCO confirmed that cable cellar shall be accessible from the staircase. The same shall be indicated in cable cellar drawing.

Refer Sr. No. 134.

SEPCO agreed.

We noted that some over head cable trays are appearing above 415V Lighting & Maintenance Switchgear, which is not acceptable. Please re-route the trays through the cable cellar room.

Cable tray crossing in Railway line should have adequtae vertical height clearance to accommodate electric traction

SEPCO to ensure that cable for standby/duplicate motor shall be routed through separate cable tray. Layout of cable tray shall be developed accordingly.

SEPCO conveyed that they will try to follow wherever possible. But it may not be possible in all the locations.

a) Please note that below ground cable trenches for outdoor area except transformer yard & switchyard are not acceptable. Cable rack / pipe-cum cable rack shall be considered for inter plant cabling.

b) Please note that there shall not be any direct connection between indoor and outdoor trenches (applicable for transformer yard & switchyard). Indoor & outdoor trenches shall be physically separated.

c) Outdoor overhead trays shall enter directly into switchgear room and then it shall drop down to the cable trench inside the switchgear room. Switchgear room layout and dimensions shall be freezed accordingly. Please confirm.

a) SEPCO agreed.

b) SEPCO agreed wherever applicable.

c) SEPCO agreed.

SEPCO agreed.

Cabling arrangement for off-site building electrical room/ switchgear room shall be explored.

SEPCO confirmed that generally bottom entry cable shall be adopted. Some exceptional case where top entry cable provision is essential, same shall discussed during detailed engg.

Aeduate illumination system, access platform, cross over sysetm, drainage system, dewatering system to be furnish in all cable trench & cable tray where ever applicable

Refer mechanical resolution.Vertical & horizontal clearance of cable tray & cable trench to be minimum 2 Meter from Steam pipe, water pipe, heater, walkway, doors, equipment, drainage system etc.,

SPECO agreed.

Discussed earlier.

SEPCO to note & confirm that the submitted switchgear room layout and cable tray layouts are conceptual drawings only. Detailed layout drawings shall be furnished during detailed engineering.

Number of cell of 220 V battery shall be 110 instaed of 104.

Type of battery & charger to be indicated.

Battery boast charging duration shall be 10 -12 hours. SEPCO agreed as per Contract.


Please furnish the legend sheet indicating the details of all components appearing in the drawing.

SEPCO agreed & shall be furnished during detailed design..

SEPCO agreed to indicate the type battery as VRLA.

Both battery charger to be provided with float cum boost charger.

SEPCO agreed as per Contract.Each DC system shall have 2x100% battery with 2x100% floot-cum-boost charger as per contract. Please clearly indicate the same in drawings.

We found that three different schemes are envisaged for 200V DC System of Unit, Network Control System and BOP System. Please clarify the technical reason.

Further, SEPCO to note and confirm that scheme for all DC system shall be identical as per contract. Please revise the drawing accordingly.

SEPCO agreed as per Contract. SEPCO will furnish the details for BOP DC system during detailed design.

From where Station / common DC loads will be fed? SEPCO to clarify and indicate as a NOTE inrespective drawing.

SEPCO will indicate the requirement in revised drawing.

Please specify the loaction of 220V DC System of BOP in the drawing.


Please provide cross sectional view of control building.

Refer resolution at Sr. No.150 & 151.

48 V DC battery system & charger to be provide for PLCC system if system requires

SEPCO confirm to provide 48V DC system for PLCC.


Please show cable entry provision for panels as well as Control Building.

SEPCO agreed.

SEPCO will indicate.

Discussed earlier.

Battery and UPS room shall be air conditioned. Please indicate the same in the drawing.

Please clearly indicate the location of NCCS in Network Control Building.

Please specify the control point of 400kV breaker/isolator.

Please clarify and indicate whether 3-ph, 4-wire or 2-ph, 2-wire power supply is required for UPS bypass panel.

SEPCO confirmed that bypass supply shall be 2-ph, 2-wire.

SPECO agreed.Please note that communication interface (RS 485) shall be connected to ESCADA instead of ECS.

a) Class of CT used for 400kV bus bar protection (87B) shall be Cl. TPY instead of 5P30. Number of cores for 400kV bus side CT shall be 8.

b) Both bus side CT (GT010 & GT030) shall be indentical with respect to number of cores, accuracy class & ratio.

c) Similarly both the CT (GT020 & GT040) used for 400kV centre breaker shall be indentical with respect to number of cores, acuuracy class & ratio.

a) SEPCO agreed & drawing will be revised accordingly.

b) SEPCO not agreed.

c) SEPCO not agreed.

SEPCO agreed.

Following protection as per contract shall be provided for linea) Distance protection (Main-I & Main-II)b) Open jumper protectionc) Single & three phase auto recloser with synchro check.

a) SEPCO agreed.b) SEPCO agreed.c) SEPCO agreed.SEPCO will revised the drawing in line with the above.

Double channel for each stub protection shall be provided.

SEPCO agreed & will revised the darwing accoringly.

Rating/ratio, accuracy class of 400kV Voltage transformers shall be indicated.

SEPCO agreed.Please interchange the CT core used for 87-1/L & 87-2/L for both BUS-II & centre breaker CT in line with Drg. No. 373-F2491C-D-34.

Differential protection of generator transformer & station transformer shall not be clubbed with 400kV stub protection. Dedicated differential protection shall be provided for GT & ST. Separate CT having accuracy class of TPY shall be provided on 400kV side of Generator & Station Transformer for GT & ST differential protection and 400kV switchyard stub protection.

1) SEPCO conveyed that 5-core CT may not be available in transformer bushing.

2) SEPCO also conveyed that there is some operational difficulty in the scheme proposed by TSPL. As per SEPCO, if the isolator of transformer feeder is opened, maintenance of CT in transformer bushing can not be made.

The identification of the location fault can be inferred by other protection like over current operate parallel differential.

TSPL agreed.

SPECO agreed.

SEPCO to ensure that CT indicated on 400kV side (both phase & neutral CT) of GT & ST are bushing CT.

Please indicate these bushing CTs with separate legend/ symbol.

SEPCO confirmed that both phase & neutral CT of transformer shall be bushing type CT.

Ratio of CT used in generator transformer neutral shall be 1250/1 A instead of 300-600/5 A.

SPECO agreed.a) Primary side voltage of generator VT shall be 22/√3 kV instead of 20/√3 kV.

b) Class of generator VTs shall be indicated. Please note that class of metering core shall be 0.2.

We noted that surge capacitor is not provided. Supporting calculation shall be provided for the same.

SEPCO will contact generator vendor regarding the same and convey their recommandation with basis.

5000/5 A CT ration is ok.

Please note that the following 51/27, 49G, 46G, 59N protection are appearing on both phase & neutral side CT/PT. SEPCO to please clarify the same.

SEPCO will check & revise the drawing accordingly.

Rated current of secondary side of Excitation Transformer is 7812.5 Amp (=3x2500x1000/1.732x0.96), whereas selected CT ratio is 5000/5 Amp. SEPCO to clarify the reason.

SEPCO agreed

SEPCO confirmed that CT class shall be 0.5.

kW and kWh meter / transducer shall be provided for excitation transfomer and same shall be taken in DCS through transducer for monitoring.

Accuracy class of CT used for metering & AVR for Excitation Transformer shall be of Cl. 0.2S instaed of 0.5.

Discussed earlier.

SEPCO agreed.

VT signal for synchronisation shall be indicated. Shown in Drg. No. D-38.

Shorting links/disconnecting links shall be provided on main run, tap-off run of UT and tap-off run of LAVT & Excitation Transformer.

SEPCO to clarify what is 'Circuit Breaker Flashover protection' with correct ANSI relay code number.

SEPCO agreed & shall be revised accordingly.

SEPCO agreed.

SEPCO agreed.

Accuracy class of energy meters used in 22kV & 400kV shall be 0.2S. Please indicate the same.

Accuracy class of CT used for UT & ST protection shall be same for both HV & LV side.

Ratio of CT used in unit transformer & station transformer neutral shall be 300/5 A.

Revised in rating of NGR accordingly.

SEPCO agreed.

Please note that only PT connections are shown for 50/51UT (for UT) & 50/51V (for ST). CT connections for above protection shall be indicated.

SEPCO clarified that CT connection are provided. TSPL noted.

Rating/ratio & accuracy class of HV & LV side PT shall be indicated.

SEPCO will indicate in the detailed design drawing.

kW, kWh, A, V meter shall be provided on 11kV side of UT & ST. Please indicate. All this paratmeter shall be taken in DCS through transducers.

SEPCO agreed.Line VT in the incomer to 11kV switchgear shall be provided for metering, protection & synchronisation during fast bus transfer.

Duplicate (double channel) protection for restricted earth fault & standby earth fault protection of LV side of UT & ST shall be provided.

SEPCO informed that relay manufacturer not provide dual channel protection for REF & standby earth fault protection for ST & UT (11kV side). TSPL noted.

SEPCO agreed.

SEPCO agreed.

PRD (Pressure Relief Device) operated alarm shall be considered.

What is 51STA/51STB? Please clarify.

Definate time overcurrent pahse & earth fault protection on 11kV Switchgear incomer feeder shall also be provided as per Contract.

SEPCO will provide definate time over current pahse & earth fault protection at 11kV incomer.

Secondary currect of CT used in 400kV phase as well as in neutral side of ST shall be 1A instead of 5A.

SEPCO agreed.Please correct the terminology as Generator Transformer instead of Alternator Transformer and Station Transformer Meters & Transducrs Panel instead of Auxiliary Meters & Transducers Panel.

SEPCO agreed as per EPC Contract.SEPCO to furnish the protection provided for (a) 400 kV Busbar,(b) 400 kV Outgoinf Line feeders,(c) 400 kV Transformer feeders,(d) Generator,(e) Unit Transformer and(f) Excitation Tramsformerin a Table form with device/relay code as per ANSI.

Generator, GT & UT protection shall be classified as Class-A, Class-B and Class-C trip. SEPCO to furnish the same in a table form.

SEPCO will submit the tripping class during detailed design.

Hydrogen purity protection, Hyrdogen sealing system protection, Stator water temp, flow alarm

SEPCO informed that these will be monitored and alarm generated in case of fault. TSPL Noted.

Please show all protection & control cabinet used for 400 kV system in drawing shall be indicated in line with Layout drawing of NCS building (Drg. No. 373-F2491C-D-32).


Please confirm that the switchyard control shall be envisaged through the SCADA system on IEC 61850. Please indicate protocol used.

SEPCO confirmed that IEC 60870-5-103 will be used.

Please confirm that all Interfaces shall have 2x100% redundancy (hot standby).

SEPCO confirmed that all Interfaces of NCCS shall have 2x100% redundancy (hot standby)..

Please clearly identify the all the equipments/components indicated in this drawing.


Digital Synchronoscope shall have provision of Auto & manual synchronisation of GT & outgoing line feeders

Normal operation including syschronisation of breaker shall be done from DCS. SEPCO not recommend for manual synchronisation. However, Synchronisation can be done from synchronisation panel (located in electric relay room) through a command.

SEPCO agreed.

SEPCO agreed.

Syncronisation of centre breaker shall be also be considered. Please revise the drawing accordingly.

Integrated Energy management / metring system from 400kV to 415V MCC level shall be established in ESCADA.

ESCADA - Breaker signals (opening & closing feedbacks) should be through I/O not through communication cable.

SEPCO confirmed that ESCADA shall be provided for monitoring. Status of breaker shall be available in ESCADA.

SEPCO will furnish the detailed design.

SEPCO agreed.

ESCADA - Manual, Hardware literature, supplier details to be furnish

Link redundancy between DCS, NCCS to ESADA to be provided.

SEPCO agreed for the link between DCS & ESCADA.

ESCADA Operating station to be provide in CCR for desk engineer.

Only monitoring shall be provided in ESCADA.All incomer & buscoupler of 11kV switchgear to 415V MCC of unit & station to be operate from ESCADA - No Backup panel envised.

Protection & metering of emergency DG system shall also be included in ESCADA.

Monitoring shall be provided in ESCADA. SEPCO confirmed & revised the drawing.

Please indicate the communication protocol used for ESCADA.

SEPCO confirmed that IEC 60870-5-103 will be used.

SEPCO will furnish during detailed design.Please furnish the write up for operation philosophy of emergency DG system.

SEPCO will revised the drawing.Please note that as per Drg. No. 373-F2491C-D-03 (1/3) there is a bus coupler between two bus section (i.e. MCC-A & MCC-B). Please revised the diagram of emergency power circuit accordingly.

11kV Breaker / Fuse-contactor grounding system shall be electrical & mechanical interlock

SEPCO confirmed that mechanical interlock shall be provided.

Energy Meter to be provide & connect to ESCADA SEPCO agreed.


CTs to be provide in all 3 outoing phases of feeders SEPCO agreed.

Signals to DCS from 11kV switch board, 415V PCC/MCC - Analog, Digital not mentioned. All shall be hardwire directly from breaker auxillary contacts, current tranducers & electrical fault from Numerical relays through dedicated multi core control cable as per contract. Please revise the drawing accordingly.


Please note in legend it is written that differential protection is provided for 2500kW above trnaformer whereas in note it is written as 2000kW. Please clarify.

SEPCO confirmed that differential protection shall be provided above 2000kVA transformer.

Over current (51), over current earth fault (51N) and under volatge (27) protection shall be provided on 415V PCC incomer. Please indicate the same.

SEPCO agreed.

Please note and confirm that restricted earth fault protection shall be provided for transformer rated 2000kVA & above and standby earth fault protection shall be provided for all LT aux. transformer. Revise the drawings accordingly.

SEPCO informed that restricted earth fault is not available for transformer rated 2000 kVA & above. TSPL noted.

Instantaneous element for over current phase fault & earth fault shal be provided for 11kV transformer feeder.

SEPCO agreed.Locked rotor and negative sequence protection shall be provided for 11kV motors.

Current signal to DCS is from 11KV switchgear should be - CT to Current transducer then 4-20 mA to DCS.

SEPCO confirmed that current transducer is intregated in protection device and shall be hardwire to DCS.

Shall decided during detailed design.Ready to start signal for local & DCS start should have Ready start & check folowing condition - Process interlock from DCS, relay failure, Emergency push button release, breaker service position & spring charging.

Shall decided during detailed design.

SEPCO agreed.

Local Push button box of motor should provide with following lamps - Run, Stop & Process interlock

Emergency Stop push button should connect directly to Breaker trip coil with aux contact to DCS for indication

Shall furnished during detailed design.


Please clarify what is GWBKQ-W? It auto transfer device.

11kV Line PT control drawing not provided. Furnish the same.

Protection function for 11kV incomer feeder shall be indicated.

Auto bus change over scheme with fast bus transfer feature to be provide in PCC tie feeder (bus coupler) & Essential MCC tie breaker (failure of one section which lead to major equipment trip under any operational contingencies)

SEPCO informed that the auto bus changeover with fast bus transfer will be carried out in DCS. SEPCO will ensure fast response in DCS as required. Drawing shall be revised accordingly. TSPL noted.

Refer Sr. No. 236.


SEPCO agreed.

The schematic drawing/wiring diagram of 415V switchgear incomer and bus coupler showing various details along with followings to be provided for momentary paralleling - (a) Provision on AUTO-MANUAL selector switch in bus coupler,(b) Bus change over feature in auto & manual mode, (c) Provision of Trip Selector Switch (TSS) with three posotions (Incomer-1 / Incomer-2 / Buscoupler) in coupler module.

Protection functions for bus coupler breaker shall be indicated.

DCS control of ACB controlled out going feeders of 415V PCC shall be provided.

SEPCO agreed as per Contract

SEPCO agreed.

Feeder rated 630A & above shall be controlled by ACB. Also note that both end (PCC & MCC end) of this feeder shall have ACB with required protection as per contract.

3 CT (one in each phase) shall be provided for protection purpose.

SEPCO agreed.Feeder rated below 630A shall be controlled by MCCB. Also note that both end (PCC & MCC end) of this feeder shall have MCCB with required protection as per contract.

Refer Sr. No. 236.415V Line PT control drawing not provided. Furnish the same.

All PT secondary wherever under voltage protection is envisaged shall be connected through NS type fuse to Numerical relay.

SEPCO confirmed that all PT secondary side protected by MCB.

Shall be as per DBR drawing.

2x100% power supply arangement for control circuit shall be provided and shown in the drawing.

415V PCC/MCC shall have 2x100% control transformer for supplying control supply to contactor controlled feeders.

SEPCO confirmed to provide 2x100%, 220V DC for control supply of MCC & PCC.

Separate power supply circuit with MCB/fuse for closing, tripping and indication circuits shall be provided and indicated in drawings.

a) Each switchgear cubicle shall have cubicle light, plug/socket, thermostat controlled space heater.

b) Space heater circuit for motor rated above 30kW shall be provided and shown in drawing.

a) SEPCO confirmed that space heater will be provided for 11kV panels. SEPCO also informed that space heater for 415V panel will not be provided as the same are located in air conditioned room.b) SEPCO agreed as per Contract.


SEPCO agreed.

Each switchgear (circuit breaker) cubicle shall be provided with - (a) One TRIP-NEUTRAL-CLOSE (TNC) breaker control switch, (b) Indicating lamps on front of compartment for Breaker open, Breaker close, Trip, Trip circuit healthy, Spring charged, Breaker service position & Breaker test position.

Trip circuit shall have no interlock with other selector switch.

SEPCO agreed.

Trip circuit supervision relay, lockout supervision relay, power supply supervision relay shall be provided and indicated in drawings.

SEPCO agreed that the same shall be provided in numerical protection device.

Quantity of equipment shall be as per requirement for safe and trouble free operation of the plant. Electrical equipment list (BOM) shall be revised in line with the above comments on DBR and drawings.

Discussed earlier.

Shall be discussed during review meeting. Refer Sr. No. 52 of DBR resolution.

SEPCO agreed.

Requirement of ABT meter shall be 12 instead of 8. Please correct.

The high frequency coaxial cable should be provided by contractor.



SEPCO REPLYTSPL / DCPL Comments of DBR / Drawing Rev A

SEPCO shall provide sizing calculation .

SEPCO shall provide all sizing calculation listed below.All sizing calculations shall be indicated immediately for approval before proceeding further engineering.Supporting documents indicating criteria and details of load , etc shall be submitted in line with contract specification














SEPCO shall provide sizing calculation . SEPCO shall submit sizing calclation later.


SEPCO yet to provide sizing calculation .Battery sizing shall be submitted along with details of load ,duty cycle etc









SEPCO shall submit tube bus sizing calculatiion .Tube bus shall be considered for individual bay bus for equipment connections

Bus CVT shall be provided for all the three phases & isolator shall be provided before bus CVT. Bus LA shall be placed between CVT and Isolator.

SEPCO guaranteed that tube bus bar shall be capable to handle 3150A current at design ambient condition (at 50 deg.C ambient temperature with permissible temperature rise of 35 deg.C).

Single phase voltage is used for relay, so three phases bus CVT is not necessary

SEPCO shall submit the technical documents. SEPCO shall the document later.

Dedicated 400 KV CT & PT for Main and Check metering on grid side shall be provided in line with PSEB/PGCIL requirement. Class of CT and PT shall be 0.2S & 0.2 respectively. CT/ PT TB, MB, Panel shall have sealing / locking arrangment.

Dedicated CT & PT for Main and Check metering on grid side shall be provided. Class of CT and PT shall be 0.2S & 0.2 respectively.

OK, Noted.

OK, Point closed. All LA rated as 390 / 900KV.

OK, Point closed, Drawing revised as per 19.76%.

Shorting link shall be shown in the drawing as DBR resolution.

shorting link for enclosure shall be provided on main run and tap-off complete with IPB. Shorting link shall be near to the equipment.

OK. Point closed.

OK. Point closed.

OK. Point closed.

OK. Point closed.

OK. Point closed.

SEPCO shall submit sizing calculations

OK, Noted.

drawing NO has been corrected.

400 KV CT ratios for the ST bay shall be revised considering Station Transformer 400 KV side current rating. Proposed 400 KV CT ratio are on very side.

400kV CT ratios for ST bay are appropriate. The ST bay and the ourline bay are in the same diameter

DRAWING NO shall be corrected as 373-F2491C-D-03 instead of 373-F2491C-D-02

OK. Point closed.

OK. Point closed.

11KV Unit & Common bus fault level rating shall be corrected 50 KA, as shown in DBR Rev 0.

according to the calculation of Rev A, fault level rating is 40kA.

Please clarify why 4 nos. Common or Station bus (2 nos each per Station transformer) as per contract specification were not considered. Instead of that only two common bus, each fed by one winding of both station transformer considered.

4 nos. common bus scheme is too complex , and there are many connection between the common bus and unit bus. It will bring more fault in the operation. two common bus scheme is simple, it is easy for busduct fixing and maintaince.and two common bus scheme is very safe for the plant, we have adopt it for many power plant.

OK. Point closed.

OK, Noted.

OK, Noted.

a) SEPCO yet to revise this in the revised drawing(3/3).b) SEPCO yet to revise this in the revised drawing

SEPCO agreed to provide Line PT at incomer of 11kV switchgear. And SEPCO has revised the drawing.

SEPCO to indiacate 11 KV spare feeder & quantity of each type in each switchgear drawing, including incomer / tie, transformer, motor with breaker and vaccum contactor module.

Spare feeder for 11kV switchgear shall be decided as per space availability. SEPCO provided one spare breaker feeder and one spare vacuum contactor feeder for each unit bus and common bus.

SEPCO yet to take care this point.The same shall be taken care by SEPCO.

SEPCO provided breaker in the DG cabinet and isolator for incomer from DG to emergency PC.

OK, Noted.

To improve reliability of the emergency power supply, incomer from other / adjusent unit also to be connected through breaker to Emergeny PC of each unit. In case of the failure of the own DG of Unit, other / adjusent unit connected DG shall start and feed load.

For each unit one DG will be provided, and each DG only provided power for one UNIT emergency loads. DG will start in 30 seconds, so it is not considered that failure to start of the particular unit DG should initiate starting and picking up load by the other unit DG

OK, Noted.

Please provide11 KV HCSD motor freder as per previous revision & also add two more 11KV feeder for transformer to distribute LT load of HCSD.SEPCO shall take care of the HCSD system electric load requirment in Station Transformer sizing, SEPCO shall also clearly indicate what capacity they hav considerd for HCSD system.

SEPCO provided two mutual backup feeder for HCSD section. Each feeder capacity is 4725kVA. 11kV HCSD motor and LV transformer of HCSD are fed by 11kV HCSD section, which are within the scope of owner.

SEPCO shall consider and include electric load requirment of the other aux. system (like HCSD, Ash Dyke, Ash Water Recovery, Railway Siding / signalling, Raw water resorvoir & water conveyence, Zero Discharge system, Auxiliary Boiler etc.) which are not part of SEPCO supply, for 11KV / 415 V Auxiliary supply system design and Station Transformer sizing.

SEPCO provided power for all the loads in the scope of EPC.

11KV/415V transformer rating appears to be on lower side, same needs to be substantied considering spare feeder, margin and other contract condition, SEPCO to submit befroe finalisationof the size.

transformer rating are based on the loads.

Chemical treatment transformer B rating indicated as 2500KVA, whereas transformer A rating is 1600KVA, noth shall be 2500KVA.

chemical treatment transformer rating shall be 1600kVA, it has been corrected in the drawing.

OK, Point closed.

OK, Noted. Tie / incomer feeder cable termination compartment to be adequetly sized for termination of multiple cables.

SEPCO shall submit calculation. during detailed design stage

OK, Noted.

OK, Noted

SEPCO to submit complete plant elctrical SLD.

OK, Noted. Layout drawing shall cover all MCC and shall be shown specifically.

Location of MCC shall be indicated during detailed design


It is noted that 11KV short circuit rating 50 kA ,as considered earlier has now been revised to 40kA. The same shall be revised back to 50 kA,as the margin is not at all avialable in both UT&ST 11KV switchgear as per final result tabulated..a)Please confirm motor contribution through UT and ST has been taken care for fault level at d1.b)Total kW contribution for 11kV Motor in different bus sections of UT &ST has been reduced as compare to previous revision.Also please confirm whether 16 MW FW pump ( electrical driven) has been included as motor contribution for short circuit current calculation Motor load shall also include HCSD, CHP, ASH etc.c) 20% ST impedance is very high .Please check votage drop during starting and running is with in limit.SEPCO shall submit ETAP data / considerations & detailed calculation sheets for our reference and review of short circuit calculation.

a) after the DBR review meeting, some loads have changed, according to the result of ETAP, short circuit rating 40kA can be considered for UT&ST 11kV switchgear.

B) FW pump has been included as motor contribution for short circuit current calculation of unit 11kV switchgear. when UT is shutdown, ST will feed the load of UT except FW pump. so FW pump has not been included as motor contribution for short circuit current calculation of common 11kV switchgear.

c) when the unit start, FW pump is fed by ST, but the capacity of FW pump is 50% during start. so the impedance of ST has been increased.

SEPCO shall submit the calculation report done in ETAP indicating consideration & assumption..

Same as above.

SEPCO shall submit calclation later.SEPCO shall submit calculation/consideration/assumption in report done through ETAP.

OK, Point closed.

SEPCO to confirm cross section & Data.

OK, Noted. SEPCO shall submit during detail engineering.

cross section & Data has been indicated in this drawing.

SEPCO shall submit calculation. SEPCO shall submit calclation later.

SEPCO yet to submit sizing calculation Minimum size of cable shall confirmed by calculation during detailed design.

OK, Point closed.

OK, Point closed.

OK, Point closed.

OK, Point closed.

OK, Noted.

OK, Point closed.

SEPCO shall revise the drawing during deatiled design.

SEPCO shall revise the drawing & take care during deatil design.

SEPCO shall check & revise the drawing during deatiled design.

Due consideration shall be taken to avoid forces on terminals of LA and transformer HV bushings. It is prefered to have BPI before LA & transformer bushing.

SEPCO shall consider the forces on terminals of LA and transformer HV bushings.

I type shall be used .SEPCO shall note that if rails are not provided then there will be problem/extra time taken to shift the fourth spare transformer to position as a replacement when necessary. Unwanted gantry shall be avoided/or located suitably to avoid obstruction of trasformer/crane movement while shifting. Alternatively D type configuration of will be better instead of I type to reduce number of gantries to connect power conductor at a proper allowable angle to 400 kV switchyard gantry.

SEPCO Shall be discuss & finalise during detailed engineering.

SEPCO shall indicate in the revised drawings. the drawings have been revised.

OK, Point closed.

OK, Point closed.

Space for piping location shall be considered while developing transformer yard layout in revised drawing.

the CW&ACW pipes has been indicated in General Layout drawing. The foundation of intermidiate gantry/transformers has avoided CW & ACW pipes.

SEPCO has corrected the drawing.

SEPCO shall take care.

SEPCO yet to revise this in the revised drawing. Also GT, ST & UAT in the list shall be corrected in line with DBR.

OK, Point closed.

SEPCOshall indicate in the revised drawings.

OK, Noted.

Minimum clearance between fence and switchyard equipment/structure exceed 5 meter， the clearance has been indicated in the drawings.

OK, Noted.

OK, Point closed..

SEPCO shall revise the drawing indicating additional road near CB and CT in the lengthwise direction( crossing between one diameter to other) for movement of personnel during maintenance/supervision.Accordingly the depth 242 Mtr ( including space for line reactor) need to be increased. Presently adopted depth 242 Mtr appears on very congested paricularly between isolators etc.Hence spacing between equipment to equipment need to be reviewed and increased for adequacy of space.The related area in Plot plan drawing Z-02 need to be revised in the same line.

the layout of switchyard has been disscused, and the design can meet the requirement of maintenance/ supervision,

SEPCO shall indicate the same in note in switchyard Equipment layout.

the stell for structures is not contained in electrical equipment list.

I type shall be used .Use of D type configuration of 400kV switchyard will help in avoiding gantry near GT and hence option may be reconsidered in view of better layout

SEPCO shall take care during detail deign.

OK, Point closed.

OK, Noted.

OK, Point closed.Please indicate conductor tension for individual phase from turbine building to 400 Kv gantry for GT & ST line.Minimum 4000Kg per phase conductor shall be considered as per CBIP recommendation.Design margin for design of switchyard gantry structure shall be indicated. SEPCO shall submit gantry structure and beem design documet.

civil design shall consider the conductor tension .

SEPCO yet to revise this in this revised drawing. SEPCO has revised the drawing.

OK, Point closed.

Rod top elevation and location shall cover the entire area for protection

SEPCO guarantee that rod top elevation and location shall cover the entire area for protection

OK, Point closed.

OK, Noted.

OK, Noted.

OK, Noted

OK, Noted.

SEPCO yet to submit sizing calculation. SEPCO shall submit calclation later.

SEPCO has revised the DBR.

OK, Point closed.

SEPCO shall revise the DBR and indicate accordingly in DBR & Drawing..

OK, Noted.

Disconnecting & shorting links shall be indicated for UT tap-off, LAVT & Ex. Transformer tap-off and NGTR neutral tap-off. Please revise the drawing accordingly.

shorting link for enclosure shall be provided on main run and tap-off complete with IPB. Shorting link shall be near to the equipment.Disconnectiong link of conductor shall be provided on main run and tap-off run between the equipment and IPB..

OK, Noted.

OK, Noted.

OK, Noted. SEPCO shall consider during detail engineering.

OK, Point closed.

OK, Noted.

OK, Noted.

OK, Noted, SEPCO shall submit detail engineering drawings.

SEPCO shall indicate in DBR

OK, Noted.

SEPCO agreed to provide flexible and metal bellow as per Contract. The position of flexible and metal bellow shall be decided in detailed design stage.

OK, Noted.


OK, Noted.

OK, Point closed.

OK, Noted.

OK, Noted.

SEPCO shall confirm that cable entry for 11kV as wel as all other 415V switchgear/MCC are at bottom and cable tray provision shall be made accordingly

generally bottom entry cable shall be adopted. Top entry cable shall be adopted for some exceptional case.

SEPCO has revised the drawing.


In. D-14 Back clearance shall be 1200 mm minimum.


OK, Noted.

OK, Point closed.

SEPCO yet to confirm. ventalition ducts shall be indicated in HVAC drawing.

OK, Noted.

OK, Point closed.


OK, Noted. SEPCO shall take care space requirment for the same also.

OK, Noted. SEPCO shall ensure that bottom cable entry during detail engineering . SEPCO shall look into the feasibility to providing cable cellar at most places.cable trench to be provided at 0.0M elecvation in all the indoor areas.

SEPCO has revised the drawing.

SEPCO yet to submit sizing calculation. SEPCO shall submit calclation later.

Battery rating is subject to approval by owner.Battery qunatity shall be revised considering 110 cells / battery set. (in line with revised DBR).

OK, Point closed.

OK, Noted. SEPCO shall take care during detail enginnering and submit all the layout drawing for our approval.

Please indicate location in equipment layout

OK, Noted.

SEPCO has revised the drawing, 400 Ah battery is for UPS, and it has been indicated in remark column.




OK, Point closed.


OK, Point closed.

SEPCO shall revise and indicate in drawing. SEPCO has revised the drawing.

Please check avilalable space for movement and turing of dry type(415V unit switchgear) transformer through corridor after opening the door between grid 17-18 otherwise corridor width 2400 mm shall be increased.

the space is enough for movement and turing of dry type transformer without enclosure.

SEPCO shall revise and indicate in drawing. SEPCO has revised the drawing.

OK, Point closed.

OK, Point closed.

OK, Noted.


OK, Noted.

OK, Noted

OK, Noted.

OK, Noted.

OK, Noted.

Degree of enclosure protection shall be IP 52 for coal handling area. Please specify the same in remarks column.

For switch gear and switch boards in coal area, the degree of protection will be IP 52 outdoor and IP42 indoor.

OK, Noted.


okSEPCO Shall be discuss during detailed engineering,arrangementt shall be shown in layout inline with the same and include in supply of tool items.

OK, Noted.

SEPCO shall mention the criteria of providing tray space for laying of power and control cable in DBR. Group deration factor while sizing cable shall be adopted accordingly

SPECO agreed to provide minimum 300mm space between bottom of upper tray to bottom of lower tray.

OK, Noted. SEPCO shall take care during detail enginnering and submit acoordingly. Number shall appear in cable interconnection schedule also

SEPCO shall indicate in layout drawing the cable cellar and the elevation for the same

it will be indicated during detailed design stage.

OK, Noted.

OK, Noted. SEPCO shall take care during detail engineering.


a) OK, Noted.

B) OK, Noted.

C)OK, Noted.

SEPCO shall take above points during detail engineering.

OK, Noted.

OK, Noted. SEPCO shall discuss exceptions during detail enginnering and submit for our approval.

OK, Noted

OK, Noted. SEPCO shall submit required drawings and document during detail engineering.

OK, Noted.

OK, Noted.

drawing has been modified

OK, Noted. SEPCO shall take care during engineering and procurment.

Please mention clearly in DBR that 2x100% FCBC ( Float cum Boost charger ) will be provided.

OK, Noted. SEPCO shall ensure during detail engineering and procurement.

OK, Noted. SEPCO shall ensure during detail engineering and procurement that all the DC system are having same sccheme and as per contract requirment.

OK, Noted.

SEPCO shall provide seperate 2X100% Battery & battery charger for station/common systemrequirement as per specification clause no:3.04.00. This is required as station & common service switchgear and illumination need to function duringoperation of any one of three unit ( other two unit may be underTOTAL shutdown).

Also 2x100% Battery shall be provided for CHP and Water system

2*100% station/common DC system will be provided. For auxiliary workshop will have one 100% 200Ah VRLA battery and one 100% charger/floating chargers. it has been discussed at DBR review meeting,and theCivil has complete design after DBR review meeting, so there is no space for 2*100% battery. 1*100% battary can meet the requirement .

OK, Noted.

OK, Noted.

SEPCO shall clarify SEPCO confirmed that generally bottom entry cable shall be adopted. Some exceptional case where top entry cable provision is essential, same shall discussed during detailed engg.

OK, Point closed.

drawing has been modified

OK, Noted.

Please indicate location of the PLCC Panels, equipments, 48 V battery & charger etc.

Ok.Please correct the drawing no as D35,instead of D36

OK, Noted, SEPCO shall take care during detail engineering.UPS output shall be connected to both the feeder panel separately..

We have modified the diagram according to contract. According to same 600MW project, one feeder panel is enough.

a) OK, Point closed.b) OK, Noted.c) OK, Noted.

OK, Point closed.

OK, Point closed.

a) OK, Point closed.b) OK, Point closed.c) OK, Point closed.

OK, Point closed.

OK, Noted.

OK, Point closed.

OK, Point closed.

OK, Point closed.

SEPCO shall confirm the requirement of surge capacitor

LA has been provided for surge protction. Generator and IPB are all capacitive equipment. No need for capacitor.

OK.

OK, Noted.

OK, Point closed.

OK, Noted.

Shorting link shall be shown

OK, Noted.

OK, Noted.

shorting link for enclosure shall be provided on main run and tap-off complete with IPB. Shorting link shall be near to the equipment.

SEPCO shall indicate same on the drawing also.

OK, Noted.

OK, Point closed.

this accuracy class of CT has been indicated on the drawing.

OK, Noted.

OK, Noted

OK, Point closed.

during detailed design stage

OK, Noted.

SEPCO shall provide line VT in the incomer to 11 KV switchgear.

OK, Noted.

OK, Noted.

OK, Point closed.

OK, Point closed.

OK, Noted.

SEPCO shall submit protection provided for switchyard,generator UT,ST,Excitation transformer in table form with device/relay code as per ANSI.SEPCO shall submit detailde contrl and protection scheme and drawings during detail engineering for our review & approval and then finalisation of the control & protection matrix.

Our relay code is according to ANSI. Generator UT,ST,Excitation transformer in table form has been provided in D33&D34

SEPCO shall submit the detailed drawing.


OK, Noted. Our suggestion is to use IEC 61850 based BCU and Protection Realy and SCADA system. Where by we can avoid separate control panel, cabling and wiring etc.

SEPCO confirmed that IEC 60870-5-103 will be used. IEC 60870-5-103 is more reliable.


OK, Noted. SEPCO shall submit detailed drawing for our review & approval during detail engineering

SEPCO shall provide manual synchroniser panel along with Auto Synchroniser panel as per contract specification. We appreciate that normally synchronisation will be done by DCS through auto-synchronisation.

Manually synchronization can be done on the auto synchronisation panel .

OK, Noted.



DBR has been modified

SEPCO shall submit ESCADA - Manual, Hardware literature, supplier details .

DETAILS OF ESCADA WILL BE SUBMITED AFTER IT'S ORDERED DURING DETAIL DESIGN.


SEPCO shall indicate same in the system diagram.

DBR has been modified

OK, Point closed.

Same shall be indicated in the drawing. DBR has been modified

SEPCO shall revise DBR clause no11.1.3.2 accordinly.

SEPCO shall furnish the write up for operation philosophy of emergency DG system.As per the DBR clause 6 and our observation on the same please indicate interconnections between DG PCC of different unit.

For each unit one DG will be provided, and each DG only provided for one UNIT emergency loads. DG will start in 30 seconds, so it is not considered that failure to start of the particular unit DG should initiate starting and picking up load by the other unit DG

OK, Noted.

OK, Noted.

OK, Noted.

OK, Noted.

Signals to DCS from 11kV switch board, 415V PCC/MCC - Analog, Digital not mentioned. All shall be hardwire directly from breaker auxillary contacts, current tranducers & electrical fault from Numerical relays through dedicated multi core control cable as per contract. Please revise the drawing accordingly.

Signals to DCS from 11kV switch board, 415V PCC/MCC - Analog, Digital are all in the diagram, and there is a form <DCS COMPARISON TABLE> collects all the information hardwired to DCS. These are directly from breaker auxillary contacts, current tranducers & electrical fault from Numerical relays, as shown in the drawings.

SEPCO shall revise this in the revised drawing. DBR has been modified

SEPCO shall confirm 50/51 for phase and earth fault protection & undervoltage protection in the revised drawings.50/51 Protection relay shall be shown with CT connection.

SEPCO agreed as per Contract. Will be done in detail design.

OK, Noted.

SEPCO shall revise drawing accordingly. Drawing has been modified. F-C circuit uses fuse to be Instantaneousover current protection

OK, Noted.

OK, Noted. SEPCO shal take care.

OK, Noted. SEPCO shall submit detailed control and protection drawings for our review and approval during detail engineering.

SEPCO shall indicate in the revised drawings. DBR has been modified

Local Push button box of motor should provide with following lamps - Run, Stop & Process interlock and same shall be indicated in the drawing.

It's dangerous to run 11kV motor at local box because little information of process and 11kV breaker can be got. DCS will do the job so local control is of no use. Local box only used for emergency stop. So no need for lamps.

SEPCO shall submit drawing. Shall furnished during detailed design.

SEPCO shall revise drawing accordingly.

OK, Noted.

protection is by G-T unit protection, not METER & PROTECTION device at 11kV cabinet. So all the protection is shown in D33

Generally dedicated microprocessor based system is employed for fast bus transfer. We do not have experience of implimenting through DCS as the system maynot be fast enough for change over instanteneously once voltage falls below 80% in 11kV UT bus. Accordingly SEPCO shall confirm provision for Seperate changeover equipment located in the control room for the purpose..

microprocessor based system will be employed for PCC auto bus transfer instead of DCS.

OK, Noted.

OK, Noted.

SEPCO shall revise the drawing accordingly. Drawing has been modified.

OK, Noted.

OK, Noted.

OK, Noted.

SEPCO shall furnish the drawing.

OK, Noted.

There is bus PT on 415V PCC so no need of line PT.

OK, Noted.

OK, Noted.

OK, Noted.

ok,drawing will be modified.

OK, Noted. SEPCO shall sumit detaled scheme and drawing during detail enginering for our approval.

Ok.SEPCO shall indicate in note:4 as "Trip circuit shall have no interlock with other selector switch" remaining shall be deleted.

OK, Noted.

Quantity mentioned in the equipment list is indicative only, and SEPCO shall supply all the equipment as per contract requirement and for safe and trouble free operation of the plant.

all the equipment and material list shall be provided during detailed design stage.

SEPCO shall submit revised drawings.

SEPCO has revised the drawings.

OK

SEPCO shall submit revised drawings. High frequency coaxial cable will be provided with PLCC terminals.The drawing has been revised.Whether it shall be revised again depends on your reply of the present PLCC situation on the remote side(outside the power plant).



SEPCO REPLYTSPL / DCPL RESPONSE ON SEPCO REPLY

SEPCO shall submit sizing calculation .

SEPCO shall provide sizing calculation as per the list below. Supporting documents indicating criteria and details of load , etc shall be submitted in line with contract specification. All sizing calculations shall be submitted immediately for approval before proceeding for further engineering and procurment. In absence of the required sizing document and approval of same by TSPL, any implecation at later stage resposibility lies with SEPCO.

SEPCO will submit calculation with DBR Rev-B。




during normal start-up of the motors with the highest capacity, the voltage of auxiliary power busbars shall be no less than 80% rated voltage.SEPCO will submit ST&UT sizing calculation with DBR Rev-B。



SEPCO agreed to provide sizing calculation during detailed design stage






SEPCO shall submit sizing calculation . SEPCO agreed to provide sizing calculation during detailed design stage.











SEPCO shall submit sizing calculation . SEPCO agreed to provide sizing calculation during detailed design stage.

SEPCO shall submit busbar sizing calculation.Bus CVT shall be provided for all the three phases & isolator shall be provided before bus CVT as per PSEB / PGCIL requirement. Bus LA shall be placed between CVT and Isolator.

in our design single phase CVT can meet the requirement of relay, so SEPCO will provide single phases bus CVT . The isolator is not necessary.

SEPCO shall submit the support document .

Dedicated 400 KV CT & PT for Main and Check metering on grid side shall be provided in line with PSEB/PGCIL requirement. CT/ PT TB, MB, Panel shall have sealing / locking arrangment as per PSEB/PGCIL requirement

Dedicated 400 KV CT & PT for Main and Check metering on grid side shall be provided. CT/ PT TB(terminal box), MB(maintenance box), Panel shall have sealing / locking arrangment

SEPCO will submit document in detailed design.。

SEPCO shall indicate same in the revised DBR and drawings.

SEPCO has indicated the shorting link for enclosure in the layout drawing D-10 Rev-B.

OK, Noted.

OK, Noted.

SEPCO shall provide short time rating as 50 KA for 11 KV switchgear as per our DBR comments. (Refer comment on DBR clause 3.2)

SEPCO shall provide short time rating as 50 KA for 11 KV switchgear

Noted.SEPCO to confirm only one incomer at atime connected toeach BUS-A & BUS-B and fast change over of incomers during failure of any incomer.(By adopting this scheme lot of saving for SEPCO in no. of incomer and tie breaker modules, Segreagred Phase Bus Duct, simplified control & changover scheme etc.)SEPCO must consider 50 KA fault current rating for 11 KV Switchgear.

we adopt 4nos. Common bus scheme .CHP system changed and the load is larger now, so 50kA fault current rating for 11kV switchgear is considered.

SEPCO shall indicate Line PT for 11 KV incomer in drw.no.373-F2491c-d-03 3/3 and Line PT for all 415 V incomers in all drawings as per contract.

drw.no.373-F2491c-d-03 3/3 is SLD for coal loads, fast change over is not necessary , so there is no PT for 11kV incomer of coal section bus.

SEPCO has revised drawing.

NOT ACCEPTABLE.. SPACE PROVISION SHALL BE MADE IN ALL SWITCHGEAR AREAS AND SPARE FEEDERS SHALL BE PROVIDED AS PER CONTRACT. ALSO THERE IS LIKELY POSSIBLITY OF INCREASE IN FEEDER QUANTITY DUE TO FOURTH UNIT.

SEPCO adopt 4nos. Common bus scheme, space and spare feeders is enough.

SEPCO shall recheck and drawing shall be revised accordingly.


By adopting either of the suggested scheme reliability and availability of the emergency power will greatly enhance.

Also as mentioned in DBR Clause no. 6 "DG Switchgear will have interconnection among themselves for reliability purpose", SEPCO shall change the Emergency Power Supply Arrangement Layout accordingly.

DG is used for fault situation, It's no need to consider fault in fault situation in China design standard. it is too complex to interconnect DG bus of different unit, and there are many connection between the DG bus . It will bring more fault in the operation.

SEPCO has revised the layout of emergency switchgear.Bus coupler is provided for emergency MCCA and emergency MCCB.

OK, Noted.

Please consider the following feeders also in ST 11KV distribution based on the location of loads. In a power plant essentially all the loads as listed below are fed from station supply, as that is only power source for all station loads.1) Zero discharge system----------- 1000 kVA2) Canteen Bldg----------------------- 1000 kVA3) Training complex,fire station, work shop,store and O&M office etc ----- 500 kVA4) Railway Siding / signalling etc. --- 500 KVA4) Colony(Approx)------------------ 4000 kVA

according to the contract (VOLUME-II SECTION-IV SCOPE OF WORK AND TERMINAL POINTS), the other aux. system (like HCSD, Ash Dyke, Ash Water Recovery, Railway Siding / signalling, Raw water resorvoir & water conveyence, Zero Discharge system, Auxiliary Boiler,Canteen Bldg ,Training complex,fire station, work shop,store and O&M office, Colony etc.) is not in the scope of EPC.

to be submited during detailed stage.

SEPCO shall submit revised drawings. SEPCO has revised drawing Rev-B.

SEPCO shall consider spare feeder, margin and others as per contract.11KV/415V transformer sizing calculation along with the load list shall be submitted for TSPL/DCPL approval and transformers/switchgears shall be revised accordingly.

SEPCO shall submit sizing calculation for approval before finalising and procurment.

load list is included in ST&UT sizing calculation.

OK, Noted.

SEPCO shall submit submit complete plant elctrical SLD.


SEPCO will submit report with DBR Rev-B.

A) SEPCO shall adopt 50kA rated 11kV switchgear as we have to consider adequate design margin, extra contribution due to addition of fourth unit etc.Also motor contribution from all the motors connected to UT and ST bus need to be considered while calculating both 11 kV UT and ST switchgear as per condition during startup( when ST and UT is connected together and also 16.5 MW FW pump is also running)B) FW pump shall be included as during startup of station, all motor connected to both 11kV UT as well as 11kV ST bus will contribute in the event of fault,and short circuit calculation shall be done inline with same. During the period, electric motor driven FW pump will come into scenario as power will flow from 11kV ST to UT bus. Hence to calculate short circuit current, all motors connected to 11kV ST and UT bus need to be considered for both 11kV unit as well as Station switchgearC) If percentage impedance is increased to control fault contribution, then simulteneously Voltage drop situation also need to be checked during running and starting of largest motor ( FW pump) as the same will be critical.SEPCO shall revise the drawing showing only two bus for station switchgear (instead of four sections) as per drawing.no:D03-2/3 AUXILIARY POWER SYSTEM SINGLE LINE DIAGRAM(STATION SWITCHGEAR) Lump motor load shall be merged accordingly.

a)50kA rated 11kV switchgear is adopt, and adequate design margin has been considered. But the load change due to adition of fourth unit is not considered according to the EPC contract. Also motor contribution from all the motors connected to UT and ST bushas been considered while calculating both 11 kV UT and ST switchgear as per condition during startup( when ST and UT is connected together and also 16.5 MW FW pump is also running).

b) FW pump shall be included as during startup of station, all motor necessary for startup connected to both 11kV UT as well as 11kV ST bus will contribute in the event of fault,and short circuit calculation shall be done inline with same.







SEPCO shall submit sizing calculation before proceeding further engineering.

SEPCO indicate cross section & Data in the drawing.


Supporting document/calculation shall be submitted during detailed design stage.

SEPCO shall submit sizing calculation. Minimum size of cable shall confirmed by calculation during detailed design.

OK, Noted.

OK, Noted.

SEPCO shall submit revised drawings. SEPCO shall submit revised drawings Rev-B。

SEPCO shall indicate location of CW&ACW pipes in the drawing to avoide fouling of foundation of intermidiate gantry/transformers and CW & ACW pipes.

the CW&ACW pipes has been indicated in General Layout drawing not in electrical drawing. The foundation of intermidiate gantry/transformers has avoided CW & ACW pipes.

SEPCO shall submit the revised drawing. SEPCO shall submit revised drawings Rev-B。

OK, Noted.

SEPCO shall revise the drawing indicating additional road near CB and CT in the lengthwise direction as indicated earlier

roads between phases are provided, during maintenance personnel shall move along the phase road.

OK.SEPCO shall indicate in note form as follows." All structures inside the switchyard shall be made of hot dipped galvanised steel".

the stell for structures is not contained in electrical equipment list.

OK, Noted.

refer to civil design document.SEPCO shall note that 4000kg per phase conductor as conductor tension for individual phase from turbine building to 400 Kv gantry for GT & ST line shall be complied as indicated earlier. Design margin for design of switchyard gantry structure shall be indicated. SEPCO shall submit gantry structure and beem design documet.

SEPCO shall submit revised drawings.

Ok. SEPCO shall indicate same in the revised drawings.

the same will be indicated in detailed drawing.

SEPCO shall submit revised drawings Rev-B。

SEPCO shall submit sizing calculation for TSPL approva before proceeding with further engineering and procurment.

SEPCO shall submit with DBR Rev-B。

SEPCO shall submit revised DBR and drawings.

SEPCO shall submit revised DBR Rev-B。

SEPCO shall indicate same in revised DBR and drawings.

SEPCO has indicated the shorting link for enclosure in the layout drawing D-10.

OK, Noted.

All cable entry shall be from bottom in main plant. Top entry shall be avoided by locating panel over trench or cable cellar.

bottom entry cable shall be adopted mostly. Top entry cable shall be adopted for some exceptional case.

OK, Noted. SEPCO shall submit revised drawing.

SEPCO shall submit revised drawing Rev-B。

SEPCO shall include note regarding the provision of ventilation duct in the switchgear room drawings.

ventilation ducts shall be marked in HVAC drawing in the detailed stage

SEPCO shall submit SLD for each 11 KV & 415 PCC / MCC / DB for TSPL review and approval during detail enginnering before finalisation and final procurment.

SEPCO shall submit SLD during detail engineering.

SEPCO shall take care during detail engg. and space shall not be constraint for the spare feeder as per the contract requirment.

SEPCO shall take care during detail engineering.

SEPCO reply / compliance is required SEPCO confirmed that bottom entry cable will considered. SEPCO shall look into the feasibility to providing cable cellar at most places.There is no cable trench at 0.0M elecvation in TG building.

SEPCO shall submit revised drawings considering 110 cells/battery set (inline with revised DBR).


SEPCO shall submit sizing calculation for TSPL approva before proceeding with further engineering and procurment.


OK, Noted.

Shall be discussed.

SEPCO shall submit revised drawing.

the dry type transformer can be moved without enclosure.


SEPCO shall submit revised drawing. SEPCO shall submit revised drawing Rev-B。

IP 42 is appropriate for switchgear indoor.Please confirm that degree of protection shall be IP 52 for indoor.

Noted, SEPCO Agreed.

Ok.noted SEPCO shall indicate same in the DBR.

SEPCO shall submit revised DBR Rev-B。

OK, Noted.

SEPCO shall submit revised drawing. SEPCO has revised drawing Rev-B.

NOT ACCEPTABLE .SPACE SHALL NOT BE THE CONSTRAINT AND ADDITIONAL SPACE NEEDS TO BE CREATED AS REQUIRED TO MEET THE TECHNICAL & CONTRACT REQUIRMENT.

ok, 2*100% auxiliary work shop DC will be furnished

ok, notedOK, Noted. SEPCO shall discuss exception and take TSPL approval.

SEPCO shall submit revised drawing. ok, noted

Noted. SEPCO shall submit the revised drawing.

Noted, the modified drawing Rev-B will be submitted

Shall be discussed. 600MW generator made in China is of this way, almost all generator in China are not equiped with surge capacitor

ok.DBR Rev-B will be modifiedSEPCO shall indicate same in DBR and drawings.

OK, Noted. SEPCO shall submit the revised drawing.

ok, noted, the revised drawing Rev-B will be submitted

OK, Noted.

ok,notedOK, Noted. SEPCO shall submit detailde control and protection scheme and drawings during detail engineering for our review & approval and then finalisation of the control & protection matrix.

Shall be discussed. IEC 61850 is latest trend, its future proof and future ready.

little experience and euipment can be used for 61850 swithcyard. Only some cut-and-try switchyard up to 220kV is under operation, so on DBR we agreeed to each other not use this immature technical to ensure the completment of the project on time. New thing means advance, but also means adventure,so reliable things is better for project

Manual synchronising device shall be different from auto synchroniser. Incoming and Bus voltage & frequncy indication shall be provided for Manual Synchroniser separately.SEPCO shall clarify loaction of selection of auto/manual synchronisation switch and manual synchronisation.

This is a 600MW unit, it's strongly advised not use manual synchronization. manual synchronization may do serious damage to generator. In China ,no one dare to do manual synchronization on such a huge unit.

we will submit as soon as order is fihished. Shall be submitted during Detail Engineering and before finalisation of order.

OK, Noted. SEPCO shall submit revised DBR indicating the same.




DG is used for fault situation, It's no need to consider fault in fault situation in China design standard. And DG power is forbidden to mix between units. Dose india standard requires to consider this? We suggest not use this ,because our DG is word famous brand, which has a very good quality,and to complex a swithgaer may result in misoperation.

OK, Noted.

OK, Noted.


ok, notedSEPCO to note that use of vacume contactor and fuse is acceptable only for feeders rated below 1000KVA.

ok, noted

Noted for no need of lamps. However, Local PB box should have both stop & start for testing. Required motor protection permissive from DCS shall be used for Local start.

only required motor protection permissive from DCS is not enough, also informaiton from switchgear should be known before start. And 11kV motor testing is not that frequently. So it's suggestted to operate from switchgear using a interphone when testing . Is't more safe.

SEPCO shall revise drawings also along with DBR and submit.

OK, Noted.

ok, notedSEPCO shall indicate in revised DBR and drawings.

SEPCO shall submit revised drawing. ok, noted

SEPCO shall note that line PT is required for synchrocheck as required during changeover as well as indication for incomer etc. SSEPCO shall provide incoming Line PT.

auto switch is done when no current in incoming line, no voltage on bus bar, so no need for incoming line PT.

SEPCO shall submit revised drawings,as same is not covered in DBR drawing Rev-A...

SEPCO shall submit revised drawings Rev-B

Ok.noted.

SEPCO has revised the drawings.

SEPCO shall submit revised drawings,as same is not covered in DBR drawings Rev-A..

SEPCO to please note that drawing has not been received by us ,SEPCO shall submit revised drawings.

SEPCO shall submit revised drawings 。

SEPCO REPLYTSPL/DCPL RESPONSE TO SEPCO REPLY DATED 14.06.2010

ok,Noted. Please submit with DBR Rev B for approval. Early submission is requested.

ok,

ok,

Noted. Please submit with DBR Rev B for approval. Early submission is requested.

Please submit ST&UT sizing calculation with DBR Rev B for approval. Early submission is requested.

SEPCO shall confirm that UT & ST sizing wiil be made considering available voltage at the motor terminal not less than 80% of rated voltage ( 11kV) for Electrical driven BFP motor during starting along with all other steady load in service

ok,

Noted. SEPCO shall submit sizing calculation as per specified criterias during detail design and before finalisation for TSPL approval.



Noted. SEPCO shall submit 11KVSwitchgear, 415V PCC & MCC busbar & Incomer size selection during detail design and before finalisation for TSPL approval.

Noted. SEPCO shall submit LV Dry Type Transformer capacity sizing calculation as per specified criterias during detail design and before finalisation for TSPL approval.

ok,

ok,




Noted. SEPCO shall submit sizing calculation during detail design and before finalisation for TSPL approval.

SEPCO shall submit Auxillary power consumption calculation in details & net output of generator.

the calculation shall be finished in detailed stage.


As per PSEB / PGCIL / Statutory Body Electrical Inspectorate requirment Bus CVT to be provided for all the three phases for voltage indication for all three phases & isolator shall be provided before bus CVT. Isolator is also required to meet the CVT routine / breakdown maintenance requirment without having 400 KV Bus Shutdown. Bus LAs shall be placed between CVT and Isolator.Also, SEPCO shall submit busbar sizing calculation.

SEPCO provide single phase Bus CVT without isolator.The single phase bus CVT can completely meet the requirement of relay.

Please submit the revised drawing with DBR Rev B for apprval. It shall comply with the PSEB/PGCIL requirement.

Main and check meters shall utilize separate current transformer cores. Refer to drawing 373-F2491C-D-33-B

Noted. SEPCO shall submit document in detailed design.

ok,Noted. Please submit the revised drawing with DBR Rev B for apprval.

ok,Noted. Please submit the revised drawing & DBR Rev B as per 50 KA for 11 KV Switchgear.

ok,Please submit the revised SLD drawing with DBR Rev B.

SEPCO shall indicate Line PT for 11 KV incomer in drw.no.373-F2491c-d-03 3/3 and Line PT for all 415 V incomers in all drawings as per contract. This is also required for incoming voltage indication.

PT for 11kV incomer of unit bus and common bus shall be provided, but there is no PT for 11kV incomer of coal section bus. There is no description for line PT of 415 incomers,refer SR.NO.243.

ok,

ok,

SEPCO shall plan space provision as per revised SLD & spare feedersfor motors and transformeres shall be provided as per contract.

Noted. Please submit the revised drawing with DBR Rev B for apprval.



In case of the DG unavailability, unit may have to be shutdown to protect main equipments due to sudden failure of grid.



Plant Aux. Systems and other essential installation loads as indicated in the load list are necessary and integral part of every Thermal power Plant and are fed from the Station Supply Source in each and every power plant. For all these loads, Station Supply System is the only power source.

Our requirment is 11KV or 415 V source point for all these loads of required capacity and neccesssry capaity provision in sizing of various equipments. We do not expect any elctrical system for these system from SEPCO.

These loads fall under the category as per the Volume II, Section-IV SCOPE OF WORK AND TERMINAL POINTS, Item No. J Electrical Systejm, Sr. No. 24 " Electrical system for auxiliary plants & other peripherals such as CHP, AHP, CWP etc. "

SEPCO design the plant according to the EPC contract, and we have considered proper margin for the ST capacity,but we did not considered such large margin in SEPCO scope. SEPCO suggest that one ST is arranged for 4th unit,and auxiliary systems excluded SEPCO scope will be supply 11kV power by the ST of 4th unit.

ok,

ok,

Noted. SEPCO shall submit required sizing and selection documents during detail design and before finalisation for TSPL approval.

Noted. Please submit the revised drawing with DBR Rev B for apprval.

ok,Noted. SEPCO shall submit with ST & UT sizing along with DBR Rev B.

Noted. SEPCO shall submit during detail design. ok,

ok,

ok,

Noted. Please submit the calculation with DBR Rev B for approval.

Noted. Please submit the report with DBR Rev B for approval.

ok,

ok,




SEPCO indicate cross section & Data in the drawing.and submit supporting document during detailed design .

ok,Noted. SEPCO shall submit the supporting document / calculation during detail design and before finalisation for TSPL approval.

ok,Noted. SEPCO shall submit minimum cable size and calculation during detailed design.

ok,Noted. SEPCO shall submit the revised drawing with DBR Rev B.

Noted.


Noted. SEPCO shall confirm that roads between the phases can fully take care the maintenance requirment, no obstruction for vehicle / lifting crane movement for maintenance activities without shutdown requirment of nearby equipments.

Our prefered choice is road across the switchyard as indicated earlier.

SEPCO confirm that roads between the phases can fully take care the maintenance requirment,

Use of Hot Dipped Galvanised Steel and details pertaining to structural material/support pedastal etc shall be indicated by SEPCO in Switchyard drawings as a note .

it shall be indicated in the drawing of civil during detailed design.

The details shall be indicated. SEPCO to note that as per CEA norms for 400kV switchyard ,2500kG per sub conductor shall be considered. (It is noted that two number LGKK-600 for GT feeder each phase has been considered. Please clarify these are stranded conductor)

this shall be a requirement for civil design, so please refer to civil design document.

ok,

Noted. SEPCO shall submit drawing and documents during detail design for approval.

Noted. SEPCO shall submit revised drawing with DBR Rev B,

ok,

ok,

Noted. SEPCO shall submit calculation with DBR Rev B for Approval.

Noted. SEPCO shall submit revised drawing with DBR Rev B,

ok,SEPCO shall recheck, indicate the same and submit revised drawing with DBR Rev B for approval.

Top entry cable not acceptable. we have discussed it during DBR interview meeting. bottom entry cable shall be adopted mostly. Top entry cable shall be adopted for some exceptional case.

ok,Noted, SEPCO shall submit revised drawing with DBR Rev B.

Noted, SEPCO shall submit revised drawing with DBR Rev B.

ventilation ducts shall be marked in HVAC drawing in the detailed stage

Noted. SEPCO shall submit SLD for each 11 KV & 415 PCC / MCC / DB during during detail engineering for TSPL approval.

Noted. SEPCO shall submit SLD for each 11 KV & 415 PCC / MCC / DB during during detail engineering for TSPL approval.

SEPCO shall provide cable trench at 0.0M elevation for bottom cable entry to swichgear wherever required. Cable cellar shall be provided as indicated . Layout shall cover all these aspects.

there is no cable trench at 0.0m of turbine hall, we use cable tray. Cable cellar shall be provided in central control buildeing , electrical and control building.

ok,

ok,

Noted. SEPCO shall submit revised drawing with DBR Rev-B.

Noted. SEPCO shall submit sizing calculation with DBR Rev-B for approval.

Noted.

ok,Noted. SEPCO shall submit revised drawing with DBR Rev-B.

ok,Noted. SEPCO shall submit revised drawing with DBR Rev-B.

ok,Noted. For switch gear and switch boards in coal area, the degree of protection will be IP 52 outdoor and IP42 indoor.

ok,Noted. SEPCO shall submit revised DBR Rev B for approval.

ok,Noted. SEPCO shall submit revised drawing with DBR Rev B for approval.

ok,Noted. SEPCO shall submit revised drawing with DBR Rev B for approval indicating following -a) 2*100% auxiliary work shop DC Systemb) 2*100% station/common DC system

ok,Noted. SEPCO shall submit revised drawing with DBR Rev B for approval.

Noted.

ok,N oted. SEPCO shall submit revised drawing with DBR Rev B for approval.

ok,N oted. SEPCO shall submit revised drawing with DBR Rev B for approval.

IEC-61850 PROTOCOL for relays and NCCS is being used for most of the projects in general in india. This technology is in existance for quite reasonable time for voltage levels upto 765 KV in India and have proven vendors like ABB / Siemens / Areva.

we think IEC 60870 is good and mature,and it will be adopted and there is no specification of 61850 in the contract.

Please provide Manual Synchronising System in addition to Auto synchroniser. This is required as back-up system and as per the contract requirment.Please clarify the features as planned to be provided

if the auto synchronization is broken, we have to change a new one, never do manual synchronization

Noted. Please submit before finalisation of the contract for TSPL review.



In case of the DG unavailability, unit may have to be shutdown to protect main equipments due to sudden failure of grid. Also DG power of different unit will mix by proper logic selection.



SEPCO shall provide inline with C&I & switchgear rquirement.

that's too complex for local start and the button is of little use. As per the contract, there is only local emergency stop button

SEPCO shall provide line PT at the incoming feeder of 415V as requested earlier and as per contract.

PCC incoming line PT is of no use because bus tie is a standby power for PCC incoming line, when PCC incoming breaker trips, the bus tie breaker will be closed through synchronization of bus PT. This process is very quick. When power shift back to incoming line, because all the power sources are the same from UT or ST 11kV section, so no use of synchronization. The power switch will be close incoming first, trip bus tie second. No need of incomming line PT.


ok,

ok,

Noted. SEPCO shall submit the revised drawing with DBR Rev B.

Noted. SEPCO shall submit the revised drawing with DBR Rev B.

Date post:	28-Oct-2014
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