Mailing list: -

1. Chief Engineer(LD),MSETCL,Kalwa.Fax-27601769/65

2. CE, SLDC, GETCO, Gotri, Vadodara

3. S.E.(Testing),GETCO,Baroda.Fax-0265-2351218

4. Supdt.Engr.,ElectricityDept.,DNH,Silvasa.Fax:0260-2642338

5. ExecutiveEngr.,ElectricityDept.DD.Fax:0260-2250889

6. DGM(O.S.),WRLDC,MumbaiFax-28235434

7. DGM,WRTS-I,PGCIL,Nagpur,Fax-0712-2631051/641366

8. AGM,WRTS-II,PGCIL,BarodaFax-0265-2480952(Telefax:2487542)

9. SME(E),TAPS-3&4,TarapurFax02525-282001/282073

10. Maintenance, Superintendant, TAPS–1&2,Tarapur.Fax-02525-282121

11. SME(E),NPCIL,Kakrapara Fax02626-234266

12. Shri K.P. Singh, A.D, NPCIL, Fax No. 25991258

Annexure

A brief agenda for the KAPS 3 & 4 units islanding meeting

1. NPCIL letter no. NPCIL/Trans/2018/M/29 dated 10.10.2018 (copy

enclosed as annexure A) have requested WRPC for evolving an Islanding

scheme for KAPS 3 & 4 so that it can be implemented before the unit

start up.

2. A meeting was held at KAPS NPCIL on 14.11.2018 to discuss the

Islanding scheme.

3. WRPC vide letter dated 07.12.2018 (copy enclosed as annexure B)

requested GETCO, NPCIL, WRLDC to furnish the required information

for doing detailed study to evolve the islanding scheme for KAPS 3 & 4.

4. KAPS, NPCIL vide their letter dated 04.01.2019 has submitted the

Generator data and the same is enclosed as annexure C.

5. GETCO vide letter dated 07.02.2019 has furnished the schematic

diagram of the 400 KV and 220 KV associated with KAPS 3 & 4 and

proposed two different schemes of islanding for KAPS 3 & 4 and the

same is enclosed as annexure D.

6. WRPC analysed the schemes furnished by GETCO and the observations

are enclosed as annexure E.

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Text Box

Annexure A

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Text Box

Annexure B

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~.3IT$".1JO'1 CIN No.: U40104MH1987GOl149458

t;!'tlINOi fa1a"~TT<'i<r DIRECTORATE OF OPERATIONS9-3"-33 ~ ~ :J:I"Cr.1, 3fUT~lfcfC1,,",dI{Q ~ - 400094~ ~

9-N-33, Vikram Sarabhai Bhavan, Anushaktinagar, Mumba;-400 094~ Tel No, : 2599 1902. ~ Fax: 25991256, ~-AA E-mail: ssarwale@!lQcil.co,in,

~ebsite : www.npcil.nic.in

~ Date: January 4, 2019

To,

Sh. J.K.RathodSuperintending Engineer (Protection)Western Regional Power CommitteeF-3, MIDC Area, Andheri (E),Mumbai 400093

~: ChICh,{lql{1 q{CHIOI f2!C\~(i q~lI~\JiOiI (CflIQf2!q-3Cf4) 2.700 cAJllcirc:..;) ,..;)

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SUb.: Islanding Scheme for 2*700 MW Kakrapar Atomic Power Station (KAPS-3&4).

~*.: tf.af.fct.~.I~arur/3tt--u:rOi"/2018/1419 1?;.07/12/2018

Ref.: WRPC/Protection/Studies/2018 11419 dated 07/12/18

Information sought vide above referred letter for system studies to evolve IslandingScheme for KAPS-3&4 is as given below:

i) Generator Trip Parameters: Generators are provided with standardprotections as stipulated in various regulatory documents i.e. CEATechnical Standards for construction of electrical plants and lines and CBIPManual (274) on protection of generators. The generators at KAPS do nottrip directly on frequency variations, however the turbines have beenprotected by incorporating high frequency time delay trip at 51.5 Hz (withdelay of 15-20 s) and mechanical over speed trip at 55 Hz (Instantaneous).On low frequency TG trips has been provided between 47 to 48 Hz for thesafety of Turbines.

ii) Speed Control operation of Governor: KAPS-3&4 turbines have beenequipped with EHC Governor with governor droop set at 4%. Preferred loadon each turbine during islanding is 500 MW and above. However, turbinecan operate at 100 MW load on generator for few hours. Islanding schemefor KAPP Site may be formulated considering various modes such as allfour units operating at rated power, one of the four units is in shut downcondition, two of the four units are in shut down condition or only one KAPS3&4 Unit of 700 MW is in operation.

It is requested to formulate a suitable islanding scheme for Kakrapar Site inconsultation with GETCO and WRLDC at the earliest so that the same canbe submitted to regulatory authorities for their review by June 2019.

tI....lIClI<:\~ I With Regards,

~ I Yours faithfully,

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Annexure – 15.4

Page 1 of 7

Ref. No: SLDC/CE/MIS/WRPC/KAPP islanding/257 Date: 07.02.19 To, The Member Secretary, WRPC, Mumbai Sub: Islanding scheme for KAPS – 3 & 4 regarding Ref: WRPC letter no. WRPC/Protection/Studies/2018/1419 dated: 07.02.18. Dear Sir, Vide above referred letter, WRPC requested to furnish data for evolving islanding scheme of KAPS 3 & 4. In this regard, please find schematic diagram of 400 KV and 220 KV network associated with KAPS 3 & 4 shown in Annexure – 1. Option – 1; With GETCO load The load of following substations may be a part of islanding scheme:

Name of S/S Load in MW

220 KV Navsari 56

220 KV Chikhli 72

220 KV Bhilad 155

220 KV Atul 80

220 KV Popda 50

132 KV Bhestan 80

Magarvada (DD) 200

Total load 693

The following EHV lines shall require to be cut off at low frequency at various substation for formation of island:

Name of substation EHV feeders to be made off Frequency at which breaker opening proposed

400 KV Navsari (PG) 400 KV D/C Navsari (PG) - DGEN 48.00 Hz 400 KV S/C Navsari (PG) - Jhanor 48.00 Hz 400 KV S/C Navsari (PG) - UTPS 48.00 Hz

Regd. Office: State Load Dispatch Centre, Gotri Vadodara – 390 021.

Telephone No.(0265) 6531132/2352103 (D) Fax No.(0265) 2352019 Web site: sldcguj.com

Email: (1) celd@gebmail.com (2) cesldcguj@gmail.com (3) oasldc.getco@gebmail.com

Annexure – 15.4

Page 2 of 7

400 KV Vapi (PG) 400 KV S/C SUGEN – Vapi 48.00 Hz

400 KV S/C Vapi - Boiser 47.80 Hz 400 KV D/C Vapi - Kala 47.80 Hz

400 KV Magarvada 400 KV D/C Magarvada - Boiser 47.80 Hz 220 KV Popda S/S 220 KV Popda - Vav 48.40 Hz 220 KV Navsari (PG) 220 KV D/C Kawas – Navsari (PG) 48.40 Hz 220 KV Chikhli 220 KV D/C Mota - Chikhli 48.40 220 KV S/C Vapi – Chikhli 48.40 220 KV Navsari 220 KV S/C Navsari - Sachin 48.40 220 KV D/C Navsari - Nashik 48.20 220 KV Bhilad 220 KV Bhilad – Vapi 48.40 220 KV TAPS - Bhilad 48.20 220 KV Vapi (PG) 220 KV Vapi – Vapi (PG) 48.40 220 KV D/C Vapi - Kharadpada 48.40 220 KV S/C Vapi - Khadoli 48.40 220 KV S/C Vapi - Sayali 48.40 220 KV Magarvada (PG) 220 KV D/C Magarvada - Rijanvada 48.40

At 48.60 Hz, the load generation balance shall be ensured. At 48.40 Hz , all 220 kV EHV lines shall be opened except Inter State connectivity at 220 KV

level At 48.20 Hz, all 220 kV inter State lines shall be opened At 48.00 Hz, the proposed 400 kV EHV lines connected to Navasari (PG) & Vapi (PG) shall

be opened. At 47.80 Hz, the proposed 400 KV EHV lines with Vapi (PG) and Magarvada (PG) shall be

opened for creating island. The islanding scheme should have automatic disarm feature i.e. there will be no tripping of

400 KV EHV lines in case of non-availability KAPP unit 3 & 4 both. Option – 2: With DNH load: The load of following substations may be a part of islanding scheme:

Name of S/S Load in MW

220 KV Sayali 50

220 KV Kharadpada 300

220 KV Khadoli 300

220 KV Bhilosa 100

Annexure – 15.4

Page 3 of 7

Total load 750

Name of substation EHV feeders to be made off Frequency at which breaker

opening proposed 400 KV KAPP 400 KV D/C Navsari (PG) - KAPP 48.00 Hz 400 KV Vapi (PG) 400 KV S/C SUGEN – Vapi 48.00 Hz

400 KV S/C Vapi - Boiser 47.80 Hz 400 KV Kala 400 KV D/C Kala - Khudus 220 KV Vapi (PG) 220 KV Vapi – Vapi (PG) 48.40 220 KV D/C Vapi - Bhilad 48.40 220 KV S/C Vapi - Bhilad 48.40 220 KV D/C Vapi - Magarvada 48.40

At 48.60 Hz, the load generation balance shall be ensured. At 48.40 Hz, the 220 KV EHV lines proposed above shall be opened at Vapi (PG). At 48.20 Hz, all 220 kV inter State lines shall be opened At 48.00 Hz, the 400 KV D/C KAPP – Navsari (PG) line shall be opened. At 47.80 Hz, the proposed 400 KV EHV lines with Vapi (PG) and Kala (PG) shall be opened

for creating island. The islanding scheme should have automatic disarm feature i.e. there will be no tripping of

400 KV EHV lines in case of non-availability KAPP unit 3 & 4 both.

This is for kind consideration please. Sd/-

Chief Engineer (SLDC) Vadodara – Gujarat

Copy to: The General Manager, POSOCO WRLDC, Mumbai

Annexure – 15.4

Page 4 of 7

400 KV Network (Option – 1)

Annexure – 15.4

Page 5 of 7

220 KV Network (Option – 1)

Annexure – 15.4

Page 6 of 7

Annexure – 15.4

Page 7 of 7

Annexure E

WRPC observations to be discussed in meeting: -

1. Triggering frequency for formation of island may be increased by 0.2 Hz, as

UFR settings have been increased from 49.2 Hz to 49.4 Hz.

2. For formation of island, tripping’s of various lines (29 in the case of option I

and 12 in the case of option 2) at various frequencies are instantaneous. This

needs to be deliberated thoroughly and proper quantum of time delay may be

incorporated as well, if required.

3. Real time power exchange on tie lines is required to be monitored or not ?.

4. It is also required to discuss the concept of real time monitoring (automation of

AUFLS) on SCADA to determine load shedding requirements for successful

survival after islanding on real time basis.

5. Close monitoring of load shedding quantum on real time increases the chances

of successful survival islanding.

6. Provision to be kept in SPS to stabilize the frequency, if it shoots up

excessively far beyond nominal value during the operation of island (auto

restoration).

7. Load flow study for option -I and option -II suggested by GETCO is required to

be carried out before the meeting and results related to variable parameters in

respect of all elements which would be the part of proposed island, may be

furnished to WRPC secretariat, well before the meeting so that this aspect can

also be deliberated in details in the meeting. In this regard GETCO is

requested to carry out the load flow study and furnish the result to WRPC

secretariat, well before the meeting.