Northern Grid Disturbance Flash Report & HP Grid Events thereof

SLDC Control Room Case Study

Impact cascading tripping of 400 kV lines due to fog

From Power Controller Desk

On dated 02.01.2010 at 03:01 Hrs, the entire Northern Grid collapsed due to outage of thirty five 400 kV lines as intimated by NRLDC. This happened due to cascading tripping of 400 kV lines due to fog. The major lines which tripped were as under:

(i) 400kV Mandola-Bareli D/C

(ii) 400kV Dadri-Malerkotla

(iii) 400kV Bhawana-Abdullpaur

(iv) 400kV Ballabgarh-Bamnauli-I

(v) 400kV Abdullapur-Jhakri

(vi) 400kV Hissar Kaithal

(vii) 400kV Panipat-Dehar-Bhiwani

(viii) 400kV Bhawana-Bamnauli D/C

(ix) 400kV Bhiwadi-Hissar

(x) 400kV Hissar-Patiala

(xi) 400kV Hissar-Khedar-Moga-Kishenpur

(xii) HVDC Rihand-Dadri Pole 1

This resulted in complete darkness in HP areas except 132kV Kala-Amb and local area of Giri where the power supply was coming from 220 kV Khodri Majri line. Steps for restoration at HP state are as under:-

1. At 03:01 Hrs. the entire Northern Grid collapsed.

2. At 03:45 Hrs. Unit-II of Giri P/H synchronized.

3. At about 04:00/04:12 Hrs., both 132 kV Giri-Solan-I & II restored from Khodri supply.

4. At about 04:12 Hrs, 220/132 kV Transformer bank no. I & II isolated from 132 kV side at Kunihar S/stn.

5. At about 04:12 Hrs. 132 kV supply restored at Solan Sub-station from Giri/Khodri side.

6. At about 04:14 Hrs, Khodri/Giri supply further extended from Solan to Kunihar.

7. At about 04:15 Hrs. 132 kV Bus-coupler closed at Kunihar and supply extended to Shimla through 132 kV Kunihar-Jutogh-I & II and local transformer at Kunihar energized. And at the same time, circuit breakers of 220 kV Kunihar-Baddi & Kunihar-Panchkula lines opened from Kunihar end.

8. At 04:22 Hrs, 220/132 kV Transformer bank no. I & II energized from 132 kV side and supply is extended up to Kotla and then Bhaba power house.

9. At about 04:15 Hrs., supply extended up to Larji Power House and Malana Power House. And at around 04:53 Hrs., Unit-III of Larji P/H synchronized.

10. At 04:50 Hrs., local area at Kangoo S/stn changed to Giri supply

11. At 04:58 Hrs., 132 kV supply restored up to Mattansidh, through Kangoo-Kunihar-Solan-Giri/Khodri.

12. At 05:00 Hrs., 132 kV Hamirpur-Anu both circuits energized at Hamirpur end. And at the same time, HP area at Kangoo opened and again restored at 05:28 Hrs.

13. At about 05:15 Hrs., supply extended upto Bassi P/H and at 05:50 Hrs supply extended upto Shanan P/H (PSEB).

14. At about 05:53 Hrs. 132 kV Hamirpur-Dehra both circuits restored.

15. At 05:53 Hrs., 132 kV supply restored upto Jassure through Dehra to back feed Bairasuil P/H (NHPC), Pong P/H (BBMB) and RSD (PSEB).

16. At 06:05 Hrs., 220/132 kV transformer bank no.I energized at Hamirpur to energize 220 kV Hamirpur-Jallandhar Ckt-I.

17. At 06:10 Hrs., Unit-II of Bhaba P/H synchronized and at the same time Unit-II of Malana P/H synchronized.

18. At 07:01 Hrs., 220 kV Kunihar-Panchkula ckt closed and at 07:02 Hrs. 220 kV Kunihar-Baddi ckt closed as per the directions of NRLDC.

19. At 07:02 Hrs., Jassure supply extended upto Bairasuil after isolating Pong & RSD feeders.

20. At 07:15/07:20 Hrs., Unit-I of Bassi P/H synchronized.

21. At 07:28 Hrs., 132/33 kV Transformer No.I shifted to Khodri supply from Solan supply.

22. At 07:32 Hrs., 132 kV Kunihar-Barotiwala-I & II restored with some load restrictions.

23. At 07:35 Hrs., Jassure supply extended upto RSD P/H.

24. At 08:00 Hrs., 220 kV Hamirpur-Jallandhar ckt-II energized and at 08:02 Hrs. 220/132 kV transformer bank no.II at Hamirpur energized.

25. At 08:04 Hrs., Jallandhar supply restored upto Kunihar and at 08:05 Hrs., 132 kV Bus coupler at Kunihar opened.

26. At 08:10 Hrs., 132 kV Giri feeders opened from Solan to disintegrate Jallandhar and Khodri supply.

27. At 08:25 Hrs, 132 kV Kunihar-Barotiwala ckt opened at 08:25 Hrs. and re-energized at 09:08 Hrs with restricted load and at the same time HP area at Kangoo S/stn isolated.

28. At 08:25 Hrs., 132 kV Bus-Coupler at Mattansidh closed.

29. At 09:05 Hrs., 220 kV Hamirpur-Jallandhar ckt-II opened due to high voltage.

30. At 09:12 Hrs., 132 kV Hamirpur-Dehra Ckt-II opened & at 09:20 Hrs., 132 kV Anu ckt-II opened at Hamirpur.

31. At 09:23 Hrs., HP area at Kangoo S/stn restored with Jallandhar supply.

32. At 09:38 Hrs., 132 kV Jassure-Kandrori feeder opened from Jassure end.

33. At 09:48 Hrs. 220/132 kV ICT at Jassure tripped due to overloading and charged at 09:56 Hrs.

34. At 10:10 Hrs., 220 kV Dehar supply restored along with ACC-I & II and at the same time, 132 kV Kandrori ckt energized from Jassure end.

35. At 10:23 Hrs., HP area at Kangoo S/stn shifted to Dehar supply again.

36. At 10:30 Hrs., supply extended upto Png P/H.

37. At 10:38 Hrs., 132 kV Hamirpur-Dehra Ckt-II closed at Hamirpur.

38. At 10:47 Hrs., 132 kV Dehar supply restored at Kanggo S/stn.

39. At 11:10 Hrs., 132 kV Giri-Solan both ckts energized.

40. At 11:28/11:30 Hrs., 132 kV Paonta shifted from Khodri Supply to Solan Supply.

41. At 11:40 Hrs., 132 kV Anu ckt-II closed at Hamirpur.

42. At 12:15 Hrs., 132 kV Bus coupler at Hamirpur opened.

Points of reference compiled by: Er. Gagan, SLDC Control Room