Sunday, December 13, 2009

Shutdown of Barotiwala & Kunihar (Restoration) Part-2

SLDC Control Room Case Study

Operations performed to facilitate Shut-downs/ Restrictions

From Power Controller Desk


Course of Action

1. 220/66/33 kV Sub-station at Baddi made its load zero at 09:32 Hrs as per the directons of SLDC (which was around 90-100 MW), so that the load on 220 kV Panchkulla-Kunihar and 220 kV Panchkulla-Baddi-kunihar circuits reduces to facilitate HVPNL to avail shut-down. But the load was not reduced as per the request of HVPNL.

2. At 09:38 Hrs. 220 kV Kunihar-Panchkulla direct circuit opened from Kunihar.

3. At 09:48/09:51 Hrs., 132 kV Kunihar-Jutogh-II/Kunihar-Jutogh-I changed from Panchkulla supply to Jallandhar supply with trippings. (As load on Kunihar transformers was high and Bus-coupler could not be closed). At the same time, HVPNL was asked to avail shut-down at their end as the load was reduced to 60-65 MW only.

4. At 09:57 Hrs., 132/33 kV, 8 MVA local transformer shifted to Jallandhar supply from Panchkulla supply.

5. At 10:10 Hrs., M/C-III of Bhaba Power House desynchronized and operated on mechanical run.

6. At 10:20 Hrs., 220 kV Bhaba-Kunihar direct circuit opened from Bhaba as well as Kunihar end and at the same time M/C-III of Andhra Power House also desynchronized.

7. At 10:28 Hrs., 220 kV Bhaba-Kotla-Kunihar circuit opened from Kunihar end.

8. At 10:35 Hrs., Barotiwala Sub-station is asked to reduce some load on 132 kV Kunihar-Barotiwala ckt-I.

9. At 10:38 Hrs., 220/132 Kv, 80/100 MVA T/F bank no.I at Kunihar S/stn isolated (load shifted to Bank no. II) & maintenance work started at Kunihar sub-station.

10. At 10:45 Hrs., Jutogh supply extended upto Kotla through Gumma-Kumarsen-Nogle (through 66 kV system)

11. At 10:50 Hrs., 66 kV supply at Kotla stepped up to 220 kV and Bhaba power house is fed back. And M/C no. 3 of Bhaba Power House & M/C No. 3 of Andhra Power house synchronized.

12. At around 10:50 Hrs., 45 MW load was allowed to Baddi S/stn which is further increased to 60 MW at 11:30 Hrs. & full load at 12:28 Hrs.

13. At 12:20 Hrs., 132/66 kV transformer bank no. I at Barotiwala S/stn taken on PTW for which 132 kV Kunihar-Barotiwala ckt-I opened from Kunihar end at 12:21 Hrs. At 12:23 Hrs., 220 kV Kunihar-Baddi ckt opened at Kunihar end & at 12:25 Hrs. at Baddi end.

14. At 12:22 Hrs., 220/132 kV, 80/100 MVA, transformer bank no. II also taken on PTW.


Restoration:


Restriction of load from HVPNL was lifted at around 16:30 Hrs. After cancellation of shut-down, following operations were carried out to restore the system as it is:-



  1. Shut-down of 220 kV buses at Kunihar cancelled at 16:35 Hrs & hence 132 kV Kunihar-Jutogh I & II changed from Jallandhar to Panchkulla bus again at 17:17 Hrs (Without interruption).

  2. Shut-down of Barotiwala S/stn on 132/66 kv transformer bank no. I cancelled at 17:30 Hrs & thus 132 kV Kunihar-Barotiwala ckt-I from Kunihar end at 17:38 Hrs.

  3. 220 kV Kunihar-Bhaba direct ckt charged at 17:45 Hrs. & 220 kV Kunihar-Kotla-Baddi ckt charged at 18:03 Hrs. (Upto Kotla, as Kotla-Bhaba was already charged).

  4. 66 kV Jutogh-Gumma-Kumarsen line isolated from Kumarsen end towards Gumma at 17:53 Hrs.


This shut-down resulted in an overall load shedding of around 6.66 LUs.


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

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