Last Grid Incident of Year – 2009

SLDC Control Room Case Study

Impact of bad weather & system constraints on HP Grid

From Power Controller Desk

Due to bad weather & system constraints Grid Incidents that happened after midnight of 31-12-2009 are summarized below.

1. At 03:55 Hrs Fax message received from SLDC, Rishikesh to restrict Load on 220KV Khodri-Majri to 30MW due to multiple line outages in UP.


2. Giri Machines Synchronized ahead of Schedule & Kala Amb fed radially from Khodri a/w Giri Machine as Verbal consent to draw 60MW load was taken from SLDC control room.


3. Load of Local Giri Transformers & paonta shifted on to Jalandhar system. Solan-I,II, GACL, Barotiwala-II load was also on same system.


4. At 08:45-08:50 Hrs. when Bhaba P/H was synchronizing Unit-I for 60MW Schedule, running Unit-II tripped due to heavy jerk in Grid. Drawl on 220KV Panchkula exceeded 320 MW & 220KV Tepla-I&II 195 MW each. Barotiwala asked to give immediate relief of 25 MW & Parwanoo feeder was opened at 08:52 Hrs. However as no practical relief was observed on Panchkula system, Barotiwala-II got opened from 220KV Substation, Kunihar at 08:53 Hrs.


5. At 08:50 Hrs. Baspa Power House tripped on 110MW generation on Unit-II due to Grid failure from Nalagarh. Running Machines ask Jhakri also tripped.


6. As Malana Generation was Nil w.e.f. 09:00 Hrs. & 220/132 KV Transformers at Mattansidh at 85-90 MW each, Larji was asked to Synchronize second unit before 09:00 Hrs with 64 MW total load & Malana requested not to bring Generation to Zero MW.


7. As Malana reduced Generation at 08:58 Hrs to 7MW, load on Mattansidh transformers shoot beyond 100MW each. Again to avoid Grid collapse, Barotiwala-II got opened from Kunihar at 08:58 Hrs.


8. After Second unit of Larji on Bar with 64MW generation, Barotiwala-II closed form Kunihar at 09:01 Hrs & was asked to keep load controlled up to 55MW.


9. Bhaba Power House synchronized Unit-II at 09:10 Hrs. while Unit-I developed Technical Snag. Barotiwala-I closed from Kunihar at 019:18 Hrs. & normal Load was allowed.


10. Unit-I at Bhaba Synchronized at 09:35 Hrs. after rectification of fault.


11. Baspa Unit-III synchronized at 09:39 Hrs.


12. As Giri Machine stopped at 09:25 Hrs, load restrictions at Kala Amb of 25MW affected thereafter due to Khodri restrictions.


13. Due to inability of Larji to Generate 64MW, & load on Mattansidh transformers exceeding 85MW , 6 MVA load of Bijni was shifted on Shanan system at 10:45 Hrs.


14. Load of Local Transformer at Kunihar shifted on Panchkula at 10:40 Hrs. to give relief to Hamirpur system.


15. Larji Unit Stopped thereafter, when loadings on Transformers were controlled.

Points of reference compiled by: Er. Vikas Sharma SLDC Control Room