NTPC, Anpara station worsened grid failure

NTPC, Anpara station worsened grid failure
Sunil Jain and Santanu Ghosh

New Delhi, Jan 4: While the inquiry committee set up to examine the collapse of the Northern Grid on January 2 is still conducting its investigations, preliminary reports appear to put a large part of the blame on the shoulders of NTPC, and the Anpara Thermal Power Station of the UP government.

According to an initial report prepared by the Powergrid's Northern Regional Load Despatch Centre (NRLDC), despite being told to back down production when frequencies on the Northern Grid went beyond safety levels, Anpara and NTPC's plant at Singrauli refused to do so, to the extent required. This, says the report, caused the grid to split into two parts (islanding, in technical jargon) -- the western side has the major demand areas and the eastern side has most of the generating units.

And once the grid split, at 4:38 am on January 2, the collapse was inevitable. The western part had low frequencies due to excess demand, and the eastern part had high frequencies due to excess supply.

Interestingly, both Powergrid which is in charge of managing the grid, and NTPC have diametrically opposite stands on what happened. Powergrid's chairman R.P. Singh told The Indian Express: `Had both Singrauli and Anpara cut production like we asked them to, the grid could have been saved.' NTPC's chief C.P. Jain, however, contends that the NRLDC report does not indict NTPC at all. While brushing aside the question of whether Singrauli backed down enough (it cut production from 1840 MW to 1480, though it was asked to cut it to 1320), Jain says the NRLDC report itself shows that the system stabilised by 4:20 am on January 2. `Thereafter the grid got separated, and the reason is yet to be found. How can anyone blame NTPC for the grid failure?' he concluded.

According to the NRLDC report, the original problem occurred at 11:21 pm on January 1, when the Rihand-Dadri HVDC pole-2 developed problems. Voltage on this line was then restricted, and various power stations were asked to back down. When the 400 kV Obra-Panki line tripped, further backing down was asked for -- this went on through the night.

By around 4 am on January 2, however, NTPC's Singrauli, however, continued to produce around 1500 MW of power though it was instructed to go down to 1320. And Anpara, which was told to cut power by 400 MW, cut only around 150. The grid, says the NRLDC report, appeared to have stabilised at 4:20 am, but then split after some tripping -- after which, the entire grid collapsed.

Powergrid's Singh's point is that had both Singrauli and Anpara cut production by another 410 MW as they had been asked to, the grid may have been saved. NTPC's Jain, on the other hand, is arguing that the problem lies in why the grid split and not in Singrauli refusing to cut production to the desired levels.

Interestingly, another war has broken out between Powergrid and BHEL on the Northern Grid collapse. The `converter transformer' on the Rihand-Dadri line (where the original problem began) which is the backbone of the Northern Grid broke down in December, and was not replaced -- BHEL says it'll be done only by March. Prior to the grid collapse, Powergrid's Singh had written to the Ministry of Heavy Industry (which controls BHEL) asking for urgent action to be taken, and warning that serious problems would occur because of this. When contacted, BHEL's officials, however said that it was premature to blame them, since there's no evidence that if the Rihand-Dadri line was fully functional, the cascading effect that led to the grid collapse would have been arrested.

The blamegame's just begun. Watch this space.