Sources also said that the panel has discovered that PGCIL's subsidiary Northern Regional Load Dispatch Centre (NRLDC) did nothing when on certain days the frequency of power transmission remained below the accepted 49.5 Hertz for 70 per cent of the time.
Report also has mentioned that even on July 29, 2012, the grid was on the verge of collapse, which technically is called a "near miss" situation in power transmission parlance.
No just the frequency, even the loading of the grid far exceeded the conductor's capacity, which is also called surge impedance loading (SIL) of 691 MW. The report further adds that violations of line overloading were permitted on both July 30 and July 31. The report points out that load on the grid remained unchecked for long periods to ultimately cause the grid to crash.
The report concluded by stating that grid failures were due to lack of vigilance and discipline by both PGCIL and SEBs. As far as indiscipline by SEBs is concerned, the report has highlighted that before the first blackout on July 30, Haryana was the biggest culprit and was overdrawing from the grid by 25.5 per cent, Uttar Pradesh by 20.8 per cent and Punjab by 5.5 per cent. Similarly, during the second blackout, Haryana was drawing excess power by 22.4 per cent, but Uttar Pradesh had reduced its overdraw to 6.4 per cent and Punjab to 1.2 per cent. The northern grid collapsed for the second time as the demand-supply gap exceeded 30 per cent. Further, the northern grid brought down with it the eastern and the north-eastern grids as it started drawing in excess from them.
The report also highlights that the power grid collapse can be indirectly linked to the excess agricultural load on the system. Officials, who didn't want to be named, say excess withdrawal would have been nominal but not big enough to really lead to a massive grid failure because of lower frequency, but since the power producing units were yet to be restarted after the first day of failure, the demand-supply gap got bigger and the second collapse brought down three grids.
Sources also say overdrawing was a regular feature in the months of June and July and the Central Electricity Regulatory Commission, along with PGCIL, was fully aware of the dangers of grid collapse, but except issuing a warning no one took any immediate action to prevent the grid from collapsing. What is more important is the fact that against the power minister's claim of India's power grid system being one of the best in world, the three-member committee pointed out that there is no 'automatic demand management system' in the northern grid.
The immediate reason for the two grid collapses was heavy power flow on the 400 kV Agra-Gwalior-Bina single circuit section. The report made a point that the power plow in a single circuit crossed 1000 MW, which is always a precarious situation. Sources say that though PGCIL had argued its case in front of the three member panel and said that the second circuit was under maintenance since July 28 for upgradation to 765 kV level, but the panel has noted that upgradation should have been done during the lean season and not when power demand is at its peak.