India's biggest power grid collapses on July 30 and 31 were caused by lack of maintenance and inaction by northern grid operators at a time when states had been overdrawing power for many days.
Senior government sources told HT that the three-member expert panel, constituted to look into the reasons behind the two consecutive grid collapses, submitted its report to Union power minister Verappa Moily on Thursday evening.
Details of the report will be presented by the minister in Parliament shortly.
According to sources, the report has concluded that the repeated grid failures were due to lack of vigilance and discipline by grid operators as well as the state electricity boards (SEBs) that overdrew power from the grid.
While observing that excess agricultural load on the system led to its failure, the expert panel report has accused Haryana, Uttar Pradesh and Punjab of overdrawing power from the grid before the first blackout on July 30.
It has reportedly pulled up the apex bodies managing the northern grid, including the Northern Load Despatch Centre as well as the Power Grid Corporation (the central transmission utility), for inaction on days when the frequency of power transmission fluctuated at levels below the accepted 49.5 hertz for 70% of the time.
Interestingly, the panel's report is also understood to have mentioned that even on July 29, 2012, the grid was on verge of collapse - technically termed as a "near-miss situation" in the power transmission sector.
Quoting from the report, sources said that Haryana overdrew from the grid by 25.5%, Uttar Pradesh by 20.8% and Punjab by 5.5%. Similarly, during the second blackout, Haryana drew 22.4% excess power. However, UP had reduced its overdraw to 6.4% and Punjab to 1.2%.
"Violations of line overloading were permitted on both July 30 and 31," the source said.
"The load on the grid remained unchecked for long periods, and this ultimately caused the grid to crash."
The collapse of the northern grid on the second day, as per the report, was due to the sudden load on the grid after the demand supply gap exceeded 30%.
This led to another failure of the northern grid, which then brought down the eastern and north-eastern grids too.