Grid collapses are nothing new to India. In the last two years, there have been instances of failure on three occasions with the latest incident as recent as September 11, 2001 involving the southern grid.
Last September, Andhra Pradesh and Karnataka plunged into darkness following the collapse of the southern grid. The Southern Regional Electricity Board at Bangalore had then reported a sudden drop in power supply from 400 kV to 75 kV in the inter-state transmission line near Raichur Thermal Station in Karnataka. This led to the tripping of the station and within minutes all the thermal and hydro power stations in Andhra Pradesh also tripped. Power was restored in about 12 hours time after the power was sought from Tamil Nadu and the Eastern Grid.
In January 2001, the entire northern India was plunged into darkness for more than 24 hours after the Northern Grid failed. This was touted to be the second largest power breakdown in the country after the collapse of the Eastern Grid a few years ago. The Central Electricity Authority in its report held Power Grid Corporation as responsible for the collapse. The CEA had pointed out that failure of the Regional Load Dispatch centre (RLDC), managed by PowerGrid, to pass on the message for immediate reduction of generation led to the blackout.
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The collapse of the Western Grid on Tuesday night already set the blame game going, with PowerGrid Corporation Ltd. (PGCIL), National Thermal Power Corporation (NTPC) and constituents of the western grid blaming Madhya Pradesh for the incident. Madhya Pradesh has countered this by insisting that it was eligible to draw 450 MW from the grid, as per an agreement with Chattisgarh, if the latter was not fully utilising its entitlement from the central stations.
The collapse was triggered by Madhya Pradesh drawing an extra 500 MW from central stations on Tuesday evening, despite several warnings to Madhya Pradesh State Electricity Board (MSEB) by the Western Regional Load Despatch Centre (WRLDC) to step down drawal. The WRLDC consequently disconnected four lines carrying power to Madhya Pradesh at Itarsi and Beena, following which Madhya Pradesh continued to draw around 300 MW extra from the grid.
The grid frequency dropped much below the desired range of 49 hertz-50.0 hertz and NTPC was forced to shut down four of its thermal plants.
At 8:11 pm on Tuesday night, the western grid collapsed due to