In the wee hours of Monday,a massive grid collapse left over 35 crore people without electricity in Delhi and in much of the northern region for several hours in the worst blackout reported in over a decade.
The failure cut power supply to eight states,waking people from sleep in the sweltering night and bringing trains across the region to a halt. The first Delhi Metro train rolled only at 7 am,and it was nearly 9 am by the time normal services were restored.
The reason for the grid collapse appeared to be the tripping of a key transmission link connecting Agra and Gwalior,triggered by heavy overdrawing by some northern states. This led to a collapse of the northern regional grid,which criss-crosses nine states and caters to about 30 per cent of the countrys population.
While the precise circumstances of the collapse would be ascertained by a three-member panel constituted by Power Minister Sushilkumar Shinde,initial evidence points to grid indiscipline by states like Uttar Pradesh,Haryana and Punjab. The panel will submit its report to the government in 15 days.
Power supply was restored to Delhi and much of Uttar Pradesh by mid-day. However,key power stations in Haryana were yet to be started by Monday evening,and most parts of the state,including the industrial towns of Gurgaon and Faridabad,continued to be without grid power. Until early evening,Rajasthan,Punjab and Jammu & Kashmir too were reported to be without full power.
This,despite Shinde promising early in the day that all power would be restored within hours,and the chairman of the state-owned transmission major Power Grid Corporation claiming late in the evening,We have completely restored the northern grid.
Mondays grid collapse came around the same time as the last such blackout in the early hours of January 1 in 2002,when fog and pollution combined to trigger a cascade tripping of several transmission lines in the northern region. This time though,both the reason for the collapse and the scale of the crisis were starkly different.
The main reason for the tripping of the grid this time was rampant overdrawing by UP,Haryana and Punjab. Also,although the Agra-Gwalior line gave way first,setting off a cascading impact on other stretched lines,there was no evidence of any fault in any of the affected lines.
Also,around the time of the collapse of the northern grid at roughly 2.35 am,frequency was reported to be a healthy 50.5 Hz. Indications,therefore,are that a state,or a combination of states,resorted to a sudden overdrawing of additional load,leading to the Agra-Gwalior line connecting the northern region to the western region to trip.
The scale of the disaster could in fact have been much bigger,as the northern region is now linked to the eastern,western and north-eastern regions in what is called the NEW grid,and a local regional fault could have resulted in a bigger collapse.
Shinde told reporters that supply to all essential services had been restored by 8 am. Responding to a query on whether overdrawal by states led to the grids failure,the minister said,It cannot be said whether overdrawing is one of the reasons or there is any other reason. The panel will find out… Right now,we are getting additional 8,000 MW hydro power,including from Bhutan,to meet our demand.
The inquiry will be headed by Central Electricity Authority chairperson A S Bakshi,the other members being Power Grid Corporation chairman and managing director R N Nayak and POSOCO chief executive officer S K Sonee.
Shinde blamed the outage on an incident near Agra,but gave no details. He said repairs were being carried out at a pace faster than what the US managed during a similar crisis four years ago. In 2008,there was a power failure in the USA. Their Federal Energy Regulatory Commission asked India for assistance and it took four days to restore power, he told reporters.