Worst crisis in 10 yrs leaves north India powerless for hours

The collapse was triggered by overdrawing of power by Uttar Pradesh,Haryana and Punjab

Written by Anil Sasi | New Delhi | Published: July 31, 2012 1:17:28 am

In the worst blackout reported in over a decade,a massive grid collapse left nine states in North India without electricity in the early hours of Monday. While power was restored in some areas by around midday,the incident exposed how brittle India’s power sector has become without drastic reforms.

The collapse,which occurred just after 2.30 am,was triggered by overdrawing of power by Uttar Pradesh,Haryana and Punjab. Along with Uttarakhand and Rajasthan,they had drawn excess power on every alternate day through the summer,making the system so weak that a fluctuation within the tolerance zone brought the system crashing down.

Taking swift action,the Uttar Pradesh government removed Avnish Awasthi,chairman and managing director of the UP Power Corporation Ltd (UPPCL). Earlier in the day,Awasthi had denied that overdrawing by UP was the cause of the grid collapse. “I don’t think that overdrawing of power from our side had any role in the grid failure. It occurred at 2.32 am when the power demand is not on the higher side,” he said.

According to Awasthi,at 8 pm,UP was drawing a total of 7,334 MW from the northern grid,with only 26 MW in excess. A P Mishra,an engineer,has been appointed as managing director of UPPCL.

To restore power,the Northern Region Load Dispatch Centre (NRLDC) drew on 8,000 MW from Bhutan to energise the generating stations,which had all tripped except for Badarpur (near Delhi),Narora and Bhinmal (Rajasthan). At one stage,the availability of power had dipped from 35,669 MW to 450 MW in the northern grid.

The failure cut power supply to about a third of India’s population,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.

While the precise circumstances of the collapse will be ascertained by a three-member panel constituted by Power Minister Sushilkumar Shinde,evidence of grid indiscipline by states like Uttar Pradesh,Haryana and Punjab is clear. The panel headed by Central Electricity Authority chairperson A S Bakshi will submit its report to the government in 15 days.

Shinde blamed the outage on an incident near Agra,but gave no details. As a result,a key transmission power line connecting Agra and Gwalior was shut down. He claimed repairs were being carried out at a pace faster than what the US had 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.

Power supply was restored to Delhi and much of Uttar Pradesh by midday. 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. But state-owned transmission major Power Grid Corporation claiming late in the evening that it had completely restored the northern grid.

Monday’s 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.

In May itself,the NRLDC issued 285 warnings to states within a 10-day period against drawing more power and,at times when availability was low,making the grid even more vulnerable. To block policing of these actions,the states have also removed the under frequency relays installed by NRLDC to check overdrawing.

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.

STORY OF A BLACKOUT

Late Sunday night

UP,Punjab,Haryana overdraw from grid,but frequency normal till around 12; western region surplus counterbalances overdrawal.

Midnight to 2.30 am

Spike in overdrawal overloads Agra-Gwalior single circuit line by some 1,200 MW. Line trips,northern grid separated from west.

Overdrawal shifts to link between north,east; Gorakhpur-Muzaffarpur line trips.

2.35 am

Heavy load-generation imbalance; northern region frequency collapses. Entire 24,000 MW generation capacity trips.

3 am-7 am

Bid to restart northern region base load stations in Dadri,Badarpur,Jhajjar by importing

Start-up power from west.

By Monday afternoon

Grid largely restored. But power stations in Haryana yet to start till late evening.

(Tentative reconstruction based on inputs from grid officials. Panel to give report in 15 days.)

Reporting: Anil Sasi

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