New Delhi, July 30
Entire North India was plunged into darkness in the early hours of Monday after the Northern Grid collapsed, throwing normal life out of gear through the day for over 35 crore persons across nine states. The Northern Grid, which caters to around 28 per cent of the country's population, was completely restored late in the evening, as per the PowerGrid.

The Northern Grid is an interconnected transmission network that delivers electricity from various generating stations to distribution utilities in nine states. The lights went out at 2.32 am when Delhi, Punjab, Haryana, Rajasthan, Uttar Pradesh, Uttarakhand, Himachal Pradesh, Jammu and Kashmir and Chandigarh were snapped from the Grid after a major breakdown. Several areas reported a breakdown of 12 hours.

All major power plants, including hydropower stations in Himachal Pradesh and thermal power stations in Punjab and Haryana, which are all a part of the Northern Grid, were forced to shut down. More than 8,000 MW capacity of the country's largest electricity producer NTPC, spread across six power plants, was hit.

Water treatment plants were also hit by the power failure, making it a double whammy for millions, who had to contend with no water as well. Around 1.5 lakh passengers of 300 trains, including Rajdhani, Shatabadi and Duronto, reported delays as the Grid failure crippled operations across eight divisions of the Northern Railway. Officials said 200 goods trains were cancelled.

Office-goers and students had a harrowing time in the National Capital where the Metro train services were disrupted. All government hospitals in Delhi were put on emergency services and generator back-up.

Power Minister Sushil Kumar Shinde blamed the outage on an incident near Agra for one of North India’s worst power outages since 2001, but gave no reasons. He said normal load on the Northern Grid must be maintained between 48.5 Hz and 50.2 Hz, but it increased to 50.46 Hz, leading to its collapse.

The Northern Grid, one of the largest in the country, had also seen a collapse in January 2010 due to fog moisture. India suffers a peak hour power deficit of about 12 per cent, which has been made worse this year by a weak monsoon. Asked whether overdrawing could have been a reason for the fault, Shinde declined to comment.

Supply was partially restored by 8 am, Shinde said, adding that 60 per cent supply had resumed till afternoon. Shinde said power was drawn from Bhutan and Eastern and Western grids as generating stations in the North had come to a halt.