This report is based on information collected by Ahmad Fraz Khan in Lahore, Ikram Junaidi and Syed Irfan Raza in Islamabad and S. Raza Hassan in Karachi

LAHORE / ISLAMABAD: A massive power breakdown plunged major parts of the country into darkness late on Sunday night. From Islamabad to Karachi, most major cities reported power outage.

There was suspension of electricity supply in Lahore, Gujranwala, Multan, Quetta, Peshawar and Sukkur and other cities and towns across the country because of a major fault in the National Power Control Centre (NPCC) system.

In Karachi, 36 grid stations tripped, plunging at least 70 per cent of the city into darkness. Other cities and towns in Sindh also reported complete power outage.

In most of Balochistan, including Quetta, there was no power supply.

The entire country suffered the blackout, third in the past decade, as the whole power generation, transmission and distribution system collapsed.

The domino effect was created by the stretched Uch Power Station which tripped at around 11pm. Its tripping took down a few 500kv transmission lines which it shared with Hubco, and the cascading effect quickly reached Hubco.

With both these plants having a combined generation of around 1,750MW constituting almost 25 per cent of total national generation at that time, the tripping down also affected Mangla Dam, followed by all generators, except one, of Tarbela Dam.

By 11.10pm, the entire country had plunged into darkness as safety mechanism in all plants switched them off to protect them from any damage.

“Luckily, there has been no damage to transmission lines, powerhouses, IPPs and dams’ generators,” an official of the national grid said. The cascading effect triggered the in-built safety mechanism in all gadgets, saving them from any damage.

For that reason it would be easier to restore the system this time than on previous two occasions, he said.

The effort had begun and two grids Sanjani and University of Islamabad had been energised within two hours after the breakdown, he said.

The official said that once the Islamabad system was put back on its feet, the engineers would start reviving supply to the rest of the country.

It should not take more than seven hours. “But it is a national tragedy and the power managers should have been more vigilant.”

A former managing director of the Pakistan Electric Power Company (Pepco) said “extremely low generation and very high demand overstretching the whole system” had caused the breakdown. Such an eventuality created a low frequency and left the entire system extremely vulnerable.

He said there was no guarantee that it might not happen again the next week if the fundamental crisis was not addressed.

On Sunday night, the generation had dipped to less than 8,000MW, with demand hovering above 13,000MW -- a deficit of 5,000MW in the winter. Such high pressure on a system which has no backup has its cost.

What makes the accident assume a criminal proportion is the fact that over 4,000MW generation capacity was lying idle even at the time when the system collapsed because of low generation. There is no fuel to run these 4,000MW plants.

It was in fact the absence of fuel having an effect on the system, triggering the national blackout.

No lessons had been learnt from the last two national breakdowns, the former official said.

In the federal capital and Rawalpindi, not only electricity supply to residential areas was disrupted but traffic signals also stopped working at about 11.30pm, due to which a blackout was observed.

An official at an electricity complaint centre told Dawn that the staff had been informed by higher management that there was a minor fault in Hubco due to which load was shifted onto the Mangla and Tarbela grid stations but they tripped, causing a blackout across most of the country.

“The Mangla and Tarbela grid stations tripped because of overloading so it should not be considered to be a fault. The supply will be restored in around two hours,” he said.

A large number of residents came out of their homes and there was panic when people started receiving phone calls from their relatives in other cities.

Soon rumours started spreading that the blackout was the result of a terrorist attack on the national grid system. There were also speculations about a cyber attack on the system.

Prof Tahir Mahmood of the Islamabad Model College, H-8, said: “I was reading a newspaper when the power went off and our uninterrupted power supply (UPS) system started working. Half an hour later I got a call from a colleague who told me about the power failure in Rawalpindi. I started worrying then because it was unusual. When I contacted other friends they also confirmed that their areas were without electricity.”

The major power breakdown hit almost the entire Karachi a little before midnight. The voltage dipped and lights went out across the city.

The breakdown hit the DHA, Gulshan-i-Iqbal, Gulistan-i-Jauhar, Nazimabad, North Nazimabad, F.B. Area, Landhi, Quaidabad, Manghopir, Northern Bypass and adjoining areas.

The voltage fluctuation apparently caused a fire in a KESC sub-station near Nagan Chowrangi.

After initial confusion, the Karachi Electric Supply Company said a fault in the National Transmission and Dispatch Company’s transmission lines had affected its system.

“Tripping in the NTDC/Wapda system has led to a cascading effect, leading to tripping in the KESC network,” a tweet by the KESC said.

The company said its teams were coordinating with the NTDC.

INQUIRY: Prime Minister Raja Pervez Ashraf ordered an inquiry to ascertain the cause of the countrywide power breakdown.

According to an official spokesman, the prime minister was monitoring the restoration work.

Javed Pervez, Chief Executive Officer of the Islamabad Electric Supply Company (Iesco), said some sections of the Mangla and Tarbela power stations had resumed functioning at 12.45am, improving the supply situation in parts of Punjab and northern areas.

Security at the Benazir International Airport and railway stations were put on high alert after the power failure.

Generators of a five-star hotel also stopped working, forcing the panicked visitors to come out.