The government has ordered an inquiry into the cause of the nationwide power outage that plunged the country into darkness for several hours.
The electricity network broke down on Sunday after a power plant in Hubco (south-western Baluchistan) developed a technical fault, officials say.
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.
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 media sources 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.
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.
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.
Though power cuts are common in the country, but a nationwide failure is rare.
Power is being restored on a phased basis, officials say.