There was no electricity for many hours in most parts of Punjab, the North-West Frontier Province, upper Sindh and Balochistan. Large parts of Karachi, which relies on Wapda to meeting a part of its power requirements, were without electricity for hours.
The first such unusual collapse of power system since 2001 that caused a blackout almost in the entire country, spread rumours about an abrupt change of government that were immediately brushed aside by Prime Minister Shaukat Aziz and his minister of state for information Tariq Azim.
An official statement said Power Minister Liaquat Ali Jatoi had ordered member power Wapda to conduct an inquiry to find out the cause of such a major disruption in power supply and submit a report within 48 hours. The minister who was in Dubai en route to Sri Lanka on an official visit cancelled the visit to return to Islamabad to attend a meeting convened by the prime minister on Monday.
Wapda’s member power Anwar Khalid told Dawn from Lahore that a former member power, Ghulam Rasool, has been asked to look into the matter and report on the real cause of the breakdown and propose remedial measures. He said Mr Rasool, who was Wapda’s member power in 2001, had been hired as an adviser to study transmission of the national grid. He said a similar breakdown in 2001 had taken about six hours before power supply was fully restored.
Mr Azim along with secretary water and power Ashfaq Mehmood said one of the three 500kv transmission lines from Ghazi Barotha to Lahore and Gatti (Faisalabad) was under routine maintenance on Sunday when a second line developed a fault at about 13:45 hours due to a sudden upsurge in load that resulted in cascading trippings and affected power supply throughout the country.
Responding to a question, he said it was ‘too early’ to estimate the economic losses and added that most factories were closed because of Sunday and perhaps it was a blessing in disguise that such an event happened on a weekly holiday. He said Islamabad and Rawalpindi were the first to get power supply restored at about 15:30.
Secretary Ashfaq Mehmood said electricity could not be restored abruptly because it could cause damage to the system and hence a phased revival would take place, segment-by-segment. He said Wapda was taking about 3,600mw of power from Tarbela and 1,100mw from Ghazi Barotha which meant that 45 per cent of total 11,000mw supply was cut off, adding pressure on the thermal system. Since the thermal system could not compensate the shortage because of capacity constraints, a major breakdown was witnessed.
He said it was a common phenomenon in large integrated transmission systems in the world and quoted the 1965 and ’77 breakdowns in New York and two in California and Canada in the recent past.
The secretary did not agree with a questioner that the source of fault was in the generation system rather than in the transmission system and sidestepped a question as to why Mangla units had not been revived, saying a machine at Mangla had been activated but its circuit also faced some problems.
He said three Wapda teams were looking at the transmission system to identify the real cause. He did not respond to a question about the outcome of a 2001 investigation into a similar breakdown. He dispelled an impression that power demand had outpaced supply leading to a crisis and said there was no such thing because the peak demand season had already passed.
Salahuddin Rifai, General Manager, National Power Control Centre, which is the main load control centre for Wapda system, said the 2001 breakdown also took place because of the transmission system. He said there used to be a major breakdown every year before 2001 but there had been none since then.
Wapda’s member power Anwar Khalid, however, had a slightly different version. In his opinion, the source of problem was generation, rather than the transmission system. He said the cause of problem could not be ascertained yet because primary objective was to restore power supply. He said the problem had started at about 13:45 hours when machines went out of order at Tarbela, and subsequently the entire hydropower producing region comprising Tarbela, Ghazi Barotha and Mangla were isolated from the national grid.
He said the cutting off of 6,000mw of supply from the hydropower stations resulted in overloading on transmission lines from Wapda’s thermal stations and independent power projects in southern part of the country, causing automatic trippings.
He said power generation from Tarbela, Rousch Power, Faisalabad Thermal Power, Kotri and Jamshoro was coming back to normal but complete restoration would be made gradually as the system investigation and its synchronisation required five to six hours.
