“A countrywide blackout has been caused by a sudden plunge in the frequency in the power transmission system,” Khan said on Twitter.
“The fault tripped the transmission system of the country… leading to the shutdown of power plants,” Khan said in a news conference following the outage, local media reported.
The minister attributed the technical faults to an out-date system as no effort was made in the past to upgrade transmission lines, and that an investigation was under way to determine the cause of the blackout, state-owned Radio Pakistan reported.
Major cities, including Islamabad, Lahore and Karachi, were impacted by the malfunction, which occurred at 11:41 pm local time (1841 GMT).
Khan later confirmed that power had been restored in some regions, including the city of Peshawar.
The grid lost about 10.3 GW capacity and the fault occurred at Guddu power plant, in Sindh Province,which rapidly tripped all power houses and grids, said local news reports. Under normal circumstance, Pakistan’s national grid has an installed capacity 37.4 GW in 2020, according to the Pakistan Economic Survey 2019–20.