Pak power grid plunges millions into darkness: News | World news
Pakistani generators produced more power than needed on Monday, causing voltage fluctuations that ended in a system collapse that plunged 220 million people into darkness, an internal government document reviewed by Reuters showed.
Complete grid failures are rare, and operators of modern grids consider local shocks from the integration of renewable energy as their main challenge. But Monday’s blackout in Pakistan was the second near-total grid failure and the third in south Asia in three months.
The grid failure left 220 million people in the dark for an entire day and disrupted business as outages also hit internet and mobile services.
The blackout was triggered by the power grid’s frequency rising to 50.75 hertz (hz) early Monday, causing severe voltage fluctuations in transmission lines in the south, according to an internal memo. A frequency above 50 Hz indicates power generated beyond demand, while a frequency below 50 Hz points to supply demand falling.
Grid operators try to keep the frequency of the grid stable at 50 Hz, with deviations over 0.05 Hz usually considered abnormal. The frequency of the grid was already 50.30 Hz times before the event, according to the note.
Severe frequency changes in transmission lines make it difficult to travel, Sajjad Akthar, general manager at the state’s National Transportation and Distribution Center (NTDC) wrote in a note issued on Tuesday.
“Transmission lines have collapsed, which has led to the separation of the north and south system,” Akthar said in the note.
The Pakistan Energy Ministry did not respond to a request for comment. The note does not mention the purpose of the overshot provision request.
About 11.35 gigawatts (GW) of power plants were operating across the country when transmission lines were hit and separated from the north and south grid, the memo read.
Such separations are intended to protect the parts of the grid not primarily affected by instabilities.
However, demand far exceeds supply in the northern grid after the split, as most power producers are located in the south, causing further instability, according to a company official who reviewed the memo.
The official declined to be named because he was not authorized to speak to the media.
Pakistan’s Energy Minister Khurram Dastgir said in a tweet on Monday that a “high voltage surge” in the south had “said in the north” to cause the outage, but did not elaborate.
Pakistan began restoring power by operating hydroelectric power stations in the north, and gas-fired power plants in the south, the note read, as they took less time to start generating electricity.
While the power plants in the south started working, it took about ten hours for the water plants to work normally and for the power restoration process to start in the northern grid, according to the report.
Akthar said that mechanisms meant to save the system from blackout have been implemented, but the grid is overwhelmed by the scale and scope of the changes.
“Although under frequency, cross-travel and rate of change of frequency plans work, the system cannot survive and (it) leads to complete blackout,” the report reads.
