A collapse of Bangladesh’s national power grid over the weekend turned out the lights for about 60% of the nation of 160 million people for more than 10 hours. 

The interruption reportedly occurred at about 11:30 a.m. on Nov. 1 at a substation in Kushtia district, western Bangladesh, which knocked out a 400-kV transmission line that was bringing in 445 MW of power from India. The loss of that power set off a cascade of failures, forcing all of the country’s power plants to shut down.

At about 4:30 p.m., the power plants that had been brought back online reportedly tripped again. Power was restored in most of the country by midnight.

“It is reported that the sub-station at Bheramara cannot handle any power beyond 400 MW,” speculated Abdul Matin, a former chief engineer of the Bangladesh Atomic Energy Commission in an opinion piece for The Daily Star. “The loss of power at Bheramara reduced the frequency to 45 cycles/second and created an electric surge that finally caused the blackout throughout the country.”

Prime Minister Sheikh Hasina on Wednesday, however, raised the possibility of a more sinister cause for the rare blackout. She called on ministers and law enforcement personnel to increase vigilance in every district to avert acts of sabotage related to recent verdicts on war crimes committed during the war of independence in 1971.

Sonal Patel, associate editor (@POWERmagazine, @sonalcpatel)