Police Identify Three Suspected Causes of Cable Failure Triggering Sumatra Blackout

Police have revealed three suspected causes of a transmission cable failure that caused a power outage in Sumatra on Friday, 23 May, according to Deputy Chief of Bareskrim Police, Inspector General Nunung Syaifuddin.

The investigation by Bareskrim, Puslabfor, and PLN suggests the incident may have been triggered by severe weather conditions. ‘The transmission cable break is still under investigation, with possible factors including mechanical issues from friction and wind effects,’ he stated during a press conference on Monday, 25 May.

He added that the cable could have been severed due to heat from loose connections creating gaps, or tension and swaying caused by extreme weather. These issues led to frequency and voltage instability, causing a cascading power plant shutdown and a widespread blackout across Aceh, North Sumatra, West Sumatra, Riau, Jambi, and parts of South Sumatra.

Nunung confirmed that the transmission tower structure showed no significant damage. Witness testimonies from locals near the site reported an explosion shortly before the power outage in the area.

He also ruled out sabotage, stating the damaged cables were frayed rather than neatly cut, which would be expected in intentional damage. Authorities urged the public not to spread misinformation about the incident.