Massive Blackout Plunges Sumatra into Darkness: Full Timeline Revealed

PT PLN has finally revealed the full timeline of the massive blackout that temporarily paralyzed several regions across Sumatra. The disturbance began with extreme weather in Jambi, causing damage to the electricity transmission network. The incident occurred on Friday evening, 22 May 2026, leading to power outages in several areas including Riau, Jambi, North Sumatra, and Aceh. PLN Transmission Director Edwin Nugraha Putra explained that the initial fault occurred on the 275 kV New Aur Duri transmission line heading towards Sumsel 5, a critical part of Sumatra’s interconnected power system. ‘On Friday, 22 May 2026 at precisely 18:44 WIB, a fault occurred on the 275 kV New Aur Duri transmission line towards Sumsel 5. This was an input to the eastern 500 kV line,’ Edwin stated at the National Police Headquarters on Monday, 25 May 2026. Edwin explained that Sumatra’s power system is divided into two main lines: a 500 kV eastern line and a 275 kV western line. These lines supply electricity to southern regions such as Palembang and Lampung, as well as northern areas including Riau, Jambi, North Sumatra, and Aceh. When the fault occurred on the 500 kV line, power distribution left the system, causing a large current shift to the 275 kV line. This sudden shift triggered a major disruption in the power system. ‘This current shift caused a phenomenon we call a power swing, or oscillation. Voltage and frequency oscillated significantly at the time due to the shift to the 275 kV line,’ he said. PLN suspects the fault was triggered by severe weather conditions, including heavy rain and strong winds. To prevent the outage from spreading, the 275 kV line was isolated to maintain system control. This measure successfully limited the blackout’s impact, as Lampung and most of Palembang remained unaffected by power outages. ‘Several power plants tripped, but our protection schemes activated, restoring the southern system to normal. There were no outages in Lampung and most of Palembang,’ he added.