PLN Reveals Cause of Sumatra Blackout

Jakarta — PT PLN (Persero) said that the widespread blackout in Sumatra on Friday, 22 May, from 18:44 Western Indonesian Time (WIB), was caused by severe weather which subsequently affected part of Sumatra’s power transmission system. “The fault on a transmission corridor caused an outage that spread to part of Sumatra’s transmission system, resulting in a drop in frequency due to heavy load on the generating plants and triggering a domino effect of disturbances in several regions,” PLN President Director Darmawan Prasodjo said in a statement confirmed by ANTARA from Jakarta on Saturday. Darmawan said that from the moment the fault occurred at about 18:44 WIB on Friday 22 May, PLN immediately moved to inspect and restore the power system. He explained that within about two hours the disturbed transmission network had been recovered. After the transmission network was restored, Darmawan continued, PLN’s main focus was to re-operate the generation plants that were previously affected and then re-synchronize them with the transmission system that had been prepared. He explained that the starting-up of the plants was done systematically and gradually while prioritising system safety. Hydro and gas-based plants can immediately help supply the system as a rapid response to accelerate the initial recovery. “Meanwhile thermal plants such as PLTU require more time, between 15 to 20 hours from start-up, synchronisation, and full operation,” he said. Recovery was carried out simultaneously starting from the transmission, switchgear, to the power plants in the Sumatra electricity system. To support the process, PLN deployed hundreds of personnel working 24 hours in affected areas ranging from Jambi, West Sumatra, Riau, North Sumatra and Aceh. (ANT)