The power blackout that affected most parts of Kuching city this afternoon was caused by a transmission fault at Mambong near the city when one of the two 275kv transmission lines tripped unexpectedly, Sarawak Energy Berhad (SEB)’s grid system operator, Yong Ying Poh said today.

He said SEB had started investigations to find the underlying cause of today’s incident which occurred when one of the lines connecting Engkilili to Mambong was taken out of service at 11.47am for urgent replacement of a failed capacitor voltage transformer and the remaining circuit tripped unexpectedly at 2.12pm due to a line fault.

“SEB acknowledges the community’s understandable frustration as a result of today’s event and deeply regret the inconvenience and disruption caused to our consumers in Kuching," he said in a statement.

He said SEB’s maintenance crews were working to complete the replacement job so that the other circuit can be back to service immediately, with full load restored to all affected areas by 5pm.

Since the second line tripped, he said, the only source of supply to Kuching was from the Sejingkat and Tun Abdul Rahman power stations, which do not have sufficient capacity to meet demand in Kuching without support from elsewhere in the state.

“To keep the system stable, it was therefore necessary to turn off supply to some areas around Kuching for up to 45 minutes at a given time,” he said, adding that information from its probe would be used to continue improving the standard of reliability in Sarawak.

- Bernama