KUCHING: Sarawak Energy Bhd (SEB) yesterday opened another investigation over the latest power outage that left some parts of the state without power for an hour.
SEB grid system operator Yong Ying Poh said the Bakun Unit 8 turbine had tripped at 9.56am, causing the combined-cycle plant in Bintulu to experience a "technical problem".
The technical problem resulted in a sudden drop of electricity load from 110MW to 47MW, he said in a statement.
"SEB immediately initiated restoration work at 10.06am and power was fully restored at 10.59am."
SEB said it deeply regretted the inconvenience and disruption caused. On July 18, a large part of the city went without electricity for nearly six hours.
Offices were left in darkness, factories stopped operating and traffic intersections were hit by gridlock.
SEB said the blackout was caused by a transmission fault when one of its two 275KV transmission lines that connected Engkilili in Sri Aman division, to Mambong here, was shut down for "urgent replacement of a failed capacitor voltage transformer".
After the line was turned off at 11.47am, the remaining line tripped unexpectedly at 2.12pm. The trip on the second line left only the Sejingkat and Tun Abdul Rahman power stations to supply electricity to the city.
Since the two stations did not have enough capacity to meet demand, SEB had to turn off power supply to some areas around the city for up to 45 minutes to keep the system stable.