The Energy Regulatory Commission (ERC) is investigating the cause of the Panay-wide power outage that started at around 2:19 p.m. on Tuesday.
The Department of Energy (DOE) said a power disturbance hit the Panay Grid and part of Negros and it is closely coordinating with the National Grid Corp. of the Philippines (NGCP) and all affected generation plants and distribution utilities (DUs).
“We assure the public that power restoration is of priority,” DOE said.
NGCP spokesperson Cynthia Perez-Alabanza said that at 12:06 p.m. Tuesday, it monitored multiple power plant tripping in Panay Island.
NGCP monitored the tripping of Panay Energy Development Corp. (PEDC) unit 1 due to an internal issue.
At 2:19 p.m., PEDC Unit 2, Palm Concepcion Power Corp., and other plants tripped in Panay Island, isolating them from the rest of the Visayas grid.
NGCP the cause of the multiple tripping is still unknown.
“The entire Panay went out with those units not generating,” Alabanza said, adding that they cannot give a timeline on when full restoration will be completed.
About 302 MW was lost to the grid, in addition to 150 on planned maintenance shutdown, including PEDC Unit 3 for a total of 452 MW.
NGCP said it is focusing its efforts on stabilizing voltage and has extended feedback power to Iloilo and PEDC.
It said load restoration will be done conservatively, by matching loads to restored generation, to prevent repeated voltage failure.
At 3:24 p.m. Tuesday, the Negros-Panay interconnection was restored after it tripped at 3:07 p.m.
Meanwhile, on Tuesday, NGCP declared a yellow alert from 4 p.m. to 10 p.m. for the Panay grid.
A yellow alert is issued due to the tripping of major plants at Panay resulting in a low operating margin.
NGCP said restoration of affected plants is ongoing.
“While NGCP did not implement manual load dropping, distribution utilities may implement load drops due to voltage sensitive loads or manual disconnection to secure voltage levels,” it said.