Yellow alert raised on Luzon power grid

MANILA, Philippines — Several power plants went on forced outages yesterday, leaving the Luzon grid with a tight supply for a few hours.

In an advisory, operator National Grid Corp. of the Philippines (NGCP) said it raised the yellow alert status on the Luzon grid starting at 1 p.m. until 2:49 p.m.

A yellow alert means there are not enough reserves to cover the largest running generating unit at the time, but does not necessarily lead to power outages.

The NGCP said the grid had only 533 megawatts of net operating margin, with supply at 12,451 MW and estimated demand reaching 11,456 MW.

It said the Luzon grid lost 1,132 MW due to the forced outages of the 150-MW Unit 1 and 50-MW Units 3 and 4 of the Southwest Luzon Power Generation Corp., 316-MW Units 1 and 2 of the GNPower Mariveles Energy Center Ltd. Co. and the 300-MW Unit 2 of the SEM-Calaca Power Corp.

Weekend outages due to right-of-way issue

Meanwhile, the NGCP has asked the Peninsula Electric Cooperative Inc. (Penelco) to remove the “underbuilt” lines that caused transmission outages on June 18.

The grid operator said the outages were caused by Penelco’s underbuilt lines – or distribution lines constructed underneath the transmission lines of the NGCP and are within its right-of-way.

The underbuilt lines breached the safety clearance along NGCP’s Hermosa-Bataan Combined Cycle Power Plant (BCCPP) 230 kiloVolt (kV) lines, causing the outage, it said.

When the system detected the disturbance at 1:53 p.m. on Saturday, the protection system of the NGCP was automatically activated to isolate the affected Hermosa-BCCPP 230 kV lines 1 and 2.

The lines were restored at 2:35 p.m. and 2:44 p.m., respectively.

The NGCP placed the Luzon grid on yellow and red alert following the incident as it caused multiple plant outages.

The red alert status was lifted at 5:30 p.m., while the yellow alert lasted until 10:19 p.m. to allow the affected generating plants to ramp back up.

As of yesterday afternoon, 596 MW from the 1,997 MW actual load of power plants that tripped remained unavailable.

Following the grid disturbance, the NGCP assured the public that necessary measures were undertaken to prevent such incidents from compromising the entire grid.