Tripping causes brief power outage in some Meralco franchise areas; ‘yellow’ alert hoisted

By Lenie Lectura @llectura

SOME parts of Manila Electric Company (Meralco) franchise area experienced power interruption on Tuesday due to a tripping that led to the decrease of 396 megawatts (MW) in the utility firm’s power supply.

“At 10:58 a.m., an automatic load dropping [ALD] occurred.… The service interruption affected approximately 500,000 Meralco customers in portions of Metro Manila, Bulacan, Cavite, Laguna, Rizal, and Quezon. Power was fully restored by 11:06 a.m. or after eight minutes,” Meralco said.

‘Yellow alert’

SEPARATELY, the National Grid Corporation of the Philippines (NGCP) issued a yellow alert notice from 1:00 p.m. to 4:00 p.m. after available capacity reached 12,705 megawatt (MW) as against a peak demand of 12,222 MW. A yellow alert is issued when the operating margin is insufficient to meet the transmission grid’s regulating reserve and contingency requirement.

In response to the NGCP’s declaration of yellow alert, we activated the Interruptible Load Program [ILP] and are currently securing de-loading commitments from our big-load customers. These customers will be on standby in case there’s a need to de-load to help avoid service interruptions. We continue to monitor the situation and are ready to implement contingency measures as needed,” Meralco added.

T he Department of Energy (DOE) said the tripping of San Lorenzo Natural Gas Power Plant Modules 50 and 60 at 267 MW each, at around 10:58 a.m., caused the decline in grid frequency to 58.915 Hz. Similarly, the DOE noted that the scheduled contingency reserve is already below the level of the highest unit online.

“Load Dropping were reported to have occurred at NGCP and Meralco feeders following the tripping of San Lorenzo, but were immediately restored at 11:06 a.m. for Meralco customers and at 11:04 a.m. for

NGCP customers. As of this report, the DOE is still coordinating with San Lorenzo and other stakeholders for the cause of the tripping,” the DOE said. M eanwhile, generators on forced outage are: SLPGC 1 (150MW), Ilijan Block A (600MW), Ilijan Block B (600MW), Ipower 1 (11MW), La Farge 2 (6MW), San Lorenzo 50 (266MW), San Lorenzo 60 (264MW). G enerators with de-rated capacities are Calaca 2 (170MW), Sual 1 (300MW), Masinloc 3 (300MW), Magat HEPP (212MW), San Roque HEPP (336MW).