The Manila Electric Co. (Meralco) cut off power in selected areas on Saturday afternoon due to the tripping of the Hermosa-Limay 230kV transmission lines 1 and 2 which led to multiple plant trappings.
Meralco spokesman Joe Zaldarriaga said an automatic load dropping (ALD) occurred at 1:53 p.m Saturday and power was fully restored by 2:11 p.m on the same day.
“This was due to the decrease of an approximate 1200MW in Meralco’s load affecting around 1.6 million customers in portions of Caloocan, Valenzuela, Malabon, Manila, Makati, Muntinlupa, Las Piñas, in Metro Manila, as well as parts of Bulacan, Rizal, Laguna and Cavite,” Zaldarriaga said.
ALD is a safety procedure wherein power is cut off at certain areas because the power supply is very low.
Grid operator National Grid Corp. of the Philippines (NGCP) reported a ‘red alert and yellow alert status on the Luzon Grid on Sunday afternoon due to “generation deficiency.”
NGCP placed the Luzon grid on ”red alert” for intervals 1500H-1600H and 1900H-2200H and ”yellow alert” for intervals 1700H-1800H and 2300H, which triggered the power interruption in the franchise areas of Meralco and other distribution utilities in Luzon.
DOE cited the report of NGCP, which stated that the Hermosa-BCCP 230kV L1 and L2 tripped and isolated the Bataan Plants resulting in ALD at Meralco and NGCP feeders at 1353H.
This prompted the DOE to instruct the NGCP to immediately resolve the transmission line issues, submit to the DOE the list of affected customers that experienced power interruption, and explain the details of the incident.
The DOE has also initiated its coordination with the Energy Regulatory Commission in addressing this matter.
As of 5:30PM Saturday, red alert has been lifted by NGCP for the Luzon grid. Available Capacity reached 10,428MW while peak demand was at 9,939MW.
However, Luzon grid was still on yellow alert from 6:00PM-11:00PM Saturday.
NGCP monitored a grid disturbance which led to the tripping of the Hermosa-Limay 230kV Lines 1 and 2, causing multiple plant trippings, it said.
The lines were subsequently restored at 2:35PM and 2:44PM, respectively.
“We are currently determining the root cause for the said outage,” NGCP said.