MANILA, Philippines (Updated 6:25 p.m.) — A red alert status was hoisted over the Luzon grid on Saturday afternoon due to a deficiency in power generation that may have been caused by the tripping of two lines connected to a transmission line, the Energy department said.
"On June 18, 2022 at 14:45 (2:45 pm), the National Grid Corporation of the Philippines (NGCP) reported that a red alert status was declared on the Luzon Grid due to generation deficiency," the Department of Energy (DOE) said in a statement.
An hour later, NGCP said that the red alert has already been lifted as of 5:30 p.m, but added that a yellow alert will be placed over the grid from 6 to 11 p.m.
A yellow alert is declared when reserves fall below ideal levels. Meanwhile, a red alert is placed over the grid when the supply to demand balance further worsens, which can lead to rotating power interruptions.
On Saturday, the DOE said that there were "power interruptions in the franchise areas of Meralco and other distribution utilities in Luzon."
DOE earlier reported that two lines from a transmission line in the Bataan area tripped and caused NGCP and Meralco to conduct automatic load dropping (ALD) in the afternoon. When there is an ALD, power is cut off in certain areas due to low power supply.
Later on, NGCP said that it first noted a grid disturbance which led to the tripping of the Hermosa-Limay 230 kiloVolt (kV) Lines 1 and 2, which affected multiple power plants in the area.
"The lines were subsequently restored at 2:35 p.m and 2:44 p.m, respectively. We are currently determining the root cause for the said outage," NGCP said.
DOE called on NGCP to resolve its transmission line issues, submit the list of affected customers and explain the incident.
Meralco, which services Metro Manila and surrounding provinces, confirmed that it had conducted ALD at 1:53 p.m., but said power was fully restored at 2:11 p.m.
"[The ALD] was due to the decrease of an approximate 1200 MW (megawatts) 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, Batangas and Cavite," Meralco said in a statement.