Meralco puts in place measures to avert metro-wide blackout

MANILA, Philippines—The Manila Electric Co. (Meralco), the country’s biggest power distributor, is hoping that the necessary measures it has put in place will help prevent a Metro Manila-wide blackout within the next few days, after a 300-megavolt ampere transformer at the Zapote substation in Las Piñas broke down last Tuesday.

In a statement issued on Thursday, Meralco admitted that the reliability of Meralco’s subtransmission system, which has been feeding power to the Makati Business District, Fort Bonifacio, Ortigas Center, Parañaque, Alabang, Cainta and Marikina, among others, has become a matter of “serious concern.”

The power utility explained that it had to reconfigure the affected sub-transmission system to avoid the overloading of  two other remaining transformers at the Zapote substation. The National Grid Corp. of the Philippines (NGCP), which has been operating the country’s transmission system, reportedly informed Meralco that it has been looking into the matter to expeditiously address the problem.

“Our system and our networks people are now on alert and ready to respond to whatever  scenario this system problem or trouble may cause,” said Meralco executive vice president and networks head Ricardo V. Buencamino.

“Given the present limitation in Meralco’s Sector 2 (sub-transmission system) as a result of  the failure of NGCP’s transformer, we are taking all necessary  measures to avert a potentially prolonged power interruption in key areas of our franchise. This is really a precarious scenario, which will continue to prevail until a replacement transformer is put in service by NGCP,” Buencamino further explained.

For its part, the NGCP assured residents of Metro Manila that the so-called “N-1 contingency” of the Luzon grid has averted and would continue to avert a blackout that could affect thousands.

The grid operator explained that the “N-1 contingency” referred to the ability of the power grid to withstand the loss of a major system component with minimal disruption to the grid, as it had the necessary reserves.

To address the immediate need of the Meralco network due to the recent incident, NGCP is considering the option of transferring one 300 MVA transformer from the Biñan Substation to replace the damaged transformer at the Las Piñas Substation.

The 300-MVA transformer broke down due to internal fault, which triggered the automatic tripping of its 230-kiloVolt (kV) and 115-kV breakers. With N-1 contingency in place, the damaged transformer was quickly isolated from the rest of Meralco’s system.

Meralco’s 115-kV network, which distributes electricity within Metro Manila, draws power from the NGCP’s Las Piñas, Sucat, Araneta, Dolores, Balintawak and Duhat Substations. Despite the incident, no power load was dropped from the Luzon grid because Las Piñas’ load was shifted to Dolores and Sucat substations. Metro Manila residents were spared from power interruptions because of this contingency.

NGCP’s major interchange points entering Meralco are looped at the 115-kV Meralco sub-transmission grid. In the south sector of Metro Manila, Las Piñas substation is looped with Sucat and Dolores substations to redirect power flow in case of emergencies. The same goes for the north sector, which relies on the looped substations of Araneta, Balintawak and Duhat substations.