NGCP's N-1 contingency averts Metro Manila blackout

March 23, 2012 9:28 am 

MANILA, March 22 – The National Grid Corporation of the Philippines (NGCP) prevented a blackout that could have affected thousands of Metro Manila residents this week.

The transmission service provider and grid operator attributes this to "N-1 contingency", a term that refers to the ability of the power grid to withstand the loss of a major system component with minimal disruption to the grid.

At 11:05AM on March 20, a 300-megavolt ampere (MVA) transformer at the Las Piñas (formerly Zapote) Substation 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 Manila Electric Co.'s system.

Meralco's 115-kV network, which distributes electricity within Metro Manila, draws power from 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.

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 Biñan Substation to replace the damaged transformer at the Las Piñas Substation.

NGCP operates the country's power transmission highway. The company is led by local investors headed by businessman Henry Sy Jr. and its technical partner State Grid Corporation of China. (PNA) DCT/RSV/ASF/utb


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