NGCP President Henry Sy, Jr. appeals for public vigilance against grassfires to ensure line safety

News Release

28 March 2011

NGCP President Henry Sy, Jr. appeals for public vigilance

against grassfires to ensure line safety

The National Grid Corporation of the Philippines (NGCP) is appealing to communities hosting transmission facilities across the country to be more vigilant in guarding and protecting high-voltage transmission lines against grassfires, especially during the summer season.

One of these grassfires was identified as the cause of the tripping of the 500-kiloVolt San Jose-San Manuel transmission line last Saturday. The grassfire was located between towers 196 and 197 of the said line in Brgy. Sumacab, Cabanatuan City, Nueva Ecija.

With more than 19,000 circuit kilometers of transmission lines in the country, NGCP is requesting the public’s assistance in protecting the lines in their communities. The public is advised not to build a fire near or under transmission structures. Planting of trees, putting up of antennas, and building of houses or other structures near or under transmission structures are also discouraged as these obstructions easily cause power outages when they come in contact with high-voltage power lines.

To maintain the security and reliability of the entire Luzon grid, NGCP implemented manual load dropping Saturday at 2:03PM at its customer Meralco's line feeders. The power interruption experienced in Metro Manila and other Meralco areas was caused by the tripping of the 500-kiloVolt line which necessitated the shutdown of three of NGCP's four transformer units at the San Jose Substation in Bulacan.

NGCP worked closely with Meralco to expedite restoration efforts in affected areas. As of 2:40PM on the same day, one transformer unit was immediately restored. By 5:14PM Saturday, the remaining two transformer units were restored and placed online into the power grid.

Amid worries of similar power interruptions in the coming summer months, NGCP assured its power customers that it is on top of the situation and fully prepared for any contingencies such as the grid disturbance which occurred over the weekend. It was an isolated incident that will not affect the integrity of the entire grid.

NGCP definitively ruled out transmission constraint as the root cause of the tripping which affected the 500-kiloVolt line and three transformers last Saturday. The expansion of San Jose Substation’s capacity last year already effectively addressed transmission congestion in the Luzon grid inherited by NGCP.

The transformer upgrade program completed in September last year increased San Jose substation's total capacity from 2,400 megavolt ampere (MVA) to 3,000 MVA. With its four 600-MVA transformers already replaced with four new 750-MVA units, San Jose Substation has more capacity to receive and transmit bulk power to Luzon grid users. An additional unit of a 250-MVA power transformer is also available as spare.

Regular maintenance works are ongoing not just in substations across the country, but also on high-voltage transmission lines, to ensure that these transmission facilities are capable of carrying power to grid customers. Trimming of trees and vegetation within the transmission line right-of-way is also part of the regular operation and maintenance procedures of NGCP linemen. The public is likewise enjoined not to impede maintenance works of NGCP. (NGCP/PIA)