THE National Grid Corporation of the Philippines (NGCP) said no fault was found along its owned segment in relation to the series of outages experienced in Negros and Panay last April.
The company said at a House Committee on Energy hearing yesterday this is despite the fact the disturbance was identified at the Bacolod-Silay 69-kilovolt (kV) line which it co-owns with the Central Negros Electric Cooperative Inc. (Ceneco)
NGCP said the protection system of its owned segment also functioned as intended during the April 27 power line disturbance that caused outages.
The company said Palm Concepcion Power Corp., with estimated generation load of 135 megawatts, tripped 1.3 seconds after a fault clearing that resulted in a severe and unrecoverable undervoltage and underfrequency, directly causing the tripping of other power plants and the Panay sub-grid’s collapse.
NGCP said these caused the subsequent line trippings that occurred on April 28 and 29.
NGCP added other contributing factors that made it difficult for the Panay sub-grid to immediately recover from the April 27 outage included unplanned outages and deration of other plants outside of the Grid Operating and Maintenance Program approved by the Department of Energy, insufficient non-variable energy sources and the unique configuration of the Negros-Panay sub-grid as well as the delay in completion of the Cebu-Negros-Panay 230kV backbone project.
NGCP said incidents like these may be caused by many factors.
“The energy sector is an interconnected system among generators, the transmission network, and distribution utilities or electric cooperatives. We have long advocated that a holistic approach to power planning, particularly proper, mindful, and responsible generation and transmission planning, are key to a stable grid. Basic principles such as individual island self-sufficiency, decreased inter-island interdependency, and transmission redundancies must be considered. Improvements must be made on the entire system,” NGCP said.
