The National Grid Corporation of the Philippines (NGCP) clarified the events which led to the series of outages in Negros and Panay on 27-29 April 2023, at the House Committee on Energy hearing today, 15 August 2023.
NGCP explained that although the April 27 disturbance was identified at the Bacolod-Silay 69kiloVolt (kV) line which is co-owned with the Central Negros Electric Cooperative, Inc. (CENECO), no fault was found along the NGCP-owned segment and its protection system functioned as intended.
Subsequently, Palm Concepcion Power Corporation (PCPC), with estimated generation load of 135MW, tripped 1.3 seconds after fault clearing.
The resulting undervoltage and underfrequency were severe and unrecoverable, directly causing the tripping of other power plants, and ultimately, the Panay sub-grid collapse. The subsequent trippings that occurred on 28 and 29 April 2023 were a direct result of the avoidable events of 27 April 2023.
Other contributing factors that made it difficult for the Panay sub-grid to immediately recover from the 27 April 2023 event includes 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 unique configuration of the Negros-Panay subgrid, and the delay in completion of the Cebu-Negros-Panay 230kV Backbone project.
The company highlighted that incidents like these may be caused by many factors and not only a single energy industry player.
“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 stated.
NGCP is thankful to the House Committee on Energy for the opportunity to explain the results of its investigation on the abovementioned outages in Panay and Negros, as it assures its stakeholders of its continuing commitment to improving the power transmission grid.
The company already identified several solutions involving all sectors of the energy industry, including clearance of line obstructions, review of generator settings, improvement in generation planning, enhancement of information dissemination, effective use of emerging technologies, acceleration of grid reinforcement projects, and review of the grid code.
“NGCP is grateful that the Committee recognized that all sectors of the industry must be involved to create a lasting solution. We continue to look for opportunities for improvement, for broader solutions to long standing energy issues, as we coordinate with other energy players for a synchronized plan of action.
For its part, NGCP is also committed to expedite transmission side solutions, including the completion of the Cebu-Negros-Panay 230kV
Backbone Project,” the company added.