Power transmission operator National Grid Corp. of the Philippines (NGCP) on Wednesday said it followed protocols set by the Energy Regulatory Commission (ERC) in responding to the multiple plant shutdowns in Panay that led to the Panay subgrid blackout on Jan. 2.
“NGCP assures all its stakeholders that our operations are fully compliant with existing rules and regulations, as stated in the Philippine Grid Code. We want to be part of the solution, but NGCP cannot do it alone,” the company said.
“We need the cooperation of other stakeholders and the support of our regulator, policymakers, and the whole of government, to ensure the stability of transmission services that will support the reliable power supply for Filipinos,” NGCP added.
NGCP cited its own records and system data, saying that it did not see “abnormality” in system voltage from the time between the shutdown of Panay Energy Development Corp. unit 1 at 12:06 pm and the subsequent shutdown of Palm Concepcion Power Corp.at 2:19 pm.
NGCP said section 6.2.3.4 of the Philippine Grid Code (PGC) states that in instances where there is an unplanned outage of a plant but the system remains stable, manual corrective intervention should not be imposed to anticipate the occurrence of a second event.
The company said this means that disengaging loads manually, or disconnecting thousands of households from their supply of power, as recommended by the Department of Energy and the Independent Electricity Market Operator of the Philippines (IEMOP), in anticipation of a subsequent grid event, is prohibited under the rules.
“There was no system indication justifying a manual load drop or disconnecting end-users –households, business, industries – from the system to regulate voltage during the two-hour period,” said NGCP.
“Had we disengaged loads without any trigger from the system, we may have also been questioned for doing so, as this clearly violates the PGC. Our actions at the time of the incident were undertaken within protocols and in compliance with established rules,” it said.
Based NGCP’s system records, the January 2 incident was due to the unplanned outages of multiple power generators in Panay Island, triggered by the unexpected shutdown of PCPC, a large plant with a capacity of 135MW, and eventually cascaded to other plants in the island.
NGCP said that while the company was ready to transmit power as early as January 2, it took PCPC 59 hours to synchronize back to the grid at 1:33AM of January 5.
PCPC declared stable operations shortly before 1:00PM the same day, or almost 3 days after it shut down.
Once PCPC operations stabilized, the supply of power to Panay consumers also stabilized.
No power supply incidents in Panay have been reported since.
NGCP said that it is a highly regulated entity monitored closely by the ERC and it strictly complies with rules and regulations applicable to the transmission operator since every violation may be penalized by the regulator.
“NGCP is doing its best as a transmission service provider to fulfill its mandate and ensure grid stability. We strictly abide by the rules to run the grid smoothly and avoid disturbances,” it said.