The directive came after the NGCP placed the Visayas grid under red and yellow alerts on July 8 following the tripping of a transmission line and the emergency shutdown of a power plant, which pushed the grid into a negative power reserve.
On July 9, NGCP again placed the Visayas grid under yellow and red alerts due to the outage of the 135-megawatt Palm Concepcion Power Corp. (PCPC) coal-fired power plant in Concepcion, Iloilo, the continued unavailability of two 169-MW units of Therma Visayas Inc. (TVI), and high electricity demand.
Alerts
The red alert was in effect from 5 p.m. to 7 p.m. on July 9, while the yellow alert was in effect from 3 p.m. to 5 p.m. and again from 7 p.m. to 10 p.m., as available capacity fell short of projected demand. Peak demand was projected at 2,568 MW against available capacity of 2,561 MW, leaving the grid with a negative reserve of 7 MW.
A red alert status is issued when power supply is insufficient to meet consumer demand and the transmission grid’s regulating requirement. A yellow alert is issued when the operating margin is insufficient to meet the transmission grid’s contingency requirement.
Probe
In a statement, the Department of Energy's Electric Power Industry Management Bureau (EPIMB) said it was investigating the circumstances behind the grid alerts that affected the Visayas.
The department was also validating the reported outage of PCPC.
Initial reports showed that the tripping of the Iloilo-Panay Energy Development Corp. (PEDC) 138-kV Line 3 isolated and forced the shutdown of PEDC Unit 3, reducing available reserves in the Visayas grid on July 8.
The Lapu-Lapu–Basak 69 kV transmission line also tripped on that day.
Two days before the resumption of the yellow alerts, the DOE issued a statement on July 6, announcing that the Visayas grid had exited from the yellow alerts with the return of the PEDC’s unit 3.
The statement also said that the DOE was coordinating the return to service of the two units of TVI and KEPCO-SPC Unit 1. The two Therma Visayas units were expected to resume operations by the end of August. —Ed: Corrie S. Narisma
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