Luzon grid saved from rotating brownouts (From ‘red’ alert to yellow)

By Myrna M. Velasco – October 20, 2017, 10:01 PM

from Manila Bulletin

Following alarm bells raised by the National Grid Corporation of the Philippines (NGCP) on probability of rotating brownouts, Luzon grid was still saved later in the day of such unwanted service interruptions.

Close to 2 p.m. on Friday, condition in the grid’s power system improved from “red alert” to “yellow alert,” which entails then that the grid had already been set free from rolling power interruptions although power reserves level still remained tight.

Several power plants were reported by the system operator to have suffered forced outages, including the Calaca Unit 2, GNPower Unit 2, Masinloc Unit 1, Pagbilao Unit 1 and Sual Unit 2. According to NGCP’s report, the level of capacity loss in the system hovered at 1,960 megawatts because of the generating facilities’ forced shutdowns.

In a statement, TeaM Energy Philippines which is the operator of the Pagbilao plant, clarified that the facility’s shutdown was due to a tripping of the Naga-Tayabas transmission lines of NGCP. Several other plants were reportedly affected by this transmission line glitch.

“Units 1 and 2 of the Pagbilao power station are running and fully available today (October 20). However, the unexpected shutdowns, one after the other of NGCP lines, rendered us unable to deliver electricity to the grid,” TeaM Energy said.

Red alert was raised between 11 a.m. to 1 p.m. initially then stretched to 3 p.m., yet still, no actual brownouts happened because there had been capacity addition that beefed up grid supply from the San Gabriel gas-fired power plant of the Lopez group.

On the duration of “red alert” situation in the grid, available power was at 9,083 megawatts; while peak demand was anticipated at 9,051MW, indicating then that reserve was already nil.

According to Manila Electric Company (Meralco), it informed its customers of the “red alert” alarm following NGCP’s announcement, noting that such was “due to generation deficiency brought about by the sudden outage of power plants.” At 2 p.m., it indicated the grid’s improvement to “yellow alert” state.

Early in the day, automatic load dropping (ALD) had also hit some Meralco customers in some parts of Metro Manila as well as in Bulacan.

Tight to almost-zero reserve conditions in the grid had been recurrent this year despite the claims of some industry players of “overcapacity,” raising questions then if dependable capacity of the plants could actually be the real hurdle in the country’s electricity system.

Last month alone, six instances of “yellow alert conditions” had stressed Luzon grid, mainly due to plants’ forced outages also.

Red alert refers to a condition in the power system when the contingency reserve is zero; while at yellow alert state, it signals that the reserve is less than the capacity of the biggest unit in the grid, which is 647MW for Luzon.