THE National Grid Corp. of the Philippines (NGCP) on Thursday said the series of “red alerts” in the Mindanao grid is isolated and is expected to normalize once the plants on scheduled or emergency shutdowns are back and synchronized to the grid.

NGCP, in a statement, said the recent series of “red alerts” was due to generation deficiency caused by the scheduled maintenance of some power plants and the unexpected shutdown or reduced capability of others.

NGCP, as system operator, issues Grid Operation Notices to grid users. “Red alert” refers to the system condition when the contingency reserve is zero or a generation deficiency exists, while a “Yellow alert” is a system condition where total of all reserves is less than 13.2 percent of the required capacity.  When system reserves are more than sufficient to meet the reserve requirements of the grid, the system is considered to be under normal condition. The system alert and the corresponding power curtailment, if any, is lifted once demand recedes or once there is enough available capacity coming into the grid from the power plants.

During periods of generation deficiency, NGCP implements the Mindanao grid-wide power load curtailment to maintain the power grid’s security and reliability. “It is NGCP’s obligation under the law and its franchise to ensure that the grid operates at an optimum level with due consideration for safety, security and reliability,” stated Cynthia P. Alabanza, NGCP spokesman and adviser for external affairs.

“The level of curtailment is based on the Mindanao generation deficiency matrix issued to us by PSALM/NPC. NGCP does not, by itself, determine which franchise area or distribution utility gets what portion of the available supply. We only follow a matrix supplied to us by Power Sector Assets Liabilities and Management/National Power Corp.”

Alabanza said beginning October 19, NGCP implemented load curtailment based on PSALM/NPC’s matrix  when available reserve energy levels dropped to negative 12 MW, and persisted until October 24 when reserves were at negative 45 MW.

“Grid conditions improved to a yellow-alert status on October 25, the day one of the plants on scheduled maintenance went back online. Still, the reduced capability of other plants led to a situation where the available reserves were insufficient to meet the grid’s required contingency.”