• Mindanao outage traced to power shortfall, plant tripping


    WITH power supply in the Mindanao grid already fragile and inadequate, the tripping of the 80-MW Agus I caused an island-wide outage that government said it has already resolved as of early morning on Friday.

    Energy Secretary Jericho Petilla called an emergency meeting of the power suppliers in Mindanao yesterday and said initial investigation showed that a circuit breaker opened at the 80-megawatt Agus 1 power plant located at the mouth of Lanao lake in Marawi City, downing five other plants in the region.

    Whether it was the frequency problem, which the NGCP [National Grid Corp. of the Philippines] is saying that there was no frequency problem, we are looking at this breaker right now,” Petilla said during a press briefing.

    However, Petilla said they are still conducting further investigation to find out if it was the plant that malfunctioned or the power grid.

    “The switch there is the suspect right now, but it needs further investigation. If you notice the plants that shut down were cascaded. We have to confirm the data, the timelines because these are just seconds,” Petilla said. He added that they are now checking if a “frequency problem” in the entire power grid caused the blackout.

    He said they were able to immediately restore power supply to about 70 percent of households in Mindanao on Thursday and at least 80 percent to 85 percent of households already have power supply on Friday.

    He explained that the power supply was restored in a staggered basis to avoid further fluctuation or breakdown of the system.

    Gladys Sta. Rita of the National Power Corp. (Napocor), which operates Agus 1, said the power plant is already back to normal operations.

    Eugene Vicar, of the NGCP said that the system blackout occurred in the Mindanao Grid at 3:53 a.m. on February 27.

    He explained that the generation was at 677.2 MW prior to the blackout where load dropped to 172.9 megawatts and that a power tripping occurred in Agus 1 hydropower plant.

    “We have a series of plants in Mindanao coming from Marawi to iIigan. Agus 1 is connected to switch yard consist of high voltage equipment connected down the line to a switchyard,” he added.

    He said the outage in Mindanao was the first time in 12 years that a total blackout happened in the region.

    He said to prevent such occurrence in the future, they are improving the technical operations of all their grids.

    “We are trying to resolve it and I think we restored the system at 12 noon.

    We have to design and improve our operations to prevent such incident,” he added.

    The NGCP said at least 12 of Mindanao’s key cities and provinces were affected by the total blackout although it was able to restore limited power in some parts a few hours later. The outage left millions of people without electricity in Mindanao on Thursday was a result of the tripping of the hydroelectric plant located in the mouth of Lanao lake but which repair crews have revived.

    Petilla ruled out a possible deliberate explosion of the plants saying if it were so then it would be impossible to restore power that fast.

    But as to what caused the tripping is still being looked at closely by the DoE and the repair crews, Petilla said.

    The power disruption began before dawn of Thursday affecting heavily populated areas in Mindanao, where 100 million live.

    The NGCP said at least 12 of Mindanao’s key cities and provinces—including major trading hubs—were affected, although limited power was restored in some parts a few hours later.

    Petilla said the plants are now waiting to be put onstream. “None of the plants were damaged that is the good news. The plants are intact. They are going on-stream one by one and we are carefully isolating those that might trip again.”

    He said that so far all PSALM (Power Sector Assets and Liabilities Management Corp) plants, except STEAG. Therma Marine Inc. of Aboitiz Equity Ventures is not yet online and the SPPC and Western Mindanao Power in General Santos and Zamboanga are not online on the grid and they are on island mode, or supplying their own areas. But anytime, they should be back online, he said.

    He said 70 percent of the Mindanao grid is back to its original volume or capacity and before nightfall, we can follow up.


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