Easter Sunday Mindanao blackout due to corroding insulator
MANILA, Philippines – The National Transmission Corporation (TransCo) submitted Thursday, April 16 its initial report to the Department of Energy (DOE) regarding the April 5 Easter Sunday blackout in Mindanao.
The blackout was due to a “corroded suspension insulator shank or shaft that gave way.” This caused the transmission line to fall and hit the other line conductors and tower parts, said TransCo President Rolando Bacani.
This resulted in a short circuit “which was not isolated on time,” he added.
Loss of power earlier occurred in the Mindanao grid at 1:01 am Easter Sunday. Power was restored 8 am on the same day.
DOE Secretary Carlos Jericho Petilla confirmed Friday, April 17 that he received the report but has yet to review it.
The energy chief formed a group to come up with a detailed report on the Mindanao-wide blackout.
Prior to the probe, energy officials pointed out that the Mindanao-wide grid was due to a detached conductor that hit the capacitor voltage transformer (CVT). The conductor connects the CVT, a metering equipment, to the Agus switchyard. The switchyard is connected to the Agus-Pulangi hydroelectric power complex in Lanao Del Sur.
TransCo’s initial recommendation is to immediately inspect or replace all suspension insulators in the area considering that these were installed a long time ago and a thorough inspection was wanting.
“We also recommended the immediate review of the timing coordination of protective relays and the installation of new and back-up protection as the case may be,” the TransCo official added.
Limited power supply
Bacani added that Mindanao, particularly in Zamboanga, continues to experience limited power supply.
Mindanao’s gross power reserve on April 18 stands at 74 megawatts (MW); 134MW on April 19; and 56 MW on April 20.
“In Mindanao, there are areas having rotational power outages due to power supply contracting deficiency by distribution utilities and low outputs from hydro power plants,” said DOE Director Myleen Capongcol in a text message Friday.
Petilla also said that his office would conduct an investigation into Therma South Incorporated (TSI), a subsidiary of Aboitiz Power, whose power facility in Davao City was damaged by the recent Mindanao wide blackout.
The property damage will delay the commercial operations of Unit 2 by approximately 10 months or until February 2016. Unit 1 and Unit 2 of the power plant have yet to be turned over to TSI by its contractors.
TSI was scheduled to synchronize Unit 2 with the Mindanao grid week of April 6. Full commercial operations was supposed to happen a month after.
“My question to them is simple. Where is their circuit breaker? Why are they the only ones affected? The can say all they want but they are a party of interest. We will investigate this,” Petilla said.
TSI President Benjie Cariaso Jr. said the company is also concerned about the incident. “We are also conducting our own investigation, assisted by a third-party consultant, to determine the root cause of the incident.”
The TSI official assured the public that the status of Unit 2 will not affect the commissioning of Unit 1, which remains on schedule and should reach commercial operation by end-June 2015.
More than 20 distribution utilities and electric cooperatives signed up to receive capacity from TSI. – Rappler.com
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