The National Grid Corporation of the Philippines (NGCP) said fluctuating power and outages that hit Negros and Panay on Thursday, April 27, were caused by power deficiency.
The NGCP monitored a system disturbance affecting the Visayas grid at 1:51 p.m., it said.
In its advisory it said there would be a red alert from 6 p.m. to 7 p.m. Thursday, which meant the supply-to-demand balance could further worsen, which could lead to rotating power interruptions.
Yellow alert was up from 2 p.m. to 6 p.m., which meant power reserves were not enough to cover the largest running generating unit at the time, but did not necessarily lead to outages, it added.*