LEGAZPI CITY, May 31 (PNA) -- Frustration hit most residents of this city, especially in the Old Albay District, after restoration of power in some areas after 12 midnight Friday, was only temporary and those who were expecting to have power resumption got an empty bag instead.
A power-tripping occurred on Saturday morning when engineers from the Albay Power and Energy Corp. (APEC) tried to load Feeder 3 in the Embarcadero Land Ventures Inc. sub-station but were unable to do so because the protection settings in that facility and in the APEC’s recloser were not coordinated.
The APEC technical men appeared to be finding it hard to determine the protection settings in both power facilities in order for these to be coordinated.
The engineers again failed on the second attempt to adjust the protection settings in both facilities as they failed to coordinate these.
This would be the fourth day that most parts of the city might experience the absence of power but Mayor Noel E. Rosal said they have been doing their best to include the Old Albay District in the areas with restored power supply.
While those in Barangay Oro Site and other villages in the city proper have had power supply since after midnight up to this writing, most parts either do not have power or are included in the areas with rotational supply.
“We are working hard to cover as wide an area as possible in power restoration up to Sunday,” Rosal said.
Latest news from the APEC management said while the tapping of the ELVI sub-station has been completed, adjustment on the settings has been ongoing after the tripping when the Bitano sub-station Feeder 3 was loaded.
It added that the two 10-MVA transformers and their accessories, which were sourced from Pampanga, are now all loaded on a trailer and are expected to arrive on Sunday afternoon.
“Please take note that there will be slippages from our commitment due to unexpected developments. Rest assured we are doing our best to normalize the power situation at the earliest time,” the APEC said.
Noting that Gov. Joey Sarte Salceda committed power supply normalization by Sunday midnight, the APEC said it would be doable.
The blackout being suffered by Legazpi City, Manito towns and some areas of Sto. Domingo town started on Wednesday morning after the 35-year-old 20-MVA transformer of the Bitano sub-station conked out.
Imported in 1979, it was originally bought as a second-hand equipment in 1991 and commissioned at the former Culliat sub-station in Daraga town.
It was then transferred to the Bitano sub-station in year 2000 for the replacement of a damaged unit.
Based on records, since its installation, the 20-MVA Wagner power transformer has not gone into a major repair or rehabilitation but only maintenance works such as correction of hot spots, injection of nitrogen and oil leak repairs -- the latest of which is the maintenance done by the Gigantic Electrical and Mechanical Contractors Inc. (GEMCO) in July 2012.
The maintenance covered hot oil flushing of the core and winding, vacuum and filtering of oil, cleaning and painting works, re-gasketting, cleaning and re-aligning of gears and latching of the off-load tap-changer.
Latest report based on the testing conducted by GEMCO in July 2012 showed that the tests such as insulation resistance, transformer turns ratio, winding resistance, polarization index excitation and dielectric breakdown voltage tests were acceptable, except for the insulation power factor test for the secondary bushing which did not meet the minimum passing criteria of the National Grid Corp. of the Philippines.
For it to be re-energized and connected to the grid, after the maintenance work of GEMCO, NGCP had Aleco submit a waiver in the event that the 20-MVA transformer would become defective due to cause of low insulation of the secondary bushing.
For the past two years, the 20-MVA power transformer has been loaded with 13.33-15.06-MVA, according to records. (PNA) CTB/FGS/CBD/rsm