National grid addresses low voltage concerns in Central Luzon

Transmission service provider, National Grid Corporation of the Philippines, recently met with its load customers in Central Luzon to address the growing concern on voltage delivery.

NGCP spokesperson Cynthia Alabanza explained, "Since the coming of the summer season, distribution utilities and industries directly connected to NGCP in Region 3 have experienced severe low voltage problem particularly during peak period specifically in the provinces of Pampanga, Tarlac, Zambales, Bataan, and Nueva Ecija. The low voltage scenario was attributed to the unusual sudden increase in power demand, which rose to as high as 7,885 megawatts (MW) on April 27. This figure was the highest peak demand recorded so far for the year 2012 thus breaking the highest peak demand last year by about 4.4 percent (7,552 MW)."

To immediately address this situation, NGCP came up with remedial measures by way of switching off all reactors, switching on all available capacitors, optimizing load tap changers, and adjusting the corresponding reactive power of generators synchronized to the grid.

Moreover, power plants such as Limay Combined Cycle, Subic, and Malaya were required by the system operator to operate as Must Run Units to further boost up the reactive support requirement in the Luzon grid.

Alabanza added that, "as a short-term solution, NGCP expedited the repair and maintenance of capacitors installed at the Mexico and San Jose Substations. From one capacitor each from the two substations, i.e. Mexico (1x50MVAR or megavolt ampere reactive, a unit of measure for capacitor banks) and San Jose (1x100MVAR) on April 12 , it was then augmented as of May 8 to 2x50MVAR and 3x100MVAR capacitors in Mexico and San Jose substations respectively. This also includes the additional 1x50MVAR capacitor at Sucat substation which was successfully commissioned on April 20."

With these actions undertaken by NGCP, a substantial improvement in system voltage was then realized and the possibility of having extreme low voltage problem due to the anticipated high system demand for these last few days of summer 2012 is now improbable.

Alabanza likewise said, "the transmission firm has come up with its medium-term plans under the Luzon Voltage Improvement Projects I & II as part of the commitment to further improve the quality of system voltage in the Luzon grid. With the additional capacitors to be installed in Central and Southern Luzon, specifically in the vicinity of Metro Manila, a total combined capacity of about 1,050MVAR will be commissioned by February and March 2013 respectively."

NGCP was formed after the government sold a 25-year license to a consortium led by China's State Grid Corp. to run the country's power grid for $3.95 billion.

The consortium is composed of the State Grid of China (40 percent), Monte Oro Grid Resources Corp. (30 percent), and Calaca High Power Corp. (30 percent). Sy-led One Taipan Holdings Corp. bought out Monte Oro Resources in March 2010. - PIA — ARA