NGCP addresses low voltage concerns in Central Luzon

May 25, 2012 10:00 pm 

MANILA, May 25 — The National Grid Corporation of the Philippines (NGCP), the country's sole transmission service provider, recently met with its load customers in Central Luzon to address the growing concern on voltage delivery.

Since the onslaught of the summer season, aside from the Meralco's franchise area (Metro Manila), the distribution utilities and industries directly connected to NGCP have experienced severe low voltage problem, particularly during peak period. Among these areas were 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, 2012. 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 the low voltage 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.

Likewise, power plants such as Limay Combined Cycle, Subic and Malaya were required by the System Operator to operate as Must Run Units (MRUs), to further boost up the reactive support requirement in the Luzon grid.

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, 2012, it was then augmented (as of May 08, 2012) 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, 2012.

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 this mid-month of May 2012 became a thing in the past.

As part of the commitment to further improve the quality of system voltage in the Luzon grid, NGCP has come up with its medium-term plans under the Luzon Voltage Improvement Projects I & II.

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 is expected to be commissioned by February and March 2013, respectively.

As part of its long-term projects, NGCP is currently doing comprehensive studies for the installation of additional transformers and construction of substations that will further strengthen and reinforce the substation capacity requirement of the major power delivery points serving the Metro Manila area. (PNA)

lgi/ASF/utb

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