Metro Manila power supply back to normal with the replacement of transformers at NGCP San Jose substation

June 10, 2009 12:06 pm 

By Marissa S. Neri

MANILA, June 10 —- Repairs and replacements of the transformers of the San Jose substation in Bulacan that caused four to five hours power interruptions in Metro Manila today had been completed.

The National Grid Corporation of the Philippines (NGCP), the operator of the country’s transmission highway, reported that they had energized as of 2 p.m. today the newly-repaired 600-MVA (megavolt-ampere) transformer at its San Jose substation.

”Replacement works, which started on the evening of June 9, lasted for around 16 hours, well ahead of the 26-hour target initially set by NGCP,” the company said in a statement.

After energization, the San Jose substation was immediately looped to the Luzon Grid and has now resumed dispatch operations.

Power supply in the affected areas has now returned to normal, NGCP said.

Distribution giant Manila Electric Company (Meralco) earlier said several areas in Metro Manila, including some portions of Bulacan, would suffer four to five hours rotating brownouts as a result of the replacement of the San Jose substation transformers.

But Meralco implemented manual load dropping through two-hour rotating brownouts in Quezon City, Caloocan, Malabon, Navotas, Valenzuela, and Bulacan.

NGCP said the replacement intends to ensure the reliability and stability of Transco/NGCP’s transmission network in the areas served by the substation. The San Jose substation serves approximately 40 percent of Metro Manila’s power needs.

The total cost of the project, amounting to US$ 60.91 million, is inclusive of installation, testing and commissioning costs and will be funded from internal cash generation of Transco/NGCP.

The replacement of the transformers of the San Jose substation came after an outage in July 2008 that prompted the System Operator (Transco/NGCP) to revise the dispatch schedule in order to sustain an uninterrupted supply of power.

Currently, the San Jose substation, which is in highly critical condition, has a 2,400 MVA capacity.

During the shutdown, San Jose substation’s maximum power transfer capacity was reduced from 1,600 MVA to 1,040 MVA.

”NGCP deemed it best to shut down and replace the said transformer which was still working but has recently exhibited a sudden increase in dissolved gas levels,” the company said.

The intermittent rainy weather initially threatened the timely completion of the repair and replacement works. NGCP engineers and technicians worked on the 500-kiloVolt structure with extreme care to prevent moisture from seeping into and damaging sensitive parts of the replacement transformer. The new management of the privately-owned transmission company is implementing a program to properly maintain its facilities. The upgrade of facilities, on the other hand, is part of the Transmission Masterplan currently under development.

NGCP intends to purchase 13 units of 250-MVA single-phase (or four 750-MVA banks with one 250-MVA spare unit) upgraded transformers for the San Jose substation alone. Target energization of the first bank of new transformers is March 2010.

Meanwhile, NGCP assures its power customers that it will continue to do all necessary activities to maintain power reliability, security, and quality at all times. (PNA)



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