Published December 5,
2016, 10:01 PM By Myrna M. Velasco
As explosion at its
substation was directly tagged as the cause of the November 15 rolling
brownouts, system operator National Grid Corporation of the Philippines (NGCP)
was directed to review and assess the operation and specifications of its
protection systems so it will not trigger another round of pestering service
interruptions in the future.
This has been contained
in the memorandum submitted by the investigation body to Energy Secretary
Alfonso G. Cusi, summing up the incident report relating to last month’s power
outages.
In the report, it was
specified that “the explosion of the San Jose substation capacitor bank 1 power
circuit breaker (PCB) CB04 is deemed the root cause of the Luzon grid
significant incident on November 15, 2016 which resulted in the severe voltage
dip and frequency anomalies which caused the tripping of several power plants,
and the actuation of ALD (automatic load dropping) and MLD (manual load
dropping) to stabilize the system frequency.”
As an aftermath of that
incident, it has been recommended that NGCP shall “review fault clearing time
of protection settings and should be consistent with the fault clearing time
allowed by the Philippine Grid Code.”
The grid operator was
further asked “to conduct an assessment of the main protection of all capacitor
banks.” It was noted that the failure of its redundancy protection system to
isolate the November 15 incident had been due to ‘not apt specification’ of its
equipment.
NGCP was similarly
urged “to conduct an accounting and review of PCB’s specifications for
capacitor banks in the Luzon, Visayas, and Mindanao grids to ensure that the
PCBs currently installed are definite-purpose PCBs with pre-insertion resistors
consistent with its network protection philosophy Section 10.0.”
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