Blackout

The partial or total loss of

power to an area.

Causes of Blackout

Tripping of generating Units

Tripping of transmission lines

Shortfall of reserves power

Blackstart Procedure The process of recovery from partial or total

blackout using a generating unit with capability to start and synchronize with system without an external power supply.

Declaration by System Operator

The Senior Grid Shift Superintendent of NGCP/RCC declares a Total Black-out.

ACC to inform respective power plant that RCC has declared a blackout and advise to initiate blackstart.

ACC to inform all parties within his area of responsibility that RCC has declared a blackout.

Substation/Power plant operators to open all circuit breakers after declaration of a blackout.

Declaration by the Regional Control Center (RCC) of a system blackout.

Delegation by the RCC of the Area Control.

Centers (ACCs) to implement island grid operations.

Priority restoration of electric power service to critical loads.

Safety considerations for personnel and equipment.

Identify and start all available generating units.

The generator terminal voltage shall be at a minimum level of 95% of the rated voltage before a line could be energized.

For power transformers, the generator terminal voltage shall be maintained at a level below 10% of its rated voltage

Line voltages shall be within 105 of the nominal voltage in energizing power transformers.

When energizing transmission lines, the nearby generators should be on automatic control and that enough reactive reserve is available at the generators to absorb the line charging reactive power..

Once a line has successfully been energized, it is best to energize some local loads to control the voltage level within an acceptable range.

Shunt capacitor banks should be removed from the service so as to prevent high voltage until such time that sufficient load has been energized.

Shunt reactors should be initially placed in service when restoring the system so as to help maintain the system voltage within the allowable levels.

Energize only one (1) line in extending power to adjacent substation so as to prevent high voltage at the receiving end.

Initially load all generators of each sub-system to at least 50% of the generator’s capability before extending power.

Disable underfrequency relays, to include those SCADA – controlled, so as to prevent initiation of ALD during low frequency oscillations.

If a high – voltage transmission line is to be energized through the low – voltage side of the transformer, consideration should be given to adjust the tap changer to its lowest tap setting.

The generator frequency must be 60.5 Hz before energizing feeder loads.

The voltage difference when synchronizing two island grids should be as minimum as practicable.

The RCC shall synchronize the different power island grids at the designated synchronizing points.

Metro

ManilaCentral

Luzon

Northern

Luzon

Southern

Tagalog

Bicol Sub-

grids