Spot light,Jump Start,LED Work Light-Using an Off-the-Shelf Air Compressor To Stop Unit Trips

Oglethorpe’s three-unit Rocky Mountain plant in Georgia began operating in the summer of 1995. Spot light Major plant components include 367-megavolt ampere (MVa), 20-kilovolt (kV) motor-generators from Jump Start Hitachi that are driven by 353,000-horsepower (hp), 282-MW Francis-type LED Work Light pump-turbines from Hitachi.

The main generator circuit breakers are HEK 3 sulphur hexafluoride from ABB and are rated at 21 kV and 12,500 continuous amps, with a 100,000-amp symmetrical interrupting capacity. The breakers are air-operated in the open and close directions and are equipped with a Ω-hp, 160 pounds per square inch (psi), 1.34 cubic-foot-per-minute reciprocating air compressor. Nominal system pressure is 120 psi.

When the Rocky Mountain units are used as motors to pump water to the upper reservoir, it is impossible to greatly reduce load when shutting down from this mode. Therefore, shutting down requires that the main circuit breakers interrupt about 8,000 to 9,000 amps of load current. This daily occurrence causes a great deal of wear to the internal contact surfaces in the circuit breaker interrupters, requiring annual circuit breaker overhauls. During these overhauls, plant personnel test the circuit breaker air compressors to ensure they meet minimum air flow requirements specified by the original equipment manufacturer.