A Half Cycle Air Blast Generator Breaker for High Power Testing Fields

Generator breakers in high-power testing fields, the back-up breakers, have the function of safety breakers: they have to protect both the generator and the test breaker from being overstressed by a short-circuit current of undesired duration. The heavy short-circuit currents of modern generators enforce the development of generator circuit-breakers of high breaking capacities. In this paper a generator c. b. is described having a rated breaking capacity of 160 kA at a service voltage of 15.4 kV. This circuit-breaker is a half-cycle breaker capable of interrupting a symmetrical current at the first current zero passage. Due to its short minimum arcing time this breaker is suitable for syn- chronized breaking operations and so permits an economical testing of circuit-breakers. This testing method is also described.