Cold Characteristic Development Test of a New SF6 High Voltage Circuit Breaker

Computer controlled triggering of an impulse generator was implemented in order to perform precisely timed lightning impulse voltage discharges on a new SF₆ high voltage circuit breaker while performing a trip operation. Successive discharges at different time intervals would provide an envelope of dielectric withstand and travel characteristic of the specific high voltage circuit breaker. This test not only evaluates the interrupter gap design but also evaluates the gas flow effect in the dynamic dielectric recovery of the interrupter chamber. Gas flow characteristics in the interruption chamber of an SF₆ breaker strongly modifies the dielectric withstand recovery rate of any design. Identifying any weakness before power test are performed not only reduces cost and time, but also simplifies design modifications required and provides an insight into the expected performance of the interrupting chamber during actual synthetic power testing. This paper presents the implementation of this testing procedure as well as the results obtained in a new design of a 245 kV, 63 kA SF₆ interrupter