New arc extension circuit design and specifications for 4000MVA high power test facility expansion project

Korea Electrotechnology Research Institute (hereinafter referred to as `KERI') has expanded 4000MVA grade high power test facilities since 2011. The test facilities to be expanded include not only direct test facilities but also the test building under construction, which is capable of additional synthetic tests using exiting synthetic test facilities. To implement the new synthetic test building, KERI utilizes existing capacitor banks to generate the synthetic test current and is additionally implementing the reignition test facility that is applied to circuit breakers that have long arcing time. This paper described the design on reignition test facility for the synthetic test of the circuit breaker with long arcing time. The reignition circuit and test facility were composed of the current zero anticipator unit and the reignition circuit and the trigger unit. The reignition circuit was composed of the capacitor bank, the DC charger unit, resistors and reactors. The current for reignition was designed as the impulse current with 4kA peak and 160μs time constant. By the result of simulation on the 72.5kV and 31.5kA rated circuit breaker, using the current zero anticipator unit capable to control the time in the unit of 100μs provided a sufficiently large slope at the current zero point and did not create current chopping, which was considered to ensure the rated arcing time of the circuit breaker.