At the request of air-operation-less substations, air-operated circuit breakers are going to bereplaced to oil-operated or spring-operated circuit breakers recently. To applya spring-actuater of lower operating energy, it is necessary to reduce the operating energy ofinterrupters.
The authors investigated a hybrid circuit breaker of series connection of thermal puffergas interrupter and vacuum interrupter. The withstand-voltage ability of thermal puffer gasinterrupter, which requires small operating energy, is high, but high-di/dt or high-dV/dtinterrupting ability is not so high. On the other hand, high-di/dt or high-dV/dt interruptingability of vacuum circuit breaker is high, but its unit voltage is difficult to increase.So the authors invented to connect them is series. Its operating energy will be quite lowerthan that of conventional puffer type gas circuit breaker.
One of the subjects for developping the hybrid circuit breaker is to reduce the distributionof transient recovery voltage of vacuum interrupter during high current interruption.Interrupting characteristics were examined experimentally. As a result, interrupting abilityof thermal puffer gas interrupter was improved by changing gas flow from single-flow todouble-flow. The principle of voltage sharing of the hybrid circuit breaker were confirmed.This means that the hybrid circuit breaker of series connection of thermal puffer gasinterrupter and vacuum interrupter will be realized as a quite low operating energy pufferlesscircuit breaker.
Takashi Sato (Hitachi Research Laboratory, Hitachi Ltd.)
Hiroshi Arita (Hitachi Research Laboratory, Hitachi Ltd.)
Masanori Tsukushi (Hitachi Research Laboratory, Hitachi Ltd.)
Yukio Kurosawa (Hitachi Research Laboratory, Hitachi Ltd.)