Research of a new type of fault current energized fast repulsive force actuator

Abstract

Based on the characters of repulsive force actuator for its fast speed in the opening and closing process, a kind of new-type fast circuit breaker energized by fault current was designed in this paper. With bus shunt as excitation current, double coil tandem repulsive force actuator and permanent magnetic actuator were composed together. This hybrid circuit breaker with new-type of excitation doesn't need receiving the order from logical judgment system or capacitor energy storage system. With spontaneous rapidity, its rapid opening speed is directly proportional related with the short current value. It has fast speed of response and action. On the basis of this structure, the simulation analysis and optimization was performed. Firstly, the coils' temperature-rise and turn-to-turn voltage under normal load were calculated to guarantee thermal stability and insulation reliability. Then the effect of output repulsive force was also analyzed to ensure the action's reliability. Besides, the break reliability was discussed when the short current meets the first zero crossing under different circuit phases and on this account the parameters of opening spring was optimized. Finally, the action mechanism of this new-type self-excitation hybrid circuit breaker was discussed in this paper. Based on finite element analysis and simulations, the fault current energized type hybrid circuit breaker prototype was manufactured. The experimental data verified that the new actuator can break circuit quickly and successfully under the presetting short-circuit threshold of 2.4kA.