Research on Voltage Sag Suppression Technique based on CLR and Artificial Current Zero Interruption of FVCB

Voltage sag suppression technique based on based on current limiting reactor(CLR) and artificial current zero interruption technique of fast vacuum circuit breaker(FVCB) is proposed. The voltage sag suppression module is composed of FVCB, current limiting reactor and artificial zero crossing branch in parallel. In normal operation the FVCB is closed. A single break of 12-kV vacuum interrupter(VI) is used in the FVCB. A electromagnetic repulsion actuator is used to provide an opening velocity of 6.5 m/s and a closing velocity of 3.0 m/s. When a voltage sag happens, short-circuit current flows through the FVCB and the FVCB immediately opens within 0.5 ms, after 2.5 ms the artificial zero crossing branch generates a inverse-phase high-frequency current to make the arc extinguishing. After that the short-circuit current flows through the current limiting reactor so the amplitude of short-circuit current is limited and the bus voltage is well maintained. The over-voltage generated during interruption is suppressed by a group of ZnO surge arrestors.