PHASE CONTROL SYSTEM FOR SWITCHING CIRCUIT BREAKER

PROBLEM TO BE SOLVED: To suppress the generation of an overvoltage applied during opening and closing of a switching circuit breaker by a method wherein by outputting a control signal by which opening closing operation of a first or a second switching circuit breaker is synchronized with the phase of a source voltage waveform corresponding to the switching circuit breaker to control an overvoltage, each switching circuit breaker is opened or closed in the zero position of a source voltage waveform or at the interpole voltage minimum value of each circuit breaker. SOLUTION: A phase control system for switching circuit breaker is constituted such that a power source applied on first and second switching circuit breakers 6A and 6B to feed a power to the middle section 7c of return feeders 7a and 7b by alternately switching first and second power sources A and B, and the middle section 7c is changed over between the first and second power sources A and B. In this case, a phase control device 40 is provided to output a signal to first and second switching circuit breakers 6A and 6B such that the closing positions or the opening positions of the power sources A and B and each source voltage waveform are changed-over in synchronism with each other.