| 摘要 |
PURPOSE:To protect a capacitor against breakdown due to overvoltage, when a circuit breaker is reclosed within a short time by providing a change-over switch for transmitting an output from a pulse generating circuit for conducting a diode to a gate pulse generator. CONSTITUTION:Upon the occurrence of a system fault, output of a flip-flop 14 makes a transition from 'O' to '1'. Consequently, a change-over switch 18 is switched and a gate pulse generator 12 is switched from coupling with the output of a phase control circuit 11 to coupling with the output of a pulse generator 17 for conducting a diode. Output from the pulse generator 17, i.e., timing pulses, are transmitted through a change-over switch 18 to the gate pulse generator 12 which provides gate pulses to thyristors 1-1, 1-2 according to the timing pulse. Consequently, the thyristors 1-1, 1-2 function like diodes to dissipate charges in a capacitor 3 discharging through resistive components of the thyristors 1-1, 1-2 and a reactor 2. reactor 2. |
