Voltage Distribution Mechanism and Voltage Balancing Measure of SF6 AC Filter Circuit Breaker with four Interrupters

In high voltage DC (HVDC) convector station, AC filter circuit breakers with four interrupters switch frequently. When the breakers open, the voltages across the four interrupters are uneven. To seek voltage distribution mechanism, the equivalent capacitance and stray capacitance across each interrupter of quadruple-break porcelain column SF6 circuit breaker were calculated by using Ansoft. The dynamic opening model of quadruple-break SF6 circuit breaker and the transient recovery voltage model were set up based on the Alternative Transients Program (ATP). The voltage distribution under different voltage-sharing measures (paralleling resistance and capacitance, paralleling resistance, paralleling capacitance) were analyzed. The results show that voltage-sharing effect of paralleling resistance and capacitance is better than the others. Besides, the resistance and capacitance of this measure must match each other. At last, experimental system was built based on Weil synthesis circuit to verify the availability of paralleling resistance and capacitance measure. In experimental condition, the effect is the best when the resistance is 24MΩ and the capacitance is 600pF.