Investigation of TRV across circuit-breaker of series compensated double-circuit UHV transmission lines

State Grid Corporation of China plans to build the Huainan-Wannan-Zhebei-Huxi UHV double-circuit transmission project and install series capacitors (SCs) in Huainan-Wannan transmission lines. During the circuit breakers clearing system faults on series compensated transmission line, the transient recovery voltage (TRV) of circuit breaker may be increased due to the impact of series capacitor. If there is no countermeasure, the TRV may higher than the limit in circuit breaker standard. This phenomenon may result in the failure of clearing system fault and the damage of circuit breaker. This paper investigated the influences of series capacitor on TRV. In order to limit the TRV, the fast bypass series capacitor based on system protection and relay system is suggested.