Influence of UHV GIL access on transient recovery voltage of circuit breaker

The access of ultra high voltage (UHV) gas-insulated transmission line (GIL) affects both the transient recovery voltage (TRV) amplitude and the rate of rise of TRV (RRRV) of circuit breakers,which may endanger the breaking capacity of circuit breakers. Based on the double-circuit UHV accurate current (AC) overhead line on the same tower and the double-circuit GIL hybrid transmission line,EMTP-ATP simulation is used to study the influence of GIL length,access position and GIL lead station measurement equipment on the TRV amplitude and RRRV of the circuit breaker when a three-phase short-circuit fault occurs at the end of the circuit breaker in the substation. The simulation results show that the access of the GIL has a greater impact on the TRV amplitude and RRRV of the circuit breaker. The increase in the length of the GIL has a greater impact on the TRV amplitude,but the impact on RRRV is small. In order to limit the RRRV,the GIL should be installed in the middle of the overhead line,and the metal oxide varistor (MOV) should be installed to limit the TRV amplitude. The measurement equipment of the GIL terminal station has little effect on the TRV amplitude and RRRV of the circuit breaker. The research results can provide a reference for the TRV calculation and parameter design of circuit breakers in UHV lines with GIL.