Effects of Current-Limiting Inductor on Power Frequency Overvoltages in Transmission Line

Current-Limiting Inductor (CLI) is used to limit the magnitude of fault current in power systems. Meanwhile, the introducing of CLI will change the transient recovery voltage (TRV) of circuit breaker, power frequency overvoltage and switching overvoltage of transmission line. Simulations by PSCAD/EMTDC are carried out to get the effect of CLI on power frequency overvoltages. Simulation results show that configuring CLI will make power frequency overvoltage, caused by capacitance effects of long distance transmission line, asymmetry grounding faults and load rejection of line, rising up to 1.29 pu, namely slightly lower than the limit 1.3 pu specified in industrial standard. It is recommended that check of line overvoltage should be done before CLI is installed in transmission line.