Side effects of Current-Limiting Reactors on power system

Air-cored Current-Limiting Reactor (CLR) has already been widely applied to limit the magnitude of fault current in power systems in many countries, Brazil for example, and meanwhile the CLR has made a significant contribution to the severity of transient overvoltages in power systems, such as transient recovery voltage (TRV), switching overvoltage (SOV), and temporary overvoltage (TOV). The present paper here did a lot of simulations on the application of CLR for a real-life transmission line, suggesting that with equipment parameters of originally draft, TRV would have exceeded the circuit breakers’ TRV ratings and necessary measures should be taken to decrease TRV. Digital simulations were made with PSCAD/EMTDC software and the results implied that the magnitude of the SOV and the TOV increased up to or even exceeded the safe limits with the CLR installed. Relevant studies are strongly recommended before the CLR is applied to ensure the safety of equipment and transmission system.

► Installing air-cored Current-Limiting Reactor (CLR) to decrease the fault current levels in the power system.
► CLRs increase the magnitude and shorten the rise-time of the transient recovery voltage (TRV).
► Installing parallel capacitors is a widely adopted measure to decrease the TRV.
► For switching overvoltages and temporary overvoltages, installing CLR will make the overvoltages rise.
► Researches show that the overvoltages go up with the increment of CLR impedance.