Theoretical evaluation of limiting resistance required for successful interruption in circuit breaker with fault current limiter

The present article describes a method to determine the limiting impedance required to obtain a successful interruption when a circuit breaker is connected in series with a resistive fault current limiter (FCL). This study is carried out for two types of faults: an FCL terminal fault and a short-line fault. The limiting impedance required for satisfactory interruption is estimated as a function of the critical mv of the circuit breaker to be associated with the FCL and the circuit parameters. For different operating voltages, the equations found in this paper show that the knowledge of the critical mv for a circuit breaker enables us to predict the magnitude of the limiting impedance needed to have a successful interruption.