Transient Recovery Voltages on Contact of SF6 Circuit Breakers in the Short Line Fault Regime

Abstract

When fault clearing at the contacts of high-voltage circuit breakers (HVCBs), a transient recovery voltage (TRV) appears. The largest contribution to TRV is caused by the component of the recovery voltage between the contact of the circuit breaker and the earth, from the side of electric transmission lines (ETL). When variations in the distances between the circuit breaker and the fault points on 110 and 220 kV ETL using the EMTP-RV software package, are taken into account, the arc model is investigated using the Cassie and Mayr equations to identify the parameters of the TRV. The extent to which the rate of increase in the TRV is influenced by the distance between the faults on the ETL and the SF6 circuit breakers with rated voltages of 110 and 220 kV is analyzed. When choosing SF6 circuit breakers with rated voltages of 110 and 220 kV in TRV parameters, we consider cases where the remoteness of the fault can be described using the ratio of the SC currents at the SC points to the values of the SC currents at the HVCB, and conclude that the recommended figure should lie between 0.7 and 0.9.