Measuring of Fault Distance Using the Fault Locator Function of Protection Relay

This article is focused on fault distance measuring with feeder protection relay REF630 from ABB and its function fault locator. This function provides impedance-based fault location. For measuring was used laboratory at Faculty of Electrical Engineering and Computer Science where is laboratory stand with inbuilt REF630 and fault module and where is also available module of transmission network. With those modules there were measured fault distance in case of phase-to-phase fault and phase-to-earth fault for various values of fault resistance. Parameters of typical 11 kV distribution network was set up in protection relay by ABB software PCM600. In case of phase-to-phase fault measured distance corresponded with parameters of model. However, in case of phase-to-earth fault measured fault distance was more than two times lower than our model. Measurement was repeated with parameters of zero sequence reactance equal to positive sequence rectance. Next results corresponded to our model parameters. All results confirmed assumption that higher fault resistance causes lower accuracy of calculated fault distance.