A Comparative Assessment of the Single-Criterion Methods in Fault Detection

Disturbances and faults cause power swing in the power system. Under these dynamic conditions, the power swing blocking (PSB) function prevents the misoperation of the distance relay. However, if a fault occurs during power swing, the relay must be unblocked and let it trip. In other words, the relay should be capable of detecting faults during power swing. The power swing phenomenon involves all three-phases of power system and thus, the detection of the symmetrical faults in this situation is great complexity. In this paper, single-criterion methods for the symmetrical fault detection during power swing are implemented and their performances in different situations including fault location, fault inception time, fault resistance and the angle difference between two buses at the ends of transmission line, are evaluated and compared with respect to speed and accuracy.