Symmetrical fault detection technique during power swing based on S-Transform

Disturbances in a power system such as line switching and sudden removal of faults may cause instability which lead to the power swing phenomenon. During a power swing, the mal-operation of distance relay is among the problem which needs to be solved. In the case of a power swing, a distance relay is designed to block detection to avoid wrong interpretation of relay current signals. However, this blocking scheme proves to be unreliable as it could block the trip signals when a genuine fault occurs in the system during a power swing. Hence, it is vital to develop a proper fault detection technique during a power swing to avoid such circumstances. This paper presents a detection technique to detect symmetrical faults during a power swing based on the time frequency transform known as S-Transform. To ascertain validity of the proposed scheme, it was verified with the IEEE 14-bus system and simulation results showed that the proposed technique was able to detect symmetrical faults occurring in the power system.