Directional relaying during power swing and single-pole tripping

This paper presents a directional relaying scheme during power swing and single-pole tripping condition using fuzzy logic approach. If any balanced or unbalanced fault occurs during power swing condition, conventional directional relaying algorithm finds limitation due to complex nature of signal. Once a fault is identified as being only on a phase, then the single-pole tripping takes place. During this situation the sequence component based directional relay will have a tendency to trip incorrectly due to the unbalanced loading condition. Again if a single-pole tripping situation happens during power swing, the situation becomes more complex. This paper highlights these issues and proposes a fault direction estimation technique using fuzzy logic approach where feature selection using mutual information technique is emphasized. Performance of the technique is evaluated using the test system simulated through PSCAD/EMTP software.