Waveform asymmetry of instantaneous current signal based symmetrical fault detection during power swing

摘要: Abstract This paper proposes a methodology for detection of short-circuit during power swing with easy adjustment, in order to unblock the distance relay and allow its operation. If fault occurs swing, it must be immediately detected removed. One major challenges these detectors is distinguish from symmetrical near electrical center (δ = 180°), as both are balanced phenomena. work aims propose detector which reliable capable detecting occurring moment that apparent impedance crosses center. The proposed presents main advantages, beside ability identify three-phase faults up δ ≤ 120°, low sampling frequency obtain shortest response time compared other techniques. In case asymmetry coefficient current signal calculated window 1 cycle (60 Hz). surpasses predefined threshold, unblocked (reset PSB function – Power Swing Blocking), allowing uses thresholds through analysis signals different frequencies. this work, defined threshold able cover great number tolerant frequencies lower than 6 Hz. avoids need extensive studies on stability estimate behavior system.