Superimposed TMI Based Symmetrical Fault Detection during Power Swing

Distance relays are mal-operated during power swing condition as they are blocked in that period. Though, a fault occurs they must be unblocked to clear the fault event with high degree of reliability. This paper presents an incipient technique for symmetrical fault detection during power swing using superimposed based transient monitor index (TMI) currents. In this regard, initially transient monitor index (TMI) currents are estimated by taking difference between the predicted current samples regenerated from the dynamic phasors and the actual sample values, helps to distinguish the fault from the power swing condition [12]. To obtain robust discrimination between faults and swing the algorithm is further implemented by processing TMI values into superimposed TMI values. Simulation results are carried out in MATLAB environment by considering different fault situations and results designate how the inhibitions of subsisting methods are overcome by the proposed method.