Improved ANN based impedance estimator for phase to ground faults in UHV transmission line

摘要

An accurate digital distance relaying scheme integrated with artificial neural network impedance estimator is developed using the weighted sum of the negative-zero sequence components of fault current assuming the voltage and current are in phase at the fault location. The modified scheme is immune to the variation in fault location for under reach and overreach problem caused by sequence current components. A series of test conducted on a 800kV, 400km transmission line for single phase to ground faults as well as simultaneous open conductor fault in PSCAD/EMTP and Matlab. Finally comparison has been done with the conventional methods in order to check the accuracy and robustness of the proposed scheme which is found to be 95%.