Solution to Fault Detection During Power Swing Using Teager-Kaiser Energy Operator

The selectivity property of distance relay is affected due to the operation of power swing blocking element which is used to prevent the false tripping imposed by power swing. Therefore, the fault detection algorithm is required to overcome such type of problems. Further, the fault detection during power swing for a series-compensated line is more challenging as the metal oxide varistor protecting the series capacitor imposes other frequency components and adds transients in the voltage and current signals. To resolve such protection challenges, this paper proposes an integrated approach for fault detection, which is based on Teager-Kaiser energy operators of instantaneous zero sequence voltage (Scheme 1) and phasor of negative sequence current (Scheme 2). Instantaneous zero sequence voltage appears only for unsymmetrical ground faults, and it is not affected by current transformer saturation. Other types of faults such as symmetrical, line-to-line faults are detected by Scheme 2, which is immune to capacitor coupling voltage transformer transients. However, both the schemes cover all fault scenarios. The main advantage of proposed scheme is that it is independent of the threshold. It is also not influenced by voltage and current inversions imposed by series capacitor and can detect the fault within 3 ms. The proposed scheme is validated using voltage and current data obtained by simulating 400 kV, 50 Hz, 9-bus multi-machine system using PSCAD/EMTDC. Further, to validate the proposed scheme in real time, the experiments are also carried out on real-time digital simulator.