A novel, fast and reliable distance relay approach is proposed in this work to detect fault during power swing. First of all, the voltage and current at relay end is measured and then processed using phasor estimation technique. Next, average of three phase active power is estimated and based on the magnitude of the calculated value the swing and different fault cases can be discriminated. During power swing, the value is always less than the threshold and with the inception of fault the value is more than the threshold. The main advantage of the proposed technique is that within one power cycle time period symmetrical fault detection is possible. The system is simulated on EMTDC/PSCAD environment using and results are presented for 230-kV, 50 Hz two-area four machine system and New England 39 test bus system to highlight the effectiveness of the proposed technique.
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