Determination of optimal setting parameters of distance relay in transmission systems

Based on the analysis of the distance seen by the relay under the effect of measurement errors, the protection capability could be evaluated from two aspects: correct trip and no-unwanted trip. The optimal distance relay settings for the transmission systems could be determined through the evaluation of correct trip probability and no-unwanted trip probability by considering the explicit desirable attributes for each protection zone. The influences of different system configurations on the optimal setting parameters of distance relay have also been studied.