A directional protection scheme during single pole tripping

This paper proposes a positive sequence superimposed current based procedure for the identification of fault directionality accomplished with single pole tripping (SPT) schemes. The proposed procedure decides the fault direction by the angle deviation between pre-fault and faulty positive sequence current components. To realize the ability of the proposed scheme under single pole tripping, several critical cases are addressed such as high fault resistance (HFR), different fault locations, different fault types, change in power flow direction, variation in source capacity and other critical system situations are addressed to prove the correct behavior of the proposed procedure. Numerous fault scenarios have been emulated for variant system configurations (single and double circuit lines) using ATP/EMTP simulation package. The current components are determined using the discrete Fourier transform (DFT). It is proved using extensive simulations tests that the proposed method is accurate and can be used for refurbishing of the conventional directional relays.