A Fault Direction Estimation Scheme for Transmission Lines based on Fault Current Power Frequency Component

Publication Name

Proceedings of 2021 IEEE 2nd International Conference on Smart Technologies for Power, Energy and Control, STPEC 2021


Conventional directional relaying algorithms use the phase angle difference between the voltage and current to detect fault direction. In series compensated transmission lines (SCTLs), due to the presence of series capacitance in the fault loop, voltage and current inversion phenomena can occur, and, for faults close to the relay location, the voltage amplitude is almost zero. Moreover, subsidence transients of coupling capacitor voltage transformers (CCVT) during close-in faults can challenge the security of directional relaying. In such conditions, conventional directional relaying methods face direction detection problems due to the lack of proper voltage polarization. This paper presents an intelligent directional relaying technique for the protection of conventional and series compensated transmission lines, based on the phase angle of the through-fault current. The above-mentioned problems are then eliminated, and the complexity associated with SCTLs can be overcome since the proposed method merely uses the phase angle of through-fault current and its performance is independent of the power flow direction. The performance of the proposed technique is evaluated under various operating conditions for both conventional lines and SCTLs with different configurations using PSCAD/EMTDC®. The studies illustrate that the proposed method improves protection resilience.

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