Summary
This paper introduces a new fault location technique for two‐terminal four‐circuit series‐compensated untransposed transmission line utilizing synchronized phasor measurements. The proposed technique is formulated based on theory of transmission lines and Taylor series expansion of distributed parameter line model considering the mutual couplings between the parallel lines. The technique does not require the fault type and the equivalent impedance model of metal‐oxide varistor (MOV) and series capacitor. Firstly, two subroutines are derived to determine the true fault location assuming that the fault occurs on both sides of the series compensator (SC). After that, the true fault location is selected based on the fact that the equivalent impedance of the SC must have resistive and capacitive components. A 500‐kV system with four‐circuit series‐compensated line is simulated in DIgSILENT Power Factory software while the fault location calculations are implemented in MATLAB. The proposed technique is investigated under different fault resistances and locations as well as all fault types including inter‐circuit faults. In addition, the effect of complex fault impedance, variation of earth resistivity, synchrophasors errors, and errors in line parameters is checked. The simulation study assures the validation of the technique for all simulated fault cases.