Fault location for series compensated parallel lines

This paper describes an error analysis and performance assessment for one-terminal and two-terminal fault locations for series compensated parallel lines, utilizing impedance measurement techniques. The one-terminal fault location method, employing only local currents and voltages, is considerably influenced by the series capacitors in series compensated parallel lines. Two major factors which influence one-terminal fault location have come to light. One is the voltage and current components of sub harmonic resonance which are close to the fundamental frequency and are generated when faults occur in series compensated parallel lines. The other is the phase angle difference of the fault current between the fault point and the measuring point. These factors increase the locating error considerably. The mechanism is explained in detail in the paper. The transient solution of the linear-circuit equation of the series compensated parallel lines is obtained and it shows that the result coincides with the simulation based on the EMTP model for series compensated parallel lines. Furthermore, two-terminal fault location using the data from both terminals is assessed. A location method using positive-sequence components is simulated with an EMTP model for the lines and shows good location accuracy.