Accurate fault location for parallel power transmission lines with series compensation requires compensating for remote infeed effect under resistive faults, mutual coupling between lines as well as for series compensation effect Itself.
The basic fault location algorithm dedicated for parallel series-compensated lines coping with all these the effects has been developed and presented in [3]. This was a
direct extension of the algorithm developed earlier for a single series-compensated line. Both the location methods are categorized as the one-end techniques. Their main drawback relies in requirement of the impedance data for the equivalent systems behind the line terminals and for the possible extra link between the substations. However, impedances of the equivalent systems can undergo fluctuations during evolving faults and impedance for the remote system can not be measured locally. Possible mismatch between the representative value of the remote system impedance provided for the location algorithm and its actual value causes additional errors in fault location. Moreover, the basic algorithm requires pre-fault measurements, which
in some cases can be unreliable or even unavailable. Thus, avoiding of using pre-fault quantities is also highly desirable