An Accurate Offline Phasor Estimation Technique For Fault Location In Series Compensated Lines

In series compensated transmission lines, current and voltage signals measured by the line protection system include considerable sub-synchronous frequency components (SSFCs) which are not sufficiently damped within a typical fault clearing time of line protection system. This does not allow accurate phasor estimation and thereby phasor-based fault location. This paper presents an accurate algorithm which effectively filters out the unwanted frequency components and noise to perform accurate phasor estimation for fault location in series compensated transmission lines. Phasor estimation of a theoretical signal is first evaluated using the proposed method, Direct-Prony analysis and 4-cycle discrete Fourier transform algorithm. Then, various fault locations of a 500 kV series compensated transmission line simulated in PSCAD/EMTDC are used to comprehensively evaluate the performance of the proposed technique. It is shown that the proposed method can effectively attenuate SSFCs and other unwanted frequency components in current and voltage signals allowing accurate phasor estimation