Phasor measurement unit-based distance protection & fault location algorithm for series-compensated transmission lines

Abstract

Distance protection and fault location in series-compensated transmission lines are complex challenges for protection engineers. This paper presents a communication-aided distance protection and fault location algorithm for EHV series-compensated transmission lines based on Phasor Measurement Unit (PMU) and Synchrophasor Measurement techniques. The proposed algorithm utilizes the PMU to develop a distance protection and fault location scheme using synchronized voltage and current measurements from both local and remote end substations. The synchronized voltage and current measurements from local end are transmitted to remote end and vice-versa. Then, the determination of the fault zone and fault location is performed in both local and remote end distance relays without exchanging of any other signals (permissive, blocking, direct transfer tripping... etc.). In the proposed algorithm, both voltage and current signals will be communicated via PMU. This will offer great advantages of reducing the required digital communication channels and ability for reducing communication time delay errors. Moreover, in case of losing of the voltage transformer signal in the remote end substation, or if there is no voltage transformer, as in some old existing substations, the scheme is capable of calculating the missing voltage signal and maintaining a higher system reliability.