A Negative‐Sequence Current‐Based Method for Asymmetrical Fault Location in Stitched Transmission Lines

ABSTRACT

Due to economic issues and the shortage of bays in high‐voltage substations, a special type of double‐circuit line called ‘stitched lines’ is used, which is connected to a bay at both ends. However, the connection of these lines to high‐voltage substations makes the current of each circuit unavailable separately. Therefore, fault location in these lines is challenging. In this paper, a new method based on a negative‐sequence network is proposed for locating asymmetrical faults using the current from the two ends of the line. It is notable that the proposed method is not affected by the mutual coupling between the two circuits and the transposition of the lines due to the use of a negative‐sequence network. The accuracy of the method for different asymmetrical faults at various locations with different fault resistances is evaluated by considering noise; uncertainty of the stitched line; and Thevenin impedances; sampling frequency change; fault inception angle; current transformer saturation; and fault clearing time, considering line shunt capacitance in all conditions. The obtained results indicate that the proposed method has appropriate performance in all scenarios, with an average error of less than 1% and a standard deviation of less than 0.5%.