Fault Feeder Identification in Non-effectively Grounded Distribution Network with Secondary Earth Fault

Abstract

Secondary earth faults frequently occur in power distribution systems during harsh weather conditions. By its nature, a secondary fault is typically hidden within the transient of the first fault, so most researchers have tended to focus on a single fault feeder while entirely ignoring the existence of secondary faults. This paper presents a fault feeder identification method that considers secondary earth faults in a non-effectively grounded system. First, the wavelet singular entropy approach is used to detect a secondary fault event. This method can identify when the second fault occurs. Next, the zero-se-quence current data can be divided into two stages. One stageis for the first fault, and the second stage is for the secondary fault. A similarity matrix containing the time-frequency transient information of the zero-sequence current in the two stages is then defined to identify the fault feeders. Finally, to confirm the effectiveness and reliability of the proposed scheme, we conduct simulation experiments and adaptability analysis based on the electromagnetic transients programme to perform simulations and adaptability analysis.