Computational Fault Time Difference-Based Fault Location Method for Branched Power Distribution Networks

Fault location in a power distribution network is a challenging task due to the presence of multilayer branches and short line lengths. Existing fault-location methods generally require measurements at both ends of each branch, which requires a large number of measuring points. The placement of measuring points at branch terminals is an approach that can be used to reduce the number of measuring points. Such a measuring point layout allows the existing fault-location methods for power distribution networks to determine fault points after identifying faulted branches. However, these methods fail to locate a fault if the faulted branch cannot be correctly identified. This paper proposes a traveling-wave-based fault-location method for branched power distribution networks without requiring faulted branches to be identified. In the proposed method, by using the first arrival times of the fault-generated traveling waves detected at the substation and each branch terminal, the computational fault time difference (CFTD) is defined. By calculating the value of CFTD, the fault point is directly searched out. Finally, the quartile method is used to eliminate the impact of the arrival-time error on the fault-location accuracy of the proposed method. The simulation results verify the high accuracy, traveling-wave velocity stability, and strong arrival-time error robustness of the proposed method.