A novel online monitoring method of ground fault in tree form distribution networks based on power line carrier devices

Abstract

The distribution network can continue to operate for a short time once a single-phase grounding fault arises, but if the defect is not monitored and corrected right away, it might cause serious harm. However, the bulk of fault monitoring algorithms struggle to identify faults when applied to complex distribution networks with a tree structure. In this article, a fault online monitoring method based on power line communication equipment is proposed. The method identifies the fault by monitoring the change of channel frequency response (CFR) of the distribution network in real-time, locates the fault branch by comparing the change amplitude of CFR of different receiving devices, calculates the impedance amplitude of the fault branch, and combines the relation between impedance and distance to further realize the accurate location of the fault point. A large number of simulations show that the method is accurate and stable, and can effectively monitor both high and low-resistance ground faults. Under the simulation conditions without considering signal interference, the fault branch detection accuracy reaches 100%, and the average error of fault distance localization is 19.38 m (1.98%). Compared with other methods, this method is highly applicable, with good real-time performance and high positioning accuracy.