Fault Location Algorithm for Distribution Network Cables Based on Power Frequency Additional Impedance Angle

In the complex urban power grid environment, traditional fault location methods struggle to quickly and accurately pinpoint fault points, leading to extended repair times and increased risks and costs for grid operation. This paper explores a rapid fault location technique based on cable fault characteristics. It analyzes the composite sequence network characteristics of faults and establishes the relationship between local measurement quantities, fault points, and electrical quantities on the opposite side. Based on the study of composite sequence network characteristics, it investigates the variation law of sequence components after a fault occurs and identifies fault characteristic electrical quantities through sequence components. Consequently, it provides the calculation formula for measuring impedance for single-ended distance protection under different fault types. Furthermore, it proposes a method for solving the impedance of the opposite end system. The paper introduces a fault location algorithm for distribution network cables based on the power frequency additional impedance angle. This fault location method, based on the additional impedance angle, constructs the impedance equation by introducing the equivalent impedance of the line's opposite end and the additional impedance angle, fundamentally overcoming the impact of transition resistance and the equivalent impedance of the line's opposite end on the location accuracy.