Performance Assessment of Single Ended Fault Locator for Lines Connected with Inverter Based Renewable Resources: Problems and Practical Solutions

Fault location on transmission lines is a critical function in protection relays for accelerating system restoration, minimizing outage durations, and reducing operational and maintenance costs. Conventional single-ended fault location algorithms rely on the assumption that the fault current at the fault point is in phase with the terminal current. However, this assumption becomes invalid in modern grids with high penetration of inverter-based resources (IBRs), such as renewable energy systems, HVDC links, and FACTS devices. IBRs introduce significant phase angle deviations between local and fault-path currents due to converter control strategies and grid code compliance, resulting in severe impedance estimation errors and inaccurate fault location. This paper addresses these challenges by introducing two novel compensation methodologies based on the estimation of a non-homogeneity factor (angle deviation between local and total fault current) to correct phase angle deviations. The first approach leverages remote current measurements in conjunction with local voltage and current data, making it suitable for implementation in line differential protection relays. The second approach estimates the non-homogeneity factor using only local measurements, enabling deployment in distance protection relays without requiring communication channels. Both methods effectively compensate for system non-homogeneity, thereby improving the accuracy of single-ended fault locators under high IBR penetration scenarios. Comprehensive validation is performed through laboratory experiments and real-world field data, demonstrating that the proposed methods achieve fault location accuracy within 2–3 tower spans. The results confirm the robustness of the proposed approaches against evolving grid conditions, including varying fault types, fault resistances, and converter control dynamics. These findings highlight the practical applicability of the proposed solutions for next-generation transmission networks, and expedited restoration in increasingly complex and converter-dominated power systems.