Faulty Cable Segment Identification of Low-Resistance Grounded Active Distributions via Grounding Wire Current-Based Approach

Faults in underground cables are hard to be detected directly from external features such as sound and light due to the harsh operating environment. Moreover, the rising penetration of distributed generations further complicates the characteristics of cable faults. Facing the challenges, this article first aims to reveal cable fault features via analyzing the generation mechanism of the cable grounding wire current (GWC). The impact of photovoltaic on GWC is then discussed, and the essential differences between faulty and healthy cables are also studied. Finally, considering both the structure of distribution network and an optimal deployment of measurement points, a novel fault cable segment identification method based on the amplitude and polarity of the starting terminal GWC steady-state variation is proposed. Simulations based on a real low-resistance grounded distribution network are performed in diverse fault scenarios and show a near 100% accuracy for all cases. In addition, the proposed method demonstrated a time complexity of O(896), showing a significant reduction in calculation time compared to common methods. These findings suggest that the proposed method is highly reliable and efficient for identifying faulty cable segments in active distribution networks.