Status of High Impedance Fault Detection

This paper presents the issues associated with the detection and clearing of high impedance faults on distribution feeders. High impedance faults are those faults with current too low to be reliably cleared by conventional overcurrent protection. These faults commonly occur as fallen conductor faults and pose a hazard to the public. The status of research on this subject is reviewed, and possible improvements are evaluated. The several complex technical, legal, economic and operational problems involved in high impedance fault detection are discussed. A complete solution to the high impedance fault problem does not exist at this time, but it is important that utilities take steps to address the problem.