High impedance faults (HIFs) are short-circuit faults that do not produce sufficient fault current and are thus not detectable by traditional overcurrent protection schemes. Research on HIF detection has been ongoing since the 1970s. Unfortunately, progress has been slow due to the complexity of HIF characteristics. This project conducted a comprehensive survey on the characteristics of HIFs and various HIF detection techniques. The techniques can be broadly classified into three types: 1) techniques that use voltage and current waveforms collected at the feeder sending end; 2) non-conventional techniques that use special equipment or data for HIF detection or prevention; and 3) new approaches resulting from advancements in sensor technology, data analytics and monitoring platforms. This report explains the basic ideas employed by these techniques and discusses their pros and cons. A survey was of relay manufacturers was also conducted, and commercial products and utility practices for HIF detection/mitigation reviewed. This project’s main finding was that reliable HIF detection techniques may need to combine the strengths of various ideas. Almost all commercial products use a combination of different detection algorithms. There is also a need to establish a benchmark dataset for evaluating HIF detection techniques and products.
High Impedance Fault, Protection, Relay, Overhead Distribution Systems