New insight into the detection of high-impedance arcing faults on DC trolley systems

High-impedance arcing faults are difficult to detect with conventional switchgear, and the presence of these faults in coal mine power systems represents a significant fire hazard. Research was performed to identify plausible techniques that would discriminate between the high-impedance arcing faults and legitimate load currents on the DC trolley system. This paper briefly summarizes that effort, and focuses on the frequency characteristics of the arc current. After the arc was modelled as a stochastic process, good agreement was obtained between experimental observations and mathematical predictions