Phase-Based Digital Protection for Arc Flash Faults

This paper presents the real-time implementation and experimental performance evaluation of the phase-based digital protection against arc flash faults. The tested digital protection is based on extracting the high frequency components from fault currents triggered by an arc flash fault. The desired high frequency components are extracted using a filter bank that is composed of five exponentially modulated Kaiser window-based high-pass filters (HPFs). The structure of the used filter bank is selected to ensure extracting high frequency components with nonstationary phases, which represent a unique signature of arc flash faults. Such a signature allows detecting and identifying arc flash faults, as well as initiating responses against such events. The performance of the phase-based digital protection is experimentally evaluated for a laboratory 3φ system that supplies linear, nonlinear, and dynamic loads. Test results demonstrate fast, accurate, and reliable detection, identification, and response to arc flash faults. In addition, test results show that the phase-based digital protection has minor sensitivity to the type of arc flash fault or supplied loads.