Signatures of Series Arc Faults to Aid Arc Detection in Low-Voltage DC Systems

Low-voltage dc (LVDC) distribution systems are increasingly used nowadays. Faults affect the safe and secure operation of the distribution network. Among various types of faults, series arc faults are challenging to detect because they produce only small changes in the circuit current. Though a variety of series arc fault detection approaches have been developed in the past, each approach has its requirements and limitations. This paper identifies characteristics in the current and voltage waveforms to aid the detection of series arc faults in LVDC systems. Fault signatures are extracted from current and voltage measurements that do not require a high sampling frequency and installation of additional devices such as capacitors. The load current and voltage experience a step change when a series arc fault occurs. For this purpose, a step-change detector is presented in this paper. The paper also presents a novel approach to distinguish between steady stable arc conditions and rapidly fluctuating arc conditions. This provides information on arc conditions useful for fault analysis. The identified fault signatures are demonstrated and validated using experimental data.