Improved Series Arc Model for Power Electronic Loads

Because of the complex electrical characteristics and detection difficulty of the series arc fault, it is prone to cause serious electrical fires. Especially, a large number of power electronic loads have been put into use in recent years, which makes the circuit topology more complex, further increasing the difficulty of series arc fault detection. In this article, series arcs are divided into long arcs and short arcs according to the differential behavior of fault currents under different arc lengths. By comparing the simulation results of series power electronic loads under various black box models and measuring the similarity of time series and other parameters, it is considered that the Cassie model with a smaller time constant is better than Mayr and its derived models. It can better reflect the oscillation of the long arc current in the time domain. Furthermore, an improved arc model is proposed in this article, considering the influence of the black box model time constant on high-frequency fault current oscillation of power electronic loads such as fluorescent lamps. The difference between the short arc fault waveform of the improved model and the actual waveform is reduced by an average of 16.07% compared to that before the improvement, which provides a reference for the accurate detection of series arc faults in power electronic loads.