The Effects of Fault Current on the Post-Arc Dielectric Recovery of 500 V Low Voltage AC Fuses

When a fuse interrupts the fault current, the ability of the fuse to withstand the TRV without dielectric breakdown after current zero determines whether the interruption is successful or not. At present, there is relatively little research on the post-arc process of fuses, and the specific process of the post-arc dielectric recovery of fuses is not clear. In this paper, the post-arc dielectric recovery process of fuses with a rated voltage of 500VAC is experimentally investigated. The dielectric recovery is measured by applying a 1500 V DC voltage pulse to the fuse after current zero. It is found that when the fault current is 6.2 times the rated current, the dielectric recovery speed of the fuse is much slower than that of 35.4 times the rated current. Meanwhile, the experimental result has significant dispersity when the fault current is 6.2 times the rated current. The post-arc dielectric recovery strength of the fuse at 100us after current zero is analyzed, and the results show that the arc voltage and arcing time of the fuse are linearly related to the dielectric recovery strength. The shorter arcing time and the larger arc voltage lead to the higher dielectric recovery strength. Based on the analysis of experimental data and the observation of fulgurate, it is found that the reason for the dispersion of the dielectric recovery strength of fuses under overload current is the uneven arcing of the series-parallel restricted sections.