Research on the Influence of Auto-Reclosing for Grounding Arc Fault in Cable Tunnel Fire Development

Arc grounding faults of high voltage cables are a strong fire hazard and this is significantly reinforced by auto-reclosing. The simulation of a cable tunnel fire caused by arc fault could help improve the relay protection strategy and fire prevention. The energy release characteristics of the arc were obtained through single-phase arc grounding fault experiment of 110 kV cable. Considering the reclosing process, the average powers of the two arcs are respectively
$1.84 \times 10^{4}\text{kW}$
and
$2.0 \times 10^{4}\text{kW}$
. The large eddy simulation method was used to calculate the smoke flow in fire. The development trend of the fire was analyzed through the temperature distribution. The results show that cables above the fault position heat up rapidly, whereas those below heat up gradually. They both finally reach the ignition point of XLPE and PVC, which are main combustible materials of cable. The highest temperature can reach up to nearly
$130 0^{\circ}\mathrm{C}$
. Owing to the re-ignition of the arc during auto-reclosing, two peaks were observed in the temperature curves. However, in the longitudinal section of the cable tunnel, a negligible difference was observed in the fire-spreading speed with or without auto-reclosing.