Optimal tuning for fast arc suppression coil

Arc suppression coils (ASC) in electrical distribution networks are normally tuned off resonance by 5%-20%. Using new magnetically controlled inductor 100% tuning is possible, even during fault. It is known, that earth fault currents have an impact on fault arc extinguishing, but no model currently exists to describe the combined effect of fault current and the rate of rise of recovery voltage (RRTRV) on the probability of earth fault arc extinguishment. This paper builds an analytical model, which establishes a functional relationship between fault current, RRTRV and autoextinction probability on short fault arcs. Performed simulation also shows, that fault resistance and compensation degree have a substantial impact on RRTRV and therefore on the fault arc extinguishing. The results of analytical and simulation models were compared to empirical field data and were found to be in agreement. Based on the new fault arc model it was established, that 100% tuning via fast ASC provides a significant improvement the probability of short arc suppression.