Experimental Study on Short-Circuit Inside an Air Switch of Power Distribution Lines due to Sparkover Between Different Poles

摘要

This study examined experimentally the possibility of the internal short-circuit of an air switch due to the sparkover between different poles under the condition that no surge arrester exists in surrounding poles and one surge arrester of three ones is omitted at the pole with an air switch. Experiments at Shiohara Testing Yard of and Akagi Testing Center of CRIEPI clarified the results as follows. (1) Fault current may flow via the grounding point of a pole with an air switch and that of other phase of the next pole, if the low voltage wire, overhead ground wire or communication wire forms a short circuit between then. And finally the air switch may burn out. (2) Fault current continues even if the length of the short-circuit between different poles which is increased. Although the increase of the short-circuit length results in the increase of wire impedance, the amount of increase is still small compared with source impedance.