抄録
In the D.C. railway system in Japan, the arc breaking of the contact wire at air section (AS, generally called as "insulated overlap") sometimes happens. Such a phenomenon causes heavy traffic confusion and it is required to propose some countermeasures as soon as possible. In this paper, firstly, the experimental results to clarify the arc breaking phenomenon of the contact wire are shown. Based on the experimental results, secondary, the possible candidates of the countermeasures to avoid the contact wire arc breaking at AS are proposed and explained. Some of the candidates are now under investigation, development and construction in the practical railway system of JR East. Lastly, the effect of the AS voltage difference suppression on the risk reduction of the contact wire arc breaking is calculated and evaluated.