Analysis of the CdCu messenger wire breakings after 10 months exposed to the leaked water and polluted air in newly electrified tunnel of railway

초록

In 2004, We experienced some messenger wires breakings of almost new ones pulled 10months ago in CheoungBuk Railway Line. That messenger wire was stranded wire and of 70 mm2 CdCu(copper contained 1~2% Cadmium) and applied 1000kgf tensile force. That messenger wire was a overhead line of AC electrification railway and the current was never flowed until breaking. But that messenger wire was exposed to the water linking and polluted air environments in middle of the long tunnel. As of trying to find the exact cause of breaking, We performed various analyses such as chemical analysis for the water and air, SEM and EDX analysis for the ruptured wire surfaces and load checking on the configured overhead line, etc. Finally we concluded breaking was caused by the corrosion especially in a short time. In this paper, we describe the various cause analysis activities and the conclusion of the cause.