Yoshimichi Ohki

Cable‐grade silicone rubber was aged thermally or by combining heat and gamma‐ray radiation, and resultant changes in chemical, thermal, mechanical and electrical properties were examined. The experimental results obtained in these analyses are clearly consistent with the mechanism that silicone rubber is degraded by forming cross‐linked structures via formation of abundant siloxane bonds. With further progress of degradation, decomposition becomes dominant. Reflecting these mechanisms, mechanic

The authors have demonstrated that the estimation of the precise locations of points in cables aged thermally or mechanically or by the irradiation of gamma rays is possible by a combination of frequency domain reflectometry and inverse fast Fourier transform. This paper examines how this ability of fault location depends on the type, structure, and insulation material of the cable, using several kinds of polymer insulated cables such as a triple core cable insulated with flame-retardant ethylen

This paper demonstrates that it is possible to locate very precisely a point showing a high temperature in a polymer insulated cable. The method is based on frequency domain reflectometry and inverse fast Fourier transform. The cables tested are a coaxial communication cable with a length of 32 m insulated by low density polyethylene and a flat in-house electric cord with a length of 21 m insulated by polyvinyl chloride. The cable or cord was heated at different positions for different lengths.