Temperature dependence of electrical parameters of coaxial cables

摘要

During long-term operation of safety cables, it is necessary to verify basic electrical parameters at a higher temperature than the temperature at which these parameters are tabulated by the manufacturer. Among cases when we need these dependencies belong accelerated thermal ageing carried out according to the Arrhenius approach, verification of the cable functionality during nuclear power plant (NPP) accident, etc. Due to requirements on monitoring of critical parameters in the process of ageing at elevated temperature, it is important to determine the effect of increased temperature on these parameters and its uncertainties. We also need these dependencies for correction of acceptance criteria of tests at elevated temperature (i.e. thermal ageing, radiation ageing at elevated temperature, simulation of accidental conditions). The same can be applied for diagnostic of the cable system in the industry, where the ambient temperature is increased. The aim of this paper is to compare and evaluate the temperature dependence of fundamental electrical parameters of cables, such as insulation resistance and frequency-dependent parameters (e.g. the capacity and dissipation factor). The experiment is conducted on three kinds of coaxial cable, each with a different kind of dielectric material: Teflon dielectric (PTFE), polyethylene (PE) and cross-linked polyethylene (XLPE).