HIGH VOLTAGE POWER CABLE DIAGNOSTICS

Abstract

Power cables are one of the most important assets in power plants. For this reason, their effective life cycle management is of vital importance. The power cables need to be replaced at the right time, in a way to maximize its use, i.e., at the end of its lifespan considering a safety factor. Many condition monitoring techniques such as Insulation Resistance, Polarisation index, Dielectric Absorption Ratio, and Arrhenius Model were discussed. The Insulation Resistance and Polarization Index techniques are investigated in more detail to evaluate their performance for health assessment and prediction of the remaining useful life of power cables. Therefore, an assessment was conducted on six three-phase power cables for which insulation resistance measurements data were used to predict their future failures. For that, a statistical method was applied to evaluate the failure rating of the cables according to their calculated polarisation indexes. The lifetime of the cables is then predicted using the linear curve fitting and the nonlinear curve fitting (Weibull). Both methods' results were discussed, contrasted against each other and against results obtained in other works. Overall, the methodology adopted yielded reasonable results in predicting the remaining useful life of the cables analysed.