Feasibility Study on Online Diagnosis of Aging and Deterioration of Medium Voltage (MV) Three-Core Cable Based on Impedance Spectroscopy

In order to explore the feasibility of impedance spectroscopy in the application of online diagnosis of aging and deterioration of medium voltage (MV) three-core cables, based on the theory of transmission line equation, an aging and deterioration model of the MV three-core cable has been established. The impedance spectroscopy of the cable head-end under healthy and different aging and degradation states has been simulated and analyzed. Further, the effects the extent of aging, local deterioration size and position, line length, load rate and other factors on the impedance spectroscopy have been studied. Based on the influence of the various factors on the impedance spectroscopy, a set of aging and deterioration diagnosis procedures and methods are proposed. The simulation results indicate that the impedance spectroscopies of healthy state and different aging and/or deterioration states have certain characteristics. These characteristics can be determined by specific criterion indicators such as the monotonous decrease of the value of the resonance peaks and the phase amplitudes, the value of the resonance peaks, and the eigen propagation frequency, etc. Therefore, impedance spectroscopy has broad application prospects for online diagnosis of aging and deterioration of MV three-core cable.