Low-cost impedance analyzer and IDC sensors: an imperfect tool for dielectric condition monitoring

Low voltage (LV) cables, like medium or high voltage ones, are prone to ageing. However, as they are usually exposed to lower electrical stresses, they are seldom monitored. In this work, an IDC (Inter-Digital Capacitive) sensor combined with two different commercial impedance analyzers (Hioki IM3570 and AD5940) is evaluated. The sensitivity and the penetration of the electric field are calculated using Comsol Multiphyisics simulations and measurements performed on low voltage PVC cables help comparing the two systems and assessing their performance. It was found that, for low capacitive samples, such as a LV cable’s insulation, the variation found between consecutive measurements is too important to consider the AD5940 as a reliable tool for dielectric condition monitoring.