Application of voltage response measurement on low voltage cables

The application of voltage response measurement is a very effective tool to determine of the aging state of oil-paper insulated cables. The initial slope of the decay voltage is directly proportional to the conductivity of the insulation and the initial slope of the return voltage is proportional to the intensity of polarization processes. Therefore, the two main deterioration processes (moistening and thermal aging) of oil-paper insulation can be examined independently. In this paper, the application of voltage response method is examined on laboratory aged low voltage polymeric (PVC and PE) insulated cables and the results were compared to the results of chemical and breakdown tests. By the using of voltage response method the aging state of the insulation i.e. the probable decrease of dielectric strength can be detected.