Research on Power Capacitor Insulation State Detection Based on Polarization Depolarization Current Method

Few effective insulation state detection methods for power capacitor can be used in field. In this paper, a power capacitor insulation state detection method based on polarization-depolarization current is proposed. Firstly, the basic principles of the method are discussed. Then, two characterized parameters are conducted based on polarization and depolarization currents, which are DC conductivity and 0.1Hz dielectric loss. A test device based on this method is developed to evaluate the insulation state of power capacitor with different aging conditions. The test results showed that the polarization and depolarization currents increased along with the aging conditions. The DC conductance and 0.1Hz dielectric loss also increased along with the aging conditions. The test indicated the polarization-depolarization current method is suitable for power capacitor insulation state detection.