Study on the Influence Factors and Criteria of PDC Diagnosis Method

When the insulation of 10 kV XLPE cable is diagnosed with polarization and depolarization current measurements, the length of cable has a strong influence on the measured current, which makes it difficult to set the proper measuring range when obtain the current. To solve this problem and design the PDC diagnostic apparatus, this paper built the polarization and depolarization model based on Debye model firstly, then the 10kV XLPE cable samples which were accelerated ageing at a 10 kVrms and 5 kHz ac voltage for 250h and 400h were polarized under -1kV for 1800s and depolarized for 1800s, polarization and depolarization current during this period were measured, lastly, the influence of cable length on polarization and depolarization current were analysed based on the model and experimental…