Development of time and Frequency Domain dielectric response testing device for power apparatus insulation

Dielectric response(DR) measurement has been deployed as a non-destructive and potential diagnostic method for moisture or aging condition of power system apparatuses. In order to promote the application of DR method, development of precise, easy-to-use and cost-effective testing devices is an urgent issue, in which accurate acquisition of the insulation current is critical. In this paper, a DR testing device which combine time-domain Polarization and Depolarization Current(PDC) and Frequency-Domain Spectroscopy(FDS), which are two major approaches for DR measurement, is developed. Firstly, the principle of PDC and FDS is introduced. Then the technical specification, hardware and software structure are demonstrated. In addition, using high input impedance PCI data acquisition card, phase lag error of the current measurement module is calibrated by measuring the voltage signal at both the input and the output ends of current measurement module. Finally, PDC and FDS test waveform of XLPE cable and bushing sample are demonstrated, and the effectiveness of this device is proved.