Simulation, VNA Test, and Calibration of Improvement Partial Discharge Detector Using Pi-Attenuator Circuit

A partial discharge is a localized electrical discharge that partially connects conductors’ insulation and could happen near the conductors. IEC-60270 suggests that the direct voltage method can detect partial discharges by utilizing an appropriate impedance circuit, which enhances the transfer of the discharge current when matched to the partial discharge measurement circuit’s impedance. This research simulated and tested circuits using Vector Network Analyzer (VNA) and Partial Discharge (PD) calibrator. The simulation results indicate that the circuit with the most favorable properties has an attenuation value of 1-6 dB. In the experiment section, three detectors were tested, detector A with an attenuation of 3dB, detector B with an attenuation of 4dB, and detector C with an attenuation of 5 dB. The VNA test results show that detector A has a gain of 12dB, the highest among the three detectors. Detector B has a gain of - 13dB, and detector C has a gain of 10dB. An impulse signal with a fixed charge of 100pC, 1nC, and 10nC is given to calibrate the detectors. The calibration results indicate that the voltage measured by each detector differs. Detector A generates the highest voltage, while detector B generates the smallest voltage.