Design of RC circuit as partial discharge detector

Partial discharge (PD) is the main cause of the failure of power apparatus insulation. The detection of PD in the early stage is useful to understand the condition of power apparatus, to design predictive maintenance program, and to prevent the breakdown of power apparatus. PD signal can be detected by the sensor. This paper deals with design of resistor capacitor (RC) circuit as PD detector. The PD detector was tested using a vector network analyzer. The bandwidth, the return loss, and the resonance frequency of the detection circuit were measured. The testing results show that the bandwidth of RC detector achieved 500 MHz. The PD detector was applied to measure PD occurring in the air insulation of needle-plane electrode. The measured PD parameters were PD inception voltage (PDIV), PD waveform PD, PD phase pattern, and PD pulse sequence. The testing results show that PD detector is able to measure PD.