UHF PD measurement system with scanning and comparing method

Based on the periodic and repetitive characteristics of partial discharge (PD) under power frequency voltage, an ultra-high-frequency (UHF) PD measurement system using scanning and comparing method is realized without analog to digital (A/D) acquisition. The UHF PD pulses are compared with adjustable reference levels by high-speed comparator, and the number of pulses higher than the reference levels is recorded by a field programmable gate array (FPGA) along with corresponding phase information. The phases, amplitudes and number of discharge pulses can be extracted from the acquired data, which is verified in needle-plate PD experiment result analysis. And PD spectrograms of proposed method proves to be highly correlated with that of pulse current method and conditional UHF method. Influence factors in PD signal acquisition process are also analyzed.