High-frequency transformers are the core components of power electronic transformers (PET), whose insulation is deeply threatened by high voltage (HV) and high frequency (HF).The partial discharge (PD) DIGEST-AID test is an effective method to assess an electrical insulation system.A PD measurement platform applying different frequencies was set up in this manuscript.
PD signals were acquired with a high-frequency current transducer (HFCT).For improving the signal-to-noise (SNR) ratio of PD pulses, empirical mode decomposition (EMD) was used to increase the SNR by 4 dB.PD characteristic parameters such as partial discharge inception voltage (PDIV) and PD phase, number, and magnitude were all analyzed as frequency dependent.
High frequency led to high PDIV and a smaller Queen Adjustable Base discharge phase region.PD number and magnitude were first up and then down as the frequency increased.As a result, a suitable frequency for evaluating the insulation of high-frequency transformers is proposed at 8 kHz according to this work.