The influence of repetitive square wave voltage parameters on PD statistical features

Abstract

According to International Electrotechnical Commission technical specification, repetitive square wave voltage (RSWV) should be used to do partial discharge (PD) measurements on low-voltage random wound inverter-fed motors. The repetitive partial discharge inception voltage (RPDIV) is used to evaluate the insulation reliability. Therefore, knowing the influence of RSWV waveform parameters on PD statistical features becomes important to obtain meaningful PDIV results by i) increasing the signal-to-noise ratio (SNR) as much as possible and design high performance ultra-high frequency (UHF) sensors according to the frequency features of PD events ii) choosing power generators with suitable waveform parameters which can easily excite the PD events and thus, find the weak points inside the insulation systems. We have been focusing on the investigation of the influence of RSWV waveform on PD features using single point contact crossed wires insulated by polyamide-imide enamel. Based on PD tests performed at different impulse voltage conditions, the influence of impulse waveform parameters, i.e. rise time, frequency, duty cycle, on PD statistical features is summarized in this study. Accordingly, the factors needed carefully considered when performing PDIV measurements on inverter-fed motor insulation systems are discussed.