Super High Frequency Components of Partial Discharge Current Pulse Waveforms and the Emitted Electromagnetic Waves measured with the SHF_PDPW System

Summary

UHF method that measures the PD-emitted electromagnetic (EM) waves with UHF (ultra high frequency) band (300 MHz-3 GHz) components is focused on as an insulation diagnosis technique of high-voltage electrical power apparatus. To sophisticate the UHF method, accurate measurement of PD current pulse is quite important because the PD current pulse is a radiation source of the PD-emitted EM wave. So far, we have developed the SHF_PDPW (Super High Frequency wideband PD current Pulse Waveform measurement) system that enables us to obtain accurately waveforms up to the SHF band (3-30 GHz). Using this system, we have investigated PD current pulse waveforms of typical insulation media such as insulation oil and SF6 gas. As for the SF6 gas, we showed that the PD current pulse waveform had the very steep rise with a few tens pico seconds in rise time. This result suggested that PD current pulse waveform of the SF6 gas has a high frequency component. In this study, we focused on gaseous dielectrics such as SF6, dry air, N2, CO2 and CF4, and investigated PD current pulse waveforms of these gases measured with the SHF_PDPW system whose measurement frequency bandwidth fBW was 20 GHz. We simultaneously measured the PD current pulse waveforms and the PD-emitted EM waves with a Horn antenna. We discussed the frequency components of the PD current pulse and the PD-emitted EM waveforms as well as those relationships by using FFT (fast Fourier transform) and the low-pass filtering processing.

Additional informations

Authors

Wan Fu, Xiong Youhui, Chen Weigen, Kobayashi Kinya