Steep rise time properties of PD Current Pulse Waveform in gaseous and oil insulations measured with the SHF_PDPW system

Since a number of high-voltage electrical power apparatuses such as GIS, power transformer and so on, it is important for precise evaluation of insulation condition to detect a partial discharge (PD) that could occur as an early signal of insulation degradation or formation of high electric field. From this background, UHF method that measures the PD-emitted electromagnetic (EM) waves with UHF band 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 EM wave. Also, in theory at the far field, the amplitude of EM wave is proportional to the current changing rate di/dt. So far, we have…