Electromagnetic noise spectrum caused by partial discharge in air at high voltage substations

We investigated characteristics of electromagnetic spectrum caused by partial discharge (PD) in air at three different types of high voltage substations. From the measured results, we characterized the electromagnetic noise spectrum depending on the type of substation. We also measured long term change of the average gain of noise spectrum and discussed the influence of atmosaheric conditions on the results. Moreover, we introduced "the equivalent charge ye" which was derived by converting the electric field strength estimated from the average gain into the charge magnitude of PD. We also proposed "phase gate control method" for better understanding of the electromagnetic noise spectrum characteristics and the mechanism causing electromagnetic wave by PD.