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

The authors investigated the characteristics of the electromagnetic spectrum caused by partial discharges (PDs) in air at three different types of high-voltage substations. From the measured results, they characterized the electromagnetic noise spectrum depending on the type of substation. They also measured the long-term change of the average gain of the noise spectrum and discussed the influence of atmospheric conditions on the results. Moreover, they introduced the "equivalent charge (q/sub e/)" which was derived by converting the electric field strength estimated from the average gain into the charge magnitude of PD. They also proposed a "phase gate control method" for better understanding the electromagnetic noise spectrum characteristics and the mechanism causing electromagnetic waves from PDs.