Verification of the detection of partial discharges by microwaves

This paper presents a new method for detecting an occurrence of a partial discharge (PD) due to a material defect in a high-voltage electrical apparatus. This method which is based on the interferometer in the field of astronomy, can detect a source of discharge by using the phase information of electromagnetic waves propagated through space. In the case that the electromagnetic wave due to an internal PD of an electrical power apparatus is to be measured in operation, the signal to noise ratio poses a problem to discuss. The background noise level is normally higher than the signal level of interest, and the signal tends to be lost in the background noise. This paper experimentally shows that our proposed "Spatial Phase Difference Method (SPDM)" is able to be applied to detection of electromagnetic waves caused by PD.