Consideration of Radiated Electromagnetic Wave from Partial Discharge Based on Half-Wave Dipole Antenna Model

Abstract

Partial discharge (PD) may take place due to residual defects like metallic particles in SF₆ gas insulated power apparatus such as GIS, However, the signal of PD occurring in SF₆ gas is very weak and susceptible to external noises in air. Moreover, because of the complicated mechanism of PD, the radiation property of electromagnetic wave from PD has not been clarified, yet, Therefore, it is hard to distinguish the PD signal in SF₆ gas from the external noises.
From the above points of view, we have been investigating the radiation mechanism of electromagnetic wave from PD. We measured the polarization characteristics of electromagnetic wave radiated from PD in comparison with that of half-wave dipole antennas. The polarization characteristics of PD was explained by the theory of half-wave dipole antenna, rather than that of an infinitesimal dipole antenna. Moreover, we compared the power spectrum received from PD measured by a biconical antenna with that received from the half-wave dipole antenna or infinitesimal dipole. It was found that the power spectrum for PD also corresponded to that for the half-wave dipole antenna with 50cm length.