DOA Estimation of Electromagnetic Wave due to Discharge Phenomena using the Signal Subspace Method

Pulsed electromagnetic waves causing interference may be emitted from power equipment owing to a discharge phenomenon, which may occur at a faulty point, such as an unintended narrow gap between metal supports or a deteriorated insulator. Therefore, it is necessary to localize the electromagnetic source or estimate its direction of arrival (DOA) effectively to reduce maintenance and eliminate its effect on communication systems.There is also a possibility that multiple sources of electromagnetic wave and multiple waves exist in power equipment. In this study, we apply the signal subspace method to the DOA estimation of the electromagnetic wave. The signal subspace method is developed to estimate the DOAs of continuous signal waves. This method can handle multiple waves and is based on the eigenvalue decomposition technique.When electromagnetic waves are emitted from spherical gaps attached to a test transmission line, We can estimate those DOAs within the errors of 2 degrees, and confirm the applicability of the signal subspace method to the DOA estimation of the electromagnetic wave due to the discharge phenomenon.