In order to improve the insulation diagnosis of C-GIS, we developed the four-terminal surface current sensor and the method to estimate an occurrence direction of partial discharges. In this method, the accuracy of the direction estimation is improved by referring only the direct wave, and the error caused by noise can be suppressed by calculating the outputs of four terminals. As the experimental result, it was confirmed that the detection characteristics of the sensor agreed well with the theoretical ones derived from the detection principle. Using the sensor and method, we have conducted the experiment to detect the surface current generated by PD occurred in a rectangular enclosure. As a result, it was confirmed that the occurrence direction could be estimated even for a rectangular enclosure. It was also found that the propagation attenuation of the surface current at the corners of the enclosure is large, and thus the installation position of the sensor needs to be optimized.
J-STAGEがリニューアルされました！https://www.jstage.jst.go.jp/browse/-char/ja/
