Lightning protection characteristics and changes in insulation tube surface of the tube type creeping discharge lightning protection devices

In this paper, the examinations on the electrical characteristics and changes in insulation tube surface of the tube type creeping discharge lightning protection device were operated by large impulse current for many times are presented. A Scanning Electron Microscope (SEM) and an Electron Probe Micro Analyzer (EPMA) were used to analyze the insulation tube of the devices and the surface of the device operated by impulse current was compared with that of virgin device. In addition, the discharge characteristics of the device applied by power-frequency voltage and lightning impulse voltage were examined respectively. The surface of the tube type device changed remarkably by operating many times. On the other hand, the characteristics as lightning protection device before and after operations has not been changed so much.