Study of DC corona inception and extinction voltage measurement on electrode surfaces using UV corona monitor

In order to guide the design and improvement of grading and shielding rings to meet the requirements of UHV projects in China, research on corona characteristics of these components is needed. One of the difficulties is that there is a lack of a proper definition of visible corona. It is common using visual observation, which is easily effected by subjectivity and the observation background. In this paper, a new definition of visible corona based on UV Corona Monitor was presented. According to the definition, measurements of the corona inception and extinction voltage on the rob tip in a rob-plate setting under both positive and negative DC voltage were carried out in laboratory. The same measurements on grading rings with different diameters under positive DV voltage were performed in Wuhan High Voltage Research Institute. The results show that the UV Corona Monitor can be used to find out visible corona and obtain the corona inception and extinction voltage.