Discharge Evolution of Metal Protrusion Defects Observed at High Time Resolution

Metal protrusion discharge is one of the most common types of partial discharges in high-voltage equipment, and understanding the patterns of its discharge evolution is of great value in accurately assessing the severity of the discharges. Traditionally, there are problems such as unclear boundaries for the classification of different stages in the evolution of protrusion defects. The relatively low time resolution of experimental observations makes it difficult to accurately characterize single discharge processes and lacks correlations between multiple physical quantities in the evolution. To this end, an experimental platform for the joint detection of multiphysical quantities with high time resolution is first built, and the current, light, and electromagnetic signals generated in each stage of the discharge process are measured simultaneously. On this basis, the variation patterns and characteristics of the characteristic parameters of multiphysics signals are summarized, and the mapping relationship between the discharge process and the characteristic quantities is established. The corresponding physical explanation and the mechanism analysis are also provided. Finally, 3-D data characteristic values composed of current, light, and electromagnetic are comprehensively constructed to objectively classify the discharge state of protrusion defects into four levels using cluster analysis methods. The results enrich the theoretical study of the development process and evolution mechanism of the discharge and also provide some theoretical basis and scientific reference for the assessment of the severity of the partial discharge by the actual corresponding detection means.