Surface Flashover Characteristics of Various Transformer Insulating Strips under AC Voltage

UHVDC transmission projects show a rapid development trend, and the insulation design is a very important part of it. The oil paper insulation structure is the main insulation in the converter transformer, and the surface flashover characteristics of the processed parts of the electrical pressboard machine can reflect the insulation performance, which are the key parameters needed in the insulation design. In this paper, needle electrodes are used as high-voltage electrodes, and surface flashover characteristics tests are carried out along the surface of various types of insulating strips from different manufacturers under the needle-plate electrode model, and the surface flashover voltage test data are obtained for the lateral comparative analyses between insulating strips from different manufacturers and different types of high density electrical pressboard machining parts. From the surface morphology of insulating strips, the reasons for the variability of the surface flashover field strength along the surface are initially discussed.