Effect of Thermal Aging on Interturn Insulation Properties of Dry-type Air-core Power Reactors

In order to research the effect of thermal aging on the interturn insulation properties of dry-type air-core power reactors, interturn insulation model samples were designed and the corresponding test platform was set up in this paper. To obtain the function model between the cumulative numbers of overvoltage and the thermal aging degree, the tests which are included in short-term power frequency breakdown voltage, insulation resistance, partial discharge parameters, and withstanding numbers of exponential decay oscillation overvoltage (switching overvoltage) were tested in accordance with the thermal aging degree of interturn insulation model samples. The influence mechanism of thermal aging on the interturn insulation of dry-type air-core power reactors was analyzed, according to the change law of mechanical properties of polyester film, the main material in the interturn insulation, such as the elongation and tensile strength of polyester film.