Abstract: As the essential component of a power electric transformer (PET), the high-voltage, high-frequency transformer has significance for power transmission and electrical isolation. Although high-frequency transformer efficiency increases with frequency, the high-frequency electro-thermal interaction phenomenon causes major insulation issues. Bipolar high-frequency square waves of various frequencies were used to conduct breakdown tests on two distinct types of inter-turn insulation materials. The two-parameter Weibull distribution was used to calculate the insulation breakdown voltage at various frequencies. The inverse power function model was used to derive the voltage life characteristic.