Characteristics of electrical breakdown in composite insulating systems: LN2-solid interface in parallel or series with the field

Breakdown characteristics of a composite insulation system for superconducting equipment consisting of LN2 and polyethylene terephtalate (PET) and glass fiber-reinforced epoxy film (FRP) solid insulators were examined. The insulators which were connected in parallel or series were experimentally studied as a function of presence applied to the LN2. It was found that in the insulation system of the parallel type, breakdown occurs in the LN2 when presence is low or it leads to surface creep when the pressure is high and in insulation systems of the series type, where the thickness of the LN2 layer increased the breakdown voltage decreases and begins to increase after passing a minimum