Influence of inorganic nano-filler to partial discharge of polyimide film under high-frequency impulses

Presently, polyimide film is applied widely in turn-to turn insulation and turn to ground insulation of inverter-fed traction motors as one kind of special project plastic film. In this paper, the measurement of partial discharge is done on nanometer hybrid polyimide film and non nanometer polyimide film with different frequency and different rise time under high-frequency square impulse. Some parameters of PD are discussed based on measurement results. The results showed: gap surface conductivity have greater impact on PD, the main impact of rise time on PD parameters mainly depends on the initial electron delay and the gap dynamic electric field, the interfaces formatted by inorganic nano-filler filling improved the conductivity of the material, the movement of charge along the gap surface become much easier, while nano-materials exist large quantities of shallow traps, so that the PD initial electronic selection engender easily.