Polyimide film is applied widely in turn to turn insulation and turn to ground insulation of inverter-fed traction motors.In this paper

measurement of partial discharge is performed on nanometer hybrid polyimide film and non nanometer polyimide film under high-frequency square impulse with different frequency and different rise time.Some parameters of PD are discussed based on the measurement resuhs.The results show that the gap surface conductivity has a great impact on PD

the impact of rise time on PD parameters mainly depends on the initial electron delay and the dynamic electric field in the gap

the large number of interfaces formed by inorganic nano-filler improve the conductivity of the material to facilitate the movement of charge along the gap surface

and PD initial electrons generate more easily due to the existence of sufficient shallow traps in the nano-materials.