Enhanced Heat Dissipation of High Voltage Generator Insulation by Reinforcing the Dielectric Strength of Mica Tape

ABSTRACT High voltage generator is an important component of energy power system. Mica tape, as the main component of generator stator bar insulation, has lower thermal conductivity that limits heat dissipation of generator. As voltage increases, heat dissipation problem caused by thickened insulation becomes prominent. Accumulation of heat inside generator affects its stable operation. In this work, polyimide (PI) film filled with hexagonal boron nitride was selected as dielectric reinforcement layer to prepare PI reinforced mica tape with high dielectric strength. Its dielectric strength reached 62.69 kV/mm when the filling amount of 1–3 μm h‐BN was 15 wt%, and its tensile strength and thermal conductivity maintained well. It was found the application of PI reinforced mica tape to the insulation of stator bar resulted in the insulation thickness reduction from 6 to 3.99 mm and a maximum temperature decrease of 3.84°C on the conductor side of the bar. Internal electric field distribution of mica tape was regulated by PI films and the electron migration in PI film was blocked by the in‐plane orientated h‐BN. PI reinforced mica tape will promote the dissipation in generator and help achieve the development of generator towards higher voltage, larger capacity, and higher power density.