<p>The end of the stator bar of a high-voltage motor is prone to generating localized high electric fields due to electric field distortion, which triggers corona discharge, causing insulation damage and shortening the life of the motor. The effective countermeasure is to apply a nonlinear corona protection coating on the end, which can adaptively adjust its conductivity according to the change of electric field strength, thus suppressing the surface charge aggregation and achieving the purpose of corona protection. In this study, samples with different doping contents were prepared using silicon carbide (SiC) and boron nitride (BN), and the dispersion was observed by scanning electron microscopy (SEM) to systematically investigate the nonlinear conductivity characteristics of the composites. COMSOL Multiphysics software was used to simulate the electric and temperature field distributions of the stator wire rod. The results show that the addition of BN to SiC/EP composites can improve the thermal conductivity and nonlinear conductivity, and the nonlinear conductivity can reach up to 3.48, and the increase of thermal conductivity can slow down the influence of nonlinear conductivity by temperature. The simulation results show that the peak surface electric field is lowest at 70 phr SiC plus 2 phr BN, and the peak surface temperature is lowest at 4 phr BN, and the improvement of the nonlinear coefficient and thermal conductivity can help to optimize the electric field distribution and reduce the peak temperature.</p>