Simulation Research on the Application of Nonlinear Conductivity Material in 110kV Cable Terminal with Electro-thermal Coupling Model

Prefabricated rubber stress cone is the key part of the high-voltage cable terminal. Material with nonlinear conductivity can smartly smooth the non-uniform electrical field of the stress cone. Reasonable selection of the nonlinear coefficient is critical for determining the applicability of the nonlinear materials. The effects of nonlinear composite with different nonlinear coefficient on field grading effect, power loss and temperature distribution are simulated by establishing finite element numerical model of the 110kV AC cable terminal. The results indicate that with the increase of nonlinear coefficient, the electric field strength of the stress cone surface gradually decreases while that of the three-phase junction gradually increases. Although the power loss of the stress cone insulation increases, the resulting temperature rise is minimal. Considering field grading effect, the power loss and temperature rise, for 110kV AC cable terminal, nonlinear material with threshold electric field of 0.8MV/m and nonlinear coefficient of 7.5-11.5 is more suitable for operation environment.