Simulation and design of 500 kV DC cable terminal accessory based on ZnO varistor microsphere composites

DC transmission has advantages over AC transmission in terms of distance and capacity and has thus received considerable research attention and development. However, the development of high-voltage DC cables is limited by the development of the associated DC cable accessories. In view of the existing problems with DC cable terminal accessories, materials with nonlinear conductivity are being applied to cable terminal accessories. Using finite element simulations, the internal electric field distribution of a DC cable terminal under a thermoelectric coupled field is calculated for different temperature gradients. It is found that cable terminal accessories made of materials with nonlinear conductivity have a stronger electric field grading effect than that of traditional cable terminal accessories. Based on the characteristics of the material with nonlinear conductivity, a simpler cable terminal accessory structure that can achieve the same electric field grading effect is proposed. The results show that the use of a material with nonlinear conductivity facilitates the development of high-voltage DC cable accessories.