Topology Optimization of Spatial Distribution of Dielectric Properties in Functionally Graded Cable Joint Insulation

Application of functionally graded material (FGM) has become a promising approach for the electric field optimization in power cable accessories. In this study, we assumed that the silicone rubber sheath of an 110kV cable joint is FGM material with non-uniform permittivity or conductivity. And then we employed topology optimization to design the spatial distribution of dielectric properties in the FGM sheath. The configuration of optimization problem, the modeling method of material distribution, and the principle of the calculation algorithm called method of moving asymptotes (MMA) were described. Simulation results verified that compared to uniform sheath, the FGM sheath in the 110 kV cable joint has much better performance on the inhibition of E-field distortion. Moreover, a larger variation range of dielectric properties induces more uniform E-field distribution, and the spatial distribution of dielectric properties in permittivity FGM (under AC voltage) and conductivity FGM (under DC voltage) shows some similarities to each other. The results indicate that proposed topology optimization method can be successfully applied in the optimization of FGM cable joints, which can promote the design and application of FGM materials in power cable insulations