Electric Field Computation and Optimization for A 400 kV Y-shaped Composite Cross-arm

A new proposed Y-shaped composite pylon has a potential to become the next new generation $2\times 400\text{kV}$ overhead line transmission tower. However, according to previous work, the electric field magnitudes inside the hollow cross-arm tube exceeds the onset electric field strength of corona, which does not meet the requirements of insulation. In this paper, an electrostatic field model is established by using finite element method analysis. Aiming to previous existing issues, we propose using low density polyethylene (LDPE) as filling material to fill the cross-arm. Meanwhile, the clamps structure is redesigned. Then, the electric field distribution results along the surface of the cross-arm and around the clamps are presented. Furthermore, through the shape optimization, the electric field distribution of clamps and sheds meets the design criteria. Finally, taking advantages of the insulation margin, the conductor enclosure is removed and the height of the clamp is decreased. The final clamp structure meets the insulation requirement.