Static Electric Field Simulation Analysis of ZW20 Type Pole-Mounted Switch Considering the Influence of Temperature Field

The ZW20-type pole switch plays a critical role in controlling and protecting distribution networks. However, partial discharge within the ZW20 pole switch can accelerate its aging and lead to failures. A two-dimensional electric-thermal coupling model of the ZW20 pole switch was developed using ANSYS to investigate the distribution of internal components and the adequacy of insulation strength. Employing finite element principles, we analyzed the internal electric field distribution of the ZW20 pole switch under the influence of temperature gradients. The results revealed that the electric field strength within the switch exceeds $3\times 10^{6}\mathrm{V}/\mathrm{m}$ due to elevated temperatures in the switch's center, weak insulation material, and small air gaps. This increases the likelihood of partial discharge occurring once the internal sealing is compromised. Therefore, optimizing the internal structure and enhancing airtightness are essential steps to ensure the reliable insulation performance of the switch.