中文摘要：

建立了相同型号,不同结构的两种40.5 k V真空灭弧室的轴对称模型。计算并分析了两种真空灭弧室的主屏蔽罩对换前和对换后的电场分布和电势分布,对比了不同主屏蔽罩结构下的触头表面的有效面积,并分析了主屏蔽罩内表面的电场分布曲线。结果表明：型号相同的两个真空灭弧室内部电场分布及电势分布主要受到主屏蔽罩结构的影响,选择合适的主屏蔽罩结构可有效降低最大电场强度并改电场和电势分布。

英文摘要：

The electric potential and field distributions of Type-A and Type-B 40.5 kV vacuum interrupters of the same model but with different axisymmetric structures, before and after exchanging their main-shields, were empirically approximated,mathematically modeled, numerically simulated in finite element method with software ANSYS. The influ- ence of the exchange of the main-shields, on the field distributions on the main-shield surfaces and effective areas of the contact surfaces was investigated. The simulated results show that the geometry of the main-shield has a major impact on the distributions of the electric potential and field. The vacuum interrupter with Type-B main-shield outperforrc~s that with Type-A main-shield. We suggest that design optimization of the main-shield structure may effectively reduce the maximum electric field and improve the potential and field distributions.