Investigation On Numerical Simulation Of Electric Field And Optimization Design For Vacuum Interrupters

With the development of the electric power system and the increase of the power capacity, there is a novel development tendency to realize the miniaturization of the vacuum circuit breaker with high capacity and insulation performance. It is very necessity to study the insulation performance based on the numerical analyses of the electric field. Among the numerical simulation methods, the finite element method (FEM) is widely to solve the electric field with complex structure and multi-dielectric medium with high precision. Recently, with the development of the computer technology, the modern optimization strategy has been effectively employed for optimizing the vacuum interrupter (VI).Based on the above analyses, the electric field of medium voltage VI has been numerically simulated using FEM. Moreover, the distribution of electric field for different structures has been obtained. In this thesis, the effect of the structure of the movable and fixed contact on the distribution of the electric field has been studied. And the mechanism of the influence of the floating electrode on the field strength has been investigated. Furthermore the distribution of the electric field along the movable and fixed contact has been obtained and figured out. From the comparison and analyses of the distribution of the electric field in the whole domain, the inverse computation and the optimization of the VI has been performed. By using the zero-rank optimizing method, the comprehensive optimization of the movable contact, the fixed contact and the floating electrode have been realized. In optimizing, the minimum of the electric field strength is considered as the objective function, and the contour of the movable contact, the fixed contact and the floating electrode are regarded as the optimized variable, the maximum iteration times is the stop criteria. The feasibility and validity of the optimized strategy has been verified with the comparison of the optimized results and the actual cases. Besides the numerical simulation, the corresponding tests have been performed, such as, the peak value duration current, short term duration current, dirtiness, mechanical service life, and the temperature rise test. And the theoretical foundation for optimizing and developing the VI has been provided.