In this paper, the magnetic force actuator (MFA), a new type of actuator, is applied for long stroke driving with simple structure and high reliability. Ansys and Matlab are adopted to study its static and dynamic characteristics and conduct parameter design. The static simulation concludes static magnetic field, end shield material, structure size of permanent magnet and processing deviation of the actuator, which will impact the characteristics of the actuator in varying degrees. Then the state equations describing the dynamic characteristics of MFA are solved by four-order Runge-kutta method and finite-element method. Interactive interface of the APDL-file and M-file and Macrosoft Visual Basic (VB) is designed to combine Ansys and Matlab to realize optimization design of structure parameters, which simplifies the operation methods and enhances the efficiency. The dynamic simulation results show its good work performance compared with the experiment characteristics of practical 40.5kV SF6 circuit breaker with the spring mechanism.

High speed mechanical switches are gradually becoming a research hotspot in power systems, for its fast switching speed, large conduction flow and voltage-withstanding. Among them, the core design of the switches focuses on optimal design of the structure of repulsion actuator. Besides traditional factors like coil turns, capacitance, voltage, which affect the output power, the material and structure of coil frame, the enclosure of repulsion mechanism are found to be important factors in this paper. Based on finite element analysis and simulation of repulsion mechanism, a novel prototype was designed, and the simulation results were verified by experiments. Moreover, during opening process of switch, the repulsion mechanism coupled with either assistant spring or assistant opening coil in permanent magnetic actuator (PMA) are compared by experiments. The results show that the switch has smaller opening oscillation and simpler structure through using assistant opening coil. This paper has provided a better guidance for the development of high-speed repulsion mechanism in interrupters.

With the rapid development of domestic economy and the construction, the application of 10 kV power system is more and more extensive and the environment of the application is also more and more complicated. Aiming at this situation, in this paper, a new-type circuit breaker is proposed for the outer environment, which is based on the Water pressure up case configuration. The configuration is fully-enclosed, small size, light-weight, and it is applicable to high temperature and humid areas. In order to study characteristics of the permanent magnetic force (PMA), the paper adopts the electromagnetic analysis software ANSOFT to analyze its static and dynamic characteristics. The experiment results show that the performance of PMA is reliable. In order to analyze the insulting property of its enclosure design with new-style and small size, ANSOFT electric field is adopted to conduct simulation analysis and the experiment results show that the design and improvement measure are stable and reliable.