The Study Of Electro Magnetic Force Driving Actuator Of Circuit Breaker

With the fast development in the electric power systems,it is put forward the higher request to the quality and function of breaker which is the most important control component in transmission and distribution systems.Actuator of circuit breaker is to determine whether the normal circuit breaker a key factor in breaking.On this basis,It is the main research focus of switch profession to put the development of the good and dependable breaker quickly.The key factor affects SF6 circuit breaker reliability is the operation of the actuator's reliability.At present,The spring actuator is adopted by SF6 circuit breakers.The mechanical tripping and locking devices of conventional actuator have been eliminated.As kind of new actuator of circuit breaker,the new operating principle is adopted by Electro Magnetic Force driving Actuator(EMFA).The closed magnetic circuit by permanent magnet is formed and a movable coil between movable core and static core is installed.Lorentz force which can drive circuit breaker to move up and down is produced by the magnetic Field from permanent magnet cutting charged coil.Circuit breaker is held on the position of opening or closing by auxiliary permanent magnet.EMFA has the advantage of less part,higher reliability and no maintenance and so on,so it has been paid more and more attention by people all over the world.In the paper,the mostly work is the study on EMFA of new middle-voltage circuit breaker,its principle,the static force,the dynamic characteristic and the design of control system.This paper presents a geometry modeling of EMFA by using the Maxwell 2D from Ansoft Corporation and 2D and 3D math model associated with geometry model.In the calculation of static magnetic field,the Finite Element Method(FEM) is used by the electromagnetic field analysis software Ansoft.The static hold force of EMFA with exciting current and the lorentz force of the moving part are calculated and analyzed.The dynamic character of EMFA is affected by permanent magnet and exciting current.In this paper,new mathematic model and equation are established.The data of displacement at any time during the opening and closing operation is obtained,providing theoretical basis for design of real model.At last experimental prototype is produced,and a control system is designed.The simple closing and opening circuit are designed by application of power electrical application and the opening and closing operation of EMFA is achieved.The dynamic experiment of experimental prototype is conducted by GKC-C dynamic characteristics of high-pressure switch tester.A number of motion parameters are obtained.The mechanical movement characteristics of EMFA are showed by the experiment.But it needs further perfect work for the design of EMFA.