The dynamic characteristic simulation and finite element method analysis of magnetic force actuator for long stroke length high voltage circuit breaker

The mechanism of high voltage circuit breaker required high reliability, recently, requirement for high voltage circuit breaker in phase-control technology need to be high controllability and low mechanical scatter. Traditional permanent magnetic actuator (PMA) and applied high-speed repulsion driver are just propitious to medium voltage and low voltage circuit breaker due to their terribly loss of magnetism on a large stroke length. As for high voltage circuit breaker, overcoming this disadvantage is very important. In this paper, a new type actuator can be applied for long stroke length with precise work performance named magnetic force actuator(MFA) is presented, its structure is simple for the force driving the interrupter work comes from the coil with current in the magnetic field of permanent magnets, which is Ampere's law. MFA not only overcomes the very disadvantage of PMA on long stroke length, but also is beneficial to realize fast-adjust of electrical control, which is a good characteristic for actuators being used in phase-control switching. At first, the static magnetic field and static magnetic force of MFA are analyzed through Ansys to design proper magnetic circuit. Then the state equations describing the dynamic characteristics of MFA is analyzed by adopting four-order Runge-kutta method and finite element method, the details of capacitor voltage, coil current, displacement and velocity of moveable part, coil flux linkage and total magnetic force of MFA in this simulation can estimate the structure design more forward and can be utilized in comprehensive optimization design, several significant structure parameters affecting the dynamic characteristics are showed and some general criteria for optimal design are summarized. Simulation results show its good work performance by comparing the experiment characteristics of practical 40.5kV SF6 circuit breaker. Structure parameters through simulation will conduct MFA prototype manufacture and its relevant experiment investigation.