Investigation On Coupled Simulation Method For Numerical Simulation Of Dielectric Recovery Property And Correlative Problems Of SF₆ Circuit Breaker

As a kind of the most important electrical apparatus, high voltage circuit breaker is indispensable in power system. It not only takes switched normal current but also takes breaking fault current of power system in the appointed time. Its interrupting characteristics are the most important and essential technical performance to high voltage SF₆ circuit breaker. The Dielectric Recovery Property of high voltage SF₆ circuit breaker during the course of interrupting is one of very important criterion for measuring its interrupting characteristics. So it is an important content for modern product design of high voltage SF₆ circuit breaker.The numerical simulation of the dielectric recovery property for SF₆ high voltage circuit breaker depends on the output dynamic characteristics of hydraulic actuator, the distribution of flow field, electric field and the transportation of magneto hydrodynamics (MHD) in the arc quenching chamber. The conventional way for numerical simulation of dielectric recovery property is to calculate those three parts separately, then using numerical results to calculate dielectric recovery property. In this dissertation, the output dynamic characteristics of hydraulic actuator, the distribution of the electric field, magnetic field and flow field in the arc quenching chamber are linked through calculating the dielectric recovery strength, the investigations of coupled numerical simulation for dielectric recovery property and correlated problems have been done.In the aspect of investigation for the best match between actuator and arc quenching chamber:The output chatacteristics of pressure reservoir, buffer gear and hydraulic cylinder have been analyzed, the relation between breaking velocity and movable contact position has been researched. The objective function for velocity performance of hydraulic actuator has been established, the output characteristics of hydraulic actuator and the movable contact position have been related, and optimization design for the breaking velocity of SF₆ circuit breaker has been carried out in the dissertation. The more reasonable match between hydraulic actuator and arc quenching chamber has been achived.In the aspect of numerical simulation of no load dielectric recovery property:The mathematics model of mechanical kinetic, electric field and flow field related by the dielectric recovery property was established according to their coupled relations; the coupled method of subdivision grid for electric field and flow field had been investigated, and the same grid for the simulation of electric field and flow field was used during the course of computation dielectric recovery strength. The figure of numerical simulation for dielectric recovery strength was auto displayed after the given data were inputted to the program. The parallel method and the visualized technology have been researched in order to accelerate compute efficiency.Considering the controlling effect of arc nozzle on gas flow property during the breaking process, the influences to dielectric strength recovery properties by contour and dimension of arc nozzle were researched. According to the theory of shock wave, the contour of arc nozzle was also researched by using the shock wave to improve the recovered speed of dielectric strength.In the aspect of numerical simulation of short circuit dielectric recovery property:The arc mathematics model between the interacting electric field and flow field has been put forward, and the mathematics model of mechanism kinetic, electric field and MHD has been set up, then the coupled relation was ascertained. The figure of short circuit numerical simulation for dielectric recover strength was auto displayed after the given data inputted to the program. The influence of arc shape and dielectric recovery property by Lorentz force was analyzed.