The Development Of Intelligent Vacuum Circuit Breaker Based On Permanent Magnetic Mechanism

Long life and reliability of the key units in the electrified railway, includingrestraining the over voltage and inrush current by intelligent phase control, is still thefocus of many departments. In this paper we make some in-depth study fromelectrified railway's characteristics, as follows:Firstly, we analyzed the permanent magnetic institution as operating part ofvacuum circuit breaker. It combines the electrified institution and permanent magnetall-rightly and further avoid of negative factor from the mechanic position's trippingand snap close of the closing. There is no need any mechanic power can holdingvacuum circuit breaker's position, and just needs permanent magnetic force. Stabletime and tiny error make it easy to implement intelligent phase control. Through thecalculation and analysis to the permanent electromagnetic field we make newcomputing method in base of permanent magnetic institution's dynamic properties,and make sure it will not demagnetize.Secondly, we study sorts of factors affect vacuum circuit breaker's synchronousclosing. The effect of Vacuum room of putting out arc weld's drubbing to the bankssynchronized energizing get along with the closing rate, to the system of 35 kV and10 kV, there is a critical closing rate, if the closing rate slower than it. When thevacuum circuit breaker close in the zero, Vacuum room's drubbing taking place leadto the closing point departing from the expect point.Thirdly, we study the control scheme of the synchronous closing. There,microcomputer control system continuously adapt voltages, currents, temperaturesand so on, and it compute the zero cross of the voltage when get the close command.Thereby, we get the sending time of control signals.Combining with electrified railway's specifies, we study and develop vacuumcircuit breaker in the basis of intelligent phase control, and adapt permanent magneticmonostability operating institution, in terms of intelligent control technique, selectphase rationally, control closing's angle. It debases the impact of over voltage andinrush current;reduce the protection system's devotion and further enhance system'swhole life.The new kind of vacuum circuit breakers make little volume, long life, lowmaintenance, restraining voltage by selecting phase, and the harms of over current asits basic design regulation, which offer equipments for electrified railway's capacitorrandom compensation, intelligent phase control technique and feedback wire'sprotection.