Research Of Novel Permanent Magnet Actuator For 126kV Vacuum Circuit Breaker

With the wide application of permanent magnetic actuator(PMA)in medium voltage vacuum circuit breaker(VCB),its advantages of simple structure and reliable operation have been explored.The deep research on the design and analysis method of PMA for high-voltage VCB and its control technology has a direct promoting role in its application in high voltage vacuum circuit breaker.This thesis deeply studied PMA for 126kV VCB,and presented two PMAs with sectional load and sectional drive respectively.By using the finite element simulation software,this thesis calculated and analyzed their static and dynamic characteristics detailedly,and optimized design scheme from load force,driving force,coil parameters and other aspects of the actuator to make their design parameters more reasonable.First of all,this thesis analyzed the structure and working principle of the above two kinds of PMAs.Taking the calculation of the brake spring as the starting point,the thesis introduced the design method of the PMA with sectional load,and preliminary designed the structure size and coil parameters of two PMAs.Then,a permanent magnet keeper for PMA was parametrically modeled by Ansoft Maxwell.The thesis obtained the change rules of the permanent magnetic holding force with the iron core thickness,permanent magnet size and its position by parameterized calculation.Based on these rules,the sizes of the actuators were optimized,and then the static magnetic fields of two kinds of PMAs were analyzed.Next,this thesis studied deeply the dynamic characteristics of combining-brake-spring PMA based on the changes of load force.The optimal design according to the number of turns,coil diameter and conduction time was carried out to obtain the optimal coil parameters.Finally,a simulation method of electromagnetic force fitting substitution was presented for the PMA with sectional drive,and its dynamic characteristics were analyzed in detail.Besides,the influence of the coupling between the closing and the opening coil on the dynamic characteristics of the PMA was also investigated.