126kV真空断路器分离磁路式永磁操动机构

A Permanent Magnetic Actuator with Separated Magnetic Circuit for 126kV Vacuum Circuit Breakers

永磁操动机构因其结构简单、可靠性高、操作寿命长、动作分散性小以及与真空断路器配合良好等特点被广泛应用于中低压等级（3.6-40.5kV）的真空断路器中。但由于高电压等级真空断路器触头的运动行程长、分合闸速度高,依靠传统结构形式的永磁机构难适应输电等级（〉72kV）真空断路器高速度要求。因此,本文提出一种适用于126kV真空断路器的新型双稳态轴对称分离磁路永磁机构,将永磁保持部分与电磁操动部分分离,减少两部分磁路在工作时的干扰,进而提高永磁机构的分、合闸速度。同时引入非工作气隙的设计,当保持动铁心离开分合闸位置时永磁力急剧下降,减少了永磁铁在运动过程中对机构运动特性的影响。本文采用有限元软件与多体动力学软件耦合仿真方法对该机构的静态特性及动态特性进行了计算,并根据计算结果制作了样机。样机的实验结果证明该新型永磁机构的速度特性可满足126kV真空断路器的要求,实验结果与仿真结果具有较好的一致性。

Vacuum circuit breakers （VCBs） are extending their applications from medium voltage level of 3.6-40.5kV to transmission voltage level（〉72kV）. Moreover, permanent magnetic actuators （PMAs） have been widely used in medium voltage VCBs due to their high reliability and controllability. However, a conventional bi-stable PMA cannot be adopted in transmission voltage level such as 126kV VCBs directly because of its low velocity characteristic. The objective of this paper is to propose a multi-magnetic circuit PMA to satisfy the high velocity requirements for 126kV VCBs. The proposed PMA offers a bi-stable structure, including holding component and driving component whose magnetic circuits are separated. Air gaps are specifically designed in the magnetic circuits in order to improve the velocity performance of the proposed PMA. Both static and dynamic characteristics of the proposed PMA model have been calculated by a finite element software coupled to a multi-body dynamics software. Furthermore, a prototype of separated magnetic circuit PMA has been developed according to the simulation results. Experimental results on the prototype have shown the velocity characteristics of the proposed PMA are able to meet the operation requirements of a 126kV VCB and agree well with the simulation results.