A new electro magnetic force actuator for 126kV vacuum circuit breaker

As a new actuator driven by Ampere force, Electro Magnetic Force driving Actuator (EMFA) is applicable to medium-high-voltage system with powerful output force, long stoke, simple structure and high reliability. In the paper, a new type of EMFA for 126kV VCB with single break is proposed on the basis of the mature manufacturing technology of 126kV vacuum interrupter. The model of EMFA is established by the simulation software Maxwell, and the structure including arrangement of permanent magnets and air-gap of end caps is then designed and optimized. In order to meet the breaking demand of 126kV VCB, the opening speed at the separating instant of contact is effectively improved by increasing the closing force. The dynamic characteristics of EMFA are further enhanced by optimizing the electrical parameters such as driving coil turns, pre-charged capacitance and initial charging voltage. According to the simulation results, the prototype of EMFA is manufactured and tested. Experimental results on the prototype have shown the motion characteristics of the proposed EMFA (opening speed at the separating instant of contact above 3m/s) are able to satisfy the breaking requirements of 126kV VCB and agree well with the simulation results.