A Contact Design Researh Of Vacuum Interrupters With The Distribution Of Concave Shape Axial Magnetic Field

Vacuum circuit breaker with its excellent breaking capability and characteristics，iswidely used in electric power system.As the key component of vacuum circuit breaker, thevacuum interrupter can directly affect performance of the vacuum circuit breaker. In orderto improve the breaking capacity of the vacuum circuit breaker,therefore, at present themagnetic field technology is widely used in the vacuum interrupter. According to thedifferent types of magnetic field, different forms of contact structure was adopted. For theVacuum circuit breaker used in breaking large current, the vacuum interrupter with axialmagnetic field was widely used. Experiments shows that, except for the magnetic fieldstrength, axial magnetic field distribution will also affect performance of the vacuumcircuit breaker.In this paper, a new coil axial magnetic field electrode structure have been designed.In this contactor structure, the crank of the conducting rod connects the contact blade withtwo parallel coil.The internal and external parallel coil generate magnetic potential inopposite directions. Due to the ipsilateral coils generate magnetic potential in samedirection, therefore, magnetic field intensity strengthened in the area. In the middle of theconducting rod, due to the internal and external coil generate magnetic potential inopposite directions,so the region’s axial magnetic field was weakened.Therefore,thiscontactor structure can generate axial magnetic field with concave shape axial magneticfield strong in edge area and weak in middle area.The vacuum interrupter with thedistribution of concave shape axial magnetic field is with stronger breaking capacity.In this paper,3D finite software ANSYS was used to analyze magnetic1/2turncontact structure, which includes the analysis of steady-state field, harmonic field andtransient field. From above analysis, the new contactor structure can generate axialmagnetic field with concave shape axial magnetic field strong in edge area and weak inmiddle area. Also this paper conducted a fem simulative analysis of1/3turn coil contactstructure, and puts forward the improvement scheme that adds the iron core in the coil. The above magnetic field simulation analysis shows that, the new coil axial magneticfield electrode structure and the coil structure joined with iron core, both have goodmagnetic field distribution and high intensity of magnetic field, and all can produceconcave shape distribution of axial magnetic field, and at the same time, both have a smallmagnetic field lag time and conductive loop resistance.