Analysis of electromagnetic field in vacuum interrupter with longitudinal magnetic field contacts

Contacts of vacuum interrupters have important influence on nominal current carrying capability and short circuit current interrupting capacity of vacuum circuit breakers. The contact with longitudinal magnetic field has the capacity of good open and close short circuit current, this field can reduce loss of radial energy of arc post plasma and make the arc voltage reduce. This paper has studied electromagnetic characteristics of the cup vacuum interrupter with longitudinal magnetic field contacts. The 3D finite integral method was used to simulate the electromagnetic field for 12kV vacuum interrupter contacts. Structural parameters of contact diameters, contact gaps and shield diameters were changed to study the influence of electromagnetic field distribution. The electric field strength, magnetic induction and electromagnetic field distribution were obtained under different structural parameters. The simulation analysis with 3D finite integral method provided accurate data for optimal design og the vacuum interrupter.