| As the key component in vacuum switchgear, vacuum interrupter, with its excellent breaking capability, is widely used in electric power system to break tens of kA short-circuit current that might appear in breaking system. According to vacuum arc theory, the contact structure of vacuum interrupter is changed to produce magnetic field in the open space of the switching house. Hence, the short-circuit current breaking capability in vacuum interrupter can be enhanced.According to the magnetic field produced from different direction, the contact structure is normally classified into perpendicular and axial magnetic field (AMF). The cup-type contact structure of axial magnetic field is popularly used in domestic manufacturers.For AMF contact structure, raising axial magnetic field density is an effective way to raise breaking current density in certain range. Through the research of AMF contact structure, several kinds of improvement are proposed and the improvement effects of AMF density have been analyzed by adopting finite element method with CAE.After fully considering the influence of the vortex and residual AMF, a new cup-type contact structure with AMF has been confirmed. Its magnetic field intensity is much higher than the original structure and there is an obvious improvement along the radial distribution. According to vacuum arc theory, we think the breaking current density could be raised by this new structure.As we know that this new contact structure was first used in current vacuum interrupter in our country, and a series of comparison tests have been performed. The results indicated that the breaking current density using the new cup-type contact structure is much higher than that of original structure. Its breaking capability is similar to the SADE contact structure of Toshiba.The application of new cup-type contact structure will effectively improve breaking capability, and reduce the size of interrupter without influencing other properties and improve its performance. |
PDF Full Text Request