| Vacuum switch plays an important role in the distribution system of power transmission and transformation because of its small size,no pollution,long life and so on.With the development of power system and the continuous improvement of voltage level and transmission capacity,higher requirements for the switching performance of vacuum switches are put forward.However,in the vacuum switch,the position of vacuum interrupter is particularly important.Its breaking performance often determines the opening performance of vacuum switch.Therefore,this paper aims at a vacuum interrupter with a new type of magnetically controlled contact system.The electromagnetic field finite element simulation software is used to simulate and analyze the influence of the internal structure changes on the internal electromagnetic field distribution,and the structure optimization is carried out.In this paper,based on the existing product and empirical formula,the specific size parameters of the components in the vacuum arc extinguish chamber of the new type TD-12/3-40 model were calculated.Then,the model of the interrupter was built by using 3D modeling software,and the electric and magnetic fields of the model were analyzed by using the finite element simulation software of electromagnetic field.The internal structure of the interrupter is improved and optimized by synthesizing the simulation results and the actual machining conditions.The three-dimensional model of the vacuum interrupter was simplified into a two-dimensional model,and then the two-dimensional steady-state electric field was analyzed by ANSYS-EMS.Then,the structure of contact edge circle chamfer and shield was optimized.The results show that the electric field distribution with the radius of 4 mm is the best,and the maximum field intensity is small and the distribution is uniform;The edge structure of shield cover adopts the form of inner coil,the radius of edge is 3 mm,the angle of winding angle is 90 °and the total length of shield is 150 mm.The electric field distribution in vacuum arc extinguishing chamber with the above structure parameters is the best.The shielding cover has good voltage equalization effect,uniform electric field distribution and small field strength at the contact gap.The electric breakdown caused by the uneven distribution of the field strength can be avoided and the breaking performance of the vacuum interrupter can be improved.The structure of the vacuum interrupter was simplified,and only the structure of the contact system was retained.The transient magnetic field solver of ANSYS-EMS was used to analyze the magnetic field,and the main structures of contact cups,contact plates and cores were optimized.The results show that the contact cup and the contact plate should have the same slotted structure.Considering the mechanical strength and other factors,the slot number is 6,which can ensure the high value and uniform distribution of the magnetic field.The slotted structure of the contact cup is used to simulate the effect.It is the main part of the magnetic field.Considering the mechanical strength,the slotted width of the contact cup and the contact plate is the same,which is considered as the optimal result of 2mm analysis.The slotted length of the contact plate is 25mm and the slot deflection angle is 25°.The magnetic field distribution field is strong and the distribution is the most uniform.The contact system with iron core structure can effectively bind the magnetic field produced by the current flowing through the contact,so it can be fully used to control the electric arc shape.The magnetic field distribution of the core structure with a circular shape,a diameter of 5 mm and a length of 5mm and a distribution distance of the core 22mm at the peak moment is relatively large and uniform. |
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