Numerical Research On The Performance Of 12kV Vacuum Interrupter

With the continuous development of Grid industry and the increasing capacity of the power system,vacuum circuit breakers(VCBs)have been widely applied in the field of medium voltage power grids.The development trend of VCBs includes large capacity,frequency diversification,etc.However,the vacuum interrupter(VI)is the central component of the VCB.Its performance always affects the breaking capacity of the vacuum.Therefore,the research on the internal performance of the vacuum interrupter is very crucial.Aiming at the service life and breaking speed of the vacuum switch,this article is proposed for performance research based on the latest research on contact materials,current levels,vacuum arc characteristics,and breaking performance.First of all,based on the basic structure for 12 kV cup-shaped longitudinal magnetic vacuum interrupter measurement,and empirical formula calculation,this article determines dimensions of guide rods,contacts,support plates,shielding covers,bellows and other parts,consult the literature to determine the material of each component,and build a 3D model by Solidworks drawing software.Secondly,the vacuum interrupter of the entire solution domain calculates the threedimensional temperature field by finite element numerical calculation method and Workbench finite element calculation software.Using the eddy current-thermal coupling method,and the controlled variable method,calculate the temperature field of the simplified 12 kV cup-shaped longitudinal magnetic vacuum interrupter.Mainly analyze the contact materials of different frequencies,different compositions and the the temperature distribution under different current,and make a detailed comparative analysis.The analysis shows that the temperature distribution will be as the Cu content in the contact material is higher,the field value will be smaller,and the temperature will be lower;in the two frequency states of 60 Hz and 50 Hz,the temperature will change linearly with the change of frequency;heat will increase significantly with the increase of current amplitude.At last,using longitudinal magnetron technology,introduce a cylindrical conductive bridge as the arc generated in the interruption process of the arc extinguishing chamber.Calculate the three-dimensional magnetic field of the vacuum interrupter by ANSYS finite element analysis software.The three-dimensional magnetic field distribution of the model is obtained when the current is at the peak moment and at the zero crossing,and lag time of residual magnetic field.Analyze the influence of different materials and frequencies on the breaking performance.The analysis shows that the increase of Cu material increases the peak magnetic field is stable at zero crossing and the residual magnetic field is small,which is beneficial to improve the breaking capacity of the arc extinguishing chamber;the magnetic flux generated at 50 Hz is more stable than 60 Hz,the residual magnetic field at zero crossing has a short dissipation time,and the breaking capacity is better.