Multi-Field Analysis And Optimization Design Of 12KV Vacuum Interrupter

Vacuum circuit breaker occupies a leading position in the field of medium voltage due to the excellent insulation characteristics of its arc extinguishing insulating medium.The vacuum arc extinguishing chamber is its core component,so the technical research and optimization design of vacuum arc extinguishing chamber has become a topic that many researchers are engaged in.This subject takes the optimization and verification of the vacuum arcing chamber model TD-12/3150-40 as the research content.The electric field and potential,static magnetic field and transient magnetic field,and temperature field are calculated respectively,which provides a theoretical basis for improving the working performance of the vacuum arc extinguishing chamber,and is of great significance.The finite element method is mainly used in this paper.Firstly,a two-dimensional model of the 12 k V vacuum arc suppression chamber is established.The electric field and potential are calculated by using the finite element analysis software Maxwell,and the potential and electric field distribution under different opening distances and reverse voltages are calculated.In view of the phenomenon of electric field concentration,part of the structure is optimized.Secondly,a three-dimensional model of the contact structure of the 12 k V vacuum arching chamber is established,and the magnetic field of the contact structure is calculated by using the finite element analysis software Maxwell.In the static magnetic field calculation,the contact structure is compared with the other two kinds of contact structures.In the transient magnetic field calculation,the distribution of the magnetic field at the peak of the alternating current and the zero time is analyzed.Finally,using the thermoelectric coupling method,the eddy current field module in Maxwell 3D and the steady-state thermal analysis module in ANSYS Workbench are used to calculate the temperature field of the contact structure and the conductive rod of the 12 k V vacuum arching chamber.According to the obtained eddy current loss field diagram and temperature distribution field diagram,the conductive rod is optimized and designed.A kind of radiating conductive rod is obtained,and the number and radius of grooves are optimized.The calculation results show that the vacuum arcing chamber potential distribution uniform at work,all the cases of the electric field focus position is consistent,the shield and the static contact spacing of shielded enclosure is 11 mm,main dynamic and static contact end skirt flip Angle 90 ° and 45 ° respectively and action contact blade edge radius of 2.5 mm,outside electric field concentration avoided.Under the static magnetic field,the longitudinal magnetic field generated by the vacuum arching chamber contact structure is more uniform,and the flux density value is larger,which can keep the arc diffusing.Under the transient magnetic field,the longitudinal magnetic field distribution is uniform at the peak current,and the flux density value is larger,while the flux density value of the remaining magnetic field is lower when the current passes zero.When the vacuum arcing chamber is working normally,the temperature at the contact resistance is too high,and the heat dissipating conductive rod can reduce the temperature of the vacuum arcing chamber to the required range.When the number of slots is 28,the heat dissipation effect and the mechanical strength of the structure are the best,and the radius of the conductive rod can also reduce the temperature of the vacuum arcing chamber by increasing to 25 mm.In this paper,the following conclusions are drawn: the potential distribution of TD-12/3150-40 vacuum arcing chamber is uniform,but there is electric field concentration phenomenon in some positions.By optimizing some positions,the electric field concentration phenomenon can be avoided.The longitudinal magnetic field generated by the TD-12/3150-40 vacuum arching chamber contact structure meets the requirements,and the remaining magnetic field is small,that is,this contact structure has excellent breaking ability.When the TD-12/3150-40 vacuum arcing chamber is working normally without radiator and forced air cooling,the loss at the contact resistance between the contact pieces is large and the temperature is too high.The conductive rod is optimized to make it have heat dissipation effect,which can effectively reduce the temperature of the vacuum arcing chamber.