| With the widely use of the vacuum switch, the re-ignition problem of vacuum switch closing-opening capacitor becomes more critcal This problem has been in the research field since the 90’s, but after more than a decade of efforts, so far capacitor breakdown is still the main flaw of vacuum switch, far below the requirement of capacitor group of low(zero) re-ignition rate, operating mechanism is still unreliable. And this is one of the major problems to be solved in current domestic vacuum switch industry. By analyzing the characters of re-ignition phenomenon of vacuum interrupter, the root cause of vacuum switch closing-opening re-ignition capacitor has been found. Main problem ccomes from the unequal distribution of internal electric field and the vacuum gap breakdown.Based on the development history and current situation of the vacuum switch at home and abroad, referencing the basic design theory and process method of vacuum switch,considering several major problems in current development and research situationgenarate the research content and aim of this article. In this study, according to quality product design process, basic parameters are given for 40.5kV vacuum interrupters, and a simulation analysis optimize the internal key part of 40.5kV vacuum chamber systematically and comprehensively by using electromagnetic theory, finite element method and the optimization theory, With these steps realizes the optimization of vacuum interrupter electric field structure, reduces breakdown weak points, improves the critical electric field of re-ignition. In terms of electric field structure, some geometric parameters of internal parts such as main shielding cylinder, end shield and contact elements are changed to uniform the internal electric field distribution.Capacitor group has a character that it operate closing-opening frequentlywhen the vacuum switch closing-opening capacitor,it reignites several times which caused high amplitude reignite over voltage.Lots of capacitor group damaged, even explosion accidents happen due to unstable quality. Because of the special requirements of capacitor group, 40.5kV level vacuum interrupter closing-opening problem has become the bottleneck of the market application of vacuum switch. This thesis focuses on how to improve the structure design of 40.5kV level vacuum interrupter and optimize the manufacturing process. By analyzing and doing experiments on several aspects such as structure simulation and electric field analysis on vacuum interrupter, selection of key parts material, manufacturing process and process after conditioning processing, find out the key factors of vacuum interrupter closing-opening capacitor and take measures. Design parameters of 40.5kV high-voltage vacuum interrupter and the post-processing technology indicated. Further enhance the vacuum interrupt withstand voltage level, improve the ability of vacuum interrupter closing-opening capacitor, reduce the breakdown probability of vacuum interrupter, eliminate accidents, ensure the safe operation of capacitor group. |
