Research On Nonlinear Vibration Characteristics Of Circuit Breaker Contact System And Parameter Optimization

The vacuum circuit breaker has the function of breaking current and is a very important switching device in the electrical system.The main function in the power grid is to protect equipment and lines.The movable contact and the static contact of the circuit breaker bounce after the collision,and the phenomenon of bounce occurs,which makes the circuit breaker appear abnormal voltage rise exceeding the working voltage during operation,and generates a large current arc,which causes the contact to be burned due to high temperature.In severe cases,fusion welding occurs.Therefore,analyzing the vibration mechanism of the circuit breaker,studying the law of contact bounce during closing,and obtaining a method to effectively reduce and restrain the contact bounce are urgent needs to improve the electrical life and reliability of the circuit breaker.Aiming at the vibration bounce problem of vacuum circuit breaker during the closing process,this paper establishes the vibration mathematical model of the vacuum circuit breaker contact system during the closing process,and uses MATLAB to solve it,and obtains the contact bounce law of the contact,and use genetic algorithm to optimize the relevant parameters of circuit breaker contact bounce.The research results and innovations obtained in this paper are as follows:(1)Using the segmented idea,the single-degree-of-freedom vibration differential equations were established for the contact before and after the collision,and the tie rod force and the static and dynamic contact collision contact force were considered at the same time,and the equations were solved to obtain the factors that affect the contact bounce.Reveals the bounce law of the contacts.(2)The improved genetic algorithm is introduced into the optimization of the contact bounce process.The mass of the moving contact,the displacement of the moving contact,the stiffness coefficient of the contact spring,and the equivalent damping of the contact system are used as optimization variables.The head closing time is taken as the optimization target.After optimization,the time required for closing and the total bounce time are greatly shortened,and the contact bounce time and maximum amplitude are reduced.(3)Use ADAMS dynamic analysis software to simulate and analyze the closing mechanism of the operating mechanism,and obtain the tie rod force curve,and apply the improved genetic algorithm to the tie rod force optimization.The time for the optimized tie rod force to reach the maximum value is shorter than that before the optimization.Which reduces the contact closing time to a certain extent.(4)Perform simulation analysis on the overall closing process,and the circuit breaker dynamic characteristic tester was used to conduct experiments on the contact closing process of the circuit breaker.The difference between the experimental data and the theoretical data of the total contact bounce time and the closing time of the circuit breaker was within 5%.