Study On Electrodynamic Force Of Oil Damping Circuit Breaker

The electrodynamic repulsion force between the contacts of oil damping circuit breaker is the effect on circuit breaker's working.Under the rated operating current,the electrodynamic repulsion force is so small that it won't affect the work of electrical apparatus.But when the current is too large,the magnetic induction intensity will increase,and the eletrodynamic force may cause the contact system to break and other serious consequences.At the same time,larger force can be helpful for breaking the circuit,and also can be used to improve the breaking capacity of the current limiting circuit breaker.This paper analyzed the electrodynamic force of oil damping circuit breaker based on ANSYS.Firstly,the three-dimensional contact systems model was established in the ANSYS software.And with the electric-magnetic coupling analysis technique,the Holm force between contacts and Lorentz force between two conductor arms at different current conditions were analyzed and simulated.After that the current density distribution,magnetic induction intensity distribution,stress cloud image and vector image were gotten,and the law of the variation of the Holm force with the surface contact coefficient was also obtained.Secondly,using MFC module to edit a Microsoft program,with which can realize the function that invoking the ANSYS software from Visual C++.The simulation of the dynamic process of the contact pressure with the variation of the electrodynamic repulsion force between the contacts was realized.And operations people could use this program to modify data and then the program would run.Finally,the contact systems optimization was completed,which could get larger electrodynamic force value under the same current condition.This optimization helped oil damping circuit breaker mechanisms to break circuit.