Research Of Closing And Opening Bounce Of Dc Breaker In Short-circuit Condition

As one of the most important switching devices in the power system,the circuit breaker not only can close,carry and break the normal running current,but also can close,carry and disconnect the specified overload current(including short-circuit current)within a specified time.The contact bounce is the unavoidable phenomenon during the closing and opening operation.The contact bounce will reduce the breaker's life,affect the performance and reduce the reliability.Through the study of contact bounce in short-current condition,the actual working conditions of circuit can be known more accurately.And it has great significance to improve the performance and reliability of the circuit breaker.In this paper,the Ansoft software is used to analyze the force of the moving iron core in rated voltage,the Lorentz Force and Holm Force of moving contact in short-circuit load.The three-variable function of force-current-angular displacement is obtained.The virtual prototype of ZDS4 DC breaker is built by ADAMS;the closing and opening contact bounce characteristics with on load is obtained by co-simulation of ADAMS and Ansoft;various bounce influencing factors were calculated;and the simulation results are verified by high-speed camera.The short-circuit opening current is obtained by using PSCAD,The closing and opening contact bounce simulation result is also obtained by combine the current curve.The conclusion is obtained by comparison with on load: In the current peak of 30 kA,time constant of 15 ms short-circuit condition,the closing contact bounce characteristics in short-circuit load are almost the same as in the condition of no load,but the opening bounce height in short-circuit is higher,and it will increase the risk of arc-voltage drop and arc re-strike.And the simulation results are also verified by experiments.