Dynamic analysis of Thomson coil actuator for fast switch of HVDC circuit breaker

In this paper, the analysis is performed on Thomson coil actuator and the dynamic characteristics is presented, which is necessary to the fast switch of HVDC circuit breaker. For analysis, electromagnetic and dynamic equations are simultaneously solved using commercial code. Whole geometry with a drive coil is simplified and applied to analysis by considering the cylindrical shape of the actuator for simulation. In calculation of current flowing through the coil as the component of electric power circuit for operation of the actuator, the resistance and the inductance are taken into account, including stray component. The calculated current is used to predict the repulsive force on the plate, and the stroke of the actuator is deduced from solving the dynamic equation by considering the forces by spring and the gravity besides friction. Through simulation, dynamic variables are calculated such as inductance of a drive coil, force on a repulsive plate, and so on. Also, flux lines, induced current density, and magnetic flux density are predicted to time. In order to confirm the simulation results, experiments are performed for the prototypes with simple contacts and a vacuum interrupter, which is designed for fast switch. Experimental results are compared with simulation and the characteristics are discussed.