Ali Kadivar - Department of Transmission Line and Substation Equipment, Niroo Research Institute (NRI), Tehran, Iran

Purpose –Nowadays, in continuously extending power systems all over the world due to increase of short circuit level of the networks, circuit breakers are reaching their physical limitations. In this work, dynamics of a type of Electromagnetic drives known as Thomson drive is simulated. In this opening mechanism of circuit breakers, a high velocity magnetic actuator is utilized. Design/methodology/approach – In this paper, advanced simulation tools based on finite element method (FEM) have been applied for ۳D simulation of imposed current pulses, induced current density as well as electromagnetic force acting on the moving contact of CB. By use of moving mesh method, velocity and acceleration of moving contact have been simulated and compared with experimental results. Findings – Mechanical characteristics like speed and acceleration of contact for fast elongating arcs have been extracted. Simulation results are in good agreement with the experimental observations. Effects of frequency and stored energy on the speed and acceleration of contact have been revealed by simulation and experimental tests. Practical implications – In this study the previously known Thomson coil has been used as an actuator for open-close of power circuit breaker instead of conventional spring mechanism that can be used in future circuit breaker and fault current limiters. Originality/value – Few papers have presented this idea but none of them has interrupted fault current with a constructed circuit breaker. Range of current and voltage which are interrupted here has not presented in previous works with other types of circuit breakers. The finite elements method (FEM) mixed with conventional measurement instruments and study of frequency and energy effects on drive have not been presented before.

Fast opening CB, Thomson electromagnetic drive, Fast elongating arcs, Fault current limiter (FCL), Finite element method ۳D simulation, Moving mesh