The world’ s largest multi-terminal flexible DC distribution network project has been successfully put into operation in Tangjiawan

Zhuhai

Guangdong Province.The（±10 kV） three-port hybrid DC circuit breaker is its core protection device.The fast mechanical switch based on electromagnetic repulsion mechanism is the key component of the hybrid DC circuit breaker.The action process of the electromagnetic repulsion mechanism involves coupling of electromagnetic field

temperature field

dynamic field and displacement field

etc.Based on the finite element method

the multi-physical field full-dynamic modeling and simulation of the fast mechanical switch based on the double-coil drive repulsion plate and the bistable spring-holding mechanism are carried out.The influence of different coil turns

opening current and slowing current input time difference on switch motion characteristics is analyzed.The analysis results show that too many turns of repulsive coil are not conducive to the rapid improvement of opening speed

while too few turns of repulsive coil are not conducive to the continuous improvement of opening speed.In a certain range

the greater the difference between opening current and slowing current input time

the shorter the time to reach the opening position

the smaller the speed.The simulation results are compared with the actual prototype during the switching process.By comparing the current and stroke curves of the driving coil obtained

they are in good agreement

which provides a certain simulation method and theoretical reference for the optimal design of such fast mechanical switches.