To satisfy the requirements of controlling and protection of modern power grid

it is necessary to develop the fast switchgear switching to be an executive device. Making full use of the advantages of repulsion and permanent magnetic mechanism

we designed a hybrid fast operating mechanism constructed with electromagnetic repulsion and permanent magnetic mechanism.The switching characteristics of fast mechanism were simulated. The mechanical structures of coil skeleton

shell and T-shaped armature were optimized for the mechanism

and the design to avoid closing bounce was conducted. Thereby

the fast mechanism was developed and the strength of vacuum interrupter was promoted. The prototypes of 12/40.5 kV fast vacuum circuit breaker were assembled and the factory performance debugging was carried out.Furthermore

the technical specifications of manufacture were formulated according to the current standard of circuit breaker

and the technical parameters of devices were provided. Two prototypes have passed the performance verification tests including insulation

machinery

temperature rise

short-time current endurance

and breaking and making ability. All results show that the performance parameters of both prototypes meet the requirements of the technical specifications. For 12 kV prototype

its closing time is no more than 10 ms

the opening time is no more than 3 ms and the mechanical life is 5 000. For 40.5 kV prototype

the closing time is no more than 15 ms

the opening time is no more than 5 ms

and the mechanical life is 3 000.