The Research On High Voltage Vacuum Circuit Breaker Based On A Novel Repulsion Actuator

With the expansion of power system and the rapid growth of power network load, short-circuit current is increased year by year, and large short-circuit current has been a serious threat to the safe operation of the power system. Therefore, new requirements are needed on the circuit breaker about how to cut off fault fast and efficiently. In recent years, a novel high-speed repulsion mechanism which is based on the principle of eddy current has causes more and more focus because of its simple features, high speed movement and a very short time to drive the switch.Although repulsion mechanism has advantage of short excitation time and high start speed, it has a short duration of output and an obviously damped output power along with the increase of stroke according to its working principle. The pulsed output characteristic of repulsion mechanism is well matched with the load characteristics of vacuum switch during opening, but it is poor matched with the load characteristics of vacuum switch during closing. It is lack of technical and economical efficiency when repulsion mechanism is used in the closing of vacuum circuit breaker. The traditional magnetic actuator has a good match with the characteristics of vacuum circuit breaker in closing, but it’s not suitable for high-speed opening due to its long starting time. Based on this kind of situation, a novel operating mechanism which has combined the permanent magnet actuator with electromagnetic repulsion mechanism is designed in this thesis. The repulsion mechanism is in charge of driving the rapid opening while the permanent magnet actuator is used for closing and holding force.Firstly the structure scheme of combined operation actuator is designed in this thesis. The simulation and modeling of the new repulsion mechanism is carried out by ANSYS Maxwell electromagnetic field finite element simulation software. On the basis of a stably closing, three key parameters including the coil, voltage of the discharging capacitor, capacitance which affect the quality of the opening time of repulsion mechanism is simulated and improved to find an optimization. Based on finite element analysis and simulation of the actuator and designed of the hardware circuit and the software program, A10KV level prototype was manufactured and tested. The results show that inherent opening time is2ms and opening time is5ms while the voltage of the discharging capacitor is350V, and capacitance is30000uF. The validity of simulation model is verified by experiments.