Development of an electromagnetic repulsion mechanism for a 40.5kV fast vacuum circuit breaker

Researches on electromagnetic repulsion mechanisms are drawing more and more attention globally. The objective of this paper is to develop an electromagnetic repulsion mechanism for a 40.5 kV vacuum circuit breaker and then to make an optimization. Design of experiments (DOE) method are used to screen the prominent factors. Result shows that three impact factors are the prominent factors, which include the number of coil turns (N), the capacitance of energy-storage capacitor(C), and the charging voltage (U). The other impact factors include: the height of the coil (H), the inner radius (r) and the outer radius (R) of the coil, the thickness (T) and the diameter (D) of the metal plate, and the initial air gap (δ) between the coil and the metal plate. The effect of these nine investigated factors on the performance of the electromagnetic repulsion mechanism is ranked as: C > N > U > H > D > δ > T > R > r. Considering the requirements of dynamic characteristics and cost, an optimum objective is achieved by minimizing the energy stored in capacitor. The optimized parameters of the electromagnetic repulsion mechanism are with the charging voltage of 650 V, the capacitance of energy-storage capacitor of 15 mF and coil turns of 15. The optimized electromagnetic repulsion mechanism is demonstrated for a prototype of 40.5 kV vacuum circuit breaker.