Optimization Design And Analysis Of Permanent Magnetic Actuator Used In Vacuum Circuit Breaker

ABSTRACT:Improving the level of intelligent power grid is the requirement for the electric power industry to fit the future sustainable development and actively respond to the challenges of the future. As an important part of smart grid, distribution network is directly connected to the user to distribute power, and closely related to people’s life. As an important equipment of power distribution network, the reliability of circuit breaker directly affects the stability of the distribution network. High reliability, quick action and smaller dispersion is the requirements for the switch in the smart grid. Simple structure, high mechanical reliability, and low power consumption make permanent magnetic actuator (PMA) an important actuator for circuit breaker. Also PMA is easy to control, which helps to achieve intelligent circuit breaker. Using mono-stable permanent magnetic actuator as the research object, in this paper, we’ll find out the ways to optimize the performance of the PMA, and design a new type of PMA, which possesses two moving core. Experiments show that the effect is remarkable.In this artical, the general situation of PMA are introduced, including the process of its development, important products in history, the market situation and the problems in China during its development. Analyze the structure characteristics and working principle of permanent magnetic actuator is studied, and a comparison between bi-PMA and mono-PMA is made. Take mono-PMA as the research object, analyze its static and dynamic characteristic, calculate the characteristic using numerical analysis method and computer simulation technology as the basis of the optimization design later.Saturation of the magnetic circuit has an effect on the characteristic of PMA and is affected by the size of PMA. Then a method is proposed to improve the characteristic of PMA by adjusting the size of PMA. Through the calculation of Ansoft Maxwell and comparison with the original PMA, an optimal size is determined and a new PMA with better performance is obtained.To reduce the energy consumption in an action, a new type of PMA with two moving core is proposed. Compared with original PMA, an auxiliary core is added in the upper part of the single core, which can play a part in the process of closing to make part of the air gap short in the magnetic circuit. So it can reduce the energy consumption in closing, slow down the closing speed in arc extinguish chamber and extend the life of circuit breaker. Then the main parameters in design are discussed in detail. The result shows that the new type of PMA has more excellent characteristic in closing and opening, compared with original PMA. As an actuator with more improvements to be made, the new type of PMA has a certain space to rise.