【作者】 邵淑文；

【导师】 孙鹏；

【作者基本信息】 沈阳工业大学 ， 电机与电器， 2010， 硕士

【摘要】 真空断路器广泛应用于电力系统中,作为真空断路器核心部件的真空灭弧室的极限开断性能,直接影响真空断路器的性能指标。目前应用较广泛的真空灭弧室均采用纵向或横向触头磁场结构,以提高真空断路器的极限分断能力。具有纵向磁场触头结构的真空灭弧室在分断短路电流时,可以使得真空电弧处于其扩散形态的极限电流得以提高,而扩散形态的真空电弧将有利于真空电弧的熄灭,从而有利于提高真空断路器的分断能力。本文提出一种新型不对称式纵向磁场触头结构,该不对称式纵向磁场触头结构与传统的对称式纵向磁场触头结构的显著区别在于:触头系统中的静触头侧设有单极磁场线圈,而动触头侧则没有任何线圈,真空灭弧室断口间的纵向磁场完全是由静触头侧磁场线圈产生的。由于静触头属于静止部件,可以将较复杂的纵向磁场线圈设置于静触头上,而对于在开断过程中运动的动触头,则尽可能简化其结构,降低动触头的质量,提高触头的开断速度。通过采用这种不对称式纵向磁场触头结构,在保证所需的纵向磁场条件下,可以大大提高真空灭弧室触头系统的机械强度,从而有利于提高真空断路器的使用寿命。本文通过三维有限元方法对新型不对称式纵向磁场触头结构进行了仿真分析,并提出了两种提高纵向磁场强度的方案:一种方案是静触头一侧加铁心,另一种方案是采用内外两层平面式串联线圈结构。对上述真空灭弧室纵向触头结构在极限分断电流下的纵向磁场强度及其分布、以及开断电流过零后剩余磁场进行了仿真分析。结果表明,新型不对称式纵向磁场触头结构及其改进的两种结构都具有较强的磁场强度和较均匀的磁场分布,其剩余磁场的滞后时间较小,触头系统的导体电阻可以控制在较小水平范围之内。更多还原

【Abstract】 Vacuum circuit breaker is widely used in electric power system. As a key component of the vacuum circuit breaker, the vacuum interrupter can directly affect performance of the vacuum circuit breaker. Currently, the vacuum interrupters widely used are designed with axial or radial magnetic field structure to improve the breaking capacity of vacuum circuit breaker. When breaking the short-circuit current, electrode structure with axial magnetic field can increase the limits of short circuit current, under which vacuum arc can burn at its diffuse form. The diffuse vacuum arc will contribute to extinguishing the vacuum arc, so that the breaking capacity of vacuum circuit breaker can be improved.In this paper, a novel asymmetric electrode structure for vacuum interrupters that can induce axial magnetic field is presented. The difference between asymmetric and traditional symmetric electrode structure applied to induce axial magnetic field is that the static contact system has a field coil, but the moving contact system has no any coil. The axial magnetic field between the two contacts is generated only by the static contact system. As the static contact system is stationary components, it is allowed the axial magnetic field coil with relatively complex structure to set on the static contact system. However, the structure of the moving contact should be designed as simply as possible, so that the quality of moving contact can be reduced and contact breaking rate can be increased. With the desired axial magnetic field, using this asymmetry axial magnetic field electrode structure can greatly enhance the mechanical strength of the vacuum interrupter contact system, and help to improve the life of vacuum circuit breakers as well.To analyze the characteristics of the novel asymmetric axial magnetic field contact structure, 3-d finite element method has been adopted. Furthermore, two kinds of design options to improve the axial magnetic field strength are proposed: the first option with an iron core in the static contact system and the second one with two section series connecting coil in plane layout. According to above vacuum interrupter contact structure, 3-d simulation of axial magnetic field at limit breaking current and residual magnetic field at breaking current zero have been carried out. The results show that the novel asymmetric axial magnetic field electrode structure and its improvement two structures have strong magnetic field density and uniform magnetic field distribution. The delay time of residual magnetic field is small. The conductor resistance of contact system can be limited in the allowable range.更多还原