一种具有1/2匝线圈纵向磁场触头结构的真空灭弧室

【作者】 吴志强；

【导师】 严高师； 陈军平；

【作者基本信息】 电子科技大学 ， 电子与通信工程， 2006， 硕士

【摘要】 在大电流水平下真空电弧的收缩特性取决于触头的材料和工作原理,在真空灭弧室中纵向磁场(AMF)触头能够阻止真空电弧收缩。扩散型电弧对电极的能量作用小,因此,纵向磁场触头提供了开断短路电流的优良性能。根据触头设计的不同,纵向磁场的分布也不同,对于单极触头纵向磁场的方向在整个电极间隙中都是相同的,对于多极触头纵向磁场的方向则是变化的。本文描述了一种新型线圈式两极纵向磁场触头结构真空灭弧室的设计及其特性,该线圈式两极纵向磁场触头不但能够产生很强的纵向磁场,而且较均匀,尤其适用于额定短路开断电流大、额定电流大的真空灭弧室。本文研究了这种新型触头设计的基本工作原理。该触头设计提供了两个纵向磁通量密度分布(数值上)基本相同的区域,也就是说,给出了两个条件相同的触头区域。本文采用积分方法对本文设计的线圈式两极纵向磁场触头结构和线圈式四级纵向磁场触头结构的纵向磁场三维分布进行了计算分析。研究了电弧燃烧期间两种触头结构纵向磁场强度的大小、均匀性,利用有限元法模拟线圈式两极纵向磁场触头结构的触头盘开槽和不开槽时涡流对纵向磁场的影响。分析结果表明,这种线圈式两极纵向磁场触头结构在触头间隙上产生的纵向磁场分布均匀程度较高,强度要比线圈式四极触头结构同等电流下大两倍。触头的有效利用面积,两极结构比四极结构有很大提高。线圈式两极纵向磁场触头结构的触头表面不需开槽仍能大大降低了涡流的影响,因此也减小了电流零点时的残余纵向磁场和纵向磁场滞后时间。采用短路电流合成试验验证了这种触头的开断性能,根据实验后触头表面的烧蚀情况,分析了线圈式两极纵向磁场在大电流时对电弧特性的影响。同时,由于在这种线圈式两极纵向磁场触头在电流过零时剩余磁场几乎为零。触头内各导体距离非常近,且导体内均有电流流过,可采用不加铁芯的方式,因此产生的涡流较小,制造工艺相对较为简单。更多还原

【Abstract】 The constriction performance of vacuum electric arc at high current levels depends on the contact material and its operational principle. Axial magnetic field (AMF) contacts can prevent the vacuum electric arc from shrinking in the vacuum interrupters. AMF contacts can provide an excellent performance of breaking short-circuit current because the diffuse arc has an small effect on the energy of electrodes. According to the different contact design, the distribution of axial magnetic field is different. The direction of the AMF for single-pole contact is the same within the whole inter-electrode gap, and it changes for the multiple-pole contact.A new double-pole axial magnetic field contact design and its characteristics are introduced . The double-pole AMF contact not only can generate very strong AMF but also has better fielduniformity. It is applied to the vacuum interrupter which is in the high rated short-circuit breaking current with the high rated current.The basic operational principle of the new contact design is researched. The contact design provides two areas with nearly the same axial magnetic flux density distribution (by amount), i.e. two areas with equal conditions are given.The integral method is adopted caculate and analyze to AMF three-dimension distruction which is the structure of coil type four-pole and the structure of coil type double-pole and study the size of two kind of electrode structure axial magnetic flux density distribution and its fielduniformity.The Finite-Element method is used simulate that eddy current has effect on AMF when contact tray of douple-pole AMF structure is slotted or no. The analytic result shows the higher fieldunification is produced between contact gap by the coil type double-pole AMF contact structure, and its intension is over 2 times than quadrupolar contact structure when they are in same current. The effective area of two-pole structure is greatly improved to quadrupolar structure. It can still decrease influence of the eddy current greatly while contace surface of coil type double-pole AMF structure is not need to be slotted, so it can also decrease surplus axial magnetic field when the current is at zero and axial magnetic field hysteresis time. Adopting the short circuit electric current of to formate the test prove that this contact turn on and cut off performance. According to ablation situation of contact surface after testing, have analysed that coil type double-pole AMF influences electric arc更多还原