导　　师： 彭咏龙;李洪秀

学科专业： 082804

授予学位： 硕士

作　　者： ;

机构地区： 华北电力大学

摘　　要： 电力变压器的抗短路能力是其重要性能之一,直接关系到电网能否可靠运行。 本文从变压器的漏磁场出发,采用有限元和数值分析的方法,以一台油浸式变压器为例论述了漏磁场计算方法。进而分析了短路电流的几种情况,以短路冲击电流、电磁感应和安培力定律为基础,结合实际变压器绕组结构分析了绕组短路力。将其沿坐标方向分解为辐向力和轴向力,并分别对辐向力和轴向力的产生原因做了阐述,并讨论了短路力的时变性和绕组的固有振频的影响,推导出在短路情况下的轴向力、轴向弯曲强度、径向力、径向稳定性等考查变压器抗短路能力的参数计算方法。 运用以上方法对一台已经通过突发短路试验的大型变压器进行建模、剖分和计算。得出了变压器内部漏磁场的分布图和低压、高压、调压磁密值沿绕组的轴向高度的分布曲线以及表征短路力的相关参数的具体数据,并将计算结果与现行国家标准规定的许用值做了比较,验证了计算方法的正确性。通过分析所得的场图,找出了绕组的端部发生弯曲、不平衡安匝以及磁中心不在同一高度等原因产生的漏磁与其所导致的短路力之间的关系。 最后针对变压器生产中经常遇到的两个实际问题,即绕组轴向错位的程度和绕组采用撑条的数量对短路力的影响做了仿真计算,通过对计算结果的后处理得到了绕组轴向错位值、撑条的不同根数和短路力之间的数量关系以及一些可供设计和使用人员参考的结论。 The ability to withstand short circuit of transformer is one of its important characters, having respect to normal work of power system. The dissertation begins with the analysis on leakage magnetic field, then represents a method utilizing Finite Element and Numerical Analysis to calculate leakage field. Then It analyzes several short-circuit currents. Based on short-circuit impulse current, the law of electromagnetic induction and Ampere force law, considering the actual construction winding, it divide the short-circuit force into radial and axial force, and elaborate the cause of the two forces. discuss the influence of the short-circuit force’s time variation and the innate vibration frequency. And some computing methods to calculate axial force, axial bending strength, Radial Force, Radial Stability are deduced. Using the method above, it models and makes subdivision of a transformer which passed a short circuit test, then calculates it. Distribution of leakage field in the transformer and curves of magnetic potential along the axial orientation are obtained. And the calculated value of parameters on short-circuit force are obtained, too. Comparing the calculated value with the standards issued by authority, the paper testifies the method is right. Having analyzed leakage field’s distribution and the curve, it obtains some relationships of the short-circuit force and some factors such as terminal winding’s bending , imbalanced ampere-turn. Finally, the influence on the short-circuit force, produced by degree of windings’axial malposition and the numbers of supporting profiles, is reckoned by simulation. And some helpful conclusions to designers and users are acquired.

关 键 词： 变压器 绕组 漏磁场 短路力 轴向错位

分 类 号： [TM41]

领　　域： [电气工程]