磁激涌流引起的变压器电动力研究与分析

发布时间：2018-06-26 19:30

本文选题：电力变压器 + 短路强度　；参考：《沈阳工业大学》2017年硕士论文

【摘要】：电力变压器对于每一台输电设备而言都是不可或缺的重要组成部分,电力变压器不仅承担着将其他能量转换成为电能的重任,还需要将电能按照一定的比例进行分配然后输送出去。只有变压器不出故障,才能保证整个电力系统安全可靠地运行。一旦变压器内部电路发生短路,首先要及时保护内部绕组,因为在变压器发生短路时,变压器内部瞬间产生巨大的短路电流会导致绕组损坏,影响变压器的正常运行。变压器线圈机械强度不足,无法承受突发的短路电流的冲击是导致变压器故障的主要原因之一。因此,避免短路故障的发生以及提高变压器内部结构的抗压能力就成为目前一项重要的研究课题。本文以提高变压器中绕组承受短路电流冲击的能力为目的,对不同匝绝缘厚度的组合线、普通换位导线、自粘性换位导线的短路机械力进行了研究与分析。首先分析了变压器线圈短路机械力产生的原因以及表现形式,并基于电磁场相关的理论知识对线圈的轴向短路机械力的大小进行了理论计算。其次,对变压器线圈进行轴向压力实验,模拟变压器在短路工况和激磁涌流工况下线圈的轴向受压状态,由此获得变压器线圈的压缩应力的实验值以及破坏形式。最后通过有限元分析方法,对变压器线圈短路轴向机械力进行仿真分析,得到变压器线圈在轴向受压时受到的最大应力的大小和位置以及变形情况。通过对理论计算、实验数据以及仿真分析的结果进行对比分析,最终总结提出了导线匝绝缘压缩应力的计算方法,引入了一个绝缘厚度系数来保证变压器在短路工况和激磁涌流工况下,线圈在轴向受压状态下导线匝绝缘的安全性。不仅能够有效减少变压器电路故障问题的产生,也能大大提高变压器的抗短路能力,增强变压器运行安全性,降低变压器短路故障所带来的不利影响。
[Abstract]:Power transformer is an indispensable and important part of every transmission equipment. Power transformer not only undertakes the important task of converting other energy into electric energy. There is also a need to distribute electricity in proportion and then transmit it out. Only if the transformer does not fail, can the whole power system run safely and reliably. Once the internal circuit of the transformer is short-circuited, it is necessary to protect the internal winding in time, because when the transformer short-circuit occurs, the huge short-circuit current in the transformer will cause the winding damage and affect the normal operation of the transformer. Insufficient mechanical strength of transformer coil can not withstand the impact of sudden short-circuit current is one of the main causes of transformer failure. Therefore, it is an important research topic to avoid short circuit faults and improve the internal structure of transformer. In order to improve the ability of transformer windings to withstand the impact of short circuit current, the short circuit mechanical force of composite wires with different turns insulation thickness, common transposition conductors and self adhesive transposition conductors are studied and analyzed in this paper. Firstly, the causes and forms of mechanical force of transformer coil short circuit are analyzed, and the magnitude of axial short circuit mechanical force of transformer coil is calculated based on the theory knowledge of electromagnetic field. Secondly, the axial pressure test of transformer coil is carried out to simulate the axial compression state of transformer coil under the condition of short circuit and magnetic inrush, and the experimental value of compression stress and the failure form of transformer coil are obtained. Finally, through the finite element analysis method, the short circuit axial mechanical force of transformer coil is simulated and analyzed, and the maximum stress, position and deformation of transformer coil under axial compression are obtained. Through the comparison and analysis of theoretical calculation, experimental data and simulation results, the calculation method of the insulation compression stress of conductor turns is summarized and put forward. An insulation thickness coefficient is introduced to ensure the safety of the coil under axial compression under the condition of short circuit and excited magnetic inrush. It not only can effectively reduce the problem of transformer circuit fault, but also can greatly improve the ability of transformer to resist short circuit, enhance the safety of transformer operation, and reduce the adverse effect of transformer short circuit fault.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM41

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