摘要
用集总参数RLC电路模型计算大型电力变压器线圈中的特快速暂态电压(VFTO)分布,即使以线匝为单元进行剖分,也不能准确模拟VFTO中的高频分量。分布参数电路模型虽然能够在较宽的频率范围内模拟快速暂态电压分布,但是由于其求解的复杂性,不能用于大型超、特高压变压器整体绕组的建模。为此,提出了一种解决思路:首先改进集总参数电路模型结构,提高其适用频率范围;其次在高频段简化分布参数电路模型,降低其求解的复杂性,使之能够适用于整个大型线圈的建模。基于这种思路形成了频域分段模型,能够比较准确和方便地求解大型变压器线圈中的VFTO分布。在改进集总参数电路模型方面,不是从场的模型出发,来改造传统的电路模型,而是从传输线的数学方程出发,在不明显提高求解复杂性的前提下,推导出一种新型的集总参数电路模型,把集总参数电路模型的适用频率范围提高近1倍。
When the distributions of very fast transient overvoltage （VFTO） in large power transformer windings are calculated using lumped RLC circuit model,the high frequency components of VFTO can not be calculated accurately even when the windings are divided on turn basis. The fast transient voltage distributions can be simulated accurately in a wider frequency range using the MTL model. However,the complexity of the solution for MTL equations limits its use in large power transformer windings. Consequently,we improved the lumped circuit model to a new one with a wider valid frequency range,simplified the MTL model for high frequency modeling,and reduced the complexity of its solution,so that the MTL model could be used for whole winding modeling of large windings. Then we established a piecewise model in frequency domain ,with which the VFTO distribution in large power transformer windings could be calculated more accurately and efficiently. On the part of the new lumped circuit model,rather than deriving the equations in electromagnetic field,we improved the original lumped circuit model from the mathematical equations of MTL model; then without increasing the complexity,the new lumped circuit model was proposed,with a valid frequency range about twice wider than the original one.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2010年第4期918-925,共8页
High Voltage Engineering
基金
国家自然科学基金(50577034)~~
