基于变压器套管电容芯子温度与tand非线性关系的一种迭代算法

高压套管作为变压器重要的附件,研究套管的温度分布是保证其安全可靠运行的关键。本文以220kV油纸电容式变压器套管为研究对象,基于电容芯子温度与介质损耗因数(tand)的非线性关系提出了一种温度的迭代算法。首先固定tand,计算电容芯子的介质损耗,再与其他热源加载到温度场分析中,得到套管初始的温度分布,根据公式对不同温度对应单元的tand修正,重新计算介质损耗,再求解温度场,直至相邻计算步之间对应节点温度的相对误差小于1%。结果表明在不同环境温度下,采用迭代算法与直接计算的结果进行对比,电容芯子上的最大温差都非常小,在进行套管温度计算时不必考虑温度与tand的非线性关系。研究对于电容式套管温度场的精确计算和tand非线性变化的问题具有一定指导意义。

An Iterative Algorithm Based on the Nonlinear Relationshipbetween Temperature of Capacitor Core and tand in Transformer Bushings

: As an important accessory of transformer, the study of bushing temperature distribution is the key to ensure its safe and reliable operation. This paper takes 220kV oil-paper capacitor bushing as the research object, based on the nonlinear relationship between the temperature of the capacitor core and dielectric loss factor (tand), a iterative algorithm of the temperature is proposed. First, the tand is fixed to calculate the dielectric loss, with which the other heat sources are loaded into the temperature field analysis to obtain the initial temperature distribution of the bushing. According to the formula, the tand is corrected of the corresponding temperature unit to recalculate the dielectric loss. The heat is generated and the temperature field is solved until the relative error of the corresponding node temperature between adjacent calculation steps is less than 1%. The results show that under different ambient temperatures, comparing with the temperature directly calculated, the maximum temperature difference on the capacitor core is very small, which indicating that it is not necessary to consider the nonlinear relationship between temperature and tand. The results are useful for the accurate calculation of the temperature field of the capacitor bushing and the nonlinear variation of the tand.