摘要
壁面对流换热系数是影响干式变压器换热分析和温度场计算结果准确与否的关键因素,但其值很难精确测量。为了更准确地计算壁面对流换热系数,提出了一种基于FEM的干式变压器流固耦合数学分析模型,同时采用Fluent对干变的3D温度场和流体场进行了仿真计算,分析了干变内部温度场的分布情况,并与解析结果进行了比较。在此基础上,分析了谐波、负载系数对干变谐波损耗及温升的影响,得到谐波损耗及温升与谐波次数、负载系数的关系。结果表明,考虑空气流场的流固耦合模型能准确分析变压器运行中的温升问题,同时指出干变谐波损耗和温升随谐波次数的增加而增大,并逐渐趋于平缓,且随负载系数的增大而急剧增大。这为变压器的定点监测提供了参考依据,有助于减少变压器的损耗,延长使用寿命,保证变压器的安全稳定运行。
The analysis of the convection heat transfer and the calculation of coal dry-type transformers＇ temperature filed are greatly affected by the convection heat transfer coefficient, which is difficult to be measured accurately. In order to get convection heat transfer coefficient more precisely, the mathematical model of fluid-solid coupling field of the dry-type transformer was proposed based on FEM. Then the three-dimensional temperature field and airflow field were simulated by using the finite element software Fluent. Consequently, the temperature distribution of transformer was derived. Finally, the influences of harmonic and load coefficient on loss and temperature rise were analyzed. The relationships between the harmonic loss and temperature rise and the order of harmonic, as well as load coefficient, were gained. In comparison with the analytical results, we have verified that the distribution of the temperature filed can be analyzed more precisely by fluid-solid coupling model considering the existence of air flow. Meanwhile, the transformers＇ harmonic loss and tem- perature rise will increase, and gradually tend to flatten out as the the order of harmonic increases, while they dramatically rise as the load coefficient increases. Therefore, the results can provide a practical reference for establishing effective monitoring on dry-type transformers, so as to reduce the loss, prolong the life, and guarantee safe and stable operation of transformer.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2016年第12期3972-3981,共10页
High Voltage Engineering
基金
国家自然科学基金(51377113
61472271)
山西省科技厅重大专项(20131101029)~~
关键词
矿用干式变压器
流固耦合分析
漏磁场分析
谐波损耗
温度场分析
负载系数
coal dry-type transformers
fluid-solid analysis
leakage magnetic field analysis
harmonic loss
temperature field analysis
load coefficient
