基于修正热路模型的油浸式变压器绕组热点温度计算研究  

Research of hot spot temperature calculation in oil-immersed transformer based on modified thermal model

作　　者：张晓华 吕志瑞 孙云生 黄彬 王永强[2] ZHANG Xiaohua;LV Zhirui;SUN Yunsheng;HUANG Bin;WANG Yongqiang(State Grid Jibei Electric Power Co.,Ltd.,Beijing 100054,China;Hebei Provincial Key Laboratory of Power Transmission Equipment Security Defense,North China Electric Power University,Baoding 071003,Hebei,China)

机构地区：[1]国网冀北电力有限公司,北京100054 [2]华北电力大学河北省输变电设备安全防御重点实验室,河北保定071003

出　　处：《电测与仪表》2025年第3期78-84,共7页Electrical Measurement & Instrumentation

基　　金：国家重点研发计划项目(2018YFB0904505);国网冀北电力有限公司科技项目(52010119006S)。

摘　　要：油浸式变压器绕组热点温度是影响变压器运行寿命和负载能力的重要因素,与变压器负荷、顶层油温和环境温度密切相关。变压器运行在高温、过负荷时,由于热点温度过高而容易发生变压器故障,影响电力系统的正常运行。为能精确计算变压器绕组热点温度,基于传热学和热电类比理论知识构造了变压器动态热路模型,建立微分方程。考虑到散热片散热系数从里到外不一致的影响,得到变压器有效散热面积,修正了热路模型。并以天威合肥变压器厂的一台180 MVA-220 kV变压器为例,建立该变压器的热路模型计算出绕组的热点温度;同时,建立三维变压器实际模型,基于Fluent仿真软件得到其内部的温度场分布。我们对这台主变进行了变压器绕组温升试验,得到了绕组的热点温度数据,结合现场实测数据对比分析热路模型及IEEE导则推荐模型计算结果,表明热路模型相对IEEE导则推荐模型计算精确度更高,证明了文中方法能更准确地计算油浸式变压器绕组的热点温度。The hottest spot temperature(HST)of windings of oil-immersed transformer is an important factor that affects load capacity and operation life of transformer,and is closely related to the transformer load,top oil and en-vironment temperature.Higher hot spot temperature,when operating at high temperature and overload,may lead to transformer failure,which will affect the normal operation of the power system.In order to accurately calculate the hot spot temperature of transformer winding,we construct the dynamic thermal model of transformer based on the theory of heat transfer and thermal-electrical analogy,and then,built a set of differential equations.By taking the effect of heat transfer coefficient of heat sink is different from inside to outside into consideration,we get the effective cooling area of transformer,and fix the thermal circuit model.Taking a 180 MVA-220 kV transformer of Tianwei transformer factory in Hefei as an example,we establish the thermal circuit model to calculate the hot spot tempera-ture.Meanwhile,we establish a three-dimensional model,and get its internal temperature distribution based on Flu-ent simulation software.Finally,we carry out a temperature rise test on the main transformer of this main transformer winding,and the hot spot temperature data of winding is obtained.Combined with online monitored values,we com-pare and analyze the accuracy of thermal model and the model calculation results recommended by IEEE guidelines.The results show that the thermal circuit model with higher accuracy relative to the IEEE guidelines model,which proves that the fixed model can accurately calculate the hot spot temperature of oil-immersed transformer.

关 键 词：油浸式变压器 顶层油温 热点温度 热模型 散热系数 

分 类 号：TM407[电气工程—电器]