基于能量流向的变压器饼式绕组散热分析及试验研究  

Theoretical Analysis and Experimental Research on Heat Dissipation of Transformer Disk-type Winding Based on Energy Flow

作　　者：李欢[1] 刘云鹏[1] 毕瀚文 李东阳 黎晏霖 范晓舟[1] LI Huan;LIU Yunpeng;BI Hanwen;LI Dongyang;LI Yanlin;FAN Xiaozhou(Hebei Provincial Key Laboratory of Power Transmission Equipment Security Defense(North China Electric Power University),Baoding 071003,Heibei Province,China)

机构地区：[1]河北省输变电设备安全防御重点实验室(华北电力大学),河北省保定市071003

出　　处：《中国电机工程学报》2024年第8期3327-3336,I0033,共11页Proceedings of the CSEE

基　　金：国网浙江省电力有限公司科技项目(5211DS220005)。

摘　　要：变压器热点温度作为运行经济性、安全性的关键指标,是设备在线监测及状态评估中的重点。该文对变压器内部散热进行研究,着眼于饼式绕组及其油道结构,基于能量流向建立绕组温度变化的物理模型。基于这一模型,在一台内置分布式传感光纤的110kV三相ONAN变压器上开展试验研究,使用分布式光纤测温(distributed temperature sensing,DTS)技术对运行状况下的绕组整体温度分布进行实时监测,分析绕组在ONAN冷却方式下的散热状况。在变压器启动初期,绕组各处散热量较低,温升速率较快。约2 h后,各饼散热量基本与损耗相一致,散热率可达98%以上,因此将这一阶段称为准稳态。准稳态阶段,绕组整体散热率基本一致。负载变化前期不同位置散热量的差异是温度梯度形成的主要原因。基于DTS手段及散热器进出口处油温,提出绕组每饼平均对流换热系数的计算方法,基于无量纲数建立绕组内外表面局部对流换热系数的计算方法,对不同位置、负载率下两种对流换热系数的变化规律进行分析获得了绕组运行过程中对流换热系数分布规律及变化趋势。Transformer hot spot temperature,as a key indicator of operating economy and safety,is the main focus in online monitoring and condition assessment of equipment.In this paper,the internal heat dissipation of transformers is investigated,which focuses on the disk-type winding and its oil duct structure.And a physical model of winding temperature variation based on the energy flow direction is established.Based on this model,an experimental study is carried out on a 110 kV three-phase ONAN transformer with built-in distributed sensing fiber.The overall temperature distribution of the winding under operating conditions is monitored in real time using distributed temperature sensing(DTS)technology,and the heat dissipation of the winding under ONAN cooling mode is analyzed.At the beginning of the transformer start-up the heat dissipation in each part of the winding is relatively low and the temperature rise rate is fast.After about 2 hours,the heat dissipation of each disk is basically balanced with the loss,and the heat dissipation ratio can reach more than 98%,corresponding the winding entering quasi-steady state.The overall heat dissipation ratio of the winding is basically the same during the quasi-steady stage.And the difference of heat dissipation in different positions in the load change is the main reason for the formation of temperature gradient.Based on the DTS temperature measurement means and the oil temperature at the inlet and outlet of the radiator,the calculation method of the average convective heat transfer coefficient every disk of the winding is proposed.The calculation method of the local convection heat transfer coefficient on the inner and outer surfaces of the winding is established based on dimensionlessnumbers. The distribution law and variation trend of convectiveheat transfer coefficient during winding operation are obtained.

关 键 词：变压器 饼式绕组 散热分析 对流换热系数 分布式光纤传感 

分 类 号：TM411[电气工程—电器]