直流分压器暂态温升及冷却特性研究  

Study on Transient Temperature-rise and Cooling Characteristic of DC Voltage Divider

作　　者：翟少磊 罗奕 段怡 胡珊珊 邓涛 王恩 魏龄 ZHAI Shaolei;LUO Yi;DUAN Yi;HU Shanshan;DENG Tao;WANG En;WEI Ling(Electric Power Research Institute of Yunnan Power Grid Co.,Ltd.,Kunming 650217,China;Electric Power Research Institute,CSG,Guangzhou 510663,China;Yunnan Yundian Tongfang Technology Co.,Ltd.,Kunming 650217,China;Yunnan Electric Power Technology Co.,Ltd.,Kunming 650217,China)

机构地区：[1]云南电网有限责任公司电力科学研究院,昆明650217 [2]南方电网科学研究院有限责任公司,广州510663 [3]云南云电同方科技有限公司,昆明650217 [4]云南电力技术有限责任公司,昆明650217

出　　处：《高压电器》2023年第3期140-149,共10页High Voltage Apparatus

基　　金：国家重点研发计划“政府间跨国合作”项目重点专项(2019YFE0118700);南方电网公司科技项目(ZBKJXM20190054)。

摘　　要：直流分压器在量值溯源、实验室等场合工作时间较短,其暂态温升会导致测量误差。文中分析了绝缘介质为流体的实验室用直流分压器的传热过程,利用电学、热学、流体力学的多场耦合构建了其暂态温升和冷却过程的数学模型,并以500 kV实验室用油绝缘直流分压器为例对其暂态温升及冷却特性进行计算分析。结果表明:变压器油的非等温流动将导致分压器上端温度高于下端,过小的绝缘套管内径使变压器油的非等温流动集中在相邻分压电阻间隔内,导致分压器最大温升、分压电阻上最大温差以及热时间常数均增大。在计算条件下,套管内径较小的直流分压器在额定工况下工作2 h后,分压器表面最高温度高达76.5℃,自然冷却11 h后温度才能降低至60℃。本研究对直流分压器结构设计及实验室应用具有指导意义。The DC voltage divider has a short working time in such occasions as value traceability and laboratory,and its transient temperature rise will cause measurement errors.In this paper,the heat transfer process of the DC voltage divider with fluid as insulation is analyzed,a mathematical model for calculating the transient temperature rise and cooling process is set up by the use of electricity,fluid and fluid mechanics and a 500 kV laboratory oil insulated DC voltage divider is taken as an example to calculate and analyze its transient temperature rise and cooling characteristic.The results show that the non-isothermal flow of transformer oil will cause the temperature at the upper end of voltage divider to be higher than at the lower end.The excessive small inner diameter of insulating bushing makes the non-isothermal flow of transformer oil concentrate in the interval between adjacent divider resistances,which leads to the increase of maximum temperature difference on the voltage divider,maximum temperature rise and thermal time constant of the voltage divider.Under the calculation condition,after a DC voltage divider with a small inner diameter of the bushing operates for 2 hours under rated conditions,the maximum surface temperature of the voltage divider is up to 76.5℃,and the temperature can be reduced to 60℃after 11 hours of natural cooling.This research has guiding significance for the structure design and laboratory application of DC voltage divider.

关 键 词：直流分压器 暂态温升 温度分布 冷却过程 非等温流动 电阻温度系数 

分 类 号：TM721.1[电气工程—电力系统及自动化] TM933.213