摘要
探究气体绝缘母线在超高压大电流工况下的温升特性对设备的正常运行以及监测维护意义重大。然而,在长期大电流负荷运行下,因接触异常等原因导致母线在较小封闭空间内产生大量热量,极易造成局部过热严重威胁设备安全运行。针对这一问题,本文以550kV气体绝缘母线为研究对象,构建了考虑接触电阻的3维电磁-温度-流体多场耦合模型,计算其在1.1倍额定电流(8800A)、气压0.3MPa条件下的母线温度分布,并搭建了大电流温升试验平台进行验证,试验测量结果与仿真结果吻合度高。基于验证后的可靠模型,进一步探究了通流水平、SF_(6)气压及接触状态对母线温度分布的影响规律。结果表明:母线最高温度位于盆子凹面处电接触部位顶部(约为54℃),该端触头上方SF_(6)温度比导杆上方高近15℃,凹面处触头径向温度梯度明显低于凸面处触头径向温度梯度;在非等温自然对流的情况下,母线温度整体呈径向上高下低、轴向端部高中间低的规律分布;母线温度随通流水平提高呈非线性上升、随SF_(6)气压增大呈近似线性下降,可在一定范围内提高设备绝缘气体压强以降低设备运行温度;异常电接触处温度随阻值增大近似线性增加,而电接触异常往往是母线过热的主要风险点。研究结果可为超高压大电流气体绝缘设备产品设计及状态监测提供参考。
Objective This study focuses on the temperature rise characteristics of ultra-high voltage,high-current gas-insulated busbars.It investigates the temperature and flow rate distribution of the busbar under 1.1 times the rated current(8800 A)and 0.3 MPa gas pressure.Additionally,a highcurrent temperature rise test platform is built to verify the model's validity.Based on this,the study examines the influence of the through-current level,the SF_(6)gas pressure,and the contact state on the temperature distribution of the busbar.Methods In this study,the 550 kV gas-insulated busbar is taken as the research subject.The contact resistance is calculated through direct current(DC)low resistance measurement.Electrical and thermal conductivities are the determined using the resistance formula and the Wiedemann-Franz law.These calculations are incorporated into the development of a three-dimensional electromagnetic-temperature-fluid multi-field coupling model of the busbar.The temperature and flow velocity distribution under 1.1 times the rated current(8800 A)and 0.3 MPa air pressure are calculated,considering factors such as contact resistance,skin effect,natural convection,and thermal radiation.The temperature differences between the busbar conductor,the maximum hot spot,and the shell are analyzed and compared with the temperature difference at the axial section where the basin convex and concave contacts are located.A high-current temperature rise test platform is built to validate the model's results,and the test measurements align closely with the simulation results.Based on the reliable model verified by the test,the influence of the throughcurrent level,SF_(6)air pressure,and contact state on the temperature distribution of the busbar is further investigated.Additonally,a variation diagram showing the maximum hot spot temperature of the busbar with each factor is obtained.Results and Discussions To calculate the bus temperature distribution,it is first necessary to determine its loss size.Considering the skin depth of
作者
侯世英
罗澳
杨帆
王鹏博
权帅峰
孙帅
HOU Shiying;LUO Ao;YANG Fan;WANG Pengbo;QUAN Shuaifeng;SUN Shuai(College of Electrical Eng.,China Chongqing Univ.,Chongqing 400044,China;Xi'an XD Switchgear Electric Co.,Ltd.,Xi'an 710077,China;Guangdong Key Lab.of Electric Power Equipment Reliability,Electric Power Research Inst.of Guangdong Power Grid Co.,Ltd.,Guangzhou 510080,China)
出处
《工程科学与技术》
EI
CAS
CSCD
北大核心
2024年第5期76-85,共10页
Advanced Engineering Sciences
基金
国家重点研发计划项目(2021YFB2401700)。
关键词
气体绝缘母线
多物理场耦合
温升特性
接触电阻
影响因素
gas-insulated busbar
multi-field coupling
temperature rise characteristics
contact resistance
influencing factors
