电热耦合场分析在±800kV穿墙套管电场分布计算应用

Application of Electrothermal Coupling Field Analysis to Electric Field Distribution Calculation of ±800 kV Wall Bushing

800 kV穿墙套管在特高压直流输电工程中发挥着重要的作用,但在应用有限元分析方法对其进行电场仿真优化设计时,往往忽略穿墙套管实际运行时的温度对电场分布的影响。文中首先建立了±800 k V穿墙套管三维仿真模型,通过仿真计算得到穿墙套管的温度场分布,考虑了实际运行中,套管发热对内部环氧芯体电导率的影响,并在温度场分布的基础上,应用电热耦合场分析计算的方法,获得穿墙套管的电场分布。计算结果表明:正常运行时,穿墙套管载流导杆及卷制管温度呈现中间高两边低的分布规律,靠近导杆的芯体温度高,沿径向方向,芯体温度逐渐降低;同时发现,在恒定电导率条件下,芯体径向电场两边高,中间低,分布均匀,在考虑温度对芯体电导率影响的条件下,芯体电场分布沿径向逐渐升高,分布不均匀。可见,温度对穿墙套管电场分布有显著的影响作用,该研究可为穿墙套管设计与优化时的仿真计算提供校正。

800 kV wall bushing plays an important role in UHVDC transmission project,but when applying the finite element analysis method for its electric field simulation and optimization design,the influence of temperature on electric field distribution of the wall bushing in actual operation is ignored.In this paper,a three-dimensional simulation model of ±800 kV wall bushing is set up firstly,and the temperature field distribution of the wall bushing is obtained through simulation calculation.With consideration of influence of heating of bushing on conductivity of internal epoxy core during the actual operation and on the basis of the temperature field distribution,the electric field distribution of the wall bushing is obtained by applying the method of electrothermal coupling field analysis and calculation.The calculation results show that in case of normal operation the temperature of the current-carrying guide rod and the winding tube of the wall bushing shows a high distribution in the middle and low on both sides,the temperature of the core body near the guide rod is high and the temperature of the core body gradually decreases along the radial direction.It is found at the same time that under the condition of constant conductivity,the radial electric field of the core is high on both sides and low in the middle and the distribution is even.Considering the influence of temperature on the electrical conductivity of the core body,the electric field distribution of the core gradually increases along the radial direction and the distribution is uneven.It can be seen that the temperature has a significant effect on the electric field distribution of the wall bushing.This study can provide corrections for simulation calculations in the design and optimization of wall bushing.