摘要
根据超/特高压交流同塔多回输电线路的导地线型号及绝缘子串参数建立线-串有限元模型,分析了不均匀覆冰随耐张段档数的变化规律,不同挂点高差模式对不均匀覆冰不平衡张力的影响,给出了不均匀覆冰不平张力的分析计算方法。对超/特高压交流同塔多回输电线路导地线挂点不均匀覆冰不平衡张力随覆冰率的变化规律进行分析,给出了定量的计算结果。在此基础上,建立塔-线-串耦合的三维有限元模型,考虑铁塔变形对不均匀覆冰不平衡张力的影响,将计算结果与线-串有限元计算结果进行对比分析。根据有限元分析给出超/特高压交流同塔多回直线塔,导、地线不均匀覆冰不平衡张力百分比取值,一般情况下导线取为10%、地线取为20%,如果从经济性考虑,对同塔不同电压等级可以取不同的不平衡张力百分比,1 000 kV导线取7%,500 kV导线取10%,地线取20%。
Based on the types of conductors and ground wires and the parameters of insulator strings for EHV/UHV AC multi-circuit transmission lines on the same tower, an finite-element model of line-insulation string coupled system is built, and the law of non-uniform ice-coating varying with the number of strain spans in one section as well as the impacts of height difference among different positions, where conductors or ground wires are suspended, on unbalanced tension caused by non-uniform ice-coating are analyzed, and a method to analyze and calculate unbalanced tension caused by non-uniform ice-coating is given. The law of unbalanced tension caused by non-uniform ice-coating at the positions suspending conductors and ground wires for UHV/EHV AC multi-circuit transmission lines on the same tower varying with ice-coating rate is analyzed and quantitative calculation results are given. On this basis, a three-dimensional finite-element model for the coupling among towers, lines and insulator strings is built, and using this model the impact of tower deformation on unbalanced tension caused by non-uniform ice-coating is analyzed, and the contrastive analysis of calculation results by the three-dimensional model with the results calculated by finite-element model of line-insulation string coupled system is performed. Based on finite-element analysis, the selected percentage values of unbalanced tension caused by non-uniform ice-coating for the suspension tower, conductors and ground Wires of UHV/EHV AC multi-circuit transmission lines on the same tower are given, and with regard to general situation the selected percentage value for conductor is 10%, the selected percentage value for ground wire is 20%. When economy is taken into account, different percentage value of unbalanced tension can be selected for conductors and ground wires of the transmission lines belonging to different voltage grades on the same tower： the selected percentage value for conductor belonging to 1 000 kV transmission line is 7%, and the selected percentage value for conductor belonging to 500 kV transmission line is 10% and that for ground wire of 500 kV transmission line is 20%.
出处
《电网技术》
EI
CSCD
北大核心
2011年第12期33-37,共5页
Power System Technology
基金
国家电网公司科技项目(GC71-09-013)~~
关键词
超/特高压交流同塔多回输电线路
不均匀覆冰
覆冰不平衡张力
不平衡张力百分比
有限元模型
UHV/EHV AC multi-circuit transmission lines on the same tower
non-uniform ice-coating
unbalanced tension caused by ice-coating
the percentage of unbalanced tension
finite element models
