输电线路塔-线耦联体覆冰不平衡张力特性分析

Analysis of Transmission Line Tower-Line Coupling System’s Load Characteristics Under Ice Coating Conditions

不平衡张力是造成高压架空输电线路事故发生的一个重要原因,为了对比分析在覆冰-风组合工况下,塔-线耦联体系在静态和动态荷载下的不平衡张力响应,以江西某220 kV输电线路为背景,在ANSYS有限元开发环境下,建立三基塔两回线塔-线耦联体系有限元模型。基于Davenport脉动风速功率谱,考虑江西当地气象条件,模拟生成风速时程,在风速时程作用下,分别以风向角、覆冰厚度和风速为变量,对耦联体系进行覆冰-风组合工况下不平衡张力的动力响应分析,并将该结果与静力响应计算结果进行对比。分析发现,动态荷载对于铁塔的不平衡张力具有显著的放大效应,与静态相比最大增幅高达19.3%。这说明现有的设计规范在进行设计时只考虑静态荷载是具有局限性的,其结果偏向保守,有待进一步改进或增加设计裕度。

Unbalanced tension is one of the most important reasons which could cause accidents on the high voltage overhead transmission line.To analyze and compare the unbalanced tension response of the tower-line coupling system under the static and dynamic load on the ice-wind combination condition,based on the background of one typical 220 kV transmission line in Jiangxi province,we establish a system with three towers and two span lines,using the development environment of international finite element method program ANSYS.Based on Davenport pulsating wind power spectrum,considering the local meteorological conditions in Jiangxi,we simulate the wind speed time history.Using the wind angle,the thickness of the ice and the wind speed as the variables,conduct the analysis of imbalance tension's dynamic response under the ice-wind combined condition,and compare the results with the static response.It is found that dynamic load has a significant amplification effect on the unbalanced tension of the tower,with a maximum increase of 19.3%compared with the static load.This indicates that the existing design specification is limited and conservative for only considering static load,which need to be further improved.