西藏地区脉动风对高压线路风偏影响研究

Study on Influence of Pulsating Wind on Wind-induced Swing-of High-voltage Lines in Xizang Region

摘要:

为了准确计算出西藏地区脉动风影响下的线路风偏响应，提出一种风荷载计算参数的修正方法。首先，基于西藏浪卡子县1年的实测大风数据，筛选出959个有效样本，并采用Davenport谱的莫宁坐标形式对这些实测数据进行拟合，得到浪卡子测风点的拟合脉动风速功率谱（简称拟合谱）；然后，通过有限元计算，将行业规范计算、Davenport谱和拟合谱的仿真结果进行对比，并对提出的修正方法进行验证。结果表明：浪卡子地区冬季的平均风速高于夏季；西藏地区拟合谱与Davenport谱有一定差别，即无论低频区还是高频区，拟合谱的值总是偏大一些；风谱对线路风偏响应影响显著，而对档距影响较小；引入考虑风谱特性的脉动风荷载修正系数后，行业规范计算的风偏角与拟合谱有限元计算出的风偏角基本相同。因此，西藏地区输电线路的风偏计算应充分考虑高原脉动风的影响，合理地选择脉动风荷载修正系数的值。

Abstract:

In order to accurately calculate the corresponding wind-induced swing response of the line under the influence of pulsating wind in Xizang region, a correction method for the calculation parameters of wind loads is proposed. Firstly, 959 valid samples are selected based on the measured wind data of Langkazi County in Xizang Autonomous Region for one year, and these measured data are fitted using Monin coordinate form of Davenport spectrum to obtain the fitted pulsating wind speed power spectrum (hereinafter referred to as the fitted spectrum) for the Langkazi wind measurement site. Finally, the simulation results of the industry standard calculation, Davenport spectrum and the fitted spectrum are compared through finite element calculation. The results show that the average wind speed in winter is higher than that in summer. The fitted spectrum of pulsating wind in Xizang region exhibits certain deviations from the Davenport spectrum, specifically, the fitted spectrum values are consistently larger in both the low-frequency and high-frequency regions. Wind spectrum has a significant effect on the wind-induced swing response of transmission lines, but a relatively minor influence on the span length. After introducing the pulsating wind load correction coefficient that accounts for wind spectral characteristics, the wind deflection angles calculated by industry standards are essentially consistent with those obtained from finite element analysis using the fitted spectrum. Therefore, wind deflection calculations for transmission lines in Xizang region should fully account for the influence of plateau pulsating wind, and the value of the pulsating wind load correction coefficient should be reasonably selected.