高海拔输电线路走廊空气密度实测

Field Observation of Air Density for Transmission Line Corridors in High-altitude Regions

开展西藏4 300 m以上海拔高度输电线路走廊附近的气温、湿度、气压实测,获得了3个海拔高度、1年以上的实测数据,确定了气温、湿度和气压对高海拔空气密度的影响差异,统计分析了3个典型海拔高度的实测空气密度均值、最大值和最小值,按照3种统计参量分别计算了实测点空气密度相对于空气密度标准值的降低率。3个实测点空气密度降低率大都高于现行规范计算值,即在4 300~4 900 m海拔范围,按现行规范确定的空气密度进行输电线路抗风设计偏于安全。空气密度按照实测最大值考虑时,海拔高于4 300 m地区的基本风压比基于标准空气密度的基本风压至少降低31.7%。研究结果可为高海拔地区输电线路抗风设计和运行维护提供参考和依据。

Field observations of air temperature,relative humidity and atmospheric pressure in high-altitude regions were carried out at the sites near the transmission line corridors in Tibet with an altitude height higher than 4300 m,and the field observation data of three different altitudes with over one year duration were obtained.The impact differences of air temperature,relative humidity and atmospheric pressure on air density in high altitude regions were determined.The mean value,maximum value and minimum value of the observed air density at three typical high-altitude sites were statistically analyzed.Based on three types of statistical parameters,the decrease ratios of the observed air density relative to the standard air density were calculated respectively.The decrease ratios of air density at the three observation sites are basically higher than that proposed in applicable standards,which means that when the altitude heights are in the range of 4300 m to 4900 m,the anti-wind design of transmission lines is on the conservative side if the air density proposed in the applicable standards is adopted.When the observed maximum air density is proposed for design,the basic wind pressure for the regions with the altitude higher than 4300 m will be decreased by at least 31.7%compared to the value determined by standard air density.The results can provide a reference for anti-wind design and maintenance works of transmission lines in high-altitude regions.