扬沙和沙尘暴电结构机理及其对电设施的影响研究--以兰新铁路第二双线为例

The sand electrical phenomenan always appear with sandstorm or blown sand. It would affect communication qualitity,cause signal interrupt, damage the power line equipment, and even threaten personal safety. This research aims to study the sand and dust movement mechanism affected by electromagnetic force and other regular force, and quantitatively analysis the influence of charged transporting particles. The two phase coupling equation of wind-blown sand movement and its electromagnetic phenomena will be built and sloved. After that, the causes and mechanism of electrical phenomena from blown sand and sandstorm will be studied theoretically and experimentally. Finally, the impacts of different sand/dust weather to electrical equipments will be clearified, and preventive measures to control the damage caused by sandstorm electricity effect will be established.In addition, the Lanzhou-Xinjiang High-speed Railway is scheduled to open, which go through many sandy and gobi deserts as well as several strong windy areas like Anxi, Yandun, Baili and Sanshili. According to the field observation, the maximum wind speed in Baili reaches to 60 m/s. Therefore, sandstorm electricity would endanger railway communication, high-voltage transmission ,railway facilities and the safety of the railway. This project has important theoretical and practical significance to social economic production.

风沙或沙尘暴导致的沙电现象，不仅影响通讯质量，造成信号中断和错误，甚至击穿线路设备，危害人身安全。鉴于此，本项目研究沙尘在电磁力与其它常规力联合作用下的运动机理，对运动带电尘粒介质的电现象所带来的影响进行定量分析，建立并求解具有电磁现象与风沙运动耦合关系的二相流方程，并从理论与实验两方面，探索扬沙/沙尘暴电现象发生的机制及其规律，弄清不同沙尘天气对电设施的影响，寻找解决风沙电现象所造成破坏的防治措施。另外，兰州-新疆铁路第二双线（客运专线）即将启动，线路穿越安西风区、烟墩风区、百里风区和三十里风区，沿线沙漠、戈壁广布。据现场观测，百里风区最大风速达60m/s。为此，伴随铁路开通运行，风沙电必将对铁路通讯、高压输电和铁路设施等造成威胁，影响铁路安全运营。此项研究不仅具有重要的理论意义，也对社会经济生产有积极的实践意义。

本项目利用多梯度风蚀传感器与阶梯式集沙仪对兰新高铁烟墩风区戈壁近地表风沙流跃移质的垂直分布特性进行了观测研究。结果表明，兰新高铁烟墩风区戈壁沙粒发生跃移运动的临界风速达12 m/s（2 m高）；戈壁近地表风沙流有明显的阵性特征，沙粒跃移发生的时间比例在50%以下，与平均风速成正相关关系，与风速脉动强度无显著相关关系；阵风7级风速下（2 m高），戈壁跃移沙粒主要集中于地表50cm范围内，近地表风沙流结构呈“象鼻”，跃移质最大质量通量出现在地表2.5~5cm高度处，沙粒最大跃移高度可达2 m，且沙粒跃移高度随2 m高风速的增加呈指数规律递增。因此，兰新高铁烟墩风区2 m高阻沙栅栏不足以完全阻截戈壁风沙流，是造成烟墩风区兰新高铁轨道积沙的重要原因之一。.在敦煌观测塔的16m、11m、6.6m和1m高度上观测到不同沙尘暴天气过程的电场和风速随时间变化。结果表明，在晴天4个高度上的电场强度均为小正值，电场随高度降低而减小，最大电场强度在5kV/m 以下，日风速变化对各层电场起伏没有较大影响。有沙尘天气，四个高度上的电场强度均随风速变化而变化。16m高度上电场均为负值，平均值为-20 kV/m；中层8m电场强度一般为较高正值， 达到10～40kV/m，与16 m高度上电场呈反相关；下层1m电场值变化一般很小，在1kV/m 以下。在强沙尘暴天气4个高度上的电场均为负电值，电场值随高度降低而减小，16m高度上最大平均电场强度达到-200kV/m以上，瞬时值超过-2500kV/m，与晴天电场矢量相反。