沙区光伏阵列对近地层风沙输移的干扰效应

Interference effect of solar photovoltaic array on near surface aeolian sand transport in sandy areas

沙漠地区建设光伏阵列后,地表吹蚀和堆积过程引起的地貌变化不仅严重威胁到了光伏组件固定结构的稳定,而且间接加速损耗了电板发电功率。为探究沙区光伏阵列扰动下近地层风沙输移特征,在库布齐沙漠中段的200MW光伏电站腹地区域,通过同步测定光伏阵列腹地电板不同部位(板间、板前和板后)和上风向无光伏设施覆盖的流动沙地近地层输沙率,同时利用HOBO小型移动气象站记录观测期风速和风向信息,分析不同风速风向条件下光伏阵列整体阻沙率、局部不同部位风沙流结构及通量模型。结果显示:光伏阵列与风向夹角在–12.30°~82.19°范围内,光伏阵列阻沙率为35.34%~93.02%,当夹角超过45°时,光伏阵列平均阻沙率可达84.63%;随光伏阵列与风向之间夹角增大,板间和板后位置风沙输移高度有向上层移动的趋势,而板前位置则更加贴近地表;双参数指数函数可以较好地模拟光伏阵列内不同部位近地层30cm高度范围内输沙率随高度的变化规律。研究结果有助于认识沙漠地区建设光伏阵列后近地层风沙输移规律,可为科学制定次生风沙危害防治技术方案提供依据与参考。

Deserts are ideal places to develop ground-mounted large-scale solar photovoltaic(PV)power stations.However,it is evitable surface erosion that may occur after the construction of a solar PV power station,where solar energy production,operation,and maintenance depend mainly on geomorphological changes in sandy areas.This study aims to investigate the characteristics of wind-sand movement under the interference of solar PV array,thereby reducing the damage to solar energy.The study area was located in the middle part of the Hobq Desert in China.The observation field was 300 m from the west edge of the test solar PV power station that was built at the end of 2018.There were no any protective measures on the surface of the solar PV power station during the test,such as sand-binding plants or sand-barriers.Field observations were conducted from 20 March to 13 April 2019.The reason was that the aeolian sand activity was the strongest in the study area during from March to May,due to the frequent occurrence of strong wind,extended drought,and limited rain.Thus,wind erosion led to the formation of trenches in the immediate vicinity of the downwind of panels,and sand ripples between adjacent north-south panels.The surface surrounding the test PV panels was smoothened,while the underlying surface was flattened before the experimental instruments were arranged.The flatting operation allowed for the comparison of experimental data.Sediment transport was measured in different wind directions above shifting dunes at three observation sites around the PV panels,such as between,in front of,and behind the panels.Meanwhile,the wind speed and direction were recorded using a HOBO sensor at the observation sites of shifting dunes.The sediment transport data was also collected at sixteen wind regimes.Sand-fixation of solar photovoltaic array,aeolian-sand flow structure and fitted model around the PV panels were then analyzed under the different wind regimes.The results showed that the near-surface sand transport rate above shifting dunes was always larger than that in the solar PV array in all cases,where the intersection angle between the solar PV array and wind direction was a key parameter to dominate the sand inhibition rate of solar PV array.Specifically,the sand inhibition rate ranged from 35.34%to 93.02%at the angle range from-12.30°to 82.19°.The mean value of sand transport rate above the solar PV array reduced to 84.63%,compared with the shifting dunes,especially with the angle exceeding 45°.There was also no change in the sand transport rate model when applying the solar PV array,similar to the shifting dunes.A two-parameter exponential function was better fit for the measured profiles of flux density on the near-surface of solar PV array.Wind-sand flow between and behind the panels tended to evidently move towards a high layer with the angle increased,where the rising range was 8-10 cm,whereas,the saltation height at the observation site before the panels tended to move towards a low layer,where the decrease range was 4-5 cm.The finding can contribute to the understanding of the wind-sand movement characteristics under the interference of solar PV array,providing insightful ideas to plan better technical schemes against wind-sand hazards at solar PV power stations.