Research On Grounding Characteristics And Resistance Reduction Technology Of Wind Turbine In Mountainous Area

As the main force of ″carbon neutral″ new era,wind energy is gradually increasing the proportion of wind energy in the energy structure in China.Many wind farms are built in mountainous areas with rugged terrain,complex soil structure,high altitude and strong thunderstorm activity.Wind turbines are expensive and easily damaged by lightning.The setting of wind power grounding system is the key to ensure the reliable dispersion of lightning current,which is of great significance to reduce lightning accidents,improve the lightning withstand level of lines,and ensure the safe and stable operation of wind turbines.This paper studies the grounding characteristics and resistance reduction technology of wind turbine in mountainous areas,and the main contents are as follows:(1)Research on resistance reduction of epitaxial auxiliary grounding grid.In this paper,the unidirectional and multidirectional extension auxiliary grounding grid of wind turbine under uniform soil is established.By comparing and analyzing the influence of different epitaxial lead length,different epitaxial lead number and different auxiliary grounding grid forms on grounding resistance of grounding grid,it is found that the resistance reduction efficiency of vertical epitaxial auxiliary grounding grid is the highest,and the resistance reduction efficiency of vertical epitaxial auxiliary grounding grid is5.33% higher than that of square epitaxial auxiliary grounding grid under the action of power frequency grounding current.In order to improve the efficiency of resistance reduction,the length ratio of epitaxial lead and vertical auxiliary grounding grid should be1:2.By comparing unidirectional and multidirectional epitaxial auxiliary grounding grids,it is found that the grounding characteristics of multidirectional epitaxial auxiliary grounding grid are more stable.(2)Considering the complex soil structure in mountainous area,the resistance reduction effect of the extension auxiliary grounding grid is studied.This paper creatively proposes to establish a mountain model with complex soil structure in the simulation software,and use the model to verify the resistance reduction effect of the extended auxiliary grounding grid in the wind turbine.Through the simulation calculation,it is found that for the wind turbines on the hillside and ridge,the multi-directional extension auxiliary grounding grid can make the grounding characteristics of the grounding device better.For the green planting area and rock area,the soil resistivity in the green planting area has the most significant effect on the resistance reduction efficiency of grounding device.Under the action of 100 k Hz earth current,the soil resistivity in the green planting area increased from 500Ω·m to 2000Ω·m.The resistance reduction efficiency of grounding device is increased from 40% to 60%.(3)The paper studies the strategy of resistance reduction of the interconnection of the ground grid of wind turbine.Firstly,the interconnection model of wind turbine is established in uniform soil.Through simulation calculation,it is found that the minimum distance between the two wind turbine units can be interconnected is 300 m.The extension auxiliary grounding network can be added on the basis of the interconnection of the grounding network of wind turbine,which can further improve the grounding characteristics of the grounding device.Then,considering the complex soil structure of mountain,the interconnection model of the wind turbine grounding network of ″ridge ridge″,″ridge hillside″,″hillside hillside″ wind turbine is established.Under the action of10 k Hz earth current,the soil resistivity in green planting area is 2500Ω·m,the drag reduction efficiency of the ″ridge hillside″ interconnection device can reach 89%.Finally,the paper establishes the multi wind turbine grounding network interconnection device in the mountain model.Through simulation,it is found that the resistance reduction efficiency of the grounding device is the highest when the ridge and the hillside wind turbine grounding network are interconnected.It can effectively reduce the wind turbine grounding resistance and improve the grounding characteristics of the grounding device by laying the extension auxiliary grounding grid and the interconnection of the wind turbine grounding grid.The conclusions of this paper can provide a reference for the resistance reduction technology of wind turbines in mountainous areas.