Research On Improved Electrical Geometry Model Of Wind Turbine Blades Based On Lightning Physics

Wind power lies at the core of global efforts to address concerns regarding anthropogenic climate change,and to embrace a move toward a cleaner,more sustainable energy society.However,the structure and the surrounding environment of wind turbines make them extremely susceptible to atmospheric lightning.In fact,turbine blade damage accounts for greater than 40%of all lightning damage suffered by wind farms,and most blade damage is irreparable.As such,the blade damage caused by lightning strikes seriously affects the economic performance of wind farms because of the high cost of repairing or replacing damaged blades.Therefore,it is necessary to develop an effective method to estimate the lightning protection efficiency of turbines.In this paper,the lightning protection efficiency of turbine blade lightning protection system is analyzed by combining the physical mechanisms of the downward leader and upward leader progression of lightning with a conventional electro-geometric model(EGM)to develop an electro-geometric model of turbine blades(EGMTB).The concept of dynamic striking distance is introduced and clarifies the physical meaning of striking distance.The new dynamic distance analysis method can be used not only for the research of lightning protection of wind turbines,but also for the lightning protection of complex ground objects.The calculation method of blade lightning protection system efficiency is deduced based on the EGMTB,and it is used to analyze the influence factors.It is indicated that the efficiency of blade lightning protection system reduces with the decrease of lightning current and the angle between the blade and horizontal,and the efficiency of blade lightning protection system can be improved by increasing the side-body receptors.Then,the effectiveness of the EGMTB is validated by the long gap breakdown experiment of blades.The new method is intended to provide a theory for lightning protection design and evaluation of wind turbine blades.In order to reduce the probability of lightning accidents on large-scale wind farms,a new electro-geometric model for multiple turbines is further proposed based on the EGMTB.In this new model,the lightning shielding amongst multiple turbines is provided,and a criterion formula is obtained for mutual shielding for multiple turbines.The Influence of environmental factors,such as temperature,atmospheric pressure,air humidity,and altitude,on lightning shielding on large-scale wind farms is also analyzed by studying the lightning shielding distance between wind turbines.The calculation shows that the larger the relative air density and the absolute humidity,and the lower the altitude,and the larger the lightning shielding distance between wind turbines.The EGM of lightning shielding between multiple wind turbines provides a new reference for the spatial optimization of large-scale wind farms.The study of this paper meets the urgent technological requirements to develop wind turbines,the achievements of which will enrich the theoretical foundation,analytical methodology and innovative technology for lightning protection of wind farms,with both theoretical significance and application potentials.