Triggered Lightning Ability Assessment Of Wind Turbine Blades Based On Lightning Leader Theoryand Research On Wind Turbine Lightning Protection Spacing

As a clean form of renewable energy power generation,wind power plays an active role in adjusting energy structure,improving energy and environmental issues,and promoting the green and harmonious development of modern society.In recent years,with the rapid development of wind power generation,the capacity of wind turbine is increasing.The rise of wind turbine capacity leads to a significant increase in wind turbine tower height,wind turbine blades length and overall size of wind turbine.Combined with the fact that majority wind farms are located in open space,the lightning damage problem to wind turbines is becoming increasingly prominent.The frequent occurrence of this problem will seriously threaten secure and stable operation of wind farms,increase maintenance cost of wind farms,and then inhibit the sustainable development of wind power related industries.In order to improve adverse effects caused by wind turbines lightning damage problem,strengthen lightning protection performance of wind turbines and wind farms,based on lightning leader theory of wind turbine,blades triggered lightning ability,and optimal arrangement of wind turbines considering lightning protection,this paper explores and studies the physical process of lightning stroke wind turbine,and lightning protection measures of wind turbines and wind farms with their effects,the main work is illustrated as followed:(1)According to establish simulation model of lightning stroke wind turbine blade physical process,space potential of lightning stroke wind turbine blade and background potential near blade tip are calculated,and change rule of background potential near blade tip is summarized with analyzing reason.Based on critical length criterion,the concept of critical background potential is put forward,and then critical background potential is deeply demonstrated based on atmospheric conditions.With listing different atmospheric conditions,this part studies the specific differences of static blade upward leader inception when atmospheric conditions vary.For rotating blade,upward leader background potential of rotating blade is defined.Meanwhile,the impact of atmospheric conditions and rotating speed on this potential is analyzed.The study proposes the assessment system of lightning upward leader inception from wind turbine blade based on atmospheric conditions,which can effectively evaluate upward leader inception of lightning stroke wind turbine blade under different atmospheric conditions.Finally,the variation of initial streamer electric field and critical length is described and analyzed when atmospheric conditions fluctuate.(2)Based on above study of wind turbine lightning leader theory considering atmospheric conditions,physical simulation models of lightning stroke wind turbine under different conditions are established.Considering simulation models parameters and actual leader development,relying on simulation results,the assessment work of wind turbine blades triggered lightning ability under different blade angles,different receptors,double wind turbines system,rising terrain is carried out,also analyzing how these conditions influence blades triggered lightning ability.Simultaneously,with the specific change characteristics of blades triggered lightning ability under different receptors,reformation direction of receptor can be preliminarily defined.(3)Developing experiments of lightning stroke wind turbine with different air gap lengths and different receptors,so that it is able to further verify change rule and rate of blade triggered lightning ability under different receptors with experiment data and results.The explanation about change trend of blade triggered lightning ability under different receptors with different air gap lengths is conducted as well,which also obtains change degree of blade triggered lightning ability.Besides,carrying out experiments of lightning stroke wind turbine with and without rising terrain,and verification of blade triggered lightning ability changing condition under rising terrain is conducted,even including analysis of change degree of blade triggered lightning ability when height and rock-soil of rising terrain vary.(4)Depending on relevant inference of above simulation analysis,experimental study work on wind turbine lightning protection spacing based on static blades is developed.Under the similar atmospheric condition,conducting lightning stroke single wind turbine experiments and analyzing relevant experiment data,thus it can describe lightning stroke characteristic of wind turbine with different polarity lightning.Under above atmospheric condition,carrying out double wind turbines system experiments based on data of single wind turbine experiments,it aims to obtain number,probability of lightning stroke wind turbine at different blade angles and different wind turbine spacing.Furthermore,this part determines and integrates wind turbine lightning protection spacing at different blade angles with considering data and results,based on these spacing,it proposes relevant suggestion on the arrangement of wind turbine lightning protection spacing in large scale wind farms,which provides technical support for the planning and formulation of overall lightning protection measures of wind farms simultaneously.