摘要
良好的接地系统对于风电机组的正常运行至关重要。基于风机接地圆环的不等电位模型研究雷电流波头时间与入地点、雷电流幅值、土壤击穿场强、土壤电阻率等因素对风电机组接地系统雷电冲击特性的影响规律以及多年冻土地区通过对接地网敷设垂直接地极的散流效果。结果表明:雷电流经风机接地圆环中心注入时具有更好的散流效果,雷电流波头时间越短,接地导体的电感效应越强烈,风机冲击接地电阻越大;随着雷电流幅值的增加,土壤的火花效应得以加强,风机接地圆环面积越小,冲击接地电阻降低越明显;土壤临界击穿场强越小,接地网附近土壤越容易发生火花效应,风机冲击接地电阻越小;风机接地网存在有效的散流半径,当接地网半径超过15 m时,散流效果不再明显增强;随着土壤电阻率的增加,风机接地圆环面积较小时的散流效果有限,冲击接地电阻几乎呈线性增长,而风机大面积接地圆环的冲击接地电阻增长有限,很快趋于饱和;对于存在多年冻土现象的地区,垂直接地极的散流效果较好,垂直接地极的布置不应过于密集,以减小导体之间的屏蔽效应。
Good grounding system is essential for the normal operation of the wind turbine. Based on the unequal potential model of the grounding ring of the fan,studies have been made on the lightning impulse characteristics of the grounding system of the wind turbine based on factors such as the time and location of the lightning current,lightning current amplitude,soil breakdown field strength,soil resistivity,as well as the effect of vertical grounding pole on the distribution of permafrost. The results show that lightning currents flow through the center of the fan’s grounding ring have much better diffusing effect. The shorter the lightning current head time,the stronger the inductance effect of the grounding conductor,and the higher the impact resistance of the fan;With the increase of the lightning current amplitude,the spark effect of the soil is strengthened. The smaller the grounding ring area of the fan,the more obvious the impact grounding resistance decreases. The smaller the soil breakdown field strength,the easier the spark effect of the soil of the fan grounding ring is,and the smaller impact resistance of the fan is;There is an effective diffuser radius in the fan grounding network. When the radius of the grounding grid exceeds 15 m the diffuser effect is no longer significantly enhanced;With the increase of soil resistivity,the effect of scattered flow when the area of the fan grounding ring is small is limited,and the impact grounding resistance increases almost linearly. The impact grounding resistance of the large area grounding ring of the fan has limited growth,and it will soon become saturated;For areas where there are permafrost phenomena,vertical earthing poles have good dispersion effect,and in order to reduce the shielding effect between conductors,vertical earthing poles should not be arranged too densely.
作者
姜龙杰
宋余来
元乙贺
杨宁
王鹏宇
孔深
JIANG Longjie;SONG Yulai;YUAN Yihe;YANG Ning;WANG Pengyu;KONG Shen(State Grid Linyi Power Supply Company,Linyi 276000,China;Electrical Engineering College,Northeast Electric Power University,Jilin 132012,China)
出处
《电瓷避雷器》
CAS
北大核心
2020年第1期104-110,共7页
Insulators and Surge Arresters
关键词
风电机组
冲击特性
火花效应
散流半径
垂直接地极
wind turbine
impact characteristics
spark effect
divergence radius
vertical grounding electrode
