雷击风机时叶片和塔筒对接地装置冲击接地特性的影响

Influence of the Wind Vane Tower Barrel on the Earthing Connection's Impulse Earthing Characteristics in a Lightning Shock

风机接地装置的冲击接地特性评估方法目前仍缺少指导规范。实际雷击中雷电流在经过叶片和塔筒时会在其中形成波过程,对接地装置的冲击接地电阻和地电位升(GPR)产生影响。为此,通过矩量法和Fouier变换的仿真计算,探讨了在不同叶片和塔筒总高度、不同土壤电阻率、不同接地装置尺寸和不同雷电流波形的情况下,在风机遭遇雷电流时叶片和塔筒对接地装置冲击接地特性的影响,并运用波过程理论对影响机理进行了分析。通过计算可以发现,由于在风机遭遇雷电流时叶片和塔筒中雷电流波会发生折反射,所以实际地电位升会出现振荡,从而会对接地装置的冲击接地电阻产生影响。

For lack of guidance and standard specifications of the assessment of wind turbines and earthing connection＇s impulse characteristics,it is necessary to study the impulse earthing characteristics of earthing connection which is of great importance to wind turbines＇ lightning protection.In real lightning strokes,the process that the surge current goes through the long wind vane tower barrel can be considered as a wave process which may have an influence on the impulse earthing characteristics of the earthing system.Thus,by using moment methods and the inverse Fourier transform,we research the earthing connection＇s transient ground potential rises（GPR） generated by surge current in different modeling conditions.The modeling conditions include different earth resistance,different grounding system sizes,different surge current waveforms,and whether the wind vane tower barrel is included in the model or not.Calculations on different models are made to get the effects of the wind vane tower barrel on the GPR generated by the surge current in different conditions.We also analyze an impact mechanism of the tower vane barrel by using the wave process theory.Through these calculations and analyses,it is found that,because of the wave process in the tower vane barrel,the real GPR oscillates in the time domain in a lightning stroke,and this oscillation will influence the earthing connection＇s impulse earthing resistance.