Lightning attachment behavior of wind turbine generator with blades equipped with two lightning receptors

Lightning striking of wind turbine generators (WTGs) has taken place frequently in recent years and usually results in severe blade damages. In order to study the lightning attachment behavior of the WTG, a scaled-down model with a ratio of 1:100 was assembled to simulate a 2 MW-class wind turbine for which each blade is equipped with two pairs of lightning receptors. In order to simulate the lightning strikes from different directions, the high-voltage rod electrode was repositioned at 29 orientations with respect to the WTG model, and by energizing the rod electrode via an impulse voltage generator, which can generate the switching impulse voltage and the lightning impulse voltage, the negative and positive impulses were generated. Obtained results show that the negative impulses tend to be intercepted by the blade-tip receptor, whereas the positive ones are also likely to attach to the insulation parts of blade and the nacelle. Moreover, the switching impulse is prone to being intercepted by the insulation parts of blade, more distinctly than that in the case of lightning impulse. The interception efficiency of the WTG model, represented by the ratio of number of discharges intercepted by blade receptors and lightning rod against the total applied strikes, is larger in the case of negative impulse than that of the positive impulse. Our test results show important implications for the phenomenon of lightning damage and the attachment behavior of WTGs affected by lightning polarity and waveform. (c) 2020 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.