Damage mechanism of wind turbine blade under the impact of lightning induced arcs

Zhang, Minhao and Li, Qingmin and Li, Hongbo and Yu, Wanshui and Guo, Zixin and Siew, Wah Hoon (2019) Damage mechanism of wind turbine blade under the impact of lightning induced arcs. Journal of Renewable and Sustainable Energy, 11 (5). 053306. ISSN 1941-7012 (https://doi.org/10.1063/1.5118717)

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Abstract

It is not clear for the damage mechanism of the blade structure under the effect of the lightning strike arc. In this paper, the damage characteristics of blades under the effect of an lightning arc are obtained by the impulse large current experiment. Based on the actual blade structure, a magnetohydrodynamics model is built to be suitable for multifield coupling of the heat-magnetic-airflow and we obtain the temporal and spatial variation of the temperature and pressure. The experimental results show that the blade tends to crack from the position of the trailing edge near the arc attachment point and the crack extends in the direction of the blade root and tip. The length of carbonization damage caused by the high temperature of the arc is much smaller than the crack length due to the airflow impact. When the down-conductor is placed on the main beam, carbonization damage distributes in the area between the left web and the trailing edge. When placed on the right web, it distributes between the right web and the trailing edge. In the finite element simulation, the temperature of the arc ignited point increases to the peak value and then decreases rapidly and then, it increases to the maximum and tends to stabilize. The high temperature inside the blade region diffuses from the boundary between the pressure surface and the right web to the trailing edge. The pressure of the trailing edge increases to the maximum and then oscillates to decrease. The airflow inside the blade continuously oscillates between the right web and the trailing edge. It is recommended to improve the toughness of the epoxy resin adhesive and set the down-conductor on the main beam.