Lightning attachment to wind turbine surfaces affected by internal blade conditions

Journal of Renewable and Sustainable Energy

et al. 2019

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 lightning arc are obtained by the impulse large current experiment. Based on the actual blade structure, An MHD (magnetohydrodynamics) model is built suitable for multi-field coupling of 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 high temperature of 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 tend 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 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 epoxy resin adhesive and set the down-conductor on the main beam.

Section: Introductionmentioning

confidence: 99%

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

Journal of Renewable and Sustainable Energy

et al. 2019

“…5. In fact, not only the down conductor, other conducting components affect the field, such as sensors or electronic devices installed in the blade for measuring purposes [12]. Thus, a reasonable setup of down conductor in the structure of blade should be taken into consideration.…”

Section: A Specimen With Clean Surfacementioning

confidence: 99%

Experimental Study on Interception Efficiency of Receptor on Wind Turbine Blade With Brine Adhesion

2018 34th International Conference on Lightning Protection (ICLP)

et al. 2018

Lightning creates a huge threat to offshore wind turbine due to its height and the marine environment. The blade surface will be polluted by brine after long operation in highsalinity and high-humidity environment. In order to study the efficiency of the receptor under the influence of brine covered on blade surface, a group controlled test is conducted in this paper. Statistical analysis is applied according to the test results. The results show that, the adhesion of brine on the blade surface reduces the interception efficiency of receptor greatly, which makes the blade exposed to a huge threat of lightning damage. Only water or salt has limited impact compared with brine. The influence of the brine area is more obvious if the area is close to the receptor. It can expand the severe area of strike and reduce the interception efficiency of the receptor. The brine area far from the receptor has a limited effect on attracting downward leader.

“…According to the lightning records of 508 wind turbines in the US wind farm, 304 blades have been struck by lightning in 5 years [1] ; Arinaga has compared the interception efficiency of different receptors. The tip receptor has the highest interception efficiency, thus can provide a better protection for the blade [2] ; Garolera points out that the metal parts inside the blade affect the electric field distribution on the blade surface [3] , and it is believed that the down conductor will increase the risk of lightning strike of the blade. In order to protect the blades from lightning strikes, new lightning protection systems will continue to emerge.…”

Section: Introductionmentioning

confidence: 99%

A Quantitative Evaluation Method for Failure Risk of the Lightning Attachment System on Wind Turbine

2019 11th Asia-Pacific International Conference on Lightning (APL)

et al. 2019

The lightning damage seriously affects the normal operation of wind turbines, but there is currently few quantitative analysis methods for the failure risk of the lightning attachment system on wind turbine. Based on leader development model, this paper proposes the definition and calculation method of the lightning shielding failure rate (LSFR) of the lightning attachment system on wind turbine. Taken into the influence of the blade orientation, the LSFR of the blades regarding different lightning attachment systems were comparatively analyzed. The proposed assessment method can provide a theoretical basis for the optimal design and failure risk assessment of the lightning attachment system on wind turbines. Keywords-lightning shielding failure rate, wind turbine, lightning attachment system, long gap dischargeI.