Prediction of Lightning Interactions with Coastal and Offshore Wind Turbines
Additional Document Info
2015. The International Society of Offshore and Polar Engineers. The potential for significant or catastrophic damage to wind turbines sited in coastal regions resulting from lightning strikes is an important aspect to consider in the design of wind farms. A recently developed 2-D physics-based model that incorporates key elements of a wind turbine geometrical configuration, cloud cover, and empirical information characterizing lightning strike observations is used to investigate this challenging problem. This predictive model is used to quantify regions of high risk, surface electrical charge, and lightning collection area as a function of hub elevation, cloud cover, leader parameters, and lightning flash density. The sensitivity to variations of key parameters and the characterization of lightning strike information characteristic of the Eastern Seaboard and the Gulf of Mexico are addressed. The surface electrical charge induced on the turbine blades is observed to increase with lightning peak current and extent of cloud coverage, indicating trends consistent with the distribution of the computed total potential field around the wind turbine. The lightning collection area is seen to increase with the hub elevation and lightning peak current and decrease with increase in the leader propagation angle. The lightning strike frequency on a nearshore wind turbine with an estimated 20-year life span is shown to be quite sensitive to ground flash density, and subsequently this is an important design parameter.