Wind turbines are commonly installed in remote areas where wind is the main asset and conditions are rough, due to the height and exposure to all kind of weather conditions lighting strikes may occurs during the year around ten times or more according to diverse studies.
Perhaps the height of the wind turbine offers a great probability of lightning and related harm to the blades, the most compromising part of the wind turbine. Wind turbines due to the height tend to trigger upward lightning strikes, this form of lightning is created by the tall structure that intensify the electric field produced by the cloud. With a difference of upward lightning downward lightning begin at the cloud reaching thru earth and the same time increasing the electric field and targeting tall or sharp objects. When a lightning flash strike a blade many things can happens,a lightning strike can cause burn to the fiberglass or composite material of the blade, holes, cracks or can even cause damage to the others blades, however, the most damage can occur when an arc flash form inside a structure the pressure of the arc can cause severe damage to his surrounding, in this case the blade or even equipment in the nacelle.
Some wind turbine blades are made with integrated lightning protection, this types of blades tend to handle lightning strikes with less damages than the blades build with out integrated lightning protections.Due to the losses and downtime caused by a lightning strikes wind turbines nowadays are protected with lightning protection systems.These lightning protection systems vary depending on the technology, availability, preferences and needs.Lightning protection should be capable of support a lightning strike without damage to the blade or the protection system which include conductors and air termination points.As the lightning strike a blade the effects can be direct effect or indirect effects, direct effects are the common damages we can see in the blades cables or equipment, however, indirect effects are the ramification or side effects of the lightning strike, these side effects can be seen in the control and electrical system of the wind turbine or in the bearings of the wind turbine.Considering that the wind turbine is made of stainless steel lightning strikes do not cause serious damages to the structure of the tower, nacelles are at great risk of strike by a lightning, however, some nacelles are build of nonelectrical conductive materials lowering down the risk of a lightning strike.Researchers have been conducting investigations about upward and downward propagation lightning in order to improve the lightning protection in wind turbines, however, lightning strikes are often blame to deficient strike protection, failure or poor grounding.In conclusion, lightning protection has increased in performance due to research and technological advances, new wind turbines nowadays rarely get strike by a lightning, however, due to the increase of offshore wind turbines and the increase in the wind turbine structures investigation and research has increased and continue to fulfil the safety and the profitability of the wind turbine industry.