Every year many wind turbines are damaged as a result of the powerful and complex impact of lightnings on the windmill. Lightning can cause fire or severe damage on for example controllers, bearings, and gearbox.
Damage to a turbine can lead to difficult negotiations between the owner of a windmill, the manufacturer, and the insurance company. There are many questions to clarify, particularly regarding the economic consequences. In such situations it is crucial to document the size of the lightning strike and to determine whether the turbine has been sufficiently protected to withstand impact.
It is crucial to document the size of the lightning strike and to determine whether the turbine has been sufficiently protected to withstand impact.
EKTOS has contributed to developing a solution for this challenge. Along with a world leader in lightning protection of wind turbines, Global Lightning Protection Services in Herning, EKTOS has developed the sensitive measuring system called The Lightning Key Data System®. This system measures all relevant data when a lightning strikes and it stores the valuable data in a box through sensors which could be mounted on the blades of the windmill. Each sensor measures the impact of a lightning strike in the mill within a time interval of 1.5 seconds. Based on this information four aspects of the impact is measured: maximum current, specific energy, charge, and maximum rise time. These are used to decide whether the turbine can continue in operation or has to be stopped completely and investigated further.
Apart from the blades, the system can also measure other locations on the turbine such as the nacelle or the tower. “For more than one and a half year we have been developing the measurement system which has resulted in a very good solution that answers a great need for the international wind industry. It is fairly new that one can measure a lightning strike in a wind turbine, but with this solution we can gather very specific knowledge and facts about the lightning strike – it contributes greatly to optimizing the operation of a wind turbine”, says technical director Søren Madsen from Global Lightning Protection Services.
“For more than one and a half year we have been developing the measurement system which has resulted in a very good solution that answers a great need for the international wind industry.” Søren Madsen, technical director, Global Lightning Protection Services.
Søren Madsen further explains that the system is designed for harsh environments and can withstand temperature fluctuations, moisture, vibration and electrical noise. The system can be mounted on wind turbines both on land and in large wind farms around the world. The system furthermore provides important data about the lightning protection system on each windmill. “We can simply measure the condition of the lightning protection system and we can use the data to conduct preventive maintenance and service. A lightning often causes lengthy downtime which is expensive for the wind turbine owner. It is important to keep the turbine running for as long as possible”, says technical director Søren Madsen from Global Lightning Protection Services.