Lightning and earthing for wind farms to the latest standards.
The principle requirement for protection against lightning (IEC 61400-24) describes measures required to protect wind turbines against lightning. A lightning protection system Class III is normally required for Turbine hubs up to 60 m and Class II if the hub is in a height of more than 60 m. In case of offshore plants a lightning protection system Class I is usually required. This can control lightning strikes with currents measuring up to 200,000 A.
These requirements are based on actual operational experience of Wind Turbines and on the assessment of the risk of damage according to IEC 62305-2 (EN 62305-2).
Principle of an external lightning protection system for wind turbines
The external lightning protection system comprises of air-termination systems, down-conductor/s and an earth termination system to protect against mechanical destruction and fire. Lightning strikes to wind turbines usually affect the rotor blades and bearings. To mitigate the damage affects, lightning receptors are integrated to defined strike points along the rotor and body.
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