Japanese develop drone that tests lightning rods on wind turbines

To prevent a wind turbine from being damaged by lightning strikes, the rotor tips and housing are fitted with lightning rods. These can lose their function over time due to lightning strikes, so the next strike can lead to a fire or worse. A Japanese company has now developed a drone to test lightning rods on wind turbines.

Lightning damage

Windmills are preferably placed as freestanding and high as possible to catch as much wind as possible. This has the inherent disadvantage that the risk of lightning strikes is high. Such an impact can be disastrous: the force of an impact can mechanically damage rotors or housing, not to mention the fire hazard. There is also a risk of a fatal peak current in the electrical installation.

For this reason, the rotors and housing are equipped with lightning rods, which safely discharge the current from a lightning strike to the ground. However, with repeated impacts, these rods can lose their functionality over time. Corrosion of connections can also lead to reduced performance. For this reason, the rods must be inspected regularly.

Test conductivity with a drone

The Japanese company Fukushima Sangikyo has developed a drone that can perform this specific inspection. At first glance, the new type of inspection drone is an odd one out. The drone does not have the usual inspection cameras but a kind of ‘catch net' at the top of the device, consisting of a piece of electrically conductive mesh.

During an inspection, the mesh is pressed against the lightning rod on each rotor tip by the drone. The gauze is then put under tension. If a leakage current starts to flow, it is a sign that the lightning rod is working properly. If not, a closer inspection should reveal what the problem is.

The idea for the mesh arose after several experiments with other conductors. The problem was that it is difficult to make good electrical contact with a hard part on the rotor tip. This problem is circumvented by using a somewhat flexible mesh. The company has even applied for a patent for this solution.

Latest tests

Fukushima Sangikyo is conducting the final tests this year. The inspection drone is expected to be operational in the spring of 2023. The hope is that the new drone can drastically reduce inspection time and thus costs for this type of inspection.

You can read more stories about the rapidly advancing drone technology on DroneXL.