The right hand rule also applies for wind turbines
When a lightning strike hits a wind turbine a current will run through the tower while producing a magnetic field. As the current always flows through the bottom section of the tower, this is the ideal place to measure the induced magnetic field.
The measurement system can be either a pair of loop antennas or based on semiconductor magnetic field sensors attached to the outside of a wind turbine tower. The key point of measuring the current flow via the magnetic field on the outside of the turbine, is that the lightning will be faithfully detected even if the lightning is fully conducted through the tower itself, rather than through an internal lightning down conductor.
See the classic products here or the Advanced products here.
Lightning detection principle
The Jomitek Lightning Sensor detection principle uses basic magnetic field theory. A direct strike will be channeled down through the tower base, resulting in opposite signs of the magnetic field on opposite sides of the tower. If the strike did not hit the structure directly, the current path will be outside of the tower base, resulting in the same sign on opposite sides of the tower.
By comparing the magnetic field strengths and signs a strike detection can be instantly evaluated, and indicated if necessary. Jomitek has realised a simple and extremely robust detection system based on this principle.
Lightning detection, analysis & protection
Jomitek lightning sensor and protection products are designed for wind turbines of all types.
The lightning indication products cover both basic and advanced detection and analysis needs. More than 1000 turbine installations are currently active, all with an excellent operational track record, and many for more than 10 years.
Jomitek lightning protection knowhow and solutions are centered around a patented approach on how to shield the surface on i.e. wind turbine blades. Using a conductive material laid out on, or in the outer layer of the surface, the inner structure is protected from lightning generated punctures. As one practical approach to achieve this protection, Jomitek offers a conductive lightning tape and guidelines on how to correctly apply the tape.