Lightning strike

Measuring lightning frequency and lightning-current parameters in the vicinity of future offshore wind farms

Fachhochschule Kiel, Institut für elektrische Energietechnik
Prof. Dr. Klaus Scheibe

Lightning currents represent a significant threat for exposed turbines such as those in offshore wind farms and may, with a direct strike, influence the operating behaviour of a wind turbine. That is why lightning protection measures must be taken. The objective of the research project is to obtain lightning current figures at sea.

This is intended to give the manufacturers of wind turbines the opportunity to conduct suitable lightning protection measures for offshore purposes. This research means that in future, outages caused by lightning impact can be largely avoided and reliable operation facilitated.

The following investigations are planned:

• measurement of lightning current frequency
• measurement of lightning current parameters in the masthead with transformer and shunt (strike frequency, lightning current amplitude, slope and path)
• measurement of the lightning current parameters in each of the three pole shafts and in a central dissipation
• measurement of side impacts
• recording the impact in the arrester with a high-speed camera
• lightning current slope measurements with open metering loop in the mast base area
• measurement of cloud-to-cloud discharges via H field sensors
• measurement of distant lightning strikes.

In view of the shortage of energy resources the metering devices on FINO3 are only to be switched on during storms. Siemens “BLIDS“ storm warning system is to be used for this as a reliable indicator of storm activities in the immediate vicinity. The additional installation of microphones on the metering container is to use the sound of thunder as an acoustic evaluation parameter when storms occur, in order to switch on the metering evaluation systems redundantly for example.