In-Situ Monitoring of Grouted Joints Using a SFCW Radar: Initial Results of an Installation Inside a 3.6 MW Offshore Wind Turbine

Many offshore wind turbines with a monopile as foundation structure use grout, a special form of concrete, to connect the monopile and the transition piece. The use of stepped-frequency continuous wave (SFCW) radar with frequencies from 100 MHz to 2 GHz is proposed for in-situ monitoring of this grouted joint. Network analyzer measurements are performed on improved grout-filled TEM horn antennas. A procedure for installing the antennas and radar systems offshore is described. Three SFCW radar systems are installed in a turbine at the Meerwind Ost offshore wind farm north of the island Heligoland. The first measurement results of these systems are presented.