Patent ID: 9000970
Filing Date: 2015-04-07
Classification: G01B,G01S

Abstract:
1. An arrangement to measure the deflection a blade of a wind turbine, comprising: the blade is connected via a root-end with a hub of the wind turbine and the hub is connected with a nacelle of the wind turbine, the blade and the hub rotate around a longitudinal axis of the nacelle; a passive reflector arranged at a tip of the blade; and an antenna system is arranged at a nacelle of the wind turbine and near the root-end of the blade, wherein the antenna system contains a transmit antenna and a plurality of receive antennas, wherein the plurality of receive antennas are arranged as a linear antenna array, wherein the passive reflector and the antenna-system are coupled by a radio signal, which is sent from the transmit antenna via the passive reflector towards the plurality of receive antennas, the plurality of receive antennas are arranged in a way that each of the plurality of receive antennas receive the radio signal with a phase-difference, which is assigned to the position of the respective antenna, and wherein the plurality of receive antennas is connected with an evaluation unit, which is configured to measure the phase differences and to calculate the deflection of the blade based on the phase-differences.