Wind turbine measurements and scattering model validation in the high frequency band (3-30 MHz)

Abstract

This paper describes the first in a series of recent wind-turbine scattering measurements conducted to validate a High Frequency (HF) wind farm interference model. This model was developed to predict the potential interference that may occur if a wind farm is constructed too close to an Over-the-Horizon Radar (OTHR) site. We begin with a review the major components of the full-field electromagnetic model that include the electromagnetic scattering from the turbines, the low-angle propagation from the turbines to the OTHR antennas, and the OTHR antenna response. We then describe the wind turbine scattering measurements that were performed during January 2017 in North Carolina. The object of this effort was to measure the electromagnetic scattering from a single wind turbine as a function of turbine aspect angle, radar frequency in the HF band, and radar bistatic angle with particular attention paid to the forward scattering case. We conclude with a comparison of the measured data to model predictions with favorable results. Subsequent measurements performed during July 2017 captured scattering from the full wind farm and will be described in a future paper.