Statistical Analysis of Radial Velocity and Spectrum Width for Wind Turbines Radar Echo

Abstract

The number of wind farms has increased rapidly in the past few years. Some studies have shown that wind farms interfere with weather radar and air traffic control surveillance radar. The radar echo signal of fast-rotating wind turbine blades has a wide Doppler spectrum, and the general radar clutter processing methods cannot remove wind turbine clutters with such characteristics, which interferes with the target detection performance of nearby radar equipment seriously. The study of statistical characteristics of the echo signal of wind turbines could provide basis for detection, recognition, elimination of wind turbine clutters. This paper provides statistical models of radial velocity and spectrum width for wind turbines based on Level II data of the WSR-88D weather radar. The orientation of blades' rotation plane has impact on statistical analysis result. In order to solve this problem, we employ the wind direction information to estimate the orientation of blades' rotation plane and we analysis the statistical characteristics in some particular orientation. The real data are utilized to obtain the empirical probability density function and then different probability density functions are used to fit the empirical probability density function. The K-S test and root mean square error are employed to compare the performance of different statistical models. Through the statistical analysis of four different types of wind turbine, the preferable statistical model for radial velocity and spectrum width are obtained.