Deterministic and Stochastic Study of Wind Farm Harmonic Currents

Abstract

Abstract-Wind farm harmonic emissions are a well-known power quality problem, but little data based on actual wind farm measurements are available in literature. In this paper, harmonic emissions of an 18 MW wind farm are investigated using extensive measurements, and the deterministic and stochastic characterization of wind farm harmonic currents is analyzed. Specific issues addressed in the paper include the harmonic variation with the wind farm operating point and the random characteristics of their magnitude and phase angle.

Measurements of harmonic emission versus active power from wind turbines

“…Ref. [15] however shows results for fixed-speed machines, where the mechanism behind the emission is different than for the turbines discussed in this paper.…”

“…Turbine I shows an increase, Turbine II a mild decrease and Turbine III remains about the same. Each turbine is different; the measurements together with earlier measurements presented in [14,15] indicate that there is no clear trend for the relation between THD (in ampere) and active-power production. Both Turbine I and Turbine II present a narrow range (by absolute value) of the emission for a certain active power production, if compared to that of Turbine III.…”

“…The paper [14] presents a constant THC (total harmonic current in percent with the rated wind turbine current), with the increasing active power production. Whereas the paper [15] points out an exponentially decreasing trend (total harmonic distortion as a percentage of fundamental current component) with respect to active power production in a wind farm, and an unapparent trend of that in percent of wind farm rated current. Ref.…”

“…A number of 600 kW squirrel-cage induction generator wind turbines have been tested according to IEC 61400-21 and IEC 61000-4-7 on the medium voltage level [15]. The paper presents an exponentially decreasing of current THD (in percent of fundamental current) with power output; the low order harmonics 3, 5 and 7 (the dominant ones in THD) are presented without obvious trend with power output.…”

The Application for Harmonic Superposition in Wind Farm Using the Methodology of Monte-Carlo

“…Nowadays, the growing use of power electronics systems in the grid verifies the importance of the research of harmonic problems [8].The deterministic and stochastic characterization of harmonic currents amplitude and phase angle is analyzed through an 18MW wind farm [9].As we all know, few research on the harmonic model of wind farm and the analysis of harmonic current have been performed, whereas, the research on harmonic current and traction load system has developed a lot [10][11][12][13].…”