Harmonic Analysis of a Wind Power Plant —Case Study of Modeling and Measurement

Abstract

This paper presents harmonic analysis of a wind plant and evaluates the resonance conditions near characteristic harmonic frequencies between the wind plant and the transmission system. A detailed model of the wind plant is developed using EMTP-RV software, and harmonic frequency scans are conducted for various operating scenarios in order to identify the natural resonance of the system. The simulations were also performed to evaluate the harmonic current and voltage distortion levels at the Point -of-Common-Coupling (PCC) and the wind plant 34.5 kV bus. These levels were compared against IEEE std. 519. Harmonic measurements were later performed to assess the real time operating conditions and were compared against the simulation results. This paper will show harmonic scans and distortion levels for various capacitor/reactor ON/OFF scenarios for both high and low wind conditions from EMTP-RV simulations. After observing some issues with the system harmonic response being closer to fifth and seventh harmonic resonance conditions, onsite measurements were taken in order to check the real time operating conditions. The measurement data collected from Dranetz PX5 will also be presented in this paper. Measurement data were used to modify the modeling data to better reflect the actual scenario. The differences in the simulation results and the measurement data will be compared. The comparison shows that despite the similarity between the modeling and measurement, there still exist some difference in the results attributed to variety of factors. Therefore, Enernex recommends both modeling and measurement analysis to obtain overall assessment of power quality for any renewable energy power plants.