On the Aggregated Emission of Large-Scale Wind Farms for Harmonic Studies

In this paper the aggregated modelling of large-scale wind farms for harmonic studies is considered. It analyzes the limitations of the IEC 61000-3-6 summation rule (IEC-SR) for harmonic emission assessment using a probabilistic framework. A new simplified analytical model is proposed to estimate the harmonic current emissions of a wind farm including several wind turbines (WTs) that are Inverter-Based Resources (IBRs). A sensitivity analysis of the WT's harmonic current emissions, considering the main operation and design parameters of WTs, allows for ascertaining the main uncertain variables to be included in the probabilistic framework. The analytical model is validated using a simplified electromagnetic transient model (EMT) of a complete wind power plant. The proposed probabilistic procedure was applied to a typical radial topology of WF to evaluate the harmonic emissions and the IEC-SR exponents comparing the results obtained by the new analytical model and the EMT time domain simulations.