Effect of wind turbine converter control on wind power plant harmonic response and resonances

Abstract

Wind turbine harmonic emissions due to power electronics are a well-known power quality concern in wind power plants (WPPs). This problem may be increased by resonances because they amplify harmonic distortion around resonance frequencies. Hence, the resonance phenomenon is widely analysed in the literature. Resonance studies usually consider wind turbines (WTs) as ideal current sources, which can lead to inaccurate results. The study explores the effect of WT converter control on WPP harmonic response. It contributes expressions of WT equivalent harmonic impedance including current control of the grid side converter. This impedance allows WT converter control to be considered in WPP modelling to analyse its effect on harmonic response and resonances. PSCAD and Matlab/Simulink simulations were performed to validate the analytical expressions and illustrate the usefulness of the work in predicting harmonic distortions at WT terminals in actual WPPs.

Sequence Domain Harmonic Modeling of Type-IV Wind Turbines

“…The deviation between |Z pp (jω)| and |Z nn (jω)| in the low-harmonic range, shown in Fig. 3, aligns with similar analyses found in [18], [27]. Resonances occurring in the lowharmonic range are found in WPPs [18], [19] and systems connected through long AC cables [16], [17].…”

“…3, aligns with similar analyses found in [18], [27]. Resonances occurring in the lowharmonic range are found in WPPs [18], [19] and systems connected through long AC cables [16], [17]. The difference between |Z pp (jω)| and |Z nn (jω)| and a system resonance in the low-harmonic range can cause sequence dependent harmonic current amplification [27].…”

Conformal mapping of impedance stability models for system-level dynamics assessments

“…Subsequently, stability is assessed by the Nyquist criterion [5], [6]. This approach has been considered in different applications: ac/dc microgrids [5], [6], renewable energies [7]- [10] and traction [11].…”

“…The impedance/admittance modeling has recently gained more and more attention in renewable energy applications, which are characterized by a high penetration of power electronics devices [7]- [10]. From a computational point of view, one main idea behind the impedance/admittance modeling is to avoid too detailed and complex implementations in platforms more focused for large power systems analysis.…”

“…From a computational point of view, one main idea behind the impedance/admittance modeling is to avoid too detailed and complex implementations in platforms more focused for large power systems analysis. By means of linearization techniques, Norton/Thevenin equivalents that closely emulate activelly-controlled power converters in the range of frequencies at which the harmonic instability problems are obtained; these linear models can be grouped/lumped and have a low computational burden [7], [9], [10].…”