Wakes of upstream turbines impinge on downstream turbines in wind farms, causing power losses and increased fatigue. Wind farm control methods, such as the Helix approach, have been proposed to actively stimulate mixing of the wake with the free stream by pitching the blades dynamically. As a result, a periodic structure is forced in the wake, which increases average downstream wind velocity and thereby improves downstream turbines’ power production. However, downstream turbines could further exploit this periodic wake structure by pitching dynamically as well, but in sync with the phase of the incoming wake structure. Depending on the phase offset between the impinging wake and the downstream pitch, this creates destructive or constructive interference between the two wakes and further improves power production downstream. This work presents and experimentally validates such a control strategy for downstream wind turbines and evaluates it on a three-turbine wind farm in an experimental wind tunnel setting using scaled wind turbines. Results validate the controller’s effectiveness and show that the third turbine’s performance improvement is strongly influenced by the phase offset between the periodic wake components generated by the second turbine and those present in the upstream wake.
Abstract As wind power becomes more prevalent in seismically active regions, the demand for accurate evaluations of seismic turbine structural response has grown. With an increase in turbine sizes, the highly flexible rotors interact with support structure modes, dynamically affecting the turbine’s overall seismic response. Given these increasing modal interactions, conventional methods for RNA modelling, i.e. lumped mass models, are not often viable. This paper investigates the seismic loads evaluation methods for the Rotor Nacelle Assembly (RNA), tower, and foundation by developing an RNA superelement model and comparing its seismic response to other RNA representations, specifically lumped mass RNA and flexible RNA models for idling conditions. The results show that the lumped mass RNA model can lead to significant deviations in maximum seismic loading due to frequency shifts in support structure modes and the absence of internal rotor modes, while the RNA superelement offers accurate seismic load capture and computational efficiency, though its accuracy may be affected by unmodeled non-linearities, indicated by large blade-tip deflections.
Abstract Efforts in wind-farm flow modelling have largely focused on developing and tuning wake models, given the dominant impact of wake losses on power production. However, wake effects are superimposed on an ambient background flow that is frequently oversimplified using steady and homogeneous assumptions – conditions that can account for a substantial portion of the discrepancies between measured and simulated performance. This article introduces a new background-flow model that incorporates more physical realism than standard approaches. The model reconstructs an unsteady, spatio-temporal inflow field by passively advecting front-row SCADA-derived wind conditions downstream at minute-scale resolution. These fields can be aggregated to 10-minute intervals for compatibility with common validation practices. The resulting no-farm baseline supports the evaluation of wake losses, the benchmarking of engineering models, and the provision of flow inputs for control-oriented applications, including estimates of advection delays relevant for closed-loop wind-farm control. The article also presents a computationally efficient method for upsampling 10-minute wind speed and direction statistics to minute-scale inputs, enabling large-scale analyses when only standard SCADA formats are available. The full framework is validated using high-frequency SCADA data and dual-Doppler radar measurements from an operational wind farm, demonstrating that the model effectively captures spatial–temporal variability and advection dynamics.
The paper describes the concept of potential application of ACS6080-based grid simulator from ABB and its newly introduced current source mode, to support the testing of grid forming mode (GFM) converters with focus on their island conditions. The obtained simulation results demonstrate promising performance and provide a base for future investigations involving real equipment, towards approaching the viable alternative to conventional test setups, enabling a broader scope and greater diversity of GFM generation units conformity testing.
Nowadays, the disposal of wind turbine blades (WTB) represents a significant challenge due to their complex construction and massive size. The reuse of decommissioned WTB in the construction sector has emerged as a promising solution that can reduce waste and create a circular economy for the valuable materials contained therein. This paper studies the possibility to reuse the main structural components of a WTB as roof beam for a multisport pavilion. The approach relies on reusing the main load carrying component of the blade (i.e., the spar caps plus shear webs) as an overhanging beam, with the thinner part of the blade cantilevered. A structural analysis was carried out using a detailed numerical model considering a WTB from the Siemens Gamesa G90–2.0 MW wind turbine, with a total blade length of 44 m. The model takes into account the actual cross section geometry along the blade length as well as the material properties and the stacking sequence of the laminates. The commercial finite element software ABAQUS is used to accurately predict the stress and deformation distribution of the blade structure acting as an overhanging beam. The preliminary results of this study show potential suitability for the WTB to be reused as beams in roof structures considering bending stresses.
