TY - JOUR

T1 - Inverse load calculation procedure for offshore wind turbines and application to a 5-MW wind turbine support structure

AU - Pahn, T.

AU - Rolfes, R.

AU - Jonkman, J.

N1 - Funding information: The research at Leibniz Universität Hannover was funded by the German Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (project ‘OGOWin’, project number 0327564C). Further financial support was granted by the German Academic Exchange Service (D/10/51623), enabling an exchange of scientific staff between Leibniz Universität Hannover (Germany) and the National Renewable Energy Laboratory (NREL, USA). NREL's involvement was supported by the US Department of Energy (DOE) under contract no. DE-AC36-08GO28308. Funding for the work was provided by the DOE Office of Energy Efficiency and Renewable Energy, and Wind and Water Power Technologies Office. The US government retains and the publisher, by accepting the article for publication, and acknowledges that the US government retains a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for US government purposes.

PY - 2017/2/20

Y1 - 2017/2/20

N2 - A significant number of wind turbines installed today have reached their designed service life of 20 years, and the number will rise continuously. Most of these turbines promise a more economical performance if they operate for more than 20 years. To assess a continued operation, we have to analyze the load-bearing capacity of the support structure with respect to site-specific conditions. Such an analysis requires the comparison of the loads used for the design of the support structure with the actual loads experienced. This publication presents the application of a so-called inverse load calculation to a 5-MW wind turbine support structure. The inverse load calculation determines external loads derived from a mechanical description of the support structure and from measured structural responses. Using numerical simulations with the software fast, we investigated the influence of wind-turbine-specific effects such as the wind turbine control or the dynamic interaction between the loads and the support structure to the presented inverse load calculation procedure. fast is used to study the inverse calculation of simultaneously acting wind and wave loads, which has not been carried out until now. Furthermore, the application of the inverse load calculation procedure to a real 5-MW wind turbine support structure is demonstrated. In terms of this practical application, setting up the mechanical system for the support structure using measurement data is discussed. The paper presents results for defined load cases and assesses the accuracy of the inversely derived dynamic loads for both the simulations and the practical application.

AB - A significant number of wind turbines installed today have reached their designed service life of 20 years, and the number will rise continuously. Most of these turbines promise a more economical performance if they operate for more than 20 years. To assess a continued operation, we have to analyze the load-bearing capacity of the support structure with respect to site-specific conditions. Such an analysis requires the comparison of the loads used for the design of the support structure with the actual loads experienced. This publication presents the application of a so-called inverse load calculation to a 5-MW wind turbine support structure. The inverse load calculation determines external loads derived from a mechanical description of the support structure and from measured structural responses. Using numerical simulations with the software fast, we investigated the influence of wind-turbine-specific effects such as the wind turbine control or the dynamic interaction between the loads and the support structure to the presented inverse load calculation procedure. fast is used to study the inverse calculation of simultaneously acting wind and wave loads, which has not been carried out until now. Furthermore, the application of the inverse load calculation procedure to a real 5-MW wind turbine support structure is demonstrated. In terms of this practical application, setting up the mechanical system for the support structure using measurement data is discussed. The paper presents results for defined load cases and assesses the accuracy of the inversely derived dynamic loads for both the simulations and the practical application.

KW - continued operation of wind turbines

KW - inverse load calculation

KW - load measurement

KW - system identification

UR - http://www.scopus.com/inward/record.url?scp=85013392790&partnerID=8YFLogxK

U2 - 10.1002/we.2088

DO - 10.1002/we.2088

M3 - Article

AN - SCOPUS:85013392790

VL - 20

SP - 1171

EP - 1186

JO - WIND ENERGY

JF - WIND ENERGY

SN - 1095-4244

ER -