Vibration Mitigation of Wind Turbine Towers Using Negative Stiffness Absorbers

Andreas E Kampitsis,Evangelos J Sapountzakis,Ioannis A Antoniadis,Konstantinos A Kapasakalis

doi:10.32732/jcec.2021.10.3.123

Andreas E Kampitsis, Evangelos J Sapountzakis + Show 2 more

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https://doi.org/10.32732/jcec.2021.10.3.123

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Abstract

The application of dynamic vibration absorbers (DVA) to Wind Turbine (WT) towers has the potential to significantly improve the damping of the tower and the nacelle dynamic responses, increasing thus the reliability of WTs. The Tuned Mass Damper (TMD) is limited by the requirement of large masses, in association to its installation location. In this study, two alternative concepts are considered. First, the nacelle is released from the WT tower, using a low stiffness connection. This option is based on the seismic isolation concept. Additionally, a novel passive vibration absorption configuration is implemented, based on the KDamper concept. The KDamper is essentially an extension of the TMD, introducing negative stiffness (NS) elements. Instead of increasing the additional mass, the vibration absorption capability of the KDamper can be increased by increasing the value of the NS element. Therefore, the KDamper always indicates better isolation properties than a TMD with the same additional mass. For the nonlinear dynamic response of the WT a build-in house software is developed. The dynamic performance of the proposed vibration mitigation concepts is numerically examined. All methods present superior dynamic behaviour as compared to the uncontrolled structure, however only the KDamper-based designs significantly increase the effective damping of the WT tower, retaining the additional masses in reasonable ranges.

Highlights

As wind power continues its rapid growth worldwide, wind farms are likely to comprise a significant portion of the total production of wind energy, and may even become a sizable contributor to the total electricity production in some countries
The NS element is realistically designed with a displacement-dependent configuration using pre-compressed positive stiffness elements, that generates ‘linear’ twodimensional negative stiffness
The schematic representation of the Tuned Mass Damper (TMD) concept implemented in Wind Turbines (WT) is depicted in the same figure, where the additional mass of the TMD is attached at the top of the WT tower or inside the nacelle, using a positive stiffness element and a linear damper

Summary

Introduction

As wind power continues its rapid growth worldwide, wind farms are likely to comprise a significant portion of the total production of wind energy, and may even become a sizable contributor to the total electricity production in some countries. The high-quality wind resource and the proximity to load centres make wind energy a compelling proposition. The installed Wind Turbines (WT) energy potential is currently estimated at 539GW, according to the WWEA [1]. An important part of the WT network is the offshore wind turbines (OWT). OWT are expected to increase significantly as European coasts and seas offer a large wind energy potential. The WWEA predicts that offshore wind farms of 150GW will operate in the EU by 2030, contributing 14% of the EU’s total electricity consumption

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