In order to attenuate these oscillations, a pendulum has been included in the design of some turbines such as Gamesa G8X wind turbines (G80, G83, G87 and G90) with various hub heights (60, 67, 78 and 100 m). The pendulums consist of a metallic ring, suspended from the tower frame by chains.
Pendulum mass is partially immersed in oil, providing viscous damping to the system. The pendulum has two main functions: dynamic absorption and viscous damping. At the time of the turbine design, it was considered beneficial to introduce an additional way to attenuate vibrations. However, field feedback has shown that pendulum generates extra maintenance costs as well as, in some cases, technical issues such as noise or oil tank cracks and leakage. Hence why, pendulums have now been removed from the design of the Gamesa turbines”.
Marion Cayla – Asset Manager