Wind turbines experience oscillations as a result of forces exerted on the nacelle and tower, further amplified by the rotating blades.

To mitigate these oscillations, a pendulum system was integrated into the design of certain wind turbines, such as the Gamesa G8X series (G80, G83, G87, and G90) with various hub heights (60, 67, 78, and 100 meters). These pendulums consist of a metallic ring suspended from the tower frame by chains. 

The pendulum mass is partially immersed in oil, providing viscous damping to the system. This system serves two main functions: dynamic absorption and viscous damping. At the time of the turbine’s design, it was considered beneficial to incorporate an additional vibration attenuation mechanism. However, operational feedback has revealed that the pendulum system introduces extra maintenance costs and, in some cases, technical issues such as noise, oil tank cracks, and leakage. 

As a result, pendulums have now been removed from the design of Gamesa turbines. 

By Marion Cayla – Asset Manager