Inertial and Frequency Response of an Offshore Wind Turbine: Effect on Extreme and Fatigue Loads

Inertial and Frequency Response of an Offshore Wind Turbine: Effect on Extreme and Fatigue Loads

Douma, Laurens Jan (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Wind Energy)

Zaaijer, M B (mentor)
von Terzi, D.A. (graduation committee)
Cvetkovic, M. (graduation committee)

Delft University of Technology

Electrical Engineering | Sustainable Energy Technology

2023-08-30

The replacement of conventional generation units with variable renewable energy sources could have a negative impact on the balance of supply and demand of electricity. Moreover, since the variable renewable energy sources are inverter based and therefore decoupled from the grid, the overall grid inertia will decrease. To solve this problem, the traditional mechanical frequency response can be re- placed by synthetic inertial response and fast frequency response (FFR) alternatives from wind turbines. However, there is uncertainty about the order of magnitude of these ancillary services and how these ancillary services will affect the ultimate and fatigue loads on the wind turbine. The aim of the study is to gain an understanding of the extent to which an offshore wind turbine can provide synthetic inertia and fast frequency response and how this affects the fatigue and ultimate loads on the wind turbine.

Simulations were performed in FASTTool to study the response of the IEA 15MW offshore wind turbine using the baseline controller, synthetic inertia controller and FFR controller. The moments at the blade roots and tower base were used to perform a fatigue and ultimate load analysis. Three different grid frequency data sets were used for the grid frequency inputs of the synthetic inertia controller and FFR controller. In addition, the response of the wind turbine was studied at two different response sizes for both the synthetic inertia controller and the FFR controller.

This study showed a significant increase in fatigue damage equivalent load and maximum stresses due to an increase in the response size of the synthetic inertia and FFR controller. The results therefore showed that the extent to which an offshore wind turbine can provide synthetic inertia and FFR depends mainly on the magnitude of the controller response and not on the size of the wind turbine.

Synthetic Inertia
Fast Frequency Response
Offshore Wind Turbine
Fatigue Analysis
Ultimate load

http://resolver.tudelft.nl/uuid:5f838875-32a3-4e9e-b289-c7ebb5dfc823

Student theses

master thesis

© 2023 Laurens Jan Douma