SC4WT – Scaled testing for the development and qualification of wind turbine drive trains

At a glance

• The increasing dimensions of wind turbines pose challenges for the existing test infrastructure for their drive trains. Scaled testing offers a very promising alternative for reducing the costs and work involved.
• However, there is currently no general guideline for drive trains describing the design of test specimens and the performance of scaled testing. The partners in the SC4WT research project now aim to close this gap.
• In a subproject, Fraunhofer IWES will develop and demonstrate an iterative scaling method for a specific test purpose. 

The challenge

As the dimensions of wind turbines increase, so do the requirements on the test benches utilized for system and component testing. Many of them are already or will soon be too small to provide the required operating loads. However, the trend of setting up larger test benches with increased load application options to satisfy the requirements is not a sustainable solution. In addition, the higher testing costs are increasingly posing a challenge, especially for smaller wind turbine manufacturers and suppliers.

Scaled testing, which has been established in aerodynamics and the aerospace industry for decades already, represents a feasible alternative. However, at present, there is no standardized and accepted guideline in widespread use in the field of wind turbine drive trains. 

The solution

This is where the SC4WT project comes into play. The project partners aim to develop a general guideline for the design of scaled test specimens and the performance of scaled testing of wind turbine drive train systems and components as well as to verify its application via simulations. A step-by step guide will then make it possible to employ the method verified by means of example tests in real life. The plan is to validate the developed method with real tests on test benches in a follow-up project.

In a subproject, Fraunhofer IWES is developing an iterative scaling method for a specific test purpose. To this end, researchers will identify critical failure modes and related test scenarios with the aim of determining the test purpose. In cooperation with industry partners, a reference drive train will be defined as the basis and used for the development of the scaling method. In addition, the transferability of the method to other test purposes is also to be demonstrated and analyzed.

The added value

Through the use of scaled test methods, it will no longer be necessary to adapt test benches continually to the increasing dimensions of the wind turbine drive trains. This renders the test infrastructure more flexible, more cost-effective, and also available to wind turbine manufacturers with smaller budgets. Furthermore, testing can be performed more quickly. As such, SC4WT will contribute to both the sustainable use of the existing test infrastructure and reducing the costs associated with the development and testing of drive trains.