Wind energy major Siemens Gamesa’s blade test centre in Aalborg, Denmark, home of the world’s largest test stand, is the first non-commercial in-house blade test facility in the world to gain approval from the International Electrotechnical Commission (IEC).
The IEC’s System for Certification to Standards Relating to Equipment for Use in Renewable Energy Applications (IECRE) certification covers the wind, solar photovoltaic and marine energy sectors. The certifications and standards set by the IEC are viewed in a similar light to the ISO standards governing other industries.
Many external independent test laboratories are IECRE approved to perform testing of wind turbine components, but by the end of 2020, that requirement will extend to in-house blade test facilities too.
The approval was granted in the highest level required (stage (4).
Turbines and components must be tested for different aspects including wind speed and direction, power performance, blade design and fatigue life, impact of diverse weather conditions and more.
Rasmus Ladevig, Head of the Blade Test Center in Aalborg, Denmark, led the IECRE approval process from Siemens Gamesa’s side and says: “The most important thing for us is to create trust with our customers. The IECRE approval means that our customers can be confident that we have carried out the blade tests according to the international standards of IEC whether it was at our own test centre or at an external test centre.
How are the blades tested?
The structural integrity of the blade is tested in several ways. In the static test, the blade is pulled quite hard once to simulate a wind gust hitting it. The test is either performed outside using mobile cranes or inside the test centre using pulling stations. The blade is equipped with loading clamps and is tested in four directions by rotating the blade on the test foundation.
In the dynamic test the blade is moved up and down 2-4 million times in order to see whether it fatigues. The purpose of this test is to simulate the stress on the blade during its lifetime in operation.
It takes nine to twelve months to perform all the tests on one blade.
Vicente Garcia Munoz, Head of Validation Means Management within Corporate Technology explained: “We want to be leaders in the wind industry, and testing plays a key role in our validation and verification strategy. Reliability of our products starts with our design teams listening to our customers’ requirements at an early stage. We discussed the IECRE accreditation with customers months ago and decided to start the certification process early instead of waiting. IECRE is all about increasing quality standards in a harmonized way across suppliers and we are leading the way.”
Siemens Gamesa recently invested significantly in a new test stand for the blade test centre in Denmark to be able to perform full-scale tests on future generations of Siemens Gamesa rotor blades.
The test stand is the largest in the world and has more steel rebar reinforcement per square meter than a wind turbine foundation, in order to be capable of accelerating the test and proving full reliability over the lifetime of the blade in the shortest possible time, while fully respecting IEC regulations.