Contributing to a sustainable world with safe wind turbines

Vestas has focused on developing and deploying renewable energy solutions since 1979. One of the top five market players, Vestas has more than 154 GW of wind turbines in 87 countries and an annual installed capacity of 15.2 GW by 2021. Wind turbines are subject to stringent safety requirements to ensure the safe conversion of wind into energy. Vestas has worked with DEKRA since 2009 to ensure that some of these safety requirements are met. We met Lars Helle (Senior Functional Lead at Vestas) to discuss the conversion of wind to energy, and the safety tests that DEKRA performs.

Converting wind to energy

Helle has been working at Vestas for 22 years. “Vestas has a clear vision: to remain the world leader in renewable energy solutions, with wind energy as our core business,” he notes. Wind turbines convert wind into electrical energy. “The wind causes the blades of the wind turbine to rotate, with the rotational movement creating kinetic energy. A generator in the wind turbine converts this energy into electricity,” explains Helle.
“To be able to harvest maximum power from the wind at all wind speeds, the generator needs to be operated at variable speed and hence cannot be connected directly to the supply grid. Hence to supply the power extracted by the generator at variable frequency into the supply grid with fixed frequency a converter is connected between the generator and the grid. All this occurs in the ‘nacelle’ – the upper part of a wind turbine.”

Safety standards certification

A 15 Megawatt off-shore wind turbine is capable of producing 80.000 MWh per year. To ensure that the transition between the generator and the converter is safe, DEKRA tests whether the switching cell in the converter meets the safety standards. In particular, DEKRA performs short-circuit tests in accordance with the IEC 61439-2 standard for low-voltage switchgear. DEKRA also issues an Attestation of Conformity for the IEC TR 61641 standard. Here, DEKRA tests specific fault conditions that cause arcs in distribution systems. “This third-party check is vitally important before a wind turbine begins operating, because these arcs could create explosions causing a great deal of damage,” says Helle. “The wind turbine equipment must be able to withstand these extreme consequences.”
Vestas have worked with DEKRA since 2009 to report on the safety of our wind turbines. Helle: “DEKRA takes enormous care and measures what needs to be measured, with an eye for detail.” Vestas defines the test conditions based on product knowledge and field experience. DEKRA carries out tests on this basis, providing an independent opinion on the test results. These tests are carried out in external labs because of the extremely high short circuit levels needed. “Performing safety tests on wind turbines is a challenging task. The extreme forces occurring inside the turbine make performing these tests very complex.”

Intelligent maintenance

Wind energy is a significant source of renewable energy. So it’s important that wind turbines are reliable, that they don’t simply stop. Helle: “Wind turbines are equipped with a sophisticated piece of technology making it possible to predict required maintenance and to detect and report on failing components. That means that when visiting the turbines, we can take exactly the right equipment with us for repair. This intelligent maintenance method increases the security of the energy generation continuity.”

Wind energy and the future

Helle: “Todays installed capacity (for all wind turbine brands) is around 100GW per year. According to GWEC (Global Wind Energy Council) the annual installed capacity by 2030 should be 280GW to meet a “net zero world” by 2050. Population demand produces a need for huge volumes of kWh. So renewable energy is more important than ever in today’s society.”
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