Step-up transformers convert generated electricity to the requisite voltage level for power transmission on high-voltage lines and cables. A step-up transformer in a nacelle of a wind turbine converts the generated wind electricity to the kV-level needed, to serve the switchgear at the bottom of the wind tower.
Siemens Energy offers two kinds of step-up transformers for wind application: Fire resistant GEAFOL cast-resin transformers for up to 40.5 kV and FITformer REN transformers up to 66 kV, with ester, a flame-retardant, biodegradable insulating fluid.
For on- and offshore windparks we delivered about 30.000 units of GEAFOL transformers and 1.000 units out of it where delivered for offshore wind projects. More than 2.500 units of the ester fluid immersed FITformer REN where installed in wind offshore applications worldwide.
The latest development is the FITformer REN model that enables power transmission at the 66 kV level for even more efficiency and highest proven reliability. The extremely compact transformers fit directly into the nacelle. To enable the transformers to withstand the strong vibrations in the nacelle, Siemens Energy developed a mechanically reinforced version specifically for wind turbines. The first practical application for the FITformer REN was the 28 MW offshore wind farm Nissum Bredning Vind located in the waters of North-western Denmark.