November 2020
Enabling higher voltage levels within offshore wind turbines
In parallel to the worldwide increasing power demand, utilities and OEMs in the power sector strive for environmentally friendly and resource efficient power generation. Wind power applications make a major contribution to meeting these goals. While wind turbines were producing 0.5 MW of power at a height of 40 meters in 1990, today’s wind turbines produce 10 MW and beyond requiring higher voltage levels and innovative technologies. A transmission voltage of 66 kV has now become standard for offshore wind projects. One core aspect: The high voltage within the wind turbine network has a positive impact on cable losses and efficiency. This is where reliable, compact and environmentally friendly high-voltage products from Siemens Energy can make an excellent contribution. We are delivering sustainable high-voltage equipment to the global wind turbine market since decades.
Transformers, installed up high, serving stable power flow on point
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.
Gas-insulated switchgear (GIS) in the bottom of the wind turbine
The switchgear protects wind turbine individually against
overloads and short-circuits and makes it possible to supply
electricity reliably and without interruption. The Siemens
Energy 8VM1 Blue GIS is specially designed for offshore
wind turbine installations, based on proven component
technology. The innovative vacuum interrupting technology
enables the implementation of clean air as insulating
medium for the 66 kV GIS. Both technologies realize the
F-gas-free insulation and support the demand for fully
environmentally compatible wind power.
Up till now we produced over 800 units of 8VM1 Blue GIS
for offshore wind turbine generators.
In 2017 the project Nissum Bredning paved the way with
the first installation of our innovative Blue GIS with a special
component design providing highest operational safety and
maintenance freedom.
1,600 t CO2e* can be saved by the application of one
8VM1 bay, compared to a standard SF6-filled gas-insulated
switchgear bay.
*Calculated with a global warming potential of 22,800
(GWP) acc. to EU-F-Gas-Regulation no. 517/2014
Siemens Energy products benefitting the environmentally friendly aspect of renewable energy
Environmentally friendly, robust and highly efficient products from Siemens Energy have many benefits to offer. Despite the power level, our low maintenance products are designed especially for the tough conditions of offshore use, are lightweight and have a particularly compact structure. Siemens Energy high-voltage transmission products score high in terms of environmental compatibility, efficiency, maximized availability and robustness. They do not apply any fluorinated greenhouse gas, nor do they apply mineral oil. As a result, they save time and money, while assuring outstanding grid and application stability. All products are successfully IEC, seismic, and IEEE tested regarding common industry standards.
Saving tones of CO2e by installing Siemens Energy high-voltage products
By supporting one of the most promising future energy sources, renewable wind power generation, we are in line with the outcome of the world energy forum report, published in 2014. In comparison to coal and gas power generation, wind power generation has significantly lower lifecycle emissions per GWh.
Source: World Energy Forum report on climate change published in 2014
The transition to a low carbon energy system can only be realized by increasing the share of renewable energy sources in the energy mix. With our innovative and sustainable products, we support the expansion of wind energy and provide our customer best in class efficiency, sustainability and availability.Eduardo Terzi, Siemens Energy’s Senior Vice-President for Non-Switching Products
For decades, high-voltage products from Siemens Energy have proven the highest level of safety in operation as well as excellent electrical, mechanical, and thermal properties. Installation of our innovative step-up transformers and GIS in wind turbine generators avoids the application of climate-damaging oil and SF6 gas and enables the highly
efficient connection of the wind turbines for bringing wind home, making power generation from renewable energy sources even more eco-friendly and economical.
The new standard voltage level of 66 kV for connection of increasingly powerful offshore wind turbines reduces the amount of cable needed for connection of a wind farm and the process losses – making wind power even more cost-efficient.
UN sustainability goals
As a leader in innovative and sustainable products, Siemens Energy Transmission is supporting the implementation of the United Nations Sustainable Development Goals. With biodegradable ester insulating fluids for step-up transformers, dry-type transformers and clean air insulation for gas-insulated switchgear we support the implementation of goals number 3 “good health and well-being”, 7 “Affordable and clean energy”, 8 “Decent work and economic growth”, 9 “Industry, innovation and infrastructure", 11 “Sustainable cities and communities”, 12 “Responsible Consumption and Production”, 14 “Life below water” and 15 "Living on land".
