The share of renewable energies is growing worldwide. However, their volatile feed-ins put
significant strain on the power grids. Due to the geographical arrangement of renewable energy
generation, the distance to the consumption centers is growing. In Germany, for example, the
space is growing between large wind farms that feed into the energy grid in the north and load
centers in other parts of the country. This makes the transmission network more susceptible to
voltage fluctuations and interference. For a long time, large power plants have provided the
reactive power necessary for grid stabilization. However, due to the energy transition many of
these conventional power plants, which are operated with nuclear or fossil fuels, are being taken
off the grid.
As a result, transmission system operators like Amprion set up STATCOM systems at important grid
nodes. They compensate for the voltage fluctuations by regulating the reactive power as required,
keeping the grid voltage in a stable range. In addition, the expansion of renewable energy
generation allows greater use of power lines, reinforcing the need for increased reactive power
compensation. This requires STATCOM systems with increasing capacities up to +/- 600 Mvar
“The restructuring of the energy system requires many individual innovative solutions,” says Dr.
Hendrik Neumann, Chief Technical Officer of Amprion GmbH. “We are very pleased to have Siemens
Energy as an experienced technology partner at our side working with us on a stable power grid for
“Powerful partnerships are the key to success to make the grids fit for the energy landscape of
tomorrow,” says Beatrix Natter, Executive Vice President Transmission at Siemens Energy. “We are
thankful for this trust and look forward to continuing to support Amprion in expanding the network
in Germany as required and thus paving the way for a climate-friendly energy system.”
German transmission system operators have calculated a minimum expansion requirement for
stationary and controllable compensation units for reactive power compensation in the network
development plan. This controllable expansion requirement was defined to be between 23 and 28
Gvar and is expected to be covered to a large extent by STATCOM systems. Due to the increasing
use of power electronic equipment in the network, network operators are also calling for new
control concepts with grid-forming behavior for all STATCOM systems. These lead to a control
behavior of the converter similar to rotating synchronous generators, such as those used in
conventional power plants. Like generators, STATCOMs could keep the voltage in the network
constantly stable by themselves.
The STATCOM systems available today do not yet have these comprehensive network-supporting
properties. They use common current control schemes that are state-of-the-art power electronic
equipment for transmission grid applications. Technology companies like Siemens Energy will
further develop the control algorithms and possibly the hardware accordingly. The new turnkey
STATCOM system that Siemens Energy will build in Polsum and Rheinau will have these new gridsupporting features.
Siemens Energy is market leader in terms of number and total installed capacity of the worldwide
installed STATCOM systems with modular multilevel power converter technology.