In the three-phase transmission system, reactive power must be in a well-balanced ratio to active power in order to keep the grid’s voltage on the required level. Without reactive power, the transmission of electricity would not be possible. In the “old” German energy landscape, mainly nuclear and other large power plants have been providing reactive power capacities. Since in the course of the energy transition more and more of these facilities go off the grid, the four German transmission system operators (TSOs) respond with the installation of reactive power compensation systems.
An outstanding example of this is given by TSCNET shareholder TenneT, the Dutch-German TSO, which is expanding the traditional Borken substation in the northern part of the federal state of Hesse to one of the most modern green power hubs of its grid. Here in Borken, practically in the middle of the German power system, the TSO is currently constructing a hybrid static synchronous compensator (Statcom) plant. From the end of 2019, the state-of-the-art facility will dynamically support the mains voltage and provide reactive power at 380kV level, thus making an important contribution to secure grid operation after the shutdown of the large power plants.
The Statcom plant in Borken, with its hybrid construction, will be the first of its kind in the entire German electricity grid. A mayor advantage of this system is its small space requirement ‒ in comparison to its wide reactive power control range. This considerably reduces the environmental impact. In the particular case of Borken, the renaturation of a nearby river has now become possible. Other reactive power compensation measures of TenneT include the new substation Bergrheinfeld/West with its phase shifting and direct coupling transformers. In addition to building new facilities, TenneT is also exploring other ways to provide reactive power, such as utilising wind power and photovoltaic systems.
> See TenneT press release, in German (html)