Röhrsdorf/Berlin - In the scope of the international conference "Controlling load flows - strengthening European electricity trade", organised by transmission system operator 50Hertz, 40 energy experts gathered today in Röhrsdorf (Saxony) to discuss first experiences in the coordinated use of so-called phase shifting transformers (PST) in Poland, the Czech Republic and Germany. With the PSTs, it is easier to control load flows in the alternating current grid, even between neighbouring countries. In the past, "unplanned loop flows" occurred more and more often via Poland and the Czech Republic as a result of the German energy transition and electricity trading with southern Europe, which led to a high load on their grids and which practically brought cross-border electricity trade to a standstill.
According to Dr Dirk Biermann, Chief Markets & System Operations Officer at 50Hertz, the first experiences in the coordinated use of the PSTs between the Czech system operator CEPS, Polish system operator PSE and 50Hertz have shown that the "unplanned loop flows" could be reduced significantly. "This is a very positive development, as the load on the grids of our Polish and Czech neighbours could be reduced as a result and we will also be able to provide more capacity on the interconnectors for European electricity trading," explains Biermann. "We can therefore state that load flow control using phase shifting transformers has very positive effects that allow us to optimally and efficiently use the existing power grid in the direction of our neighbouring countries but also inside Germany itself. This will play a much larger role in the future than it does today, so that we can successfully accomplish the energy transition with ever higher shares of renewable energy and normally high system stability. However, in Germany we also need to further the equally necessary grid conversion and expansion, as current and future load flows can only be controlled within a properly dimensioned grid," continued the 50Hertz manager.
The phase shifting transformers, which can control the load flow similarly to a valve, have been in operation in Röhrsdorf since January 2018 in the scope of the project coordinated between 50Hertz, CEPS and PSE, and has been in test operation in Vierraden since July. At the German-Polish border, there are two cross-border line connections ("interconnectors"): from Vierraden in Brandenburg to Krajnik in Poland and from Hagenwerder in Saxony to Mikulowa in Poland. PSE already installed four phase shifting transformers in Mikulowa in mid-2016. Between the grids of 50Hertz and Czech system operator CEPS there is an interconnector from Röhrsdorf in Saxony to Hradec in the Czech Republic. In Hradec, CEPS already installed PSTs in early 2017.
Press release as PDF file