A solution for the problem of unplanned cross border power flows between Poland and Germany has been found: Today, transmission system operators of both countries – Polskie Sieci Elektroenergetyczne S.A., PSE, and 50Hertz – are signing an Agreement on the Operation of Phase Shifting Transformers (PST) in Warsaw. As a result, system security will be strengthened and additional capacities between Germany and Poland will be available for cross-border electricity exchange, thus fostering the European energy market.

The concluded PST Agreement elevates the cooperation between PSE and 50Hertz to a new level: The contract includes the coordinated installation of physical Phase Shifting Transformers (pPST) on the German-Polish border and will initiate the operational phase of virtual Phase Shifting Transformer (vPST) mechanism on 18 March 2014. The agreed measures will help to improve power system security in both countries and increase capacities between Germany and Poland to exchange electricity, thereby strengthening the internal energy market

The search for a suitable joint solution for better controlling unplanned loop flows between PSE and 50Hertz were initiated in mid-2012, leading to a pilot agreement on a virtual Phase Shifting Transformer (vPST Pilot) on the German-Polish border based on redispatching measures. In the course of the vPST Pilot, it became obvious that these measures were insufficient: subsequently, both TSOs agreed upon the necessity of installing physical Phase Shifting Transformers (pPSTs) at the German-Polish border. According to the PST Agreement, PSE commits to install the pPSTs in the Mikułowa substation. This will enable the control of power flows on the cross border line Mikułowa-Hagenwerder (planned December 2015). 50Hertz will install pPSTs in Vierraden substation that controls the power flows on the cross border line Vierraden-Krajnik (planned October 2017).

The PST Agreement constitutes an important step towards the coordinated operation of interconnected system paving the way to limiting negative effects of unplanned cross border power flows in Central Eastern Europe and increase overall security of system operation. PSE and 50Hertz look forward to playing an active role in developing future approaches for coordinated power system operation and cross-border capacity allocation in other European regions.