Application concepts of phase-shifting transformers for the targeted control of power flows between the transmission and distribution grid

Inhalt:
This paper focuses on different placement strategies for phase-shifting transformer (PST). The integration of renewable energy sources in the German power grid means, among other things, that the previously unidirectional power flow across almost all voltage levels has become bidirectional over time. The critical points are all the coupling points between the various voltage levels. In the case of a parallel distribution grid with several interconnection points, a huge power flow in the transmission network means a power transit flowing through the distribution network according to the impedance ratio. It is important for both grid operators to be able to restrict and control this transit. This article describes how phase-shifting transformers can be placed between the transmission and distribution networks in the most suitable way to fulfil these purposes. The data is based on three anonymized grid topologies at which possible locations are examined. The results show that the coupling point, i.e. the connecting substation, is the most effective point at which phase shifting transformers can be placed.