Assessing DER flexibility in a German distribution network for different scenarios and degrees of controllability

Within the Smart Grids paradigm, the future electricity distribution system will be characterized by more observability and controllability, offering the conditions for bidirectional control of Distributed Energy Resources (DER) with high penetration of Distributed Renewable Energy Resources (DRES). The flexibilities available in the network may be used to solve local technical problems such as under/overvoltage or branch congestion. They may be also used in order to meet regulatory restrictions and to avoid penalties or to offer flexibilities to the TSO. Today, in Germany, the scheduled operating point at the primary substation must fit in the TSO rules. Therefore, the DSO optimizes the scheduled operating point to avoid penalties and to find the minimum cost by using an optimal power flow (OPF). In the future, it is also in discussion whether the DSO should provide the TSO with a specific operating point as an additional service