Voltage control in electric distribution grids by aggregation of distributed energy units

Keeping voltage limits in electric networks is obligatory. Voltage constraints often cause additional costs for network reinforcement or more distance connection points when distributed generators are to be connected in medium- and low-voltage grids. In this paper, we present three different approaches for voltage control by aggregation of controllable distributed energy units. We also present the results of a physical hardware test of two of the approaches: (1) aggregation by virtual power plant control and (2) aggregation by incentive-based control with bidirectional energy management interfaces. One further experiment demonstrates the result of combining both approaches. All three approaches contribute effectively to keeping voltage limits. In combination they generate even larger impact.