Division of Energy Systems and Energy Management (ESEM)

Development of a Cost-Efficient Smart Gird Communication System Based on Ripple Control (CheapFlex)


Flexible control of load and generation units is, along with the expansion of electrical grids and storage capacity, a necessary requirement to ensure a cost efficient energy transition (German: Energiewende). The opportunity of using smart grids to activate the, today barely used, decentralized flexibility is also supported by the latest Distribution Grid Study of the German Energy Agency (dena). Yet, the smart grid concept failed at distribution grids because of excessively high prices for smart metering systems. The innovative use of ripple control technology, as part of today's network control technology, offers the opportunity to inexpensively and promptly implement the core functions of the smart grid idea.


Within the project it will be analysed how the use of ripple control technology can enable the essential functionalities of distribution grid operation and lead to an overall power system optimization. Following functionalities of distribution grid operation are taken into consideration:

  •   Power management of renewable power plants.
  •   Remote parameter adjustment of decentralized power factor controllers.
  •   Partial off time in case of critical network conditions.
  •   State dependent switching of load and generation unit groups.
  •   Flexible tariff switching for generation, load and storage units

To do so, the existing algorithms and protocols for ripple control must be improved. The concept will be analysed with simulations and the feasibility will be tested with prototypes at the SmartEnergyLab, located at Fraunhofer ISE, and in the distribution grid of Stadtwerke Ahaus.


First the potential of different grid components for flexible network control will be investigated.

Building on this, the individual functionalities of all grid component required to be implemented will be specified. Further, the hardware and software technical specifications of a communication link from the control system to all customer units, required for the realisation of a smart grid based on ripple control, will be established. The communication link will be built, tested and calibrated at the SmartEnergyLab (Fraunhofer ISE). Estimation algorithms of the current grid utilization and forecast based control algorithms for the dynamic adjustment of system operation will be tested and adjusted with simulations.

The algorithms will then be implemented in the SmartEnergyLab communication link and the dynamic adjustment of system operation will be analysed. Finally a field test in the distribution grid of Stadtwerke Ahaus will be realized.

Publicly funded collaborative project

[Content not yet translated. Original:] „Entwicklung eines kostengünstigen Smart Grid Kommunikationssystems auf Basis der Rundsteuertechnologie (CheapFlex)“ ist ein Verbundprojekt und wird im Rahme des 6. Energieforschungsprogramms des Bundesministeriums für Wirtschaft und Energie im Bereich „Netze für die Stromversorgung der Zukunft“ gefördert.

Neben dem Lehrstuhl für Energiesysteme und Energiemanagement der TU Kaiserslautern sind dabei folgende Verbundpartner am Projekt beteiligt:

  •   Fraunhofer ISE (Projektkoordinator)
  •   Stadtwerke Ahaus GmbH
  •   Swistec GmbH

Photo of project partners

From left to right:  Dr. Andreas Fitzler (Swistec), Klaus Frohn (Projektträger Jülich), Andreas Overbeck (Stadtwerke Ahaus), Dr. Erik Busche (Projektträger Jülich), Gaby Matthes (Swistec), Robert Brandalik (Technische Universität Kaiserslautern), Prof. Christof Wittwer (Fraunhofer ISE), Rafael Hollinger (Fraunhofer ISE), Oliver Lutz (Fraunhofer ISE), Gerd Hoepfner (Swistec), Karl-Heinz Siekhaus (Stadtwerke Ahaus), Bruno Kramer (Stadtwerke Ahaus)

Person in Charge

M. Sc. Robert Brandalik

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