Research project Green Access

Intelligent distribution network automation for increased network integration of renewable energy



How can the power network incorporate the maximum number of renewable energies at the lowest possible cost? One solution lies in the automation of medium and low-voltage networks, which are generally used to integrate photovoltaic and wind power plants. The Green Access research project examines how the building blocks of an intelligent network work together for optimum efficiency.

Research project Green Access



April 2015 until December 2018

Funded by

Federal Ministry for Economics and Energy

Project participants

  • EWE Netz AG
  • Institute of Networked Energy Systems
  • Bergische Universität Wuppertal
  • BTC Business Technology Consulting AG
  • Fraunhofer-Institut for Solar Energy Systems
  • OFFIS – Institute for Informatics
  • PHOENIX CONTACT Energy Automation GmbH
  • SMA Solar Technology AG

Until just a few years ago, the power network was based around a few large power plants rather than many decentralised suppliers. Finding cost-effective and reliable ways to integrate renewable energies is therefore a major challenge for the energy transition. Smart grids are one possible solution for this. The building blocks of smart grids optimise the use of the existing infrastructure and thereby reduce the need for network expansion.

The Green Access project, which is funded by the Federal Ministry for Economic Affairs and Energy, focuses on "intelligent" distribution grids that adapt independently to changes in load and supply situations in accordance with the "plug and automate" principle. For example, when new photovoltaic, biogas or wind power plants are connected to the network, then intelligent algorithms should detect them and incorporate them automatically into the system. Unlike the high and medium-voltage level, local networks are not very transparent for operators. When they supply renewable energy their behaviour can be difficult to predict. This should also improve in future with the use of intelligent algorithms aimed at maintaining network stability and efficient exploitation.

Networked Energy Systems
Network behaviour between households, the low-voltage network and the medium-voltage level are being researched in the Green Access project. The increasing share of volatile renewable energies requires smart grids to be constructed in an attempt to optimise the existing infrastructure.

In Green Access, the Institute of Networked Energy Systems is working on a sub-project to gain an accurate insight into the low-voltage lines that lead directly to households. This involves the interaction between the network and households. The researchers are doing field tests using measurement boxes to ascertain network behaviour at high resolution, with the goal of reviewing the algorithmic controls. The measurement data is also used to improve controls at the medium-voltage level.

The Institute of Networked Energy Systems is carrying out additional sub-projects to investigate issues such as the interplay of photovoltaic inverters with the network, and developing scenarios for future energy consumption. The low-voltage network is not only challenged by new producers, but also by changes in loads, e.g. when heat pumps and charging for electric vehicles consume large amounts of electricity at the same time in the evenings. Algorithms should help to maintain network stability via automation in these situations as well.


Power Grid Technologies

Research Group
Institute of Networked Energy Systems
Carl-von-Ossietzky-Str. 15, 26129 Oldenburg