Effective grid planning and smart grids lower demand for grid expansion

Project state

The real-time testing and simulation solution “OpSim” allows for realistic simulations of complex electric power systems. It takes into account the electricity grid, and controllers and management systems acting on the grid. It can, for example, simulate a power system in which a virtual power plant controls different generation plants, while a grid optimiser monitors the voltage taking corrective action where necessary. In the research project “OpSimEval”, the project partners Fraunhofer IWES and the University of Kassel add two important functions to this simulation environment: accelerated annual simulation, and linking annual simulations to grid planning scenarios.

Example of an accelerated annual simulation with integrated operational management strategies (TSO, DSO, VPP) in OpSim.
Image: Fraunhofer IWES

The first objective of “OpSimEval” is the flexible design of accelerated annual simulations of complex energy systems (see image to the right). The essential characteristics of a scenario are saved in a configuration file. Users can define which grid is to be used, which operational management systems are involved in the simulation, and which specific tuning concepts between the operational management systems exist. The extended “OpSim” system reads the configuration file, loads all necessary components and the suitable scenario data. It is crucial that new simulations, such as other parameters, require only a change in the configuration file, whereas the remaining work such as combining grid and optimiser or geographically correct time series takes place automatically. This means less effort and a flexible, automated broad range of application for the system.

The developers are also planning to integrate the accelerated test and simulation environment in a grid planning tool. They aim to take into account the impact of various operational management concepts in grid planning, and especially grid expansion. For example, smart voltage regulators could help to avoid some expansion measures in the distribution network. However, the installation of voltage regulators also incurs investment costs for grid operators. The aim of the planned simulation in “OpSimEval” is therefore to determine cost-optimal expansion paths for a grid, taking into account these grid operational measures.

Project aims at a glance

  • Creation of an appropriate system concept for accelerated annual simulations, in which the grid as well as operational management strategies are calculated
  • Development of a functionality to create appropriate scenario data, for any grid area, of electrical load and generation on the basis of geo-information and forecasts. These data are the input parameters of the annual simulation
  • Accelerated calculation methods for distribution network, transmission system and virtual power plant optimisation measures developed in previous IWES projects
  • Linking these control strategies to a high-performance annual simulation of the grid
  • Integration of this annual simulation with grid planning algorithms
  • Performance tests to answer initial questions regarding grid planning, for some with exemplary grid areas. In addition, these questions can be considered by the industry’s research group accompanying the project

Project duration

02/2015 – 01/2018


Dr. Frank Marten
Project manager
Fraunhofer IWES
Königstor 59
34119 Kassel
+49 (0)561 7294-200

Basic information

Virtual power plants, active distribution grids, smart meters and adaptive protection systems – here you can find information about the most important aspects of smart grids.


How is our power grid structured? What sort of networks are there? What do security and quality of supply mean?


The energy generated in a grid must always be equal to the energy consumed. The ancillary services are tasked with ensuring this.


What do direct and alternating current mean? How do they differ and what are the advantages and disadvantages?