Smart grid

Management of Distributed Energy Resources in Smart Grids

Smart grids are enhanced electricity grids that aim at improving reliability, safety and performance, while integrating new distributed energy resources (e.g. solar panels, wind turbines) with traditional bulk facilities. Besides enhancing existing processes, smart grids provide new services and applications that improve the transmission and distribution systems through remote monitoring and control of the grid, sub-station automation, consumption, optimization, etc. These new capabilities are based on a highly interconnected ICT (Information and Communication Technologies) infrastructure, allowing monitoring of the different components of the electric system.

Although smart grids can take substantial advantage of this new ICT infrastructure, at the same time, they become more vulnerable because they are now exposed to communication networks and computer applications. Cyber attacks could cause serious damage to the electric network.

DER management in Smart grids:

In the future smart grid landscape, DER (Distributed Energy Resources) are expected to occupy an important part of the global energy generation through an important number of small-scale energy sources (solar panels, small wind turbines, etc.), highly dispersed across the whole grid. Therefore, their integration in the grid will imply new challenges for the electric grid management, which has to ensure, in a decentralized way, the operational requirements (reliability, safety, control, stability, etc.) of the electric system.

Examples of Security & Safety issues:

  • Inserting a DER into the distribution network requires precautions to ensure the safety of the system (which was not initially built with important DER presence in mind):

  • DER behaviour must be compliant with the existing protection plan of the host network. Particularly, in case of the presence of a fault on the feeder, requiring action from a breaker located upstream, the DER must be uncoupled from the network to permit fault clearance.

  • DER presence shall not impair the electrical constraints set for the network. If certain thresholds are exceeded (e.g. overvoltage), the DER can be required to disconnect from the network.

  • DER presence must conform to the provisions taken for the execution of work (by field crew members) under tension on the network. Protections must be able to adapt to these specific operation modes.

  • IT management orders support and contribute to some current safety rules but at the same time may introduce safety flaws if they are erroneous. The secure transmission of these orders is compulsory to the safe operation of the distribution network.

For the SESAMO project, we will focus on the IT links used to manage DER sites and on their impacts on the dependable (secure and safe) operation of the distribution network, including impacts on existing safety measures; it consists precisely in the DSO-DER link and the Substation-DER Link (Cf. Figure 2). We consider that the DSO-Substation Link is out of the scope of the present study as it does not directly manage DER sites.

Image: DER integration in smart grids