Power-electronic solutions for resiliency and capacity enhancement in MV grids
The aim of this project is to propose, develop and evaluate power-electronic based solutions for enhancement of the resiliency and capacity of the future distribution grids in the voltage range between 10 kV and 33 kV. In particular, the focus will be on the development of converter topologies and configurations that will facilitate integration of energy storage and hydrogen production, and services for the grid, such as power re-routing, voltage control, power quality improvement, system strengthening, phase balancing and losses minimization/optimization, thus allowing grid expansion and large integration of renewables.
Today’s distribution grids are going through a major evolution, driven primarily by the electrification of industrial processes and the integration of new types of loads. Furthermore, the connection of distributed energy resources at the medium voltage level is continuously growing, mainly due to the increase in renewable generation and energy storage systems.
The distribution grid is evolving from a passive network characterised by unidirectional power flow, predictable loads, and passive elements toward a distribution grid that is part of an integrated energy system that combines several energy sectors (for example, electricity, heat, gas, and transportation), with unpredictable loads, local generation, and storage. In this context, system flexibility is essential to cope with some of the challenges of future power systems. Solutions that provide advances in flexibility are of utmost importance for the future power system, making this an increasingly important topic to consider for operation and planning and for policy makers. The evolution of the distribution grid requires new flexibility mechanisms to integrate the different resources safely and efficiently, together with effective use of existing infrastructures and better levels of quality and supply security. This calls for a holistic approach for optimal coordination and control of the generation, storage, and end units connected to electric power systems. Power electronics will be one of the key flexibility enablers, which acts as an interface between generation, storage, and loads and will allow to effectively cope with energy balancing. As a difference compared to the transmission grid, the distribution grid is relatively uncontrolled. Power-electronic based devices are typically installed for power quality enhancement and for grid code compliance of large loads.
With the growing integration of distributed generation and variable loads, a major challenge is the need to expand and strengthen the existing distribution network. Although this could be solved by building new lines, in practice, this can be difficult and economically inconvenient. This raises another important challenge: the need to maximise and effectively use the hosting capacity of existing grids. In practice, it is common for some feeders to be partially loaded, while others tend to be more saturated. Power electronics can be used to allow power/energy rerouting and to take advantage of all existing assets to allow for an increasing level of generation and loading without the need to build new lines. These energy hubs can be seen as an integrated solution to efficiently accommodate power flow control, virtual meshing, and integration of generation and consumption of different types and nature, such as renewables, fuel cells, batteries, thermal storage, or electrolyzers.
Project goals
To achieve its aim and objectives, the project will have the following specific goals:
Goal 1: To have developed, investigated and ranked different power-electronic configurations and topologies characterized by two or more interfacing ports for the investigated distribution grids, and to have validated the effectiveness of the different solutions analytically and in simulation. Selected configuration will also be validated in a small-scale laboratory prototype.
Goal 2: To have identified key grid services to be offered by the power-electronics system and its optimal location in a distribution grid.
Goal 3: To have developed tailor-made solutions for the different energy-storage technologies and load characteristics and profiles.
Goal 4: To have investigated and developed solutions for efficient use of power electronics to interface different energy-storage technologies and flexibility providers in an integrated manner, aiming at the development of “energy hubs” for the future distribution grid.
Involved in the project
Lluc Figueras Llerins, Massimo Bongiorno, Mebtu Beza, Jan R. Svensson, Anna Martinelli, Lisa Göransson.
Partners
Hitachi Energy, Göteborg Energi, Västra Götalandsregionen, Akademiska Hus, Herrljunga EL, Mölndal Energi, Vattenfall, Soltech Energy, Port of Göteborg.
Funders
Energimyndigheten, Hitachi Energy, Göteborg Energi, Västra Götalandsregionen.