Next generation of smart grid technologies for a flexible, resilient and digital distribution grid
Smart grid technologies have transformed electricity networks, in particular medium and low voltage distribution networks. The need for increasing Renewable Energy Sources (RES) hosting capacity and ensure an efficient management of grid assets, have led the industry to develop new technologies for the monitoring, control and management of smart distribution grids.
The deployment of advanced metering infrastructures and distribution automation have extended monitoring and control capabilities of medium and low voltage distribution networks that allow the implementation of decentralized network control and self-healing functionalities.
However, reaching a 100% RES and consumer centric power system, enabling new concepts such energy communities, is quite ambitious, requiring a new generation of smart grid technologies and network applications for increasing the flexibility and resilience of distribution grid.
Flexibility will allow future distribution networks to ensure the efficiency and security of operation in a more complex operation scenario, characterized by high variability of RES.
On the other hand, operating the system closer to their operation limits and the more frequent occurrence of extreme climate events, requires a more resilient system. This means that resilience will need to be included in the planning and operation of future distribution networks, enabling a more secure and efficient response treats ranging from extreme climate events to cyber-attacks.
The integration of distributed energy resources such as distributed storage are key to increase the flexibility of distribution networks, increasing RES integration and providing grid support services to help manage congestions, provide volt/var regulation and optimize network asset operation (e.g. minimize breakers, OLTCs maneuvers).
More importantly, distributed storage enables the implementation of microgrids concept, which has the potential to increase the distribution network resilience under extreme climate events, by dividing it in small controllable and autonomous clusters. Under normal operation, storage systems are controlled in order to improve operation efficiency and in emergency conditions they can provide electricity to a small community for at least a few hours.
For an effective use of the available flexibility new advanced network applications are also needed, optimizing flexibility together with the distribution network assets. These applications plan the operation for the next hours/day, ensuring that flexible resources are dispatched when they are most needed. This also means that it is necessary to forecast network operation state, based on accurate load, generation and flexibility forecasting tools. For example, distributed storage has a limited capacity, and will charge typically in the hours of higher generation from RES and discharge during peak hours. However, depending on the load diagram and network characteristics this may not represent the optimal use of flexible resources. These tools change the operation paradigm towards a preventive distribution network management.
In European project SENSIBLE1[1], that ended recently, this preventive management framework for distribution grids was developed and demonstrated. The project as shown the benefits of distributed storage owned by the DSO, communities and consumers that contributed to a more efficient management of the grid as well as increased capacity in the event of disturbances.
In the Portuguese demonstrator, implemented in Évora, the islanding of a distribution feeder has been demonstrated, based in the coordinated control of battery storage units installed at the MV and LV networks. The project also showed the importance of developing adequate planning tools that allow to quantify the benefits in distributed storage against conventional planning solutions.
Preventive management strategies need to be complemented by improved self-awareness and real-time control capabilities, enabled by a new generation of digital technologies. AI and data visualization technologies promise to change network control centers, with new decision support tools and visualization strategies for network operators. Similarly, IoT and distributed computing enable the deployment of improved monitoring and advanced analytics downstream the network, truly deploying a decentralized control architecture for the protection, automation and control of MV and LV networks.
A new generation of smart grid technologies supported by advanced network applications will turn up as a result of the digitalization of the distribution system, enabling resilience and flexibility driven planning and operation strategies.
[1] European Project SENSIBLE website https://www.projectsensible.eu/
This article has been written by Clara Gouveia, area manager of DMS/EMS and network automation at INESC TEC in May 2019.
Clara Gouveia is a member of the Centre for Power and Energy Systems of INESC TEC since 2011, currently holding a Senior Researcher position. Clara has received her MSc and PhD degrees in Electrical Engineering from the Faculty of Engineering, University of Porto (FEUP) in 2008 and 2015 respectively. Her research interests are focused on the operation of distribution networks within smart grid context, considering the large-scale integration of Distributed Energy Resources and micro grid concepts. This researcher has been involved in several national and European projects, such as MERGE, SENSIBLE and UPGRID project, namely in the development and demonstration activities in INESC TEC Smart Grids and Electric Vehicles laboratory of control and management strategies to enable the safe integration of Distributed Energy Resources in distribution networks, particularly when operating islanded from the main grid.
