Smart Grid Technologies in Europe: An Overview

The old electricity network infrastructure has proven to be inadequate, with respect to modern challenges such as alternative energy sources, electricity demand and energy saving policies. Moreover, Information and Communication Technologies (ICT) seem to have reached an adequate level of reliability and flexibility in order to support a new concept of electricity network—the smart grid. In this work, we will analyse the state-of-the-art of smart grids, in their technical, management, security, and optimization aspects. We will also provide a brief overview of the regulatory aspects involved in the development of a smart grid, mainly from the viewpoint of the European Unio

Resilience-oriented control and communication framework for cyber-physical microgrids

Climate change drives the energy supply transition from traditional fossil fuel-based power generation to renewable energy resources. This transition has been widely recognised as one of the most significant developing pathways promoting the decarbonisation process toward a zero-carbon and sustainable society. Rapidly developing renewables gradually dominate energy systems and promote the current energy supply system towards decentralisation and digitisation. The manifestation of decentralisation is at massive dispatchable energy resources, while the digitisation features strong cohesion and coherence between electrical power technologies and information and communication technologies (ICT). Massive dispatchable physical devices and cyber components are interdependent and coupled tightly as a cyber-physical energy supply system, while this cyber-physical energy supply system currently faces an increase of extreme weather (e.g., earthquake, flooding) and cyber-contingencies (e.g., cyberattacks) in the frequency, intensity, and duration. Hence, one major challenge is to find an appropriate cyber-physical solution to accommodate increasing renewables while enhancing power supply resilience. The main focus of this thesis is to blend centralised and decentralised frameworks to propose a collaboratively centralised-and-decentralised resilient control framework for energy systems i.e., networked microgrids (MGs) that can operate optimally in the normal condition while can mitigate simultaneous cyber-physical contingencies in the extreme condition. To achieve this, we investigate the concept of "cyber-physical resilience" including four phases, namely prevention/upgrade, resistance, adaption/mitigation, and recovery. Throughout these stages, we tackle different cyber-physical challenges under the concept of microgrid ranging from a centralised-to-decentralised transitional control framework coping with cyber-physical out of service, a cyber-resilient distributed control methodology for networked MGs, a UAV assisted post-contingency cyber-physical service restoration, to a fast-convergent distributed dynamic state estimation algorithm for a class of interconnected systems.Open Acces

Reliable and Robust Cyber-Physical Systems for Real-Time Control of Electric Grids

Real-time control of electric grids is a novel approach to handling the increasing penetration of distributed and volatile energy generation brought about by renewables. Such control occurs in cyber-physical systems (CPSs), in which software agents maintain safe and optimal grid operation by exchanging messages over a communication network. We focus on CPSs with a centralized controller that receives measurements from the various resources in the grid, performs real-time computations, and issues setpoints. Long-term deployment of such CPSs makes them susceptible to software agent faults, such as crashes and delays of controllers and unresponsiveness of resources, and to communication network faults, such as packet losses, delays, and reordering. CPS controllers must provide correct control in the presence of external non-idealities, i.e., be robust, and in the presence of controller faults, i.e., be reliable. In this thesis, we design, test, and deploy solutions that achieve these goals for real-time CPSs. We begin by abstracting a CPS for electric grids into four layers: the control layer, the network layer, the sensing and actuation layer, and the physical layer. Then, we provide a model for the components in each layer, and for the interactions among them. This enables us to formally define the properties required for reliable and robust CPSs. We propose two mechanisms, Robuster and intentionality clocks, for making a single controller robust to unresponsive resources and non-ideal network conditions. These mechanisms enable the controller to compute and issue setpoints even when some measurements are missing, rather than to have to wait for measurements from all resources. We show that our proposed mechanisms guarantee grid safety and outperform state-of-the-art alternatives. Then, we propose Axo: a framework for crash- and delay-fault tolerance via active replication of the controller. Axo ensures that faults in the controller replicas are masked from the resources, and it provides a mechanism for detecting and recovering faulty replicas. We prove the reliable validity and availability guarantees of Axo and derive the bounds on its detection and recovery time. We showcase the benefits of Axo via a stability analysis of an inverted pendulum system. Solutions based on active replication must guarantee that the replicas issue consistent setpoints. Traditional consensus-based schemes for achieving this are not suitable for real-time CPSs, as they incur high latency and low availability. We propose Quarts, an agreement mechanism that guarantees consistency and a low bounded latency- overhead. We show, via extensive simulations, that Quarts provides an availability at least an order of magnitude higher than state-of-the-art solutions. In order to test the effect of our proposed solutions on electric grids, we developed T-RECS, a virtual commissioning tool for software-based control of electric grids. T-RECS enables us to test the proper functioning of the software agents both in ideal and faulty conditions. This provides insight into the effect of faults on the grid and helps us to evaluate the impact of our reliability solutions. We show how our proposed solutions fit together, and that they can be used to design a reliable and robust CPS for real-time control of electric grids. To this end, we study a CPS with COMMELEC, a real-time control framework for electric grids via explicit power setpoints. We analyze the reliability issues..

Federated Embedded Systems – a review of the literature in related fields

This report is concerned with the vision of smart interconnected objects, a vision that has attracted much attention lately. In this paper, embedded, interconnected, open, and heterogeneous control systems are in focus, formally referred to as Federated Embedded Systems. To place FES into a context, a review of some related research directions is presented. This review includes such concepts as systems of systems, cyber-physical systems, ubiquitous computing, internet of things, and multi-agent systems. Interestingly, the reviewed fields seem to overlap with each other in an increasing number of ways