Cyber-physical Energy Systems Research Articles

Guest Editorial Modeling, Simulation, and Application of Cyber-Physical Energy Systems

Guest Editorial Modeling, Simulation, and Application of Cyber-Physical Energy Systems

Design, Modeling, and Simulation of On-Demand Communication Mechanisms for Cyber-Physical Energy Systems

Advanced communication technology is the enabling factor for distributed sensing and control in smart grid. The performance of communication has a significant effect on the performance of the controllers that manage a power system. This effect is more profound when transient level behavior and critical applications are concerned. In these cases, an important issue is to design control-aware communication strategies for utilizing available communication technologies. Such strategies should describe what needs to be communicated when and between which nodes. In this paper, an “on-demand” strategy is presented that describes how communication subsystems should be configured, almost agnostically to the underlying technologies, to achieve significant performance improvement for the application. The on-demand method relies on the concept of error-dependent communication for tracking dynamical systems over communication networks. The paper also introduces the design of an embedded communication simulator integrated with PSCAD for cosimulation of communication strategies/protocols and power system components.

Survey, Illustrations and Limits of Game Theory for Cyber-Physical Energy Systems

Abstract Cyber-physical systems integrate physical components and computational processes, setting up reciprocal feedback loops between them. The natural questions arising are how software processes can be integrated with the physical components in a clever way, and which algorithmic approaches have to be considered according to the objectives pursued. This paper presents a non-exhaustive review of game-theoretic approaches applied to cyber-physical energy systems.

Simulating Cyber-Physical Energy Systems: Challenges, Tools and Methods

The energy system of the future is expected to be composed of a large variety of technologies and applications. However, the diverse nature of these components, their interlinked topology, and the sheer size of the system lead to an unprecedented level of complexity. Industry is confronted with severe problems in designing interoperable grid components, analyzing system stability, and improving efficiency. This paper describes the main challenges of continuous time-based and discrete event-based models of such cyber-physical energy systems. Using a characteristic test model, the scalability of the two approaches is analyzed. The results show the strengths and weaknesses of these two fundamentally different modeling principles that need to be considered when working with large scale cyber-physical energy systems.

A Routing Scheme for Voltage Stabilization in Cyber Physical Energy Systems

Abstract The rapid advancement of smart grid technology has led to inundation of vast amount of sensors and distributed controllers into the grid which requires unconventional methods for treating problems like stability, reliability, etc. This paper deals with stabilization of grid dynamics after modeling it a Cyber-Physical Energy System. The design of the communication system between the sensors and the distributed controllers play an important role in achieving stability of bus voltages in the grid. A greedy-based network routing scheme was employed while considering both bandwidth and connection constraints. The approach was successfully tested over a sample 4-bus system.

Toward A Framework for Sustainable Cyber-Physical Energy Systems: Frequency Regulation Revisited

AbstractIn this paper we propose a possible framework for sustainable cyber-physical energy systems. Given any physical ecological system and its social governance which defines its objectives, the two combined represent a Socio-Ecological System (SES). Motivated by the general SES framework for sustainability proposed by a recent Nobel Prize winner Elinor Ostrom, we define a Socio-Ecological Energy System (SEES) framework first, its core variables and second-order variables whose characteristics can be used to assess the likelyhood of an SEES being sustainable. We then propose that such system can be greatly shaped by directly embedding cyber into its core variables, resources, governance and users. However, due to vast spatial dispersion of core variables and their poor mobility, it is not possible to align the second-order variables within an SEES without engineering a network system, both physical and cyber. This leads to introducing the taxonomy of deeper-order variables and interaction variables relevant for modeling the physical system. The objectives of cyber system design are to use sensing, communications, computing and control to coordinate the physical interactions variables to best align temporal and spatial characteristics of the core variables. Examples of several qualitatively different SEES architectures are shown in support of the main conjecture in this paper that not all architectures need the same cyber. Cyber, as everything else, must be designed with clear objectives. Recent trends toward smart grids are discussed using the proposed taxonomy. Simple examples are shown to illustrate the type of sensing and observation required by the controllers to ensure pre-defined performance. The inter-dependencies between the complexity of observation and control, on one side, and the performance are illustrated in light of frequency regulation for qualitatively different power grid architectures.

Efficient Utilization of Renewable Energy Sources by Gridable Vehicles in Cyber-Physical Energy Systems

The main sources of emission today are from the electric power and transportation sectors. One of the main goals of a cyber-physical energy system (CPES) is the integration of renewable energy sources and gridable vehicles (GVs) to maximize emission reduction. GVs can be used as loads, sources and energy storages in CPES. A large CPES is very complex considering all conventional and green distributed energy resources, dynamic data from sensors, and smart operations (e.g., charging/discharging, control, etc.) from/to the grid to reduce both cost and emission. If large number of GVs are connected to the electric grid randomly, peak load will be very high. The use of conventional thermal power plants will be economically expensive and environmentally unfriendly to sustain the electrified transportation. Intelligent scheduling and control of elements of energy systems have great potential for evolving a sustainable integrated electricity and transportation infrastructure. The maximum utilization of renewable energy sources using GVs for sustainable CPES (minimum cost and emission) is presented in this paper. Three models are described and results of the smart grid model show the highest potential for sustainability.

Modeling of Future Cyber–Physical Energy Systems for Distributed Sensing and Control

This paper proposes modeling the rapidly evolving energy systems as cyber-based physical systems. It introduces a novel cyber-based dynamical model whose mathematical description depends on the cyber technologies supporting the physical system. This paper discusses how such a model can be used to ensure full observability through a cooperative information exchange among its components; this is achieved without requiring local observability of the system components. This paper also shows how this cyber-physical model is used to develop interactive protocols between the controllers embedded within the system layers and the network operator. Our approach leads to a synergistic framework for model-based sensing and control of future energy systems. The newly introduced cyber-physical model has network structure-preserving properties that are key to effective distributed decision making. The aggregate load modeling that we develop using data mining techniques and novel sensing technologies facilitates operations of complex electric power systems.