Optimal Wind Bidding Strategies in Day-Ahead Markets

This paper presents a computer application for wind energy bidding in a day-ahead electricity market to better accommodate the variability of the energy source. The computer application is based in a stochastic linear mathematical programming problem. The goal is to obtain the optimal bidding strategy in order to maximize the revenue. Electricity prices and financial penalties for shortfall or surplus energy deliver are modeled. Finally, conclusions are drawn from an illustrative case study, using data from the day-ahead electricity market of the Iberian Peninsula

An Integrated Research Infrastructure for Validating Cyber-Physical Energy Systems

Renewables are key enablers in the plight to reduce greenhouse gas emissions and cope with anthropogenic global warming. The intermittent nature and limited storage capabilities of renewables culminate in new challenges that power system operators have to deal with in order to regulate power quality and ensure security of supply. At the same time, the increased availability of advanced automation and communication technologies provides new opportunities for the derivation of intelligent solutions to tackle the challenges. Previous work has shown various new methods of operating highly interconnected power grids, and their corresponding components, in a more effective way. As a consequence of these developments, the traditional power system is being transformed into a cyber-physical energy system, a smart grid. Previous and ongoing research have tended to mainly focus on how specific aspects of smart grids can be validated, but until there exists no integrated approach for the analysis and evaluation of complex cyber-physical systems configurations. This paper introduces integrated research infrastructure that provides methods and tools for validating smart grid systems in a holistic, cyber-physical manner. The corresponding concepts are currently being developed further in the European project ERIGrid.Comment: 8th International Conference on Industrial Applications of Holonic and Multi-Agent Systems (HoloMAS 2017

IP-XACT for Smart Systems Design: Extensions for the Integration of Functional and Extra-Functional Models

Smart systems are miniaturized devices integrating computation, communication, sensing and actuation. As such, their design can not focus solely on functional behavior, but it must rather take into account different extra-functional concerns, such as power consumption or reliability. Any smart system can thus be modeled through a number of views, each focusing on a specific concern. Such views may exchange information, and they must thus be simulated simultaneously to reproduce mutual influence of the corresponding concerns. This paper shows how the IP-XACT standard, with some necessary extensions, can effectively support this simultaneous simulation. The extended IP-XACT descriptions allow to model extra-functional properties with a homogeneous format, defined by analysing requirements and characteristic of three main concerns, i.e., power, temperature and reliability. The IP-XACT descriptions are then used to automatically generate a skeleton of the simulation infrastructure in SystemC. The skeleton can be easily populated with models available in the literature, thus reaching simultaneous simulation of multiple concerns

Modeling and Simulation of Cyber-Physical Electrical Energy Systems with SystemC-AMS

Modern Cyber-Physical Electrical Energy Systems (CPEES) are characterized by wider adoption of sustainable energy sources and by an increased attention to optimization, with the goal of reducing pollution and wastes. This imposes a need for instruments supporting the design flow, to simulate and validate the behavior of system components and to apply additional optimization and exploration steps. Additionally, each system might be tested with a number of management policies, to evaluate their economic impact. It is thus evident that simulation is a key ingredient in the design flow of CPEES. This paper proposes a framework for CPEES modeling and simulation, that relies on the open-source standard SystemC-AMS. The paper formalizes the information and energy flow in a generic CPEES, by focusing on both AC and DC components, and by including support for mechanical and physical models that represent multiple energy sources and loads. Experimental results, applied to a complex CPEES case study, will prove the effectiveness of the proposed solution, in terms of accuracy, speed up w.r.t. the current state of the art Matlab/Simulink, and support for the design flow

Design, modelling, simulation and integration of cyber physical systems: Methods and applications

The main drivers for the development and evolution of Cyber Physical Systems (CPS) are the reduction of development costs and time along with the enhancement of the designed products. The aim of this survey paper is to provide an overview of different types of system and the associated transition process from mechatronics to CPS and cloud-based (IoT) systems. It will further consider the requirement that methodologies for CPS-design should be part of a multi-disciplinary development process within which designers should focus not only on the separate physical and computational components, but also on their integration and interaction. Challenges related to CPS-design are therefore considered in the paper from the perspectives of the physical processes, computation and integration respectively. Illustrative case studies are selected from different system levels starting with the description of the overlaying concept of Cyber Physical Production Systems (CPPSs). The analysis and evaluation of the specific properties of a sub-system using a condition monitoring system, important for the maintenance purposes, is then given for a wind turbine

Cost-aware design and simulation of electrical energy systems

One fundamental dimension in the design of an electrical energy system (EES) is the economic analysis of the possible design alternatives, in order to ensure not just the maximization of the energy output but also the return on the investment and the possible profits. Since the energy output and the economic figures of merit are intertwined, for an accurate analysis it is necessary to analyze these two aspects of the problem concurrently, in order to define effective energy management policies. This paper achieves that objective by tracking and measuring the energy efficiency and the cost effectiveness in a single modular framework. The two aspects are modeled separately, through the definition of dedicated simulation layers governed by dedicated virtual buses that elaborate and manage the information and energy flows. Both layers are simulated concurrently within the same simulation infrastructure based on SystemC-AMS, so as to recreate at runtime the mutual influence of the two aspects, while allowing the use of different discrete time scales for the two layers. Thanks to the tight coupling provided by the single simulation engine, our method enables a quick estimation of various cost metrics (net costs, annualized costs, and profits) of any configuration of EES under design, via an informed exploration of the alternatives. To prove the effectiveness of this approach, we apply the proposed strategy to two EES case studies, we explored various management strategies and the presence of different types and numbers of power sources and energy storage devices in the EES. The analysis proved to allow the identification of the optimal profitable solutions, thereby improving the standard design and simulation flow of EES

Systematic review of features for co‐simulating security incidents in Cyber‐Physical Systems

Cyber-Physical Systems (CPS) and Internet-of-Things (IoT) plus energy are the enabling technology of modern power systems also known as the Smart Grid (SG). A SG may consist of thousands of interconnected components communicating and exchanging data across layers that stretch beyond technical capabilities, for instance, markets and customer interactions. Cyber-physical security is a major source of concern due to the high reliance of the SG on Information and Communication Technologies (ICT) and their widespread use. Addressing security requires developing modeling and simulation tools that approximate and replicate adversarial behavior in the SG. These tools have in fact two simulators, one handling continuous power flows and another for capturing the discrete behavior when communicating across CPS or IoT components. The technique of composing two models of computation in a global simulation of these coupled systems is called co-simulation. Although there are many frameworks and tools for co-simulation, the set of features for modeling cyber-physical security incidents in the SG lacks thorough understanding. We present a systematic review of features and tools for co-simulating these concerns in CPS. We also highlight and discuss research gaps with respect to the most used tools in industry and academia and comment on their relevant features

Arquitecturas system-on-chip para cyber physical system gateway en smart grid

178 p.La forma en que funciona la red eléctrica no ha cambiado mucho desde su creación en la década de 1930, los métodos y medios de transmisión de los datos siguen siendo similares. Aunque la infraestructura general permanece inalterada, algunas tecnologías han cambiado desde entonces, y el ritmo de cambio ha aumentado significativamente en la última década. Por ejemplo, la introducción de las Tecnologías de la Información y las Comunicaciones (TICs) en la operación de las redes eléctricas ha dado como resultado una red compleja denominada Smart Grid. En términos generales, el sistema eléctrico actual consiste en una compleja red en la que están interconectadas las centrales eléctricas, la infraestructura de transporte de electricidad, la infraestructura de distribución, y la carga.Desde un punto de vista tecnológico, la Smart Grid puede ser vista como una superposición de una red de comunicación sobre la red eléctrica. La red de comunicaciones de la Smart Grid es un tipo de red capaz de proporcionar servicios avanzados, como el envío de datos de sensores en tiempo real, la redundancia y la ciber-seguridad. Se implementa utilizando una variedad de tecnologías de redes y medios de comunicación, incluyendo el mismo cableado eléctrico, redes inalámbricas y otras infraestructuras de comunicaciones existente, como las redes Ethernet basadas en cables de cobre o fibra óptica. Existen ventajas y desventajas asociadas a cada opción y es probable que los tres enfoques puedan utilizarse para las comunicaciones en la Smart Grid. Como resultado, las redes mencionadas se integran finalmente en el sistema, lo que obliga a que los equipos utilizados para gestionar las comunicaciones sean completamente heterogéneos. Por ello, desde una perspectiva global que favorezca la interoperabilidad, es imprescindible disponer de dispositivos de comunicaciones que combinen requisitos de procesamiento en tiempo real, sincronización avanzada, alta disponibilidad en las comunicaciones, reconfigurabilidad y ciber-seguridad. Estos dispositivos se conocen comúnmente como Cyber Physical System (CPS).A modo de resumen, un CPS típico se compone de varios dispositivos conectados a través de redes cableadas e inalámbricas. Estos dispositivos abarcan desde plataformas embebidas, sistemas en tiempo real, sensores y actuadores, hasta dispositivos en red. Por lo tanto, los CPS se benefician de los continuos desarrollos de nuevas plataformas de computación y sensórica de bajo coste, las comunicaciones inalámbricas, las redes de comunicación de gran ancho de banda y sistemas que permiten realizar una gestión más eficiente de la energía de los dispositivos.La propuesta de investigación presentada en esta tesis busca realizar contribuciones en el campo de los sistemas embebidos, planteando una arquitectura común de nodos que sirva como referencia de arquitectura CPS para la Smart Grid. Esta arquitectura deberá dar solución a la integración directa de los nodos en la red, permitiendo a su vez procesamiento en tiempo real, necesario en ciertas secciones y operaciones de la Smart Grid.En primer lugar, se presentará una visión general de la red eléctrica actual (Smart Grid). En particular, se describirá los elementos fundamentales de una subestación, y se presentará los estándares de comunicación utilizados para garantizar y satisfacer los requisitos de interoperatividad que deben cumplir las redes de transmisión y distribución modernas. A continuación, se describirán los requisitos y las características de funcionamiento que debe cumplir un dispositivo CPS Gateway para poder ser utilizado en la red eléctrica inteligente. Por otra parte, se definirá un CPS y se describirán sus partes, características y campos de aplicación. A continuación, se realizará un estudio detallado de varias arquitecturas existentes que representan ventajas significativas para su utilización en la Smart Grid. En segundo lugar, se propondrán arquitecturas CPS Gateway sobre plataformas reconfigurables System-on-Chip que garantice procesamiento en tiempo real, necesario en ciertas secciones y operaciones de la Smart Grid. También, deberá incorporar mecanismos avanzados de sincronización, comunicaciones de alta disponibilidad mediante comunicaciones redundantes, compatibilidad con la infraestructura de automatización de subestaciones actualmente en fase de despliegue (IEC 61850) y ciber-seguridad para las tramas SV y GOOSE.Para finalizar, el dispositivo Zynq de Xilinx será utilizado como plataforma de validación de las arquitecturas propuestas. La última parte de la tesis, describirá el hardware utilizado para realizar los experimentos. A continuación, se describirán los experimentos realizados para validar las arquitecturas. En este sentido, se implementarán tres arquitecturas para verificar el funcionamiento del CPS Gateway. La primera arquitectura, tendrá como finalidad validar los requisitos de sincronización, interoperabilidad y alta disponibilidad. En la segunda arquitectura se implementará un protocolo y un módulo de comunicaciones que permita la configuración remota del CPS Gateway. Finalmente en la tercera arquitectura se propondrá el uso de cifrado simétrico como mecanismo de ciber-seguridad para las tramas SV y GOOSE

Microrrede no âmbito da energia 4.0 face a incerteza e risco e ao mercado de eletricidade

Esta tese incide sobre o tema da gestão e planeamento de operação de uma microrrede no âmbito da Energia 4.0 por parte do novo agente de mercado, dito de agregador da microrrede. O agregador da microrrede tem como objetivo a maximização do lucro esperado, resultante da participação em mercado de eletricidade. A microrrede inclui fontes de produção distribuída, nomeadamente, microturbinas, eólica, fotovoltaica, armazenamento de energia, veículos elétricos, ditas de microfontes, e o uso de energia, dito de carga. O planeamento é fundamental não só para a microrrede ser um sistema sustentável de energia, mas também para a participação de fontes de energia renováveis integradas em microrrede numa matriz energética mais ampla. É necessário face à incerteza e risco e ao mercado de eletricidade a tomada de decisões apoiadas por um sistema de suporte e informação, que constitui o sistema de suporte de gestão da microrrede, que é vital para a sustentabilidade deste agente de mercado. O sistema de suporte de gestão da microrrede em estudo é baseado na formulação de um problema de programação estocástica linear inteira mista que depende do conhecimento dos processos estocásticos que descrevem os parâmetros incertos. Os parâmetros incertos são descritos por um conjunto de cenários plausíveis apropriados à representação dos eventos que ocorrem na microrrede. Atendendo ao elevado grau de incerteza e às limitações computacionais os cenários são reduzidos a um número razoável de cenários representativos. Ainda, o sistema de suporte de gestão da microrrede permite ao agregador da microrrede apresentar propostas de licitação confiáveis ao considerar o risco na tomada de decisão. Por fim, casos de estudo são simulados com intuito de avaliar o desempenho da microrrede e validar a metodologia em que é baseado o sistema de suporte de gestão da microrrede nesta tese; Abstract: Microgrid under the scope of Energy 4.0 facing uncertainty and risk and electricity markets This thesis focuses on the management and operation planning of a microgrid within the scope of Energy 4.0 by the new market agent, said to be the microgrid aggregator. The microgrid aggregator's goal is to maximize the expected profit, resulting from the participation in the electricity market. The microgrid includes sources of distributed production, namely, microturbines, wind, photovoltaic, energy storage, electric vehicles, called micro-sources, and the use of energy, said to be the load. Planning is fundamental not only for the microgrid to be a sustainable energy system but also for the participation of renewable energy sources integrated into the microgrid in a broader energy matrix. It is necessary for the facing of uncertainty and risk and the electricity market to make decisions supported by a support and information system, which constitutes the microgrid support management system, which is vital for the sustainability of this market agent. The microgrid support management system under study is based on the formulation of a mixed-integer linear stochastic programming problem that depends on knowledge of the stochastic processes that describe the uncertain parameters. The uncertain parameters are described by a set of plausible scenarios suitable to represent the events that occur in the microgrid. Given the high degree of uncertainty and the computational limitations, the scenarios are reduced to a reasonable number of representative scenarios. Also, the microgrid support management system allows the microgrid aggregator to present reliable bidding proposals taking into account risk in decision making. Finally, case studies are simulated to assess the performance of the microgrid and validate the methodology on which the microgrid support management system in this thesis is based