Sparse Voltage Measurement-Based Fault Location Using Intelligent Electronic Devices

This paper proposes a fault-section location method based on sparse measurements, aimed at asymmetrical faults. A virtual current vector is defined to indicate the faulted section, which is sufficiently sparse except that the fault position corresponding entries are nonzero. To simplify the algorithm, the virtual vector is fixed by amplitudes of voltages and impedances and the feasibility is demonstrated. The Bayesian Compressive Sensing theory is introduced to reduce the number of required intelligent electronic devices (IEDs). In addition, the minimal number of IEDs and their allocation are discussed. The performance of the proposed method is validated in a 69-bus, 12.66 kV distribution system with six distributed generations (DGs) in response to various fault scenarios. The simulation results show that the method is robust for single-phase, double-phase, and double-phase to ground faults with high resistance under noisy condition. Furthermore, the method is applicable for networks with inverter interfaced DGs

Data Acquisition Applications

Data acquisition systems have numerous applications. This book has a total of 13 chapters and is divided into three sections: Industrial applications, Medical applications and Scientific experiments. The chapters are written by experts from around the world, while the targeted audience for this book includes professionals who are designers or researchers in the field of data acquisition systems. Faculty members and graduate students could also benefit from the book

Protection and fault management in active distribution systems

The integration of renewable energy resources (RES), as a type of distributed generation (OG) units, is increasing in distribution, systems. This integration, changes the topology, performance and the operational aspects of conventional distribution systems. Protection is one of the main issues that are affected after the high penetration of OGs. Therefore, new protection methods are necessary to guarantee the safety and the reliability of active distribution systems. On the other hand, most RESs are interfaced with the AC grids through power-electronic devices. These interfaces consist of at least one AC/DC conversion units. Hence, using OC distribution systems can contribute to the loss/cost reduction, as some power conversion stages are eliminated. Enhancement in system stability, reduction of power losses, and power quality 1 improvement are other advantages of OC networks. For these reasons as well as the simple integration of electronic loads that are supplied by OC power, the concept of OC distribution systems has attracted a considerable attention over the last years. In 1 fact, MVOC and LVDC grids can be an important part of the future distribution systems. Furthermore, AC and OC system can contribute to construct hybrid AC/DC distribution systems. According to these significant changes in the distribution systems, it is necessary to modify the algorithm of existing protection methods or to propose new protection schemes for both active AC and OC distribution systems. Moreover, in conventional distribution systems, loads are supplied by upstream grid, i.e. transmission lines; therefore, when a fault impacts the upstream grid and the faulty part disconnected by the protection system, all loads connected to distribution systems are disconnected as well. However, in active distribution systems, DGs can support the on-outage zones if the grid equipped with an appropriate fault management system. Therefore, automatic self-healing methods can increase the network reliability and power supply continuity. To provide the self-healing capability, distribution grids should be equipped with adequate algorithms that are able to guarantee the continuous and optima! operation for the isolated section of the grid. In this thesis, differences between protection issues in OC and AC systems are investigated and analyzed. Then, based on this analyze, effective protection and fault management methods are presented far OC distribution systems and microgrids. In the other part of this thesis, a fault management and self-healing algorithm is proposed far active distribution systems. The proposed methods have been evaluated by the hardware-in-the-loop approach using real-time simulators and suitable controllers.La creciente integración de recursos energéticos renovables en el sistema eléctrico ha propiciado el aumento de sistemas de generación distribuida (DG) en los sistemas de distribución. Esta integración,influye en la topologla, el rendimiento y los aspectos operacionales de los sistemas de distribución convencionales. Su impacto sobre los sistemas de protección es uno de los principales problemas que se derivan de la alta penetración de DG. Por ese motivo es preciso diseñar nuevos métodos y sistemas de protección que sean capaces de garantizar la seguridad y la fiabilidad de los sistemas de distribución activos. Por otro lado, la mayoria de sistemas de generación basados en renovables están interconectados con la red de AC a través de convertidores electrónicos de potencia.Estas interfaces consisten en unidades de conversión DC/AC. Por lo tanto, el uso de sistemas de distribución de corriente continua puede contribuir a la reducción de las pérdidas/ costes, ya que algunas etapas de conversión de energía pueden ser eliminadas. La mejora en la estabilidad del sistema, la reducción de las pérdidas de energía,y la mejora la calidad de energía son otras de las ventajas que las redes de corriente continua pueden ofrecer. Por estos motivos, junto con la fácil integración de cargas electrónicas alimentadas en OC, el concepto de sistemas de distribución en OC ha atraido una considerable atención en los últimos anos. De hecho, los sistemas MVDC y las redes LVDC están llamados a ser una parte importante delos sistemas de distribución y transmisión en el futuro. Además, los sistemas de conversión OC y AC pueden contribuir a la construcción de sistemas de distribución de AC I DC híbridos. De acuerdo con estos cambios, significativos en los sistemas de distribución, es necesario modificar el algoritmo y los métodos de protección existentes y proponer nuevos esquemas de protección tanto para los sistemas de distribución en AC como para los de OC. Por otra parte, en los sistemas de distribución convencionales, las cargas son alimentadas por la red aguas arriba, es decir;por las lineas de transmisión; Por lo tanto, cuando una falta se produce en la red aguas arriba la parte defectuosa es desconectada por el sistema de protección, asimismo todas las cargas conectadas a los sistemas de distribución se desconectan también. Sin embargo, en los sistemas de distribución activos, los sistemas DG pueden soportar las zonas de no disponibilidad si la red está equipada con un sistema de gestión de fallos. Por lo tanto, los métodos automáticos de 'self-healing' pueden contribuir a aumentar la continuidad y la fiabilidad del suministro en ta red. Para proporcionar la capacidad de 'self-healing', las redes de distribución deben estar equipadas con algoritmos adecuados que sean capaces de garantizar el funcionamiento continuo y óptimo para la sección aislada de la red. En esta tesis, las diferencias entre tas protecciones para sistemas de OC y CA son investigadas y analizadas. Luego, en base a este analísis, se presentarán los métodos de protección y gestión de fallos adecuados para los sistemas y microrredes de distribución OC. En la otra parte de esta tesis, se propone un algoritmo de gestión de fallos y 'self-healing ' para sistemas de distribución activos. Para validar los métodos propuestos se ha trabajado con plataformas hardware-in­ the-loop avanzado utilizando simuladores en tiempo real y controladores trabajando en base a plataformas de control reales

Detection and Mitigation of Cyber Attacks on Time Synchronization Protocols for the Smart Grid

The current electric grid is considered as one of the greatest engineering achievements of the twentieth century. It has been successful in delivering power to consumers for decades. Nevertheless, the electric grid has recently experienced several blackouts that raised several concerns related to its availability and reliability. The aspiration to provide reliable and efficient energy, and contribute to environment protection through the increasing utilization of renewable energies are driving the need to deploy the grid of the future, the smart grid. It is expected that this grid will be self-healing from power disturbance events, operating resiliently against physical and cyber attack, operating efficiently, and enabling new products and services. All these call for a grid with more Information and Communication Technologies (ICT). As such, power grids are increasingly absorbing ICT technologies to provide efficient, secure and reliable two-way communication to better manage, operate, maintain and control electric grid components. On the other hand, the successful deployment of the smart grid is predicated on the ability to secure its operations. Such a requirement is of paramount importance especially in the presence of recent cyber security incidents. Furthermore, those incidents are subject to an augment with the increasing integration of ICT technologies and the vulnerabilities they introduce to the grid. The exploitation of these vulnerabilities might lead to attacks that can, for instance, mask the system observability and initiate cascading failures resulting in undesirable and severe consequences. In this thesis, we explore the security aspects of a key enabling technology in the smart grid, accurate time synchronization. Time synchronization is an immense requirement across the domains of the grid, from generation to transmission, distribution, and consumer premises. We focus on the substation, a basic block of the smart grid system, along with its recommended time synchronization mechanism - the Precision Time Protocol (PTP) - in order to address threats associated with PTP, and propose practical and efficient detection, prevention, mitigation techniques and methodologies that will harden and enhance the security and usability of PTP in a substation. In this respect, we start this thesis with a security assessment of PTP that identifies PTP security concerns, and then address those concerns in the subsequent chapters. We tackle the following main threats associated with PTP: 1) PTP vulnerability to fake timestamp injection through a compromised component 2) PTP vulnerability to the delay attack and 3) The lack of a mechanism that secures the PTP network. Next, and as a direct consequence of the importance of time synchronization in the smart grid, we consider the wide area system to demonstrate the vulnerability of relative data alignment in Phasor Data Concentrators to time synchronization attacks. These problems will be extensively studied throughout this thesis, followed by discussions that highlight open research directions worth further investigations