Communication Technologies for Smart Grid: A Comprehensive Survey

With the ongoing trends in the energy sector such as vehicular electrification and renewable energy, smart grid is clearly playing a more and more important role in the electric power system industry. One essential feature of the smart grid is the information flow over the high-speed, reliable and secure data communication network in order to manage the complex power systems effectively and intelligently. Smart grids utilize bidirectional communication to function where traditional power grids mainly only use one-way communication. The communication requirements and suitable technique differ depending on the specific environment and scenario. In this paper, we provide a comprehensive and up-to-date survey on the communication technologies used in the smart grid, including the communication requirements, physical layer technologies, network architectures, and research challenges. This survey aims to help the readers identify the potential research problems in the continued research on the topic of smart grid communications

Automatic fault location in electrical distribution networks with distributed generation

Nowadays the electrical network is continuously evolving due to the increasing deployment of Information Technologies and the Distribution Energy Resources. This scenario affects directly to the quality of service in the electrical distribution networks. For this reason, the Power Quality is a key important concern to make the electrical network evolve towards a Smart Grid. Power quality is defined through three important focal points: availability, wave quality and commercial quality. The presence of the Distribution Energy Resources in the current electrical distribution network is showing a new scenario where the fault detection is more complex due to the flow current is in both directions. This thesis is focused in the analysis of several methods to locate a fault in electrical distribution network and also how the current communication standards can improve considerably this fault location. It is important to remark that the main contribution of this thesis is in the analysis of several propositions and algorithms to enhance the fault location in a distribution network using the current Intelligent Electronic Device with international standards such as IEC 61850. All of these algorithms have been focused to work in a mesh distribution networks. Another important contribution of this thesis is in the adaptive protection system in order to isolate correctly the fault in a ring system distribution. Although this proposition could be extended to a mesh network where the elements of the network can operate under a fault. Finally, the thesis concludes that the use of communication standards and Internet of Things with current developed Intelligent Electronic Devices technology can contribute significantly to enhance the current and future electrical network distribution.La xarxa elèctrica evoluciona contínuament a causa del creixent desplegament de les Tecnologies de la Informació i dels Recursos Energètics Distribuïts. Aquest escenari afecta directament a la qualitat de servei de les xarxes de distribució elèctrica. Per aquest motiu, el mantenir i millorar el nivell de qualitat d'energia és un punt clau per fer evolucionar la xarxa elèctrica cap a una xarxa Smart Grid. Aquesta qualitat de l'energia es defineix per medi de de tres punts importants: disponibilitat, qualitat d'ona i qualitat comercial. La presència dels Recursos Energètics Distribuïts mostra un nou escenari en què la detecció de defectes es complica afectant a la disponibilitat del servei. Aquesta tesi es centra principalment en l'anàlisi de diversos mètodes per localitzar un defecte a la xarxa de distribució elèctrica i també en com l'ús dels estàndards de comunicació actuals poden contribuir considerablement a la localització del defecte. És important remarcar que la principal contribució d'aquest document ha estat en l'anàlisi de diverses proposicions i algoritmes per millorar la localització de faltes en una xarxa de distribució utilitzant Dispositius Electrònics Intel·ligents amb estàndards internacionals com l'IEC 61850. Tots aquests algoritmes han estat definits per treballar en xarxes de distribució mallades. Una altra contribució important d'aquesta tesi es troba en el sistema de protecció adaptatiu per tal d'aïllar correctament el defecte en una distribució del sistema d'anell amb interruptors automàtics. Aquesta proposta es podria ampliar a una xarxa mallada. Finalment, la tesi conclou amb que l'ús d'estàndards de comunicació i l'Internet of Things en combinació amb Dispositius Electrònics Intel·ligents, desenvolupats actualment, poden contribuir significativament a millorar la distribució de la xarxa elèctrica actual i futura.Postprint (published version

Security protocols suite for machine-to-machine systems

Nowadays, the great diffusion of advanced devices, such as smart-phones, has shown that there is a growing trend to rely on new technologies to generate and/or support progress; the society is clearly ready to trust on next-generation communication systems to face today’s concerns on economic and social fields. The reason for this sociological change is represented by the fact that the technologies have been open to all users, even if the latter do not necessarily have a specific knowledge in this field, and therefore the introduction of new user-friendly applications has now appeared as a business opportunity and a key factor to increase the general cohesion among all citizens. Within the actors of this technological evolution, wireless machine-to-machine (M2M) networks are becoming of great importance. These wireless networks are made up of interconnected low-power devices that are able to provide a great variety of services with little or even no user intervention. Examples of these services can be fleet management, fire detection, utilities consumption (water and energy distribution, etc.) or patients monitoring. However, since any arising technology goes together with its security threats, which have to be faced, further studies are necessary to secure wireless M2M technology. In this context, main threats are those related to attacks to the services availability and to the privacy of both the subscribers’ and the services providers’ data. Taking into account the often limited resources of the M2M devices at the hardware level, ensuring the availability and privacy requirements in the range of M2M applications while minimizing the waste of valuable resources is even more challenging. Based on the above facts, this Ph. D. thesis is aimed at providing efficient security solutions for wireless M2M networks that effectively reduce energy consumption of the network while not affecting the overall security services of the system. With this goal, we first propose a coherent taxonomy of M2M network that allows us to identify which security topics deserve special attention and which entities or specific services are particularly threatened. Second, we define an efficient, secure-data aggregation scheme that is able to increase the network lifetime by optimizing the energy consumption of the devices. Third, we propose a novel physical authenticator or frame checker that minimizes the communication costs in wireless channels and that successfully faces exhaustion attacks. Fourth, we study specific aspects of typical key management schemes to provide a novel protocol which ensures the distribution of secret keys for all the cryptographic methods used in this system. Fifth, we describe the collaboration with the WAVE2M community in order to define a proper frame format actually able to support the necessary security services, including the ones that we have already proposed; WAVE2M was funded to promote the global use of an emerging wireless communication technology for ultra-low and long-range services. And finally sixth, we provide with an accurate analysis of privacy solutions that actually fit M2M-networks services’ requirements. All the analyses along this thesis are corroborated by simulations that confirm significant improvements in terms of efficiency while supporting the necessary security requirements for M2M networks

Integrating Low Voltage Distribution Systems to Distribution Automation

The aim of this thesis is to define and study the key elements and the main characteris-tics of the integration of the low voltage (LV) distribution systems to distribution auto-mation (DA). The key elements are defined by studying the development of essential systems in LV distribution networks as well as by studying the development of the net-works by way of evolution phases. The key elements and the main characteristics of the integration to DA are illustrated by a certain model of a LV distribution network under its development. For a start DA is reviewed by generally used functions and by technologies. The review includes the data and the information systems and in addition the communication net-works are studied generally. Thereafter the main elements of LV distribution networks are presented and their evolution visions are introduced. The main elements comprises of the distribution network, distributed generation, smart energy metering, electric vehicles and energy storages. The approach to the integration is the evolution of LV distribution networks, so four main evolution phases are introduced; traditional, boom of distributed generation, mi-crogrid and intelligent microgrid. The evolution phases bases on general research publi-cations and visions of Smart Grids. Management architectures for the networks are pre-sented. Also requirements for communication are evaluated by studying the number of nodes, capacity requirements for transferred data types and fault and event frequencies. In order to define a proposal for integrating LV distribution networks to DA, the man-agement architectures and the studied requirements are compared to produce functions for DA. As a result, the proposal is presented based on the studied architectures and re-quirements. In addition considerable issues are introduced relating to the functions in devices or sub-systems, which are needed for DA applications. This thesis indicates the need for further studies, such as: Which are the desired DA functions to be extended to LV distribution networks? Which device or system should offer the desired functions? How well the potential protocols using some media type serves the functions?fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

Contribution to the traffc engineering in wireless mesh networks

Premi extraordinari doctorat UPC curs 2019-2020, àmbit d’Enginyeria de les TICNowadays, we live in a modern society in which people and devices are interconnected anywhere and anytime. Under this premise, both the infrastructure and the services offered have evolved and diversified in a drastic way. In fact, many of these services are transported in decentralized networks. Among them, Wireless mesh networks are decentralized networks that have been widely studied in different research areas such as community networks, public safety and surveillance. Wireless mesh networks have been also studied and evaluated in the Smart Grid scenario. Smart Grids are a new paradigm in which the electricity network is no longer focused only on the generation, distribution and transport of electricity to subscribers. Now, it is a robust network that includes a data communication network. The associated data network is divided in different subnetworks. This thesis is mainly focused on the improvement of the performance of one of those subnetworks, the so-called Smart Grid Neighborhood Area Network. Several applications are transmitted between the users and the control center. In general, upstream communication involves tasks such as meter reading, billing data or electricity consumption, while downstream communication allows the smart grid to take actions in different network situations such as power peaks or emergency situations. In the first part, the work is focused on improving the routing mechanism. To do this, a multipath routing mechanism is proposed, where the traffics that are most important are transmitted over the best communication links. In order to improve even more the benefits obtained, a multichannel scheme is proposed to separate both control traffic and data traffic, and use the less congested channels to transmit the most priority traffic types.Smart Grids offer many services and some of them are very demanding in terms of QoS. Besides, infrastructure failures, attacks and high congestion situations can greatly reduce the network performance. Therefore, the network must be able to offer a minimum QoS to the most priority applications handling some traffic control techniques. With this goal in mind, in this thesis some congestion control mechanisms are also proposed. In the first of these mechanisms, the decision of whether a packet should be retransmitted or not is made in a distributed and independent way by each one of the network nodes, depending on the network conditions that the node itself is observing. This mechanism considers again the existence of traffics with different priorities, so that, less priority traffic has a higher probability of being discarded. Furthermore, an emergency system is coupled to the congestion control mechanism. With this strategy, the NAN is able to take global actions (in a short time) to face anomalous situations.In a Smart grid scenario, the nodes are static and each of them transmits upstream data flows to the data concentrator. Therefore, depending on their geographical location, some nodes may be more favored than others. Besides, some nodes can monopolize the network resources if they are not regulated. For this reason, in this thesis another distributed solution is proposed that runs in each node. The objective here is to provide a fair distribution of network resources regardless of the geographical position and the transmission rate. The last contribution is focused on the application of machine learning techniques to obtain again a better performance of the data networks under study. In this sense, a new congestion control mechanism is proposed, which, like the previous ones, provides different quality of service to data flows with different priorities. For this, a complete framework is proposed, including the generation, preprocessing and evaluation of the data necessary for the training of the machine learning algorithms that will be used. The proposal is also implemented and evaluated in the Smart Grid NANs environmentAvui dia, vivim en una societat en què les persones i els dispositius estan interconnectats en qualsevol lloc i en qualsevol moment. Sota aquesta premissa, la infraestructura com els serveis oferts han evolucionat i diversificat de manera dràstica. De fet, molts d'aquests serveis s'envien en xarxes descentralitzades. Entre elles, les xarxes de malla sense fils són xarxes descentralitzades que han estat àmpliament estudiades en diferents àrees com xarxes comunitàries, seguretat pública i vigilància. Les xarxes de malla sense fils també s'han estudiat i avaluat en les xarxes elèctriques intel·ligents. Aquestes xarxes són un nou paradigma on la xarxa elèctrica ja no es centra només en la generació, distribució i transport d'electricitat als subscriptors. Ara, és una xarxa robusta que inclou una xarxa de comunicació de dades. La xarxa de dades associada es divideix en diferents subxarxes. Aquesta tesi se centra a millorar el rendiment d'una d'aquestes subxarxes, l'anomenada xarxa d'àrea de veïnatge de les xarxes elèctriques intel·ligents. Diverses aplicacions s'envien entre els usuaris i el centre de control. En general, la comunicació de pujada implica la lectura de mesuradors, dades de facturació o consum elèctric, mentre que la comunicació de baixada permet que la xarxa intel·ligent prengui mesures davant diferents situacions, com pics d'energia o d'emergència. La primera part de la feina es centra a millorar el mecanisme d'enrutament. Per això, es proposa un mecanisme de múltiples rutes, on els tràfics més prioritaris s'envien a través dels millors enllaços de comunicació. A més, es proposa un esquema multicanal per separar el tràfic de control del de dades, i utilitzar els canals menys congestionats per enviar les dades més prioritàries.Les xarxes elèctriques intel·ligents ofereixen molts serveis i alguns són exigents en termes de qualitat de servei (QoS). A més, les falles d'infraestructura, els atacs i les situacions d'alta congestió poden reduir el seu rendiment. Per tant, la xarxa ha d'oferir una QoS mínima a les aplicacions més prioritàries mitjançant algunes tècniques de control de tràfic. Amb aquest objectiu, en aquesta tesi també es proposen alguns mecanismes de control de congestió. En el primer d'aquests mecanismes, cada node de forma distribuïda i independent, decideix si un paquet s¿ha de retransmetre o no depenent de les condicions de la xarxa que el mateix node està observant. Aquest mecanisme considera novament tràfics amb diferents prioritats, de manera que, el tràfic menys prioritari té una major probabilitat de ser descartat. A més, un sistema d'emergència està acoblat amb el mecanisme de control de congestió. Amb això, la xarxa pot prendre accions globals (en poc temps) per enfrontar situacions anòmales.A les xarxes elèctriques intel·ligents, els nodes són fixos i cadascun envia dades a un concentrador de dades. Per tant, depenent de la seva ubicació geogràfica, alguns nodes poden ser més afavorits que altres. A més, alguns nodes poden monopolitzar els recursos de xarxa si no són regulats. A causa d'això, en aquesta tesi es proposa una altra solució distribuïda que s'executa en cada node. L'objectiu és proveir una distribució justa dels recursos de la xarxa, independent de la posició geogràfica i la velocitat de transmissió. L'última contribució es centra en l'aplicació de tècniques d'aprenentatge automàtic per obtenir de nou un millor rendiment de les xarxes de dades en estudi. En aquest sentit, es proposa un nou mecanisme de control de congestió que, a l'igual que els anteriors, proveeix diferent qualitat de servei d'acord amb la prioritat de les dades. Per això, es proposa un sistema, que inclou la generació, el processament i l'avaluació de les dades necessàries per a l'entrenament dels algoritmes d'aprenentatge que s'utilitzaran. La proposta també s'implementa i avalua a l'entorn de les xarxes elèctriques intel·ligents en l'entorn de Smart Grid NANsHoy en día, vivimos en una sociedad moderna en la que las personas y los dispositivos están interconectados en cualquier lugar y en cualquier momento. Bajo esta premisa, tanto la infraestructura como los servicios ofrecidos han evolucionado y diversificado de manera drástica. De hecho, muchos de estos servicios se transportan en diferentes tipos de redes. Las redes descentralizadas (o sin infraestructura) se están utilizando ampliamente para soportar estos servicios. Permiten una mayor accesibilidad para los usuarios debido a una gran cantidad de ventajas. Por ejemplo, la creación automática, la configuración automática, la instalación fácil en áreas de difícil acceso, mantenimiento y escalabilidad hacen que este tipo de redes sean atractivas para los proveedores de servicios. Entre ellas, las redes de malla inalámbricas son redes descentralizadas que han sido ampliamente estudiadas en diferentes áreas de investigación, como redes comunitarias, escenarios de desastres, seguridad pública y vigilancia. Además, estos tipos de red son más estructurados que las redes ad hoc inalámbricas tradicionales y, por lo tanto, pueden admitir protocolos más complejos. Las redes de malla inalámbricas también se han estudiado y evaluado en el escenario de redes eléctricas inteligentes. Las redes eléctricas inteligentes son un nuevo paradigma en el que se abordan las infraestructuras tradicionales de transporte de electricidad. En este contexto, la red eléctrica ya no se centra solo en la generación, distribución y transporte de electricidad a los suscriptores. Ahora, es una red robusta que incluye una red de comunicación de datos. El objetivo de tener una red de comunicación de datos junto con la eléctrica es proporcionar un servicio eficiente desde el centro de control al usuario, así como dar retroalimentación sobre el correcto funcionamiento de las redes de electricidad y datos al centro de control. Como la infraestructura de transporte eléctrico, la red de datos asociada se divide en diferentes subredes. Esta tesis se centra principalmente en la mejora del rendimiento de una de esas subredes, la llamada red de área de vecindad de las redes electrices inteligentes. Las contribuciones se centran en mejorar el enrutamiento de datos, proporcionando una diferenciación del tráfico con la provisión de calidad de servicio (QoS), mecanismos de control de congestión, un sistema de emergencia que trata situaciones anómalas de la red y una distribución justa de los recursos de la red. Varias aplicaciones se transmiten desde los usuarios al centro de control, así como desde el centro de control hacia los usuarios. En general, la comunicación hacia el centro de control implica tareas como la lectura de medidores, los datos de facturación o el consumo de electricidad, mientras que la comunicación hacia los suscriptores permite que la red eléctrica inteligente tome medidas en diferentes situaciones de la red, como picos de energía o situaciones de emergencia. En la primera parte de la tesis, el trabajo se centra en mejorar el mecanismo de enrutamiento. Para hacer esto, se propone un mecanismo de enrutamiento de múltiples rutas, donde los tráficos que son más importantes se transmite a través de los mejores enlaces de comunicación, mientras que los tráficos de menor prioridad se transmiten a través de las rutas con menos reputación (menos métrica de enrutamiento). Para mejorar aun más los beneficios obtenidos, se propone un esquema multicanal para separar tanto el tráfico de control como el tráfico de datos, y utilizar los canales menos congestionados para transmitir los tipos de tráfico más prioritarios. Las redes eléctricas inteligentes ofrecen muchos servicios y algunos de ellos son muy exigentes en términos de QoS. Por lo tanto, las fallas de infraestructura, los ataques y las situaciones de alta congestión pueden reducir en gran medida el rendimiento de la red. Para enfrentar estos problemas, la red debe poder ofrecer una calidad de servicio mínima a las aplicaciones más prioritarias mediante algunas técnicas de control de tráfico. Con este objetivo en mente, en esta tesis también se proponen algunos mecanismos de control de congestión. En el primero de estos mecanismos, cada uno de los nodos de la red decide de manera distribuida e independiente si un paquete debe o no ser retransmitido, dependiendo de las condiciones de la red (principalmente la utilización promedio del canal y la ocupación de los buffers) que el nodo mismo está observando. Es decir, un nodo intermedio puede descartar directamente un paquete de datos si observa que el canal de transmisión se está utilizando por encima de un cierto umbral. Este mecanismo considera nuevamente la existencia de tráficos con diferentes prioridades, de modo que, el tráfico menos prioritario tiene una mayor probabilidad de ser descartado. Además, un sistema de emergencia está acoplado al mecanismo de control de congestión. Con esta estrategia, la NAN puede tomar acciones globales (en poco tiempo) para enfrentar situaciones anómalas, lo que proporciona aún más probabilidad de transmisión para tráficos con mayores requisitos de QoS. Con este fin, también se propone una señalización de emergencia que puede activarse automática o manualmente. Una distribución justa de los recursos de la red también es un campo de investigación importante en las redes eléctricas inteligentes. Tenga en cuenta que, en este escenario, los nodos son estáticos y cada uno de ellos transmite flujos de datos hacia al concentrador de datos. Por lo tanto, dependiendo de su ubicación geográfica, algunos nodos pueden ser más favorecidos que otros. Además, algunos nodos pueden monopolizar los recursos de la red si no están regulados. Por esta razón, en esta tesis se propone otro algoritmo de control de congestión distribuido que se ejecuta en cada nodo. El objetivo aquí es proporcionar una distribución justa de los recursos de la red, independientemente de la posición geográfica y la velocidad de transmisión. Es decir, todos los nodos tendrán las mismas oportunidades para transmitir sus datos al centro de control. La solución propuesta es independiente de la red, mac y capas físicas. La última contribución realizada con esta tesis se centra en la aplicación de técnicas de aprendizaje automático para obtener nuevamente un mejor rendimiento de las redes de datos en estudio. En este sentido, se propone un nuevo mecanismo de control de congestión que, al igual que los anteriores, proporciona diferente calidad de servicio a los flujos de datos con diferentes prioridades. Para esto, se propone un marco completo, que incluye la generación, el preprocesamiento y la evaluación de los datos necesarios para la capacitación de los algoritmos de aprendizaje automático que se utilizarán. La propuesta también se implementa y evalúa en el entorno de Smart Grid NANs.Award-winningPostprint (published version

Smart grid technology deployment and impact assessment at eThekwini electricity.

M. Sc. Eng. University of KwaZulu-Natal, Durban 2014.The world‟s population is increasing rapidly and is projected to reach 8 billion within the next few decades. Urban migration is also on the rise and it is estimated that there would be significant growth in Africa and more Africans will reside in urban rather than rural areas by 2030. eThekwini, as a leading city in Africa has to establish practices to enable that it utilizes its current resources optimally and sustainably to cater for its future energy and resource requirements. The role of Smart Grid (SG) systems as an electricity industry enabler has been recognized throughout the developed world. The effective introduction and implementation of SGs is also regarded as a major enabler to realize some of the key objectives at local, provincial and national government levels. Significant investment has gone into modernizing the existing electricity grid infrastructure at eThekwini to make it smarter, albeit with varying degrees of success. The term “SG” refers to optimizing, automating and modernizing of the electrical network so that it monitors, protects and automatically optimizes the operation of its interconnected elements. In the eThekwini context, this would include the electricity purchase points from Eskom; distributed generation injection points; the high-, medium- and low voltage networks as well as the industrial, commercial and domestic consumers and their applications and devices. The SG is characterized by a two way flow of electricity and information to create an optimized and automated network that has self-healing properties. It would incorporate the benefits of distributed computing and modern communication systems to deliver information in real-time which enables the almost instantaneous balance of supply and demand. SGs will be designed to ensure high levels of reliability, security, quality, availability and will also aim to improve economic productivity, minimize environmental impact, maximize safety and improve quality of life. The aim, objective and research question of this study will address as to how eThekwini‟s SG maturity levels compare to local and international peers, whether the SG technology deployment is aligned with its objectives, to ascertain the impact of SG implementation and whether the anticipated benefits are being realized. The concept of SG has only been recently formalized at eThekwini and very little research has been conducted in this area which this study aims to address

Distribution System Disturbance Analysis and Outage Management Using Hybrid Data-Driven and Physics-Based Approaches

Securing cyber-power distribution systems (DS) against malicious events is critical with the integration of distributed energy resources (DERs), supporting automation and increasing vulnerabilities. Situational awareness utilizing power data (e.g., data from distribution phasor measurement units (D-PMUs)) and cyber data (e.g., network packets data) is the main focus of this dissertation by means of which, an opportunity for real-time monitoring and decision-making is provided. To further improve the DS’s reliable and resilient operation, in this Ph.D. work, the aim has been put towards the development of an automated tool consisting of multiple modules to precisely investigate any type of data anomalies, followed by root cause finding. For this purpose, a data aggregation scheme is developed to synchronize the resolution and time stamp of multiple metering sources throughout the DS, using an enhancement of the conventional Kalman Filter, named Ensemble Extended Kalman Filter (EEKF). EEKF is implemented as an automated module by exploiting the real-time measurements as well as deriving the system physics. Furthermore, this dissertation develops online cyber-physical event detection and classification as well as proposal of the novel Outage Root Cause Analysis (ORCA) system. Different sections of the work have been tested on IEEE and OPAL-RT test systems as well as real-filed measurements from installed actual hardwares