Software Defined Networks based Smart Grid Communication: A Comprehensive Survey

The current power grid is no longer a feasible solution due to ever-increasing user demand of electricity, old infrastructure, and reliability issues and thus require transformation to a better grid a.k.a., smart grid (SG). The key features that distinguish SG from the conventional electrical power grid are its capability to perform two-way communication, demand side management, and real time pricing. Despite all these advantages that SG will bring, there are certain issues which are specific to SG communication system. For instance, network management of current SG systems is complex, time consuming, and done manually. Moreover, SG communication (SGC) system is built on different vendor specific devices and protocols. Therefore, the current SG systems are not protocol independent, thus leading to interoperability issue. Software defined network (SDN) has been proposed to monitor and manage the communication networks globally. This article serves as a comprehensive survey on SDN-based SGC. In this article, we first discuss taxonomy of advantages of SDNbased SGC.We then discuss SDN-based SGC architectures, along with case studies. Our article provides an in-depth discussion on routing schemes for SDN-based SGC. We also provide detailed survey of security and privacy schemes applied to SDN-based SGC. We furthermore present challenges, open issues, and future research directions related to SDN-based SGC.Comment: Accepte

Investigation of Wireless LAN for IEC 61850 based Smart Distribution Substations

The IEC 61850 standard is receiving acceptance worldwide to deploy Ethernet Local Area Networks (LANs) for electrical substations in a smart grid environment. With the recent growth in wireless communication technologies, wireless Ethernet or Wireless LAN (WLAN), standardized in IEEE 802.11, is gaining interest in the power industry for substation automation applications, especially at the distribution level. Low Voltage (LV) / Medium Voltage (MV) distribution substations have comparatively low time-critical performance requirements. At the same time, expensive but high data-rate fiber-based Ethernet networks may not be a feasible solution for the MV/LV distribution network. Extensive work is carried out to assess wireless LAN technologies for various IEC 61850 based smart distribution substation applications: control and monitoring; automation and metering; and over-current protection. First, the investigation of wireless LANs for various smart distribution substation applications was initiated with radio noise-level measurements in total five (27.6 and 13.8 kV) substations owned by London Hydro and Hydro One in London, ON, Canada. The measured noise level from a spectrum analyzer was modeled using the Probability Distribution Function (PDF) tool in MATLAB, and parameters for these models in the 2.4 GHz band and 5.8 GHz band were obtained. Further, this measured noise models were used to simulate substation environment in OPNET (the industry-trusted communication networking simulation) tool. In addition, the efforts for developing dynamic models of WLAN-enabled IEC 61850 devices were initiated using Proto-C programming in OPNET tool. The IEC 61850 based devices, such as Protection and Control (P&C) Intelligent Electronic Devices (IEDs) and Merging Unit (MU) were developed based on the OSI-7 layer stack proposed in IEC 61850. The performance of various smart distribution substation applications was assessed in terms of average and maximum message transfer delays and throughput. The work was extended by developing hardware prototypes of WLAN enabled IEC 61850 devices in the R&D laboratory at University of Western Ontario, Canada. P&C IED, MU, Processing IED, and Echo IED were developed using industrial embedded computers over the QNX Real Time Operating System (RTOS) platform. The functions were developed using hard real-time multithreads, timers, and so on to communicate IEC 61850 application messages for analyzing WLAN performance in terms of Round Trip Time (RTT) and throughput. The laboratory was set up with WLAN-enabled IEC 61850 devices, a commercially available WLAN Access Point (AP), noise sources, and spectrum and network analyzers. Performance of various smart distribution substation applications is examined within the developed laboratory. Finally, the performance evaluation was carried out in real-world field testing at 13.8 and 27.6 kV distribution substations, by installing the devices in substation control room and switchyard. The RTT of IEC 61850 based messages and operating time of the overcurrent protection using WLAN based communication network were evaluated in the harsh environment of actual distribution substations. The important findings from the exhaustive investigation were discussed throughout this work

A study of the applicability of software-defined networking in industrial networks

173 p.Las redes industriales interconectan sensores y actuadores para llevar a cabo funciones de monitorización, control y protección en diferentes entornos, tales como sistemas de transporte o sistemas de automatización industrial. Estos sistemas ciberfísicos generalmente están soportados por múltiples redes de datos, ya sean cableadas o inalámbricas, a las cuales demandan nuevas prestaciones, de forma que el control y gestión de tales redes deben estar acoplados a las condiciones del propio sistema industrial. De este modo, aparecen requisitos relacionados con la flexibilidad, mantenibilidad y adaptabilidad, al mismo tiempo que las restricciones de calidad de servicio no se vean afectadas. Sin embargo, las estrategias de control de red tradicionales generalmente no se adaptan eficientemente a entornos cada vez más dinámicos y heterogéneos.Tras definir un conjunto de requerimientos de red y analizar las limitaciones de las soluciones actuales, se deduce que un control provisto independientemente de los propios dispositivos de red añadiría flexibilidad a dichas redes. Por consiguiente, la presente tesis explora la aplicabilidad de las redes definidas por software (Software-Defined Networking, SDN) en sistemas de automatización industrial. Para llevar a cabo este enfoque, se ha tomado como caso de estudio las redes de automatización basadas en el estándar IEC 61850, el cual es ampliamente usado en el diseño de las redes de comunicaciones en sistemas de distribución de energía, tales como las subestaciones eléctricas. El estándar IEC 61850 define diferentes servicios y protocolos con altos requisitos en terminos de latencia y disponibilidad de la red, los cuales han de ser satisfechos mediante técnicas de ingeniería de tráfico. Como resultado, aprovechando la flexibilidad y programabilidad ofrecidas por las redes definidas por software, en esta tesis se propone una arquitectura de control basada en el protocolo OpenFlow que, incluyendo tecnologías de gestión y monitorización de red, permite establecer políticas de tráfico acorde a su prioridad y al estado de la red.Además, las subestaciones eléctricas son un ejemplo representativo de infraestructura crítica, que son aquellas en las que un fallo puede resultar en graves pérdidas económicas, daños físicos y materiales. De esta forma, tales sistemas deben ser extremadamente seguros y robustos, por lo que es conveniente la implementación de topologías redundantes que ofrezcan un tiempo de reacción ante fallos mínimo. Con tal objetivo, el estándar IEC 62439-3 define los protocolos Parallel Redundancy Protocol (PRP) y High-availability Seamless Redundancy (HSR), los cuales garantizan un tiempo de recuperación nulo en caso de fallo mediante la redundancia activa de datos en redes Ethernet. Sin embargo, la gestión de redes basadas en PRP y HSR es estática e inflexible, lo que, añadido a la reducción de ancho de banda debida la duplicación de datos, hace difícil un control eficiente de los recursos disponibles. En dicho sentido, esta tesis propone control de la redundancia basado en el paradigma SDN para un aprovechamiento eficiente de topologías malladas, al mismo tiempo que se garantiza la disponibilidad de las aplicaciones de control y monitorización. En particular, se discute cómo el protocolo OpenFlow permite a un controlador externo configurar múltiples caminos redundantes entre dispositivos con varias interfaces de red, así como en entornos inalámbricos. De esta forma, los servicios críticos pueden protegerse en situaciones de interferencia y movilidad.La evaluación de la idoneidad de las soluciones propuestas ha sido llevada a cabo, principalmente, mediante la emulación de diferentes topologías y tipos de tráfico. Igualmente, se ha estudiado analítica y experimentalmente cómo afecta a la latencia el poder reducir el número de saltos en las comunicaciones con respecto al uso de un árbol de expansión, así como balancear la carga en una red de nivel 2. Además, se ha realizado un análisis de la mejora de la eficiencia en el uso de los recursos de red y la robustez alcanzada con la combinación de los protocolos PRP y HSR con un control llevado a cabo mediante OpenFlow. Estos resultados muestran que el modelo SDN podría mejorar significativamente las prestaciones de una red industrial de misión crítica

Performance evaluation of information and communications technology infrastructure for smart distribution network applications

This thesis was submitted for the degree of Master of Philosophy and awarded by Brunel University.Current electrical networks require secure, scalable and cost-effective Information and Communications Technology (ICT) solutions to facilitate the novel functionalities required by Smart Grids. Countries around the globe are investigating alternative energy sources to mitigate the current energy crisis and environmental issues experienced by many countries due to global warming, rapid growth of population, inefficient energy management, dwindling fossil fuel resources, etc. Therefore, alternative or renewable energy sources, such as wind, solar, hydro, combined heat and power, etc., are required to mitigate such a crisis and such sources will also need to be integrated in to the power grid in a distributed manner. Such distributed energy sources are mainly connected to the distribution networks and introduce huge challenges to the distribution network operator (DNO). Many of these challenges cannot be dealt with effectively using existing network operation mechanisms therefore the research and development of novel ICT solutions to support smart distribution network operation is required. This research investigated suitable ICT solutions to enable the Smart Grid to tackle these challenges and proposes ICT infrastructure models that can be used for simulation studies in order to investigate cost-effective, scalable and secure solutions for the DNOs. Initially, a Quality of Service (QoS) monitoring test-bed was proposed to evaluate the performance of bandwidth intensive applications, such as smart meter data transmission. Simulation studies for different communication technologies, cellular and Power Line Communication (PLC), were also carried out and the simulation models were verified using experimental test results. Finally, the modelling and analysis of smart metering infrastructure was carried out using simulation and extensive studies were performed to evaluate the data transmission rate performance for different configurations of smart meters and concentrators

Automation, Protection and Control of Substation Based on IEC 61850

Reliability of power system protection system has been a key issue in the substation operation due to the use of multi-vendor equipment of proprietary features, environmental issues, and complex fault diagnosis. Failure to address these issues could have a significant effect on the performance of the entire electricity grid. With the introduction of IEC 61850 standard, substation automation system (SAS) has significantly altered the scenario in utilities and industries as indicated in this thesis