Dissertations / Theses on the topic 'Substation Automation System'

Modern society is unquestionably heavily reliant on supply of electricity. Hence, the power system is one of the important infrastructures for future growth. However, the power system of today was designed for a stable radial flow of electricity from large power plants to the customers and not for the type of changes it is presently being exposed to, like large scale integration of electric vehicles, wind power plants, residential photovoltaic systems etc. One aspect of power system control particular exposed to these changes is the design of power system control and protection functionality. Problems occur when the flow of electricity changes from a unidirectional radial flow to a bidirectional. Such an implication requires redesign of control and protection functionality as well as introduction of new information and communication technology (ICT). To make matters worse, the closer the interaction between the power system and the ICT systems the more complex the matter becomes from a reliability perspective. This problem is inherently cyber-physical, including everything from system software to power cables and transformers, rather than the traditional reliability concern of only focusing on power system components. The contribution of this thesis is a framework for reliability analysis, utilizing system modeling concepts that supports the industrial engineering issues that follow with the imple-mentation of modern substation automation systems. The framework is based on a Bayesian probabilistic analysis engine represented by Probabilistic Relational Models (PRMs) in com-bination with an Enterprise Architecture (EA) modeling formalism. The gradual development of the framework is demonstrated through a number of application scenarios based on substation automation system configurations. This thesis is a composite thesis consisting of seven papers. Paper 1 presents the framework combining EA, PRMs and Fault Tree Analysis (FTA). Paper 2 adds primary substation equipment as part of the framework. Paper 3 presents a mapping between modeling entities from the EA framework ArchiMate and substation automation system configuration objects from the IEC 61850 standard. Paper 4 introduces object definitions and relations in coherence with EA modeling formalism suitable for the purpose of the analysis framework. Paper 5 describes an extension of the analysis framework by adding logical operators to the probabilistic analysis engine. Paper 6 presents enhanced failure rates for software components by studying failure logs and an application of the framework to a utility substation automation system. Finally, Paper 7 describes the ability to utilize domain standards for coherent modeling of functions and their interrelations and an application of the framework utilizing software-tool support.

QC 20140505

An entirely digital system is presented which has several benefits as compared to the systems that are deployed currently. Utilizing digital capabilities to a much greater extent than is currently used within the power system allows for various improvements upon the current system. One such improvement is the ease of configuring and using the system. Each device can easily alter its functionality through a user interface, and the addition of devices is as easy as plugging it in. Additionally, the burden on the transformer due to the increase in the number of devices is nullified. The information remains accurate and unchanged, even when new devices are added to the system. The entire system conforms to the IEC 61850 standard, such that it adheres to the requirements of the actual power system.
Master of Science

IEC 61850 standards are the global standard for communication in substations. It is gaining popularity in power substation automation and will dominate the future substation automation and protection system design. The standards provide new approaches for protection, control and metering function via communication. The secondary circuits in substation are simplified significantly and the massive hardwired cables are replaced by the high-speed process bus which transmit analogue and binary signals with Ethernet messages. However, the conformity of a device with the standards does not necessarily guarantee the interoperability with devices from different manufacturers. The use of devices compatible with IEC 61850 standards presents a challenge to many system integrators, especially due to lack of familiarity with features such as Generic Object Oriented Substation Event (GOOSE), reporting, Sampled Values and the need for system redundancy. To facilitate a smooth implementation, all the features and the data exchanges between devices need to be tested to ensure the system operates correctly. This project was carried out to study the protection performance of secondary schemes with IEC 61850 process bus architecture in substation. The tests were performed including current differential protection and distance protection on a transmission substation of the type used in the UK on the transmission network. The protection schemes were tested under IEC 61850 environment with multi-vendor IEDs like Alstom MiCOM IEDs, NARI IEDs with the OMICRON test set. More tests were carried out to verify the interoperability and the performance of time-critical messages were evaluated under different network architectures. The impact of the background traffic on these two messages was investigated and the response of the IEDs when the Sampled Values packets were lost or overwritten was recorded and provided to utility as a reference. This project also presented a technique to assess the performance of Merging Units from different manufacturers, when operating with Intelligent Electronic Devices (IEDs) performing a distance protection function. The performance of the process bus with parallel redundancy protocol is evaluated using a closed loop approach involving a Real Time Digital Simulator. The results indicate that protection using process bus communication is feasible, and meets grid code requirements when implemented with commercially available products. It was found that process bus operation is robust, even with network traffic conditions far beyond what would be experienced in an active substation.

Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Electrical Engineering in the Faculty of Engineering at the Cape Peninsula University of Technology, 2012
The introduction of the IEC 61850 standard in substations for communication networks and systems by the International Electrotechnical Commission (IEC) in 2003 provided the possibility for communication between devices of different manufacturers. However, the advent of this standard also brought about many challenges associated with it. The challenges introduced by this fairly recent standard of communications in Substation Automation Systems (SAS), and the need for the development of cost effective IEC 61850- compliant devices, motivated the decision of the Centre for Substation and Energy Management Systems within the Electrical Engineering Department of the Cape Peninsula University of Technology to focus on the implementation of the IEC 61850 standard using an embedded hardware platform. The development of an IEC 61850 embedded application requires substantial knowledge in multiple domains such as data networking, software modelling and development of Intelligent Electronic Devices (IEDs), protection of the electrical system, system simulation and testing methods, etc. Currently knowledge about the implementation of the IEC 61850 standard usually resides with vendors and is not in the public domain. The IEC 61850 standard allows for two groups of communication services between entities within the substation automation system. One group utilizes a client-server model accommodating services such as Reporting and Remote Switching. The second group utilizes a peer-to-peer model for Generic Substation Event (GSE) services associated with time-critical activities such as fast and reliable communication between Intelligent Electronic Devices (IEDs) used for protection of the power network. The messages associated with the GSE services are the Generic Object Oriented Substation Event (GOOSE) messages. The use of GOOSE messages for protection of the electrical system is very important in modern substations. Detailed knowledge of the structure of these messages is important in instances requiring fault diagnosis to determine the cause of mal– operation or to address interoperability concerns or when developing custom IEC 61850- compliant devices with limited functionality. A practical protection application (overcurrent) case study is presented where GOOSE messages are exchanged between a commercial IED and an IEC 61850-compliant controller based on an embedded platform. The basic data model and software development of an actuator node for a circuit breaker is proposed using an IEC 61850 communication stack on an embedded platform. The performance of the GOOSE messages is confirmed to be as per the functional behaviour specified, and per the IEC 68150 standard in terms of the temporal behaviour required. This thesis document tables the methods, software programs, hardware interfacing and system integration techniques that allow for the development and implementation of a low cost IEC 61850-compliant controller unit on an embedded systems platform for the substation automation system. The overcurrent case study distributed between a commercial IED (SIEMENS Siprotec device) and the actuator application developed on an embedded platform for this project (DK60 board) is in compliance with the IEC 61850 standard and utilizing GOOSE messaging is successfully completed both in terms of functional and temporal behaviour. This novel research work contributes not only to the academic community, but to the international Power Systems community as a whole. Keywords: IEC 61850 standard, IEDs, GOOSE message, software modelling, software development, substation automation systems, communication stack, embedded systems, actuator.

Esta dissertação apresenta uma proposta de integração sistêmica da automação das subestações retificadoras do sistema metrô-ferroviário brasileiro. Esta dissertação também apresenta os ganhos de confiabilidade que podem ser obtidos, caso a mesma seja implementada, e a priorização da eficiência de operação do sistema em questão. A motivação deste trabalho deve-se à necessidade de atender à perspectiva de aumento de demanda de energia elétrica nos processos de expansão e modernização deste sistema, amplamente usado pela população brasileira. A partir do estudo e análise do atual sistema de automação existente nas subestações do sistema metrô-ferroviário brasileiro, da arquitetura de hardware e software, foi possível investigar como a integração dos dados pertencentes aos sistemas de controle da subestação e do Centro de Controle Operacional CCO - pode permitir o aumento da confiabilidade e da flexibilidade de operação. Para quantificar estes ganhos de confiabilidade é apresentado o desenvolvimento do modelo de confiabilidade de Markov aplicado ao sistema de automação de subestações retificadoras. A metodologia utilizada procedeu ao levantamento e análise das ocorrências abertas nos anos de 2006, 2007 e 2008 nas subestações retificadoras do metrô de São Paulo, calculando o seu MTBF (Mean Time Between Failures). O estudo conclui que o ganho de confiabilidade é significativo no que se refere à melhoria do transporte público com a aplicação da integração da automação das subestações retificadoras.
This dissertation there presents a proposal for the integrated automation of the Brazilian subway system rectifier substations, supported on the gains of reliability which may be obtained in case it is implemented, and in the improvement of the efficiency of operation of the system open to question. The inquiry was supporting in the necessity of paying attention to the perspective of increase of demand of electric energy in the processes of expansion and modernization of this system, widely used by the Brazilian population. From the study and analysis of the current system of existent automation in the substations of the system Brazilian subway, of the architecture of hardware and software, was possible to investigate like the integration of the pertaining data to the systems of control of the substation and of the Centre of Operational Control CCO can allow the increase of the reliability and of the flexibility of operation. To quantify these profits of reliability there is presented the development of the model of reliability of Markov devoted to the system of automation of rectifying substations. The used methodology proceeded to the lifting and analysis of the incidents when they were opened in the years of 2006, 2007 and 2008 in the rectifier substations of the subway of Sao Paulo, calculating the MTBF (Mean Time Between Failures). The study ends that the profit of reliability is significant in what it refers to the improvement of public transport with the application of the integration of the automation of the rectifying substations.

Thesis (MEng (Electrical Engineering)--Cape Peninsula University of Technology, 2019
The purpose of an electrical power system is to supply electrical energy to the customers. Power transformers are required to transform the system voltage from generation to transmission and distribution levels. Protection and control systems must ensure that power system high voltage equipment such as transformers operate and deliver save, reliable and secure electricity supply. The aim of the project research work is to develop and implement a strategy, methods and algorithms for monitoring, protection and voltage control of parallel power transformers based on IEC 61850-9-2 process bus standard. NamPower is a power utility in Namibia. The IEC 61850 protocol for electrical substation automation system is used for the protection and control of 5 power transformers operated in parallel in an existing substation system. The IEC 61850-9-2 process bus standard is however not used in regards of Sampled Values (SV). Protection and control devices are connected to a substation communication network, routers and switches using fibre optic linked Ethernet. Inductive Current Transformers (CTs) and Voltage Transformers (VTs) secondary circuits are hardwired to Intelligent Electronic Devices (IEDs) and fibre optic links are not used for this purpose at process level communication. The research focuses on the implementation of the IEC 61850 standard with Merging Units (MUs) and sampled values to improve the existing implemented protection and control system at NamPower. This includes substation communication networks and MUs used for transformer protection, voltage regulator control and cooling fan control. At the present the CTs located at the transformer bushings and switchgear and the VTs located at the switchgear are hardwired to the inputs on protection and control IEDs. The research focuses on issues with the copper wires for voltage and currents signals and how these issues can be eliminated by using the MUs and the SV protocol. The MUs which are considered in this Thesis is to improve the voltage regulator control and the control of the cooling fan motors. The voltage regulator control IED is situated at the tap change motor drive of the On-Load Tap Changer (OLTC). The IED of each transformer is required to regulate the voltage level of the secondary side bus bar it is connected to. All the regulating IEDs are required to communicate with each other and collectively to control the bus bar voltage depending on the switching configuration of the parallel transformers. The control circuit for controlling the cooling fan motors is hardwired. Temperature analogue signal input into a programmable automation controller IED can be used for controlling the transformer cooling fans. A strategy, methods and algorithms for transformer protection, voltage regulator control and cooling fan motor control of parallel power transformers need to be developed and implemented based on IEC 61850-9-2 process bus. Power utilities and distributors can benefit from interpretation of the IEC 61850-9-2 standard and implementing MUs and SV in substations. MUs can be included in the power transformer protection, automation and control systems. A cost reduction in high voltage equipment, substation installation and commissioning costs and better performance of protection and control system are anticipated.

Power systems in the industry today are adopting automated substations because of a growing trend of digitization. Substation automation has greatly reduced intervention from human as well as operation and maintenance costs. Although it has brought benefits, new challenges arise regarding security vulnerabilities, which can be opportunities for attackers to damage whole systems and eavesdrop communication. To keep the automated substations secure and free from attackers, threat modeling is one of the alternative methods that can be used to do attack simulation and assess the security of systems. KTH has developed Meta Attack Language, a framework for constructing domain specific languages in which threat models can be produced, based on which attack graphs will be created and attacks can be simulated. It is a framework for developers that eases them to generate attack graphs with new languages. Meta Attack Language has been applied to various of domains by now, such as In-vehicle Network and Amazon Web Services. This thesis is carried out in ABB, extending the previous work of SCLLang and ABB’s existing security assessment tool, and doing threat modeling specifically for substation automation. The final threat model is used to assess the security of products in ABB, which will also serve as a basis for further extension for the company.
Energisystemen i industrin i dag antar automatiserade transformatorstationer på grund av en växande tendens till digitalisering. Automatisering av transformatorstationer har väldigt minskat interventionen från såväl mänskliga som drifts-och underhållskostnader. Även om det har medfört fördelar uppstår nya utmaningar när det gäller säkerhetsmässiga sårbarheter, vilket kan ge möjligheter för angripare att fördärva hela system och tjuvlyssna kommunikation. För att hålla de automatiserade transformatorstationerna säkra och fria från angripare är hotmodell en av de alternativa metoder som kan användas för att utföra attacksimulering och bedöma systemens säkerhet. KTH har utvecklat Meta Attack Language, en ram för att konstruera domänspecifika språk där hotmodeller kan framställas, på grund av vilka attackgraf kommer att skapas och angrepp kan simuleras. Det är en ram för utvecklare som underlättar för dem att skapa attackgraf med nya språk. Meta Attack Language har tillämpats på olika dömäner vid det här laget, såsom fordons-IT och Amazon Web Services. Avhandlingen genomförs hos ABB, som utvidgar SCLLang och ABB:s tidigare arbete med det befintliga säkerhetsbedömningsverktyget, och gör hotmodeller särskilt för automatisering av transformatorstationer. Den sista hotmodellen används för att bedöma säkerheten av produkter hos ABB, som också kommer att tjäna som grund för ytterligare utvidgning av företaget.

Thesis submitted in fulfillment of the requirements for the degree Master of Technology: Electrical Engineering in the Faculty of Engineering at the Cape Peninsula University of Technology
The electric power distribution network, an essential section of the electric power system, supplies electrical power to the customer. Automating the distribution network allows for better efficiency, reliability, and level of work through the installation of distribution control systems. Presently, research and development efforts are focused in the area of communication technologies and application of the IEC 61850 protocol to make distribution automation more comprehensive, efficient and affordable. The aim of the thesis is to evaluate the relevance of the IEC61850 standard-based technology in the development and investigation of the distribution automation for a typical underground distribution network through the development of a distribution automation algorithm for fault detection, location, isolation and service restoration and the building of a lab scale test bench Distribution Automation (DA) has been around for many decades and each utility applies its developments for different reasons. Nowadays, due to the advancement in the communication technology, authentic and automatic reconfigurable power system that replies swiftly to instantaneous events is possible. Distribution automation functions do not only supersede legacy devices, but it allows the distribution network to function on another lever. The primary function of a DA system is to enable the devices on the distribution network to be operated and controlled remotely to automatically locate, isolate and reconnect supply during fault conditions. Utilities have become increasingly interested in DA due to the numerous benefits it offers. Operations, maintenance and efficiencies within substations and out on the feeders can be improved by the development of new additional capabilities of DA. Furthermore, the new standard-based technology has advanced further than a traditional Distribution Supervisory and Control Data Acquisition (DSCADA) system. These days the most important components of a DA system include Intelligent Electronic Devices (IEDs). IEDs have evolved through the years and execute various protection related actions, monitoring and control functions and are very promising for improving the operation of the DA systems. The thesis has developed an algorithm for automatic fault detection, location, isolation and system supply restoration using the functions of the IEC61850 standard-based technology. A lab scale system that would meet existing and future requirements for the control and automation of a typical underground distribution system is designed and constructed. The requirement for the lab scale distribution system is to have the ability to clear faults through reliable and fast protection operation, isolate faulted section/s, on the network and restore power to the unaffected parts of the network through automation control operation functions of the IEC61850 standard. Various tests and simulations have been done on the lab scale test bench to prove that the objective of the thesis is achieved. Keywords: IEC61850 Standard, Distribution automation, Distribution automation system, IEDs, Lab scale test bench, Protection, Algorithm for automatic control

Un système de distribution électrique est le cœur de tous types de sites industriels, aussi bien les sites producteurs d'énergie que les sites consommateurs. La sécurité de ce système doit être impérativement assurée par la mise en place des unités assurant plusieurs fonctionnalités de protection contre les dédauts électriques. Parmi ces fonctionalités il existe celles qui se basent sur des échanges d'information entre plusieurs unités de protection. Le standard IEC 61850 guarantit cet échange des informations via des signaux ‘temps réel' échangé via le réseau de communication. Vue l'aspet non deterministe de ces signaux, une étude poussée de leur fiabilité doit être effectuée. Pour ces raisons notre travail de thèse a pour objectif de mettre en place une méthodologie, basée sur une plateforme de Co-Simulation conçue pendant notre étude, qui permet la validation de la fiabilité de ces messages tout au long du cycle de vie d'un système de communication IEC 61850
From 2004, a new worldwide standard of communication IEC61850 is introduced in the majority of substation automation system carrying out new innovation prospects to the world of substation. One of these feature is that it allows the exchange of security real time communication messages all over the communication network. These messages are used as control information for the Distributed Automation Application 'DAA'. Taking into consideration that DAA have a direct effect on ythe dependability of a smart grid architecture, the fiability of these real time IEC 61850 should be evaluated. For these reasons, our research delas with the development of a Co-Simulation platform that permits the evaluation and validation of an IEC 61850 communication network

Thesis (Master of Engineering in Electrical Engineering))--Cape Peninsula University of Technology, 2018.
As far as substation automation systems are concerned, one of the prime requirements of most utilities today is the interoperability between Intelligent Electronic Devices (IEDs) of different manufacturers. The standard IEC 61850 - Communication Networks and Systems in Substations - allows such interoperability between IEDs for protection and automation of substations. Presently, many manufacturers have implemented, or are in the process of implementing this standard in their IEDs. This has encouraged some utilities to specify IEC is to ensure that both system requirements are met and the features and benefits of the standard are fully exploited. The author of this thesis investigated and brought forward the design of an integrated monitoring protection and control system of a network in Cape Peninsula University of Technology (CPUT) campus based of the IEC 61850 standard. A method of testing the physical IED based on Hardware-In-Loop (HIL) configuration with the Real-Time Digital Simulator (RTDS) is developed and implemented. Mapping of IED Substation Configuration Language (SCL) with that of the RTDS GTNET cards is discussed and implemented to further exploit the use of realtime testing with Generic Object Oriented Substation Event messages (GOOSE). The thesis highlight the benefits of interconnecting the reticulation IEDs into a standardised communication network for protection, control and monitoring of each substation event. This improves the access to information and reduces maintenance cost on the reticulation network.

In power substations. electric and magnetic emissions are generated during all operational conditions. In particular, switching operations of primary plant components such as disconnect switches and circuit breakers generate significant electromagnetic fields, which constitute potential electromagnetic interference (EMI) to sensitive electronic equipments within the substations. This thesis describes the design and implementation of a wireless automatic high -speed data acquisition system for EMI measurements in power substations. The system presented adopts a novel network concept to implement effective measurements. Instead of consisting of just one or several stand alone measurement devices used in conventional measurement setup, the system is designed as an interactive multi-node network, in which thousands of measurement devices could be distributed and managed through flexible wireless networking protocol. The nodes at different locations could cooperate to simultaneously measure the electromagnetic interferences so that the data from them could be correlated in time domain. This system is more like a wireless distributed network with high data acquisition capability compared to a static amplitude-only measurement system. The nodes in the measurement network could measure the transient signals both in time domain and in frequency domain. Two different implementations of frequency domain measurement are investigated. One is using short-time Fourier transform to conduct real-time spectrum measurement. The other is using trigger mechanism to synchronously measure transient signal's spectrum. In addition, the measurement networks could be controlled and monitored through Internet. The measurement data would be automatically sent to a database for collective processing. In a word, the system presented provides a versatile and powerful tool to characterize the transient phenomena in power substations.

Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Electrical Engineering in the Faculty of Engineering at the Cape Peninsula University of Technology 2014
The IEC 61850 standard, “Communication networks and systems in substations” was promulgated to accommodate the need for a common communication platform within substations for devices from different vendors. The IEC 61850 standard proposes a substation automation architecture that is Ethernet-based, with a “station-bus” for protection devices within the substation and a “process bus” where raw data from the voltage and current transformers are published onto the data network using a device known as a Merging Unit. To date, most of the standardization efforts were focused at the station bus level where event-triggered messages are exchanged between the substation automation devices, commonly referred to as Intelligent Electronic Devices (IEDs). These messages are known as Generic Object Oriented Substation Event messages. Equipment from vendors to accommodate the “process bus” paradigm, however is still limited at present. The Centre for Substation Automation and Energy Management Systems was established within the Electrical Engineering Department at the Cape Peninsula University of Technology with one of its objectives being the development of equipment either for simulation or real-time purposes in compliance with the IEC 61850 standard. In order to fulfil this long-term objective of the Centre, an in-depth understanding of the IEC 61850 standard is required. This document details the efforts at acquiring the requisite knowledge base in support of the educational objectives of the Centre and the research project implements a simulation of a merging unit which is compliant with the functional behavior as stipulated by the standard. This limited functional implementation (i.e. non-real-time) of the merging unit, is achieved through the development of a virtualized data acquisition node capable of synthetic generation of waveforms, encoding of the data and publishing the data in a format compliant with the IEC 61850-9-2 sampled value message structure. This functional behavior of the virtual sensor node which was implemented has been validated against the behavior of a commercial device and the sampled value message structure is validated against the standard. The temporal behavior of the proposed device is commented upon. This research project forms the basis for future real-time implementation of a merging unit.

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Power system operation and maintenance require attention, precise diagnostics on failure and agility on system recovery. On the other hand, power systems involve high risks, where each operation needs to be carefully planned and executed, once errors can be fatal. Power system satisfactory operation and maintenance consist on finding equilibrium between these extremes, acting on a cautious, but agile, way. For this purpose, we propose the development of an intelligent system with the ability of detecting abnormal patterns on the electrical signal, providing support for decisions on Power Distribution System real time operation, from the analysis of power substation transformers primary and secondary currents, including learning at each new information acquired by the system. The challenge of this study is to research and develop a method based on ANN for classifying patterns and providing support for decisions, aiming fault detection and/or fault recovery. The method di↵erentiates disturbances that will lead to faults from disturbances generated by transients on power system (for example an undervoltage caused by powering on an engine). A SCADA supervisory system was developed to contain ANN implementation code and also to provide an interface for Operators, generating visual and sound alarms and messages guiding system recovery. The proposed method was evaluated using real data collected from transformers protection digital relays of CEMAR system substations, achieving excellent results. The ANN developed on this study presented satisfactory performance classifying signals and detecting faults properly.
A operação e manutenção do sistema elétrico requerem atenção, diagnósticos precisos em caso de falhas e agilidade na recomposição do sistema. Por outro lado, sistemas elétricos têm um elevado risco, onde cada manobra precisa ser cuidadosamente planejada e executada, pois erros podem ser fatais. A boa operação e manutenção do sistema elétrico consistem em encontrar o ponto de equilíbrio entre esses dois extremos, atuando de forma cautelosa, porém ágil. Com esse intuito, propomos o desenvolvimento de um sistema inteligente dotado da capacidade de detectar padrões anormais no sinal elétrico, fornecendo apoio à decisão na operação em tempo real do SDEE, a partir da análise das correntes primárias e secundárias de transformadores de força de subestações de energia elérica, incluindo aprendizado a cada nova informação integrada ao sistema. O desafio deste estudo é pesquisar e desenvolver um método baseado em RNA para classificação de padrões e apoio à decisão, visando a detecção e/ou recuperaçao de falhas. O método diferencia perturbações que culminarão em uma falta de perturbações geradas por transitórios na rede elétrica (por exemplo o afundamento de tensão gerado pela partida de uma máquina). Um sistema supervisório SCADA foi desenvolvido para hospedar o código de implementação da RNA, além de fornecer uma interface para o Operador, gerando alarmes visuais e sonoros e mensagens orientando a retomada do sistema. O método proposto foi avaliado utilizando-se dados reais coletados diretamente de relés digitais de proteção de transformadores de subestações do sistema da CEMAR, obtendo-se excelentes resultados. A RNA desenvolvida neste estudo apresentou desempenho satisfatório na classificação dos sinais a ela apresentados, detectando corretamente as faltas.

The next-generation electric power system, known as smart grid, relies on a robust and reliable underlying communication infrastructure to improve the efficiency of electricity distribution. Cellular networks, e.g., LTE/LTE-A systems, appear as a promising technology to facilitate the smart grid evolution. Their inherent performance characteristics and well-established ecosystem could potentially unlock unprecedented use cases, enabling real-time and autonomous distribution grid operations. However, cellular technology was not originally intended for smart grid communication, associated with highly-reliable message exchange and massive device connectivity requirements. The fundamental differences between smart grid and human-type communication challenge the classical design of cellular networks and introduce important research questions that have not been sufficiently addressed so far. Motivated by these challenges, this doctoral thesis investigates novel radio access network (RAN) design principles and performance analysis for the seamless integration of smart grid traffic in future cellular networks. Specifically, we focus on addressing the fundamental RAN problems of network scalability in massive smart grid deployments and radio resource management for smart grid and human-type traffic. The main objective of the thesis lies on the design, analysis and performance evaluation of RAN mechanisms that would render cellular networks the key enabler for emerging smart grid applications. The first part of the thesis addresses the radio access limitations in LTE-based networks for reliable and scalable smart grid communication. We first identify the congestion problem in LTE random access that arises in large-scale smart grid deployments. To overcome this, a novel random access mechanism is proposed that can efficiently support real-time distribution automation services with negligible impact on the background traffic. Motivated by the stringent reliability requirements of various smart grid operations, we then develop an analytical model of the LTE random access procedure that allows us to assess the performance of event-based monitoring traffic under various load conditions and network configurations. We further extend our analysis to include the relation between the cell size and the availability of orthogonal random access resources and we identify an additional challenge for reliable smart grid connectivity. To this end, we devise an interference- and load-aware cell planning mechanism that enhances reliability in substation automation services. Finally, we couple the problem of state estimation in wide-area monitoring systems with the reliability challenges in information acquisition. Using our developed analytical framework, we quantify the impact of imperfect communication reliability in the state estimation accuracy and we provide useful insights for the design of reliability-aware state estimators. The second part of the thesis builds on the previous one and focuses on the RAN problem of resource scheduling and sharing for smart grid and human-type traffic. We introduce a novel scheduler that achieves low latency for distribution automation traffic while resource allocation is performed in a way that keeps the degradation of cellular users at a minimum level. In addition, we investigate the benefits of Device-to-Device (D2D) transmission mode for event-based message exchange in substation automation scenarios. We design a joint mode selection and resource allocation mechanism which results in higher data rates with respect to the conventional transmission mode via the base station. An orthogonal resource partition scheme between cellular and D2D links is further proposed to prevent the underutilization of the scarce cellular spectrum. The research findings of this thesis aim to deliver novel solutions to important RAN performance issues that arise when cellular networks support smart grid communication.
Las redes celulares, p.e., los sistemas LTE/LTE-A, aparecen como una tecnología prometedora para facilitar la evolución de la próxima generación del sistema eléctrico de potencia, conocido como smart grid (SG). Sin embargo, la tecnología celular no fue pensada originalmente para las comunicaciones en la SG, asociadas con el intercambio fiable de mensajes y con requisitos de conectividad de un número masivo de dispositivos. Las diferencias fundamentales entre las comunicaciones en la SG y la comunicación de tipo humano desafían el diseño clásico de las redes celulares e introducen importantes cuestiones de investigación que hasta ahora no se han abordado suficientemente. Motivada por estos retos, esta tesis doctoral investiga los principios de diseño y analiza el rendimiento de una nueva red de acceso radio (RAN) que permita una integración perfecta del tráfico de la SG en las redes celulares futuras. Nos centramos en los problemas fundamentales de escalabilidad de la RAN en despliegues de SG masivos, y en la gestión de los recursos radio para la integración del tráfico de la SG con el tráfico de tipo humano. El objetivo principal de la tesis consiste en el diseño, el análisis y la evaluación del rendimiento de los mecanismos de las RAN que convertirán a las redes celulares en el elemento clave para las aplicaciones emergentes de las SGs. La primera parte de la tesis aborda las limitaciones del acceso radio en redes LTE para la comunicación fiable y escalable en SGs. En primer lugar, identificamos el problema de congestión en el acceso aleatorio de LTE que aparece en los despliegues de SGs a gran escala. Para superar este problema, se propone un nuevo mecanismo de acceso aleatorio que permite soportar de forma eficiente los servicios de automatización de la distribución eléctrica en tiempo real, con un impacto insignificante en el tráfico de fondo. Motivados por los estrictos requisitos de fiabilidad de las diversas operaciones en la SG, desarrollamos un modelo analítico del procedimiento de acceso aleatorio de LTE que nos permite evaluar el rendimiento del tráfico de monitorización de la red eléctrica basado en eventos bajo diversas condiciones de carga y configuraciones de red. Además, ampliamos nuestro análisis para incluir la relación entre el tamaño de celda y la disponibilidad de recursos de acceso aleatorio ortogonales, e identificamos un reto adicional para la conectividad fiable en la SG. Con este fin, diseñamos un mecanismo de planificación celular que tiene en cuenta las interferencias y la carga de la red, y que mejora la fiabilidad en los servicios de automatización de las subestaciones eléctricas. Finalmente, combinamos el problema de la estimación de estado en sistemas de monitorización de redes eléctricas de área amplia con los retos de fiabilidad en la adquisición de la información. Utilizando el modelo analítico desarrollado, cuantificamos el impacto de la baja fiabilidad en las comunicaciones sobre la precisión de la estimación de estado. La segunda parte de la tesis se centra en el problema de scheduling y compartición de recursos en la RAN para el tráfico de SG y el tráfico de tipo humano. Presentamos un nuevo scheduler que proporciona baja latencia para el tráfico de automatización de la distribución eléctrica, mientras que la asignación de recursos se realiza de un modo que mantiene la degradación de los usuarios celulares en un nivel mínimo. Además, investigamos los beneficios del modo de transmisión Device-to-Device (D2D) en el intercambio de mensajes basados en eventos en escenarios de automatización de subestaciones eléctricas. Diseñamos un mecanismo conjunto de asignación de recursos y selección de modo que da como resultado tasas de datos más elevadas con respecto al modo de transmisión convencional a través de la estación base. Finalmente, se propone un esquema de partición de recursos ortogonales entre enlaces celulares y D2

Dissertação de mest., Engenharia Electrónica e Telecomunicações, Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2011
The Substation Automation System (SAS) is the backbone of the Energy Power System (EPS) and IEC 61850 is becoming its single most important standard. This is a world wide accepted standard that is being adopted by the industry in order to provide for all current and future needs. This standard defines not only the communication protocols but also its own Substation Configuration Language (SCL) and even best practices for related engineering processes. In order to keep up with the current fast technological developments the substation data model is separated from the communication protocols allowing both to be changed without affecting each other. Also defined in the standard is an extensive conformance testing procedure in order to guarantee that different vendors interpret and implement the standard correctly. The substation and its SAS must undergo thourough testing procedures specificaly in the Factory Acceptance Test (FAT) and Site Acceptance Test (SAT). The conformance tests insures that the SAS devices, the Intelligent Electronic Devices (IEDs), conform to the same standard but on its own does not guarantee its interoperability. An automated testing tool capable of, quickly and easily, testing the SAS functions (IEDs interoperability) provides significant savings in both time and money to the testing process. This work aim is to develop such a tool, capable of interoperability testing. In order to achieve such big accomplishment this initial work focus on only two of the most used functions of the SAS: switching and interlocking. A simulation model, built on top of OMNeT++, for both the IEDs and the substation was developed. In this work an initial stage prototype with an IED simulation model capable of communicating with real devices will be developed. In a later stage, postponed for future work, the substation simulation model will be extended in order to include real-time interaction with external devices that emulate the substation switchgear.

IEC 61850 is rapidly becoming the internationally recognized standard for substation automation systems making it an indispensable element in power system protection and automation education. In order to facilitate teaching this very practical subject, a laboratory setup was developed to demonstrate IEC 61850 station bus inter Intelligent Electronic Device (IED) communication. In this setup, an electrical substation was implemented in a real time digital simulator (RTDS) and protection schemes were implemented in IEC 61850 station bus compliant IEDs from different vendors. Trip signals and breaker statuses were exchanged between RTDS and IEDs using GOOSE (Generic Object Oriented Substation Event) messages. Several protection applications including a novel backup bus protection scheme were developed based on the setup to demonstrate the use of GOOSE messages in time critical applications. The developed test setup along with the designed laboratory exercises will undoubtedly enhance teaching, training and research in this important field.
February 2016

碩士
國立高雄海洋科技大學
輪機工程研究所
92
Facing the prospect of a more competitive environment, many utilities around the world have devised and implemented various types of substation automation system （SAS） to improve the reliability and quality of power supply. In the new SAS, all of operation data in the substation are transferred and processed via a local area network （LAN）. All SCADA functions and protective relays are integrated through intelligent electronic devices （IEDs）. For a combined LAN and IEDs based SAS, the main concern of the system design is that the integrated functions are to not jeopardize the performance of SCADA functions and protection system. The aim of this thesis is to build a set of analysis models to estimate the performance of a SAS under different event report scenarios and LAN schemes. Performances regarding hardware utilization and SAS functions response times are measured and analyzed. Test results have indicated that when the switch LAN scheme is adopted, the response times of major SAS functions and hardware utilization under the worst case condition are within the acceptable ranges. With appropriate LAN configuration, the performance of the SAS can be greatly enhanced, which would then result in the promotion of whole distribution operation efficiency.

A thesis which models the DNP3 and IEC 61850 protocol in OPNET
Supervisory Control and Data Acquisition (SCADA) is a critical part of monitoring and controlling of the electrical substation. The aim of this dissertation is to investigate the performance of the Distributed Network Protocol Version 3.3 (DNP3) protocol and to compare its performance to that of International Electro-technical Commission (IEC) 61850 protocol in an electrical substation communication network environment. Building an electrical substation control room and installing the network equipment was going to be expensive and take a lot of time. The better option was to build a model of the electrical substation communication network and run simulations. Riverbend modeller academic edition known as Optimized Network Engineering Tool (OPNET) was chosen as a software package to model substation communication network, DNP3 protocol and IEC 61850 Protocol stack. Modelling the IEC 61850 protocol stack on OPNET involved building the used Open System Interconnection (OSI) layers of the IEC 61850 protocol stack onto the application definitions of OPNET. The Transmission Control Protocol/Internet Protocol (TCP/IP) configuration settings of DNP3 protocol were also modelled on the OPNET application definitions. The aim is to compare the two protocols and determine which protocol is the best performing one in terms of throughput, data delay and latency. The substation communication model consists of 10 ethernet nodes which simulate protection Intelligent Electronic Devices (IEDs), 13 ethernet switches, a server which simulates the substation Remote Terminal Unit (RTU) and the DNP3 Protocol over TCP/IP simulated on the model. DNP3 is a protocol that can be used in a power utility computer network to provide communication service for the grid components. DNP3 protocol is currently used at Eskom as the communication protocol because it is widely used by equipment vendors in the energy sector. DNP3 protocol will be modelled before being compared to the new recent robust protocol IEC 61850 in the same model and determine which protocol is the best for Eskom on the network of the power grid. The network load and packet delay parameters were sampled when 10%, 50%, 90% and 100% of devices are online. The IEC 61850 protocol model has three scenarios and they are normal operation of a Substation, maintenance in a Substation and Buszone operation at a Substation. In these scenarios packet end to end delay of Generic Object Oriented Substation Event (GOOSE), vi © University of South Africa 2020 Generic Substation Status Event (GSSE), Sampled Values (SV) and Manufacturing Messaging Specification (MMS) messages are monitored. The throughput from the IED under maintenance and the throughput at the Substation RTU end is monitored in the model. Analysis of the results of the DNP3 protocol simulation showed that with an increase in number of nodes there was an increase in packet delay as well as the network load. The load on the network should be taken into consideration when designing a substation communication network that requires a quick response such as a smart gird. GOOSE, GSSE, SV results on the IEC 61850 model met all the requirements of the IEC 61850 standard and the MMS did not meet all the requirements of the IEC standard. The design of the substation communication network using IEC 61850 will assist when trying to predict the behavior of the network with regards to this specific protocol during maintenance and when there are faults in the communication network or IED’s. After the simulation of the DNP3 protocol and the IEC 61850 the throughput of DNP3 protocol was determined to be in the range (20 – 450) kbps and the throughput of IEC61850 protocol was determined to be in the range (1.6 – 16) Mbps.
College of Engineering, Science and Technology
M. Tech. (Electrical Engineering)