Thesis (Master of Engineering in Electrical Engineering)--Cape Peninsula University of Technology, [2018]. / Introduction of IEC 61850 standard defined substation automation system communication. The need of interoperability among the relevant devices coming from different vendors is a necessity to ensure utilities/municipalities obtain value for money. Vendors used their own proprietary tools to achieve communication in a substation. This caused an Intelligent Electronic Device (IED) from vendor A could not communicate with an IED from vendor B. Utilities/municipalities are forced to depend on single vendor solutions in a substation automation system. IEC 61850 systems tout Interoperability as a major gain in the Substation Automation System (SAS) environment. The implementation of interoperable systems in SAS environment requires extensive testing and careful selection of vendors. This involves extensive testing to meet the required requirements of a certain SAS. Interoperability implementation and testing methods need to be formulated and tested rigorously with various scenarios of interoperability in an SAS. GOOSE messages form the foundation of IEC 61850 standard as they are responsible for the copper-less connections for peer to peer communications. GOOSE messages are based on peer to peer communications to enable interoperability at the bay level which is called horizontal communication. IEDs need to be carefully selected to ensure GOOSE messaging interoperability is achieved. Test methods are equally important as methodology to achieve interoperability. The purpose of this research is to perform an investigation on interoperability of IEC 61850 conformant IEDs based on evaluation of their protection functions. The research looks at various vendors on how each has interpreted the IEC 61850 standard. Also an analysis on requirements to achieve interoperability is conducted. Investigation on various vendor independent system configuration tools to ease the implementation burden of a multivendor application is done. Evaluation into flexible object modelling and naming conventions in order to achieve interoperability is performed. Various tests using different tools to assess the integrity of interoperability are completed. The research delivers a methodology to evaluate and implement GOOSE message interoperability. The interoperability methodology can be used for improvement of interoperability applications. The methodology can also be implemented as procurement requirement to ensure interoperability. The evaluation/implementation of interoperability can be included in Factory Acceptance Test (FAT). The methodology to achieve interoperability is only usefully when requirements are clear with regard to what needs to achieved by SAS.

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.

Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2016. / Electricity substation monitoring and control systems have evolved over the years from simple systems capable of achieving minimalistic functions to autonomous, self-healing smart grid schemes (Farhangi, 2010). The migration of technology to networked smart grid systems was driven by the need for standardisation of communication networks, system configuration and also the reduction of system implementation costs and engineering time. Before the introduction of a uniform communication standard, legacy (non-standardised) communication protocols, for example, the Distributed Network Protocol (DNP3) were used by Remote Terminal Units (RTUs) for information exchange (Luwaca, 2014). These communication protocols could not provide a standard naming convention or data semantics since the data/information was accessed using an address-based system. The implementation of automation systems based on legacy protocols and RTUs was expensive because of parallel copper wiring required to connect instrument transformers and circuit breakers to multiple RTUs for protection and monitoring functions (Iloh et al., 2014). Legacy systems refer to Supervisory Control and Data Acquisition (SCADA) systems implemented using RTUs and legacy communication protocols. Legacy systems tended to be vendor specific because devices from different vendors did not support the same communication protocol. These issues led to the introduction of the IEC 61850 standard. The IEC 61850 standard for “communication networks and systems in a substation” provides standardised naming convention, data semantics, standardised device configuration and also device interoperability and interchangeability in some instances. The IEC 61850 standard provides a solution to expensive parallel copper wiring and standardisation issues experienced with legacy protocols. In as much as the introduction of the IEC 61850 standard addresses problems experienced with legacy system there is still a need to provide inexpensive access to IEC 61850-compliant devices and effective knowledge transfer to facilitate implementation of automation systems based on this standard. The development of an IEC 61850-compliant device requires a specialised skillset and financial investment for research and industrialisation therefore only a few vendors manufacture these devices resulting in an increase in production and manufacturing costs. For this reason this research project develops VHDL modules for mapping IEC 61850-9-2 Sampled Value (SV) messages and IEC 61850-8-1 Generic Object Oriented Substation Event (GOOSE) messages on a Field Programmable Gate Array (FPGA) platform. Sampled values are used for transmitting current and voltage transformer (CT and VT) measurements to protection devices while GOOSE messages exchange information/commands between primary equipment (CT, VT and circuit breaker) and protection devices over an Ethernet network known as the process bus.

Nos Sistemas de Automação de Subestação atuais são utilizados equipamentos digitais chamados IED (Dispositivos Eletrônicos Inteligentes), incorporando as funções de proteção, automação e medição. Estes, para trocarem informações entre si, utilizam um canal de comunicação serial, sendo os dados transmitidos de forma digital por meio de vários protocolos, muitos deles proprietários, o que dificulta a integração entre eles. Neste cenário entra a norma IEC 61850 oferecendo um padrão a ser seguido entre os fabricantes de IED. Este trabalho tem por objetivo apresentar um estudo da norma e a análise de sua aplicação no Sistema de Automação de Subestação. O estudo proposto da norma a analisará utilizando os principais conceitos estabelecidos por ela para atingir os objetivos propostos: interoperabilidade, liberdade de configuração e estabilidade a longo prazo. Como ensaio de aplicação da norma será apresentado um comparativo com um protocolo utilizado atualmente e a implementação de funções de proteção. No comparativo entre protocolos foi escolhido o DNP3, um dos mais utilizados atualmente no setor elétrico, com o objetivo de verificar as principais diferenças entre eles e vantagens de cada um. Para a implementação de funções de proteção foram escolhidos dois exemplos: a falha de disjuntor e o bloqueio reverso, implementadas da forma tradicional, por meio de sinais elétricos de comando transmitidos por cabos, e por meio dos serviços de mensagens prioritárias da IEC 61850, com o objetivo de analisar suas dinâmicas, seus tempos de atuação e o comportamento frente a eventuais defeitos. / In current Substation Automation System, digital equipaments called IED (Intelligent Electronic Devices) are used with protection, automation and measurement functions incorporated. These devices, to exchange information among them, use serial communication buses with information transmitted in digital form through many procotols, many of them proprietary, making their integration very hard. In this scene, IEC61850 standard appears offering a standard to be followed by IED manufacturers. This research presents a IEC 61850 standard study and an analysis of its application in Substation Automation System. The proposed study will analise the standard through the most important topics used by the standard to reach its main goals: interoperability, free configuration and long-term stability. In the application analysis, a comparative with a protocol used nowadays and a implementation of protection functions will be presented. In the comparative between protocols the chosen was DNP3, one of most used protocols in electric plants, with the purpose of verifying the main diferences and advantages of each one. Two examples of protection functions implementation were chosen: breaker failure and reverse blocking, implemented through traditional techniques, using wires and electrical signals, and through high performance IEC 61850 services, with the purpose of analising their dynamics, their actuation times and their behavior in eventual failures.

Orientador: Carlos Roberto Minussi / Banca: Anna Diva Plasencia Lotufo / Banca: Mara Lúcia Martins Lopes / Banca: Fernanda Caseño Lima Trindade / Banca: José Carlos de Melo Vieira Junior / Resumo: Apresenta-se, nesta pesquisa, uma metodologia para realizar a detecção e classificação de distúrbios de tensão em sistemas de distribuição de energia elétrica, usando como ferramenta, as análises estatística e direta multinível dos sinais de tensão no domínio wavelet para o processo de detecção e uma rede neural ARTMAP Euclidiana Modificada com Treinamento Continuado (ARTMAP-EMTC) para o processo de classificação. Com o auxílio destas duas ferramentas obtém-se maior precisão, segurança e confiabilidade na tomada de decisão para o restabelecimento das operações normais do sistema. A rede neural ARTMAP-EMTC é capaz de se adaptar às constantes mudanças que sofre o setor elétrico, e.g., fornece o diagnóstico de um distúrbio desconhecido pela rede neural que possa surgir com o passar do tempo. Além disso, permite a inclusão de novos padrões na memória da rede neural sem a necessidade de reiniciar o treinamento, o que não ocorre com outros tipos de redes neurais. Trata-se, por conseguinte, de uma nova abordagem da aplicação de redes neurais onde é realizada, permanentemente, a extração do conhecimento do sistema sob análise, a partir de informações disponibilizadas na operação do sistema (resultado das análises, simulação, etc.). Os sinais de tensão, necessários para realizar os diagnósticos de distúrbios de tensão, foram obtidos por meio de simulações de um modelo de alimentador radial no software ATP (Alternative Transients Program) e Matlab, empregando-se a transformada wavelet discreta, análise multirresolução e o conceito de energia. Os resultados obtidos mostram a eficiência da metodologia proposta, o que possibilita sua aplicação, com sucesso, na proteção dos sistemas de distribuição, auxiliando os operadores no processo de decisão visando restabelecer o sistema e contribuindo, desta forma, para a melhoria da qualidade da energia elétrica fornecida aos consumidores. / Abstract: This research presents a methodology to detect and classify voltage disturbances in electrical distribution systems using as tool, statistical and multilevel direct analysis of voltage signals in wavelet domain for the detection process and modified Euclidean ARTMAP neural network with continuous training for the classification (ARTMAP- MECT). These two tools provide velocity, security and reliability for decision making when it is necessary to restore the normal operations. The ARTMAP-MECT is able to adapt to continuous changes at the electrical system, e.g. to provide a diagnosis of unknown disturbances by the neural network Furthermore, it allows the inclusion of new patterns in the memory of the neural network without reinitializing the training, which is not possible in other neural networks. It is a new approach of neural network application where the knowledge is permanently extracted from the system under analysis from information available in the system operation (results from analysis, simulation, etc.). The voltage signals that are necessary to execute the voltage disturbance diagnosis are obtained from simulations of a radial feeder using the ATP (Alternative Transients Program) and MATLAB using the discrete wavelet transform, multi-resolution analysis and energy concept. The obtained results show the efficiency of the proposed methodology allowing the application in distribution protection, aiding the operators in decision procedures to restore the system and contributing to improve the power quality provided to the users. / Doutor

M. Tech. Electrical Engineering. / This dissertation presents an effective method to determine current/voltage harmonic emission levels caused by various devices in the network. The method is implemented based on the existing power monitoring devices installed in power generation plants. The Digital Fault Recorders (DFRs) are used in this work as the monitoring devices. Due to the advancement of data processing and communication capabilities of such devices, a large amount of information generated by DFRs is concentrated in the utilitys head office. This data is archived for permanent storage and analysis. The presented work aims to assist the power utilities in harmonic invigilation problems based on DFRs.

In order to sustain transmission grid availability and reliability it is imperative that the condition of vital and costly high voltage equipment is ascertained on a continuous or regular basis. It is necessary to establish the effective diagnostic tools or surveillance devices that can be used to assess equipment condition. Emphasis has been placed on refining well-established and more novel but developing condition assessment techniques. It is important to note that condition assessment of equipment also allows the opportunity to predict failure. Based on a complete and systematic assessment, the failure of defective equipment may be evident or predicted in time, thus preventing a forced outage and loss of valuable 'system minutes'. It has also become necessary to extend the life of existing equipment since most of them are reaching the end of their useful life. Replacement strategies have proven to be ineffective due to financial and resource constraints experienced by utilities. Life extension is the work required to keep equipment operating economically beyond its anticipated life, with optimum availability, efficiency and safety. One of its principal components is condition assessment, with the possibility of predicting remnant life. As a result, refurbishment projects are then raised. Refurbishment by replacement, uprating, modifications or change of design of certain key components to extend the life usually requires a substantial amount of capital to be invested. These projects must be economically justified. This thesis focuses on establishing condition assessment techniques for major power equipment such as power transformers. Assessment techniques for instrument transformers and circuit breakers are included, since these are commonly replaced or modified under refurbishment projects. An experimental investigation was carried out to determine the effectiveness of integrating data of two diagnostic techniques i.e. dissolved gas analysis (on-line) and acoustic detection of partial discharges. It was found that there is a correlation between data obtained from an acoustic detection system and an on-line single gas (Hydrogen) analyser. By integrating the data of both on-line monitoring systems, the diagnostic process is further enhanced. In addition, the location of a fixed discharge source was verified by using an acoustic detection system. Further, the sensitivity of the acoustic technique to partial discharge inception voltage, relative to the established electrical detection technique was determined for the experimental arrangement used. The results obtained indicated that this is an effective technique for the evaluation of activity within a transformer structure. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2004.

The objective of the proposed research is to quantify the limits of overstressed and aging circuit breakers in terms of probability of failure and to provide guidelines to determine network reconfigurations, generator commitment, and economic dispatch strategies that account for these limits. The proposed temporary power system operating strategies address circuit breaker adequacy issues and allow overstressed breakers to be operated longer and more reliably until they are replaced with adequate equipment. The expansion of electric networks with new power sources (nuclear plants, distributed generation) results in increased short-circuit or fault currents levels. As fault currents increase, they will eventually exceed circuit breaker ratings. Circuit breakers exposed to fault currents in excess of their ratings are said to be overstressed, underrated, or inadequate. Insufficient ratings expose overstressed breakers to increased failure probabilities. Extensive common-mode outages caused by circuit breaker failures reduce the reliability of power systems. To durably avoid outages and system unreliability, overstressed breakers must eventually be replaced. Large-scale replacements of overstressed breakers cannot be completed in a short time because of budgetary limits, capital improvement schedules, and manufacturer-imposed constraints. Meanwhile, to preserve the ability of old and overstressed breakers to safely interrupt faults, short-circuit currents must be kept within the limits imposed by the ratings and the age of these breakers by using the substation reconfiguration and generator commitment strategies described in this study. The immediate benefit of the above-mentioned operating strategies is a reduction of the failure probability of overstressed breakers obtained by avoiding the interruption of currents in excess of breaker ratings. Other benefits include (i) increased network reliability, (ii) restored operating margins with respect to existing equipment, and (iii) prioritized equipment upgrades that enhance the long-term planning of power systems.

Thesis (M. Tech. Electrical engineering) -- Central University of technology, Free State, 2012 / Infrared thermography is a non-contact method of identifying the thermal behaviour of various plant equipment and machines, including their components, qualitatively via pattern recognition and quantitatively via statistical analysis. This allows for the development of condition monitoring and predictive failure analysis. It is well established that optimized maintenance planning can be more effective when a problem is detected in the early stages of failure. For example, in electrical systems an elevated electrical resistance caused by loose or corroded connections, broken conductor strands and dirty contact surfaces, results in localized heating, and a unique infrared pattern when analysed leads to the location of the problem and an indication of its severity. In recent years industrial thermography has used infrared detectors in the long wave portion of the electromagnetic spectrum normally between 8μm and 15μm, due partly to the fact that these wavelengths are not susceptible to solar radiation and/or solar glint. A number of scientific experiments were carried out on test apparatus to improve the understanding of the impact of convection, ambient air temperature and relative humidity on resultant infrared thermal images. Two similar heat sources, simulating a hotspot, at different temperature settings were used to determine whether the hotspot temperature should also be considered in conjunction with the atmospheric elements. The need for these experiments has also been identified by EPRI (Electrical Power Research Institute) in the USA as necessary to develop international severity criteria, and it is hoped that this study will contribute to this goal.

Em subestações de transmissão e distribuição de energia elétrica são utilizadas estruturas metálicas ou de concreto para o suporte de equipamentos e ancoragem de linhas de transmissão. Nestas estruturas os esforços principais atuam horizontalmente pela ação do vento e da tração nos cabos de transmissão de energia elétrica. Devido aos baixos esforços verticais, normalmente, utilizam-se como solução fundações rasas, uma vez que apresentam menor custo e maior facilidade de execução quando comparadas com fundações profundas. Devido a distância de aplicação das cargas horizontais em relação à base, os momentos gerados por estas se tornam elevados em relação à carga vertical atuante. Esta configuração faz com que a resultante dos esforços, frequentemente, esteja fora do núcleo central da fundação. Segundo a NBR 6122 (1996), para a avaliação da capacidade de suporte das fundações nos casos de cargas excêntricas, deve ser adotada uma área efetiva onde os esforços de compressão são considerados uniformemente distribuídos. Este procedimento simplificado muitas vezes torna os dimensionamentos extremamente conservadores, tendo em vista os baixos carregamentos verticais e as grandes excentricidades. Esta pesquisa visa, através de utilização de modelos computacionais numéricos, caracterizar o comportamento de ruptura dos solos solicitados por fundações superficiais sujeitas a esforços combinados verticais, horizontais e momentos. Além disso, os resultados obtidos nos modelos numéricos são comparados com as formulações clássicas de dimensionamento de fundações. / For power substations, both steel and reinforced concrete structures are normally used to support the equipments and the high voltage wiring. In such cases, the wind forces predominate and cause tension in the electrical cables and structures. As the vertical loads are relatively small, generally shallow foundations apply, being also easily executed under lower costs. Due to the distance between the horizontal forces and the structural foundation, high moments are generated comparatively to the vertical loads present, defining big eccentricity in the foundation. According to ABNT-NBR 6122 (1996), to determine the foundation bearing capacity, an effective area way be considered for the compression stresses to act. This situation often yields to unrealistic foundation design. The present dissertation intend to model the failure behavior of the soil supporting shallow foundation by means of computational methods, considering vertical and horizontal forces acting along with moments. A comparison is also mode with commonly used bearing capacity equations for the same type of foundations.