A proteção de Sistemas de Distribuição (SDs) é de fundamental importância considerando as condições adversas de operação e faltas elétricas a que os mesmos podem estar submetidos. A crescente utilização de Geradores Distribuídos (GDs) conectados aos SDs e as possíveis operações em ilhamento promovem interferências consideráveis aos dispositivos de proteção. Dessa forma, evidencia-se a importância de estudos para esses novos cenários. Neste contexto, esta pesquisa tem como proposta analisar o desempenho do sistema de proteção, quando na presença de uma elevada contribuição de geração distribuída, e aprimorar a proteção tradicional, quando tem-se a mudança do cenário de operação para o modo ilhado. Sendo assim, evidencia-se através de simulações no Real-Time Digital Simulator (RTDS) os efeitos da perturbação nos Relés de Sobrecorrente (RSC). Na metodologia desenvolvida implementa-se um sistema de proteção adaptativo, cujos parâmetros são definidos por um algoritmo de otimização. Também são adicionadas as proteções associadas aos GDs, recomendadas por norma. Tal prática é dificilmente abordada em trabalhos correlatos a pesquisa, no entanto através dos resultados observou-se que esses dispositivos podem influenciar na respostas dos elementos de proteção implementados nos SDs. Como diferencial também buscou-se implementar todo o sistema de controle dos GDs e utilizou-se da simulação em malha fechada com relés comerciais, afim de aproximar a modelagem da realidade encontrada nos SDs. Por fim, evidenciou-se que a utilização de relés adaptativos pode viabilizar a operação em ilhamento. / The protection of Distribution Systems (DSs) is of fundamental importance, considering the adverse operating conditions and electrical faults to which they may be submitted. The increasing usage of Distributed Generators (DGs) connected to DSs, and possible islanded operations promote considerable interference to protective devices. Thus, it is evident the importance of studies for these new scenarios.This research aims to analyze the performance of the protection system, when in the presence of a massive contribution of distributed generation, and to improve the traditional protection when there is a change from the operating scenario to island mode. Thus, via simulations, carried out in the Real-Time Digital Simulator (RTDS), the effects of the disturbance on the Overcurrent Relays (OCs) were evident. The developed methodology implements an adaptive protection system, whose parameters are defined by an optimization algorithm. The protections associated with DGs were also added, as recommended by the standard. This practice is hardly approached in related studies however, through the results, it was observed that these devices could influence the responses of the protective elements implemented. The closed-loop simulations carried out considering the standard controls systems regarding DGs and commercial intelligent eletronic devices, ensuring the test bed verisimilitude to actual DSs. This approach is not standard on the literature related. Finally, it was evidenced that the use of adaptive relays can contribute to the islanded operation.

Este trabalho propõe um novo método de proteção de geradores síncronos baseado em inteligência artificial, mais especificamente lógica fuzzy, com o propósito de melhorar a proteção destes componentes vitais aos sistema elétricos de potência. Um sistema elétrico de potência completo composto por geradores, linhas de transmissão e cargas foi simulado através do Real Time Digital Simulator para fornecer dados para realização de testes e validação do algoritmo de proteção inteligente. Adicionalmente, foram desenvolvidos dois esquemas experimentais que proporcionaram a obtenção de um conjunto extensivo de ensaios de faltas internas em dois geradores síncronos reais, com o objetivo de fornecer dados para comprovar a eficácia da proteção proposta. Um sistema integrado de software e hardware cujo objetivo é servir de plataforma para desenvolver e executar em tempo real algoritmos de proteção aplicados foi desenvolvido. Esse sistema integrado foi utilizado nos testes embarcados em tempo-real do algoritmo de proteção desenvolvido. Apresenta-se também um arranjo composto por funções de proteção tradicionais mais utilizadas em campo, as quais serviram como base de comparação de desempenho para o esquema de proteção inteligente desenvolvido. Os resultados apresentados mostram que o método de proteção inteligente proposto é mais sensível para detectar instantaneamente faltas fase-terra em geradores síncronos com aterramento de alta-impedância, além de ser capaz de identificar faltas entre-espiras e entre-caminhos / This work presents the development of a synchronous generator protective technique based on artificial intelligence, specifically fuzzy logic, in order to improve the protection of these vital components of the electric power system. A complete electric power system composed of generators, transmission lines and loads was simulated using the Real Time Digital Simulator to provide data for testing and validating the intelligent protection algorithm. Additionally, an extensive set of internal fault experiments conducted on two actual synchronous generators provided oscillograms to demostrate the proposed protection effectiveness. An integrated hardware and software system whose purpose is to serve as a platform for developing and executing real-time protection algorithms is presented. This integrated system was used for real-time embedded testing of the protection algorithm developed. An arrangement composed of traditional protection functions most used in the field is also presented, this arrangement served as a comparison basis for the intelligent protection scheme performance. The results show that the intelligent protection is more sensitive to detect instantly ground faults in synchronous generators with high-impedance grounding, it is also shown that the proposed scheme is able to identify inter-turns and inter-circuits faults

Este trabalho propõe um novo método de proteção de geradores síncronos baseado em inteligência artificial, mais especificamente lógica fuzzy, com o propósito de melhorar a proteção destes componentes vitais aos sistema elétricos de potência. Um sistema elétrico de potência completo composto por geradores, linhas de transmissão e cargas foi simulado através do Real Time Digital Simulator para fornecer dados para realização de testes e validação do algoritmo de proteção inteligente. Adicionalmente, foram desenvolvidos dois esquemas experimentais que proporcionaram a obtenção de um conjunto extensivo de ensaios de faltas internas em dois geradores síncronos reais, com o objetivo de fornecer dados para comprovar a eficácia da proteção proposta. Um sistema integrado de software e hardware cujo objetivo é servir de plataforma para desenvolver e executar em tempo real algoritmos de proteção aplicados foi desenvolvido. Esse sistema integrado foi utilizado nos testes embarcados em tempo-real do algoritmo de proteção desenvolvido. Apresenta-se também um arranjo composto por funções de proteção tradicionais mais utilizadas em campo, as quais serviram como base de comparação de desempenho para o esquema de proteção inteligente desenvolvido. Os resultados apresentados mostram que o método de proteção inteligente proposto é mais sensível para detectar instantaneamente faltas fase-terra em geradores síncronos com aterramento de alta-impedância, além de ser capaz de identificar faltas entre-espiras e entre-caminhos / This work presents the development of a synchronous generator protective technique based on artificial intelligence, specifically fuzzy logic, in order to improve the protection of these vital components of the electric power system. A complete electric power system composed of generators, transmission lines and loads was simulated using the Real Time Digital Simulator to provide data for testing and validating the intelligent protection algorithm. Additionally, an extensive set of internal fault experiments conducted on two actual synchronous generators provided oscillograms to demostrate the proposed protection effectiveness. An integrated hardware and software system whose purpose is to serve as a platform for developing and executing real-time protection algorithms is presented. This integrated system was used for real-time embedded testing of the protection algorithm developed. An arrangement composed of traditional protection functions most used in the field is also presented, this arrangement served as a comparison basis for the intelligent protection scheme performance. The results show that the intelligent protection is more sensitive to detect instantly ground faults in synchronous generators with high-impedance grounding, it is also shown that the proposed scheme is able to identify inter-turns and inter-circuits faults

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-04-20T22:58:46Z No. of bitstreams: 1 JAMILE PINHEIRO NASCIMENTO - DISSERTAÇÃO PPGEE 2014..pdf: 2146495 bytes, checksum: e397e112357d55c0badad1a62f5324cf (MD5) / Made available in DSpace on 2018-04-20T22:58:46Z (GMT). No. of bitstreams: 1 JAMILE PINHEIRO NASCIMENTO - DISSERTAÇÃO PPGEE 2014..pdf: 2146495 bytes, checksum: e397e112357d55c0badad1a62f5324cf (MD5) Previous issue date: 2014-08 / Um algoritmo de proteção adaptativa para solucionar o problema da proteção de sistemas com geração distribuída é proposto. O algoritmo modifica as configurações dos relés de forma on-line, utilizando como informação de entrada, os estados dos disjuntores. Ao final, constatou-se que mesmo com a entrada ou saída dos geradores distribuídos, o sistema de distribuição continuou a ser protegido. Para validar o algoritmo utilizou-se um sistema-teste do IEEE e o Real Time Digital Simulator (RTDS). / An adaptive protection algorithm to solve protecting systems with distributed generation problem is proposed. The algorithm modifies relays settings on on-line form, using circuit breakers state as input information. At the end, it was found that even with the input or output of distributed generators, distribution system continued to be protected. To validate the algorithm it was used an IEEE test system and the Real Time Digital Simulator (RTDS).

Shipboard Power Systems (SPS) play a significant role in next-generation Navy fleets. With the increasing power demand from propulsion loads, ship service loads, weaponry systems and mission systems, a stable and reliable SPS is critical to support different aspects of ship operation. It also becomes the technology-enabler to improve ship economy, efficiency, reliability, and survivability. Moreover, it is important to improve the reliability and robustness of the SPS while working under different operating conditions to ensure safe and satisfactory operation of the system. This dissertation aims to introduce novel and effective approaches to respond to different types of possible faults in the SPS. According to the type and duration, the possible faults in the Medium Voltage DC (MVDC) SPS have been divided into two main categories: transient and permanent faults. First, in order to manage permanent faults in MVDC SPS, a novel real-time reconfiguration strategy has been proposed. Onboard postault reconfiguration aims to ensure the maximum power/service delivery to the system loads following a fault. This study aims to implement an intelligent real-time reconfiguration algorithm in the RTDS platform through an optimization technique implemented inside the Real-Time Digital Simulator (RTDS). The simulation results demonstrate the effectiveness of the proposed real-time approach to reconfigure the system under different fault situations. Second, a novel approach to mitigate the effect of the unsymmetrical transient AC faults in the MVDC SPS has been proposed. In this dissertation, the application of combined Static Synchronous Compensator (STATCOM)-Super Conducting Fault Current Limiter (SFCL) to improve the stability of the MVDC SPS during transient faults has been investigated. A Fluid Genetic Algorithm (FGA) optimization algorithm is introduced to design the STATCOM's controller. Moreover, a multi-objective optimization problem has been formulated to find the optimal size of SFCL's impedance. In the proposed scheme, STATCOM can assist the SFCL to keep the vital load terminal voltage close to the normal state in an economic sense. The proposed technique provides an acceptable post-disturbance and postault performance to recover the system to its normal situation over the other alternatives.

Este trabalho apresenta uma análise de algoritmos computacionais aplicados à estimação de fasores elétricos em SEPs. A medição dos fasores é realizada por meio da alocação de Unidades de Medição Fasorial nestes sistemas e encontra diversas aplicações nas áreas de operação, controle, proteção e planejamento. Para que os fasores possam ser aplicados, são definidos padrões de medição, sincronização e comunicação, por meio da norma IEEE C37.118.1. A norma apresenta os padrões de mensagens, timetag, fasores, sistema de sincronização, e define testes para avaliar a estimação. Apesar de abranger todos esses critérios, a diretriz não define um algoritmo de estimação padrão, abrindo espaço para uso de diversos métodos, desde que a precisão seja atendida. Nesse contexto, o presente trabalho analisa alguns algoritmos de estimação de fasores definidos na literatura, avaliando o comportamento deles em determinados casos. Foram considerados, dessa forma, os métodos: Transformada Discreta de Fourier, Método dos Mínimos Quadrados e Transformada Wavelet Discreta, nas versões recursivas e não-recursivas. Esses métodos foram submetidos a sinais sintéticos, a fim de verificar o comportamento diante dos testes propostos pela norma, avaliando o Total Vector Error, tempo de resposta e atraso e overshoot. Os algoritmos também foram embarcados em um hardware, denominado PC104, e avaliados de acordo com os sinais medidos pelo equipamento na saída analógica de um simulador em tempo real (Real Time Digital Simulator). / This work presents an analysis of computational algorithms applied to phasor estimation in Electrical Power Systems. The phasor estimation process uses the allocation of Phasor Measurement Units in the system and the measures can be used in many control, operation, planing and protection applications. Therefore, the power system phasors are very useful, specially if they have a common time reference, allowing the determination of the system\'s condition at a given time. The procedures necessary for power system\'s phasors estimation and application are defined by IEEE C37.118.1 standard. The standard defines the requirements for phasor estimation, presenting tests and a methodology to evaluate the algorithms performance. Thus, the standard defines the time tag and data patterns, some synchronization methods, and message examples, simplifying the communication requirements. Despite defining all these parts, the standard does not state which estimation algorithm should be used, making room for the use of various methods, since the standard precision is met. In this context, this work analyzes some phasor estimation algorithms defined in the literature, evaluating their behavior for some cases. It was adopted the recursive and non-recursive versions of the methods: Discrete Fourier Transform, Least Squares and Discrete Wavelet Transform. They were submitted to the standard signals, evaluating the Total Vector Error, time delays, and overshoots. The algorithms were also embedded in hardware (named PC104) and evaluated by real time simulated signals, measured by the PC104 using the analog outputs of a Real Time Digital Simulator.

Este trabalho apresenta uma análise de algoritmos computacionais aplicados à estimação de fasores elétricos em SEPs. A medição dos fasores é realizada por meio da alocação de Unidades de Medição Fasorial nestes sistemas e encontra diversas aplicações nas áreas de operação, controle, proteção e planejamento. Para que os fasores possam ser aplicados, são definidos padrões de medição, sincronização e comunicação, por meio da norma IEEE C37.118.1. A norma apresenta os padrões de mensagens, timetag, fasores, sistema de sincronização, e define testes para avaliar a estimação. Apesar de abranger todos esses critérios, a diretriz não define um algoritmo de estimação padrão, abrindo espaço para uso de diversos métodos, desde que a precisão seja atendida. Nesse contexto, o presente trabalho analisa alguns algoritmos de estimação de fasores definidos na literatura, avaliando o comportamento deles em determinados casos. Foram considerados, dessa forma, os métodos: Transformada Discreta de Fourier, Método dos Mínimos Quadrados e Transformada Wavelet Discreta, nas versões recursivas e não-recursivas. Esses métodos foram submetidos a sinais sintéticos, a fim de verificar o comportamento diante dos testes propostos pela norma, avaliando o Total Vector Error, tempo de resposta e atraso e overshoot. Os algoritmos também foram embarcados em um hardware, denominado PC104, e avaliados de acordo com os sinais medidos pelo equipamento na saída analógica de um simulador em tempo real (Real Time Digital Simulator). / This work presents an analysis of computational algorithms applied to phasor estimation in Electrical Power Systems. The phasor estimation process uses the allocation of Phasor Measurement Units in the system and the measures can be used in many control, operation, planing and protection applications. Therefore, the power system phasors are very useful, specially if they have a common time reference, allowing the determination of the system\'s condition at a given time. The procedures necessary for power system\'s phasors estimation and application are defined by IEEE C37.118.1 standard. The standard defines the requirements for phasor estimation, presenting tests and a methodology to evaluate the algorithms performance. Thus, the standard defines the time tag and data patterns, some synchronization methods, and message examples, simplifying the communication requirements. Despite defining all these parts, the standard does not state which estimation algorithm should be used, making room for the use of various methods, since the standard precision is met. In this context, this work analyzes some phasor estimation algorithms defined in the literature, evaluating their behavior for some cases. It was adopted the recursive and non-recursive versions of the methods: Discrete Fourier Transform, Least Squares and Discrete Wavelet Transform. They were submitted to the standard signals, evaluating the Total Vector Error, time delays, and overshoots. The algorithms were also embedded in hardware (named PC104) and evaluated by real time simulated signals, measured by the PC104 using the analog outputs of a Real Time Digital Simulator.

This thesis proposes a novel out-of-step protection technique using the state-plane representation of the generator speed and power angle. The critical clearing angle is computed using the principle that the total energy of the system at the instant the fault is cleared should be equal to the maximum potential energy of the system. The critical clearing time corresponding to this value of critical clearing angle is obtained directly using the time calibration of the relative speed versus power angle solution curve. The simultaneous calculation of the critical clearing angle and the time makes the proposed state plane approach much faster than the two-blinder scheme, Equal Area Criterion (EAC) method, rate of change of impedance method, the Swing Center Voltage (SCV) technique, transient energy calculation method, and the frequency deviation calculation from voltage signal method discussed in the literature. The proposed state plane prediction scheme is used to detect the rst swing out-of-step condition in single machine in nite bus (SMIB) system as well as larger power system con gurations (two-area and IEEE 39-bus test systems) using system wide information. A coherency analysis is performed in a multi-machine system to find out the two critical groups of generators. The critical generator groups are then represented with a SMIB equivalent system, and the state plane algorithm is applied to the reduced equivalent. Electromagnetic transient simulations are carried out using PSCAD/EMTDCTM to test the proposed algorithm in the above discussed test systems. The simulation studies show that the proposed method is computationally e cient, and accurate even for the larger power systems. The technique also does not require any o ine studies. This thesis also proposes another out-of-step protection technique using generator state deviations to detect multi-swing instability conditions in power system. It uses wide-area measurements of generator electrical power and speed deviations as inputs to the proposed scheme to detect instability. This technique is not as fast as the state plane approach but can predict multi-swing instability conditions in power system. The state plane method and state deviation method are used together to nd rst swing and multi-swing instability conditions. Two-area power system con guration is used to demonstrate multi-swing instability prediction. Di erent power swing conditions such as stable, rst swing unstable and multi-swing unstable scenarios are created and the proposed techniques are tested to verify their performance. The proposed techniques are also compared with the conventional two blinder technique. A facility for hardware-in-the-loop testing of the relays using a digital simulator is available in the Power System Laboratory at the University of Saskatchewan. An out-of-step relay module is developed in a digital signal processing board (ADSP BF533TM from Analog Devices Inc.) and a closed loop test is performed using the real time digital simulator (RTDSTM). The simulator mimics the power system behaviour in real time, and the analog time signals from simulator can be communicated to the relay module. The relay can also feed back the signals to the simulator which can be used to operate the circuit breaker elements in the power system. The SMIB and two area systems are used to test the relay in real time. The relay prototypes for both of the proposed techniques are developed in this thesis. The hardware-in-the-loop implementation and testing show that the calculation times required for the proposed methods are small, and the state plane method especially can predict instability condition much faster than all other methods in current literature.

The purpose of this research is to develop a method of making system equivalents for the Real Time Digital Simulator (RTDS), which should enhance its capability of simulating large power systems. The proposed equivalent combines a Frequency Dependent Network Equivalent (FDNE) for the high frequency electromagnetic transients and a Transient Stability Analysis (TSA) type simulation block for the electromechanical transients. The frequency dependent characteristic for FDNE is obtained by curve-fitting frequency domain admittance characteristics using the Vector Fitting method. An approach for approximating the frequency dependent characteristic of large power networks from readily available typical power-flow data is also introduced. A new scheme of incorporating TSA solution in RTDS is proposed. This report shows how the TSA algorithm can be adapted to a real time platform. The validity of this method is confirmed with examples, including the study of a multi in-feed HVDC system based network.

The purpose of this research is to develop a method of making system equivalents for the Real Time Digital Simulator (RTDS), which should enhance its capability of simulating large power systems. The proposed equivalent combines a Frequency Dependent Network Equivalent (FDNE) for the high frequency electromagnetic transients and a Transient Stability Analysis (TSA) type simulation block for the electromechanical transients. The frequency dependent characteristic for FDNE is obtained by curve-fitting frequency domain admittance characteristics using the Vector Fitting method. An approach for approximating the frequency dependent characteristic of large power networks from readily available typical power-flow data is also introduced. A new scheme of incorporating TSA solution in RTDS is proposed. This report shows how the TSA algorithm can be adapted to a real time platform. The validity of this method is confirmed with examples, including the study of a multi in-feed HVDC system based network.