El síndrome de adelgazamiento multisístemico postdestete (postweaning multisystemic wasting syndrome, PMWS) es una enfermedad caracterizada por adelgazamiento y linfoadenopatía generalizada en cerdos de la etapa de maternidad y engorde, y se considera como agente causal al circovirus porcino tipo 2 (PCV2). En esta tesis fueron realizados tres estudios. En el primer estudio se compararon los títulos de anticuerpos frente a circovirus porcino tipo 1 (PCV1) y los títulos de anticuerpos frente a PCV2 de cerdos con y sin PMWS. Los resultados demostraron que títulos de anticuerpos frente a PCV2 fueron detectados en cerdos de granjas afectadas, pero también fueron encontrados en cerdos de granjas sin historia previa de PMWS. Muchos cerdos con PMWS y ácido nucleico en tejidos tenían altos títulos frente a PCV2 al momento de la necropsia. Este hecho indica que altos títulos de anticuerpos pueden coexistir con lesiones características de PMWS durante la replicación viral activa en los tejidos. El estudio retrospectivo de la infección por PCV2 en España demostró la presencia de anticuerpos frente a PCV2 y lesiones características de PMWS con ácido nucleico de PCV2 presente en los tejidos lesionados desde 1985, sugiriendo así que la introducción de este virus en la población porcina ocurrió previamente. Se observó un incremento de la prevalencia de PMWS después de 1997 en España, aparentemente debido a otros factores más que la sola introducción de un nuevo virus en la población porcina. En el estudio sobre la dinámica de la infección atribuible a PCV2 en una población de cerdos seleccionada de una granja afectada por PMWS, se realizó un diagnóstico previo de esta enfermedad basado en signos clínicos, histopatología, serología, hibridación in situ (HIS), y reacción en cadena de la polimerasa (PCR). Los signos clínicos característicos de la enfermedad fueron observados así como también una alta mortalidad, se observó adelgazamiento tanto en cerdos livianos como pesados, lo cual coincide con resultados de otros estudios. El estudio demostró un patrón de seroconversion para PCV2 equivalente a la típica dinámica de anticuerpos observada para otros agentes virales que afectan a los cerdos. Hubo una disminución de los anticuerpos calostrales durante el período de maternidad, con los títulos más bajos a las 7 semanas, y todos los cerdos seroconvirtieron activamente durante el período de crecimiento. Por otro lado, una clara relación se observó entre la mortalidad asociada con PMWS y los títulos serológicos bajos a las 7 semanas de edad. Estos resultados sugieren que la inmunidad maternal es aparentemente protectiva frente al desarrollo de la enfermedad clínica asociada con la infección con PCV2, en otras infecciones víricas porcinas se han realizado observaciones similares. Los primeros cerdos virémicos fueron detectados a las 7 semanas de edad, la mayor cantidad de cerdos positivos fueron observados a las 12 semanas de edad, momento en el cual los sígnos clínicos de PMWS fueron disminuyendo. Asímismo, el brote de PMWS coincidió con el incremento de la viremia por PCV2 entre la semana 7 y 12 de edad. Un porcentaje similar de cerdos virémicos fue detectado entre las semanas 7 y 28 de edad, aunque en las últimas semanas los cerdos eran clínicamente normales. Los largos períodos de viremia en cerdos aparentemente sanos sugieren que los anticuerpos detectados mediante la técnica de inmunoperoxidasa en monocapa celular (IPMA), no fueron capaces de neutralizar el virus y la producción de anticuerpos neutralizantes puede haber sido tardía o más bien extremadamente tardía. Otras infecciones víricas de cerdos, como el síndrome respiratorio y reproductivo porcino (PRRSV), parvovirus porcino (PPV), y el virus de la enfermedad de Aujeszky (ADV), han sido asociadas a la presentación y brote clínico de PMWS. En este estudio debido a que los cerdos de la granja resultaron negativos a otras patologías de importancia en los cerdos, se sugiere que el PCV2 fue el principal agente etiológico involucrado en el brote clínico de PMWS en la granja estudiada. / Postweaning multisystemic wasting syndrome (PMWS) is a disease characterized by wasting and generalized lymphadenopathy in pigs in the nursery and growing stages caused by porcine circovirus type 2 (PCV2). In this thesis were performed three studies. In the first study were compared porcine circovirus type 1 (PCV1) antibody titres against PCV2 antibody titres of pigs with and without PMWS. The results show PCV2 antibody titres were mainly presents in pigs and farms affected with PMWS, but antibody against PCV2 were also found in pigs of farms without a known history of the syndrome. Most pigs with PMWS and PCV2 nucleic acid in tissues already had high titres against PCV2 at the time necropsy. This fact indicates that high antibody titres against PCV2 may coexist with characteristic lesions of PMWS during active viral replication in tissues.The retrospective study, showed the presence of PCV2 antibody titres and pathological lesions typical of PMWS with PCV2 nucleic acid in this tissues in Spain since 1985, suggesting that the introduction of this virus in the livestock occurred previously. Therefore, the emergence or the highest prevalence of PMWS after 1997 in Spain was apparently due to other factors rather than the introduction of a new virus in the swine population.The study about the dynamics of infection attributable to PCV2 in a selected population of pigs in a herd affected by PMWS, previously diagnosed based of clinical, histopathologic, serologic, in situ hybridisation (ISH) and polymerase chain reaction (PCR), and analysis. Major clinical signs and high mortality were observed, also revealed that wasting could occur in heavy and light pigs at weaning, which is in accordance with other results of another study. This study revealed a seroconversion pattern for PCV2 equivalent to that of typical antibody dynamics for most viral agents that affect swine. There was a decrease in colostral antibodies during the nursery period with the lowest concentrations at 7 weeks of age, an all pigs actively seroconverted during the grower period. On the other hand, a clear relationship between mortality associated with PMWS and low serologic titres at 7 weeks of age was observed. This result indicates that maternal immunity is apparently protective against the development of clinical disease associated with infection to PCV2, similar to the observations for most viral infections in swine. Viremic pigs were first detected at 7 weeks of age, an the peak in the number of pigs with positive results was at 12 weeks of age, an age at which the clinical signs of PMWS were declining. Therefore, the outbreak of PMWS coincided with the increase of PCV2 viremia between 7 and 12 weeks of age. A similar percentage of viremic pigs were detected at 7 and 28 weeks of age, although the latter pigs were clinically normal. Long periods of viremia in apparently healthy pigs suggest that antibodies detected by use of the immunoperoxidase monolayer assay (IPMA) were not able to neutralize virus and that production neutralizing antibodies may have been delayed or perhaps even extremely delayed. Other viral infections of swine, such as respiratory syndrome virus (PRRSV) and porcine parvovirus (PPV), Aujeszky disease virus (ADV), on the final outcome of pigs with PMWS have been investigated. In this study, because pigs on the selected farm were negative for others viral infections, was suggested that PCV2 was the major etiologic agent involved in the clinical outcome.

Present-day economic and environmental constraints push power systems to be operated closer to their limits. A common limiting factor for power transmission is the risk of voltage instability in recent years. As the ultimate countermeasure to voltage collapse, load shedding is normally considered the last resort, when there are no other alternatives to stop an approaching voltage collapse. The requirements of a practical load shedding scheme are to prevent a power system from voltage collapse and to maximize its reliability. In order to design such a scheme, the following tasks are equally important: 1. Recognizing the approaching voltage collapse. 2. Determining the best load shedding locations. 3. Minimizing the amount of load shedding. This thesis firstly investigates the widely used undervoltage load shedding schemes (UVLS) and the single-port impedance match (SPIM) based schemes. The findings explain the difficulties faced by them. An original load shedding oriented voltage stability monitoring scheme, which involves developing a new multi-port network equivalent, is then developed. With the help of the multi-port network equivalent, the monitoring scheme can not only recognize the approaching voltage collapse in time, but also can easily rank the load buses based on their weakness. The results of ranking are consistent with those obtained from modal analysis method. This thesis then proposes a practical event-driven load shedding scheme based on the experiences learned from the schemes implemented by various utilities. The scheme involves developing a multistage method, which is to optimize the amount of load shedding. A general design procedure for the scheme is presented in the thesis. Using a real 2038 bus system as an example, the design methodology is described in detail. The methodology is expected to help power system engineers develop their own load shedding schemes. A practical emergency demand response scheme is also developed and presented in the appendix. It is aimed at choosing the proper demand response participants and minimizing the total cost while achieving a certain level of operation reserves. / Power Engineering and Power Electronics

No description available.

The world of power systems is ever changing; ever evolving. One such evolution was the advent of Phasor Measurement Units (PMUs). With the introduction of PMUs in the field, power system monitoring and control changed for the better. Innovative and efficient algorithms that used synchrophasors came to be written. To make these algorithms robust, it became necessary to remove errors that crept into the power system with time and usage. Thus the process of calibration became essential when practical decisions started being made based on PMU measurements. In the context of this thesis ‘calibration’ is the method used to estimate a correction factor which, when multiplied with the respective measurement, negates the effect of any errors that might have crept into them due to the instrument transformers located at the inputs of a PMU or the PMU device itself. Though this thesis mainly deals with the calibration of instrument transformers, work has been done previously for calibrating other components of a power system. A brief description of those methods have been provided along with a history on instrument transformer calibration. Three new methodologies for instrument transformer calibration have been discussed in details in this thesis. The first method describes how only voltage transformers can be calibrated by placing optimal number of good quality voltage measurements at strategic locations in the grid, in presence of ratio errors in the instrument transformers and Gaussian errors in the PMUs. The second method provides a way to calibrate all instrument transformers (both current and voltage) in presence of only one good quality voltage measurement located at the end of a tie-line. This method assumes that all the instrument transformers have ratio errors and the PMUs have quantization errors. The third method attains the same objective as the second one, with the additional constraint that the data obtained from the field may be contaminated. Thus, the third method shows how calibration of all the instrument transformers can be done with data that is intermittent and is therefore, the most practical approach (of the three) for instrument transformer calibration. / Master of Science

Monitoring and protection of power systems is a task that has manifold objectives. Amongst others, it involves performing data mining, optimizing available resources, assessing system stresses, and doing data conditioning. The role of PMUs in fulfilling these four objectives forms the basis of this dissertation. Classification and regression tree (CART) built using phasor data has been extensively used in power systems. The splits in CART are based on a single attribute or a combination of variables chosen by CART itself rather than the user. But as PMU data consists of complex numbers, both the attributes, should be considered simultaneously for making critical decisions. An algorithm is proposed here that expresses high dimensional, multivariate data as a single attribute in order to successfully perform splits in CART. In order to reap maximum benefits from placement of PMUs in the power grid, their locations must be selected judiciously. A gradual PMU placement scheme is developed here that ensures observability as well as protects critical parts of the system. In order to circumvent the computational burden of the optimization, this scheme is combined with a topology-based system partitioning technique to make it applicable to virtually any sized system. A power system is a dynamic being, and its health needs to be monitored at all times. Two metrics are proposed here to monitor stress of a power system in real-time. Angle difference between buses located across the network and voltage sensitivity of buses lying in the middle are found to accurately reflect the static and dynamic stress of the system. The results indicate that by setting appropriate alerts/alarm limits based on these two metrics, a more secure power system operation can be realized. A PMU-only linear state estimator is intrinsically superior to its predecessors with respect to performance and reliability. However, ensuring quality of the data stream that leaves this estimator is crucial. A methodology for performing synchrophasor data conditioning and validation that fits neatly into the existing linear state estimation formulation is developed here. The results indicate that the proposed methodology provides a computationally simple, elegant solution to the synchrophasor data quality problem. / Ph. D.

Cette thèse porte sur la surveillance des perturbations de la qualité de l’énergie d’un réseau électrique via des techniques paramétriques de traitement du signal. Pour élaborer nos algorithmes de traitement du signal, nous avons traité les problèmes d’estimation des différentes grandeurs du réseau électrique triphasé et de classification des perturbations de la qualité d'énergie. Pour ce qui est du problème d’estimation, nous avons développé une technique statistique basée sur le maximum de vraisemblance. La technique proposée exploite la nature multidimensionnelle des signaux électriques. Elle utilise un algorithme d’optimisation pour minimiser la fonction de vraisemblance. L’algorithme utilisé permet d’améliorer les performances d’estimation tout en étant d’une faible complexité calculatoire en comparaison aux algorithmes classiques. Une analyse plus poussée de l’estimateur proposé a été effectuée. Plus précisément, ses performances sont évaluées sous un environnement incluant entre autres la pollution harmonique et interharmonique et le bruit. Les performances sont également comparées aux exigences de la norme IEEE C37.118.2011. La problématique de classification dans les réseaux électriques triphasés a plus particulièrement concerné les perturbations que sont les creux de tension et les surtensions. La technique de classification proposée consiste globalement en deux étapes : 1) une pré-classification du signal dans l’une des 4 préclasses établis et en 2) une classification du type de perturbation à l’aide de l’estimation des composants symétriques.Les performances du classificateur proposé ont été évaluées, entre autres, pour différentes nombre de cycles, de SNR et de THD. L’estimateur et le classificateur proposés ont été validés en simulation et en utilisant les données d’un réseau électrique réel du DOE/EPRI National Database of Power System Events. Les résultats obtenus illustrent clairement l’efficacité des algorithmes proposés quand à leur utilisation comme outil de surveillance de la qualité d’énergie. / This thesis deals with electric grid monitoring of power quality (PQ) disturbances using parametric signal processing techniques. The first contribution is devoted to the parametric spectral estimation approach for signal parameter extraction. The proposed approach exploits the multidimensional nature of the electrical signals.For spectral estimation, it uses an optimization algorithm to minimize the likelihood function. In particular, this algorithm allows to improve the estimation accuracy and has lower computational complexity than classical algorithms. An in-depth analysis of the proposed estimator has been performed. Specifically, the estimator performances are evaluated under noisy, harmonic, interharmonic, and off-nominal frequency environment. These performances are also compared with the requirements of the IEEE Standard C37.118.2011. The achieved results have shown that the proposed approach is an attractive choice for PQ measurement devices such as phasor measurement units (PMUs). The second contribution deals with the classification of power quality disturbances in three-phase power systems. Specifically, this approach focuses on voltage sag and swell signatures. The proposed classification approach is based on two main steps: 1) the signal pre-classification into one of 4 pre-classes and 2) the signature type classification using the estimate of the symmetrical components. The classifier performances have been evaluated for different data length, signal to noise ratio, interharmonic, and total harmonic distortion. The proposed estimator and classifier are validated using real power system data obtained from the DOE/EPRI National Database of Power System Events. The achieved simulations and experimental results clearly illustrate the effectiveness of the proposed techniques for PQ monitoring purpose.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-05-16T17:51:25Z No. of bitstreams: 1 guilhermedeoliveiraalves.pdf: 1293169 bytes, checksum: a76074780b2af177b66be7c6435b16d1 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-06-28T12:25:31Z (GMT) No. of bitstreams: 1 guilhermedeoliveiraalves.pdf: 1293169 bytes, checksum: a76074780b2af177b66be7c6435b16d1 (MD5) / Made available in DSpace on 2016-06-28T12:25:31Z (GMT). No. of bitstreams: 1 guilhermedeoliveiraalves.pdf: 1293169 bytes, checksum: a76074780b2af177b66be7c6435b16d1 (MD5) Previous issue date: 2015-09-18 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O presente trabalho tem por objetivo apresentar uma nova metodologia para estimação estática de estados em sistemas de distribuição de energia elétrica que estima as correntes nos ramos como variáveis de estado utilizando medições de tensão e corrente de ramo fasoriais oriundas de unidades de medição fasorial (Phasor Measurement Units - PMUs). A metodologia consiste em resolver um problema de otimização não linear minimizando uma função objetivo quadrática associada com as medições e estados estimados sujeito às restrições de carga das barras da rede que não apresentam PMUs instaladas baseadas em dados históricos, sendo esta a principal contribuição deste trabalho. Uma proposta de alocação de PMUs também é apresentada e que consiste em alocar duas unidades em cada ramificação do sistema, uma no começo e outra no final do trecho, procurando utilizar o menor número possível e que não comprometa a qualidade dos estados estimados. A resolução do problema de otimização é realizada de duas formas, através da ‘toolbox fmincon’ do software Matlab, que é uma ferramenta muito utilizada na resolução de problemas de otimização, e através da implementação computacional do Método de Pontos Interiores com Barreira de Segurança (Safety Barrier Interior Point Method - SFTB - IPM) proposto na literatura utilizada. Durante o processo de estimação de estados são utilizadas medidas obtidas através de um fluxo de potência que simulam as PMUs instaladas nos sistemas analisados variando o carregamento de cada sistema em torno da sua média histórica de carga até atingir os limites superior e inferior estabelecidos, sendo verificado o comportamento do estimador de estados perante a ocorrência de ruídos brancos nas medidas de todos os sistemas analisados. Foram analisados um sistema de distribuição tutorial de 15 barras e três sistemas encontrados na literatura contendo 33, 50 e 70 barras respectivamente. No sistema tutorial e no de 70 barras foram incluídas unidades de geração distribuída para se verificar o comportamento do estimador de estados. Todos os resultados do processo de estimação de estados são obtidos com os dois métodos de resolução apresentados e são comparados o desempenho de cada método, principalmente em relação ao tempo computacional. Todos os resultados obtidos foram validados usando um programa de fluxo de potência convencional e apresentam boa precisão com valor de função objetivo baixo mesmo na presença de ruídos nas medidas refletindo de maneira confiável o real estado do sistema de distribuição, o que torna a metodologia proposta atraente. / This work aims at presenting a new methodology for static state estimation in electric power distribution systems which estimates the branch currents as state variables using voltage measurements and current phasor branch obtained from phasor measurement units (Phasor Measurement Units - PMUs). The methodology consists of solving a nonlinear optimization problem minimizing a quadratic objective function associated with the estimated measurements and states, subject to load constraints for the non monitored loads based on historical data, which is the main contribution of this work. A PMU allocation strategy is presented which consists of allocating two PMUs for each system branch, one at the beginning and another at the end, trying to use as little PMUs as possible in such a way that the quality of the estimated states are not compromised. The solution of the optimization problem is obtained through two ways, the first is the toolbox ‘fmincon’ from Matlab solver software which is a widely used tool in the optimization problem. The second is a computer implementation of interior point method with security barrier (SFTB - IPM) proposed in the literature. Comparisons of computing times and results obtained with both methods are shown. A power flow program is used to obtain the voltages and branch currents in order to emulate the PMUs data in the state estimation process. Additionaly the non monitored loads are varied from the minimum bounds to their maximum, allowing white noise errors from the PMUs measurements. A tutorial test system of 15 buses is fully explored and three IEEE test systems of 33, 50 and 70 buses are used to show the effectiveness of the proposed methodology. For the tutorial and 70 bus systems, distribued generation units were included to see the state estimator behavior. All results from the state estimation process are obtained considering the two presented solving methods and the computing times performance compared. The results obtained were validated using a conventional power flow program and have good accuracy with low objective function value even in the presence of white noise errors in the measurements reflecting the reliability of the proposed methodology, making it very attractive for distribution system monitoring.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-01-09T11:36:05Z No. of bitstreams: 1 brauliocesardeoliveira.pdf: 2150243 bytes, checksum: 62faa254539b7873aa1393d8cd8f1bf2 (MD5) / Approved for entry into archive by Diamantino Mayra (mayra.diamantino@ufjf.edu.br) on 2017-01-31T11:23:24Z (GMT) No. of bitstreams: 1 brauliocesardeoliveira.pdf: 2150243 bytes, checksum: 62faa254539b7873aa1393d8cd8f1bf2 (MD5) / Made available in DSpace on 2017-01-31T11:23:24Z (GMT). No. of bitstreams: 1 brauliocesardeoliveira.pdf: 2150243 bytes, checksum: 62faa254539b7873aa1393d8cd8f1bf2 (MD5) Previous issue date: 2016-03-08 / O presente trabalho tem por objetivo apresentar uma metodologia para estimação de estados em sistemas de distribuição de energia elétrica. São utilizadas como variáveis de estado as correntes nos ramos. As medições são obtidas por meio de medições fasoriais sincronizadas(PhasorMeasurementUnits-PMUs),sendoqueostiposdemedidasadvindos desses equipamentos são as tensões nodais e as correntes nos ramos. A abordagem é trifásica, portanto representa as características próprias de um sistema de distribuição. A metodologia consiste em resolver um problema de otimização não linear cuja função objetivo associa o erro quadrático das medidas em relação aos estados estimados sujeito às restrições de carga das barras da rede que não possuem PMUs instaladas baseadas em estimativas de cargas obtidas para o instante “t-1”, partindo-se da premissa que em curtos intervalos de tempo a carga não sofre grandes variações, sendo esta em conjunto com a abordagem trifásica as principais contribuições deste trabalho. Outra contribuição do trabalho é a descentralização, com esta técnica pode-se dividir uma determinada rede em vários subsistemas que podem ser resolvidos de forma separada e independente. Isso torna o processo mais rápido do ponto de vista computacional além de permitir o uso do processamento paralelo, visto que já existe um paralelismo natural entre as tarefas que devem ser resolvidas. Outra vantagem da divisão em subsistemas reside no fato do monitoramento de áreas de interesse. Para utilizar a descentralização foi proposta uma alternativa de alocação de PMUs que consiste em posicionar duas unidades em cada ramificação do sistema, uma no começo e outra no final do trecho, procurando utilizar o menor número possível e que não comprometa a qualidade dos estados estimados. A resolução do problema de otimização é realizada através da implementação computacional do Método de Pontos Interiores com Barreira de Segurança (Safety Barrier Interior Point Method - SFTB - IPM) proposto na literatura especializada. As medidas das PMUs foram obtidas através de um Fluxo de Potência Trifásico via Injeção de Correntes (FPTIC). Foram realizadas diversas simulações variando-se o percentual da carga e os resultados obtidos foram comparados com outra metodologia existente na literatura e com os valores verdadeiros que foram obtidos através do FPTIC para as barras não monitoradas. Foram tambémcomparadosotempocomputacionalentreaexecuçãoserialeaexecuçãoutilizando o processamento paralelo. Os testes mostraram bons resultados o que torna a metodologia proposta aplicável na supervisão de sistemas de distribuição. / This work aims to present a methodology for static state estimation in electric power distribution systems. Branch currents are used as state variables. Measurements are obtained by means of Phasor Measurement Units (PMUs), in which voltage and current branches measurements are used. The approach is three-phase, thus represents the distribution system characteristics. The methodology consists of solving a nonlinear optimization problem minimizing a quadratic objective function associated with the estimated measurements and states subject to load constraints for the non monitored loads based on estimated load obtained from the ‘t-1’ instant, starting from the assumption that in short time intervals the load does not have large variations, which together with the the three-phase approach are the main contributions of this work. Another contribution of this work is the descentralided approach, with this assumption the network can be divided into several subnetworks that can be solved separately and independently. This speeds up the process of being solved from a computational point of view and allows the use of parallel processing, since there is already a natural parallelism among tasks to be solved. Another advantage of the division into subsystems is the fact that the monitoring areas of interest. With the aim of allowing the decentralization was proposed PMUs allocation strategy that consists of allocating two units for each lateral feeder, one at the beginning and one at the end, trying to use as little PMUs as possible in such a way that the quality of the estimated states are not compromised. The resolution of the optimization problem is done through a computer implementation of Interior Point Method with Security Barrier (SFTB - IPM) proposed in the literature. The PMUs measurements were emulated using a Three-PhasePowerFlowusingtheCurrentInjectionmethod(FPTIC).Severalsimulations were performed varying the load percentage and the results obtained were compared with other existing methodology in literature and also the true values that were obtained from the FPTIC to non monitored loads. The computational time using serial and parallel processing were also compared. Results show good results which makes the proposed methodology applicable in monitoring distribution systems.

Over the last decade, power systems have evolved dramatically around the world, owing to higher demand, stringent requirements on quality and environmental concerns that are becoming increasingly critical. With the introduction of new technologies like large-scale renewable energy, wide-area measurement based on phasor measurement units (PMUs) and consumer interaction in the distribution system, the power grid today has become more potent than ever before. Most of the defining features of the smart grid today rest on the integration of advanced communication capabilities into the grid. While communication infrastructure has become a key enabler for the smart grid, it also introduces new and complex control challenges that must be addressed. As we increasingly rely on information transmitted to distant areas over communication networks, it becomes imperative to model the effects of the communication system on the stability of the power grid. Several approaches exist in control theory to study such systems, widely referred to as Networked Control Systems (NCS). Networked control theory provides mathematical tools for system stability analysis and control in the presence of communication delays, packet dropouts and disordering due to transmission of sensor and actuator signals via a limited communication network. In this thesis, a networked control framework for smart grids with integrated commu-nication infrastructure (ICT) is developed. In particular, a networked control systems perspective is developed for two scenarios - wide-area monitoring control, and coordinated control of distributed generation sources. The effects of communication delays and packet dropouts on power system stability are modeled in detail. In the wide-area monitoring control problem, system state measurements are trans-mitted from remote locations through a communication network. The system is modeled as an NCS and a control design approach is presented to damp inter-area oscillations arising from various power system disturbances in the presence of communication constraints. In the coordinated control scenario, a power system with geographically dispersed sources is modeled as an NCS. A networked controller is designed to stabilize the system in the presence of small signal disturbances when system measurements are subject to communication delays and packet dropouts. A realistic output feedback networked control scheme that only uses voltage measurements from PMUs is also developed for practical implementation. The networked controllers designed in this thesis are validated against controllers designed by standard methods, by simulation on standard test systems. The networked controllers are found to enhance power system stability and load transfer capability even in the presence of severe packet dropouts and delays. Several extensions and theoretical problems motivated by this thesis are also proposed.