Дисертації: "Development of power grids"

1

Keskin, Müge. "Smart Grids and Turkey: An Overview of the Current Power System and Smart Grid Development." Thesis, Uppsala universitet, CEMUS, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-438553.

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Successful integration of the smart grids is crucial for ensuring the efficiency, resiliency, and sustainability of future power systems. With a 46.53% increase in total primary energy supply between 2008 and 2018 (IEA, 2020a), Turkey has the fastest-growing energy market within OECD countries (Erdin and Ozkaya, 2019).Though, Turkey’s current electrical grid faces many challenges; such as high loss rates from the transmission and distribution lines (Damar, 2016; Düzgün, 2018; IBRD/The World Bank, 2016; TEİAŞ, 2019), frequent power outages (Guner and Ozdemir, 2011; Öztürk, 2017; Yanılmaz, 2016) and several incidents of large-scale blackouts (OECD/IEA, 2016; Project Group Turkey, 2015). Smart grid technologies can address Turkey’s power system’s challenges with a holistic approach, as the smart grid does not have a strict definition yet but has distinctive characteristics. This paper provides an overview of Turkey’s current electric power system’s challenges while analyzing Turkey’s progress up to the present day towards the smart grid transition. Also, in order to summarize fundamental smart grid technologies globally, a smart grid framework was designed. Founded upon the framework; Turkey’s previous actions for its power system development were assessed from the smart grid perspective, and further steps were proposed to accomplish a successful smart grid transition. Country-specific remarks regarding the electrical grid were highlighted, such as the risk of terrorism, high seismic activity in the region, and emerging nuclear power in the country. As a result, it is concluded that Turkey has initiated the process towards the smart grid transition not only to achieve a “smart grid ideal” but mainly to meet its growing energy demands. Furthermore, it is also concluded that if the smart grid technologies’ scope could be extended throughout the country, Turkey would overcome the challenges with its power system in short to medium-term.

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2

Martinez, Parrondo Yago. "Smart Meters : Basic Elements in the Development of Smart Grids." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elkraftteknikk, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-13630.

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The necessity of a revolution in the electrical system is obvious, and smart meters will be the solution. The development of smart grids will be built over the new electronic measuring devices, which imply a challenge for the next few years in the engineering field.In order to understand the basics of smart grids, we have carried a description and comparison of both the current and the next-gen electrical systems. Emphasizing the advantages and opportunities obtained by changing into the smart grids, it demonstrates the importance of moving towards a more modern measurement system.A very important issue is to decide which should be the minimum features in Smart Meters, therefore this thesis analyzes the different exiting models and also proposes several suggestions for the future. Finally, it was conducted a report of the current deployment situation of this new technology in various representative countries. Describing the settings and options chosen by each country, we can achieve a conclusion that unifies a standard solution by the choice of the best proposals.

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3

Wong, Mau-yee, and 黃漫宜. "Stakeholders' perspectives on smart grid policy development in Hong Kong." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/194552.

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Achieving a low carbon economy has been the focus of Hong Kong in recent years. Strategies are put forth to support sustainable energy, because Hong Kong has inadequate local and renewable energy reserves. Smart grid technologies have benefited many countries in the world, and countries such as the United States, the United Kingdom, China, and South Korea are exploring this new green energy strategy. Hong Kong’s power companies have considered smart grid technologies, conducting pilot projects to test their local feasibility. In this research, stakeholders’ perspectives of the current status of smart grids are overviewed in Hong Kong from the angle of policy aspect. Stakeholder theory is utilized as the framework for understanding and analyzing the perceptions of stakeholder groups. An integrated and modified stakeholder power-interest matrix was developed for analyzing level of power and interest of stakeholder groups on smart grid from policy dimension. Through the course of this research project, qualitative interviews were conducted for 11 interviewees with subjectsfrom1six stakeholder groups, including: academics, advisory bodies, business, government, non-governmental organizations, and power companies. Follow-up quantitative questionnaires were distributed to the same target group for stakeholder analysis and to map the level of power and interest of stakeholder groups regarding smart grid policy development in Hong Kong. The data collected from interviews were compared with and contrasted against each stakeholder groups and other countries, with a view to identifying common motivations, barriers, and policy suggestions. The findings reveal that the six stakeholder groups hold medium to high power and interest in smart grid policy development in Hong Kong. Common motivations identified by local stakeholder groups include: the right to choose their own energy mix for power generation, potential behavioural change via smart meter and tariff restructuring, possible energy savings and emissions reductions for the environment, and corporate social responsibility. The most significant motivation for smart grid development shared with other countries is the goal of achieving low carbon economy and energy efficiency. Shared barriers perceived by the six stakeholder groups are: unreliable renewable power supplies, significant capital investments required, impracticalities of supplying electricity back to the grid, transfers of additional power generation costs to consumers, and limited smart grid knowledge by the public. The most significant barrier shared with international countries is funding mechanism, yet it may be difficult for Hong Kong to secure funding from the government because of problems of trust. Three stages of recommendations are suggested. Short-term recommendations centre on the policy development direction of smart grid in Hong Kong, and include implementing dynamic pricing, undertaking a large-scale pilot program and establishing an awareness campaign (funded by the government)for educating the general public. Medium-term recommendation is to establish a joint green fund with the contributions of companies with large carbon footprints. Long-term recommendations include market liberalization and increases in market competition.
published_or_final_version
Environmental Management
Master
Master of Science in Environmental Management

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4

Bottura, Riccardo <1986&gt. "Modelling and analysis of networked control strategies in smart power distribution grids: development of co-simulation tools." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/7062/.

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This thesis is focused on Smart Grid applications in medium voltage distribution networks. For the development of new applications it appears useful the availability of simulation tools able to model dynamic behavior of both the power system and the communication network. Such a co-simulation environment would allow the assessment of the feasibility of using a given network technology to support communication-based Smart Grid control schemes on an existing segment of the electrical grid and to determine the range of control schemes that different communications technologies can support. For this reason, is presented a co-simulation platform that has been built by linking the Electromagnetic Transients Program Simulator (EMTP v3.0) with a Telecommunication Network Simulator (OPNET-Riverbed v18.0). The simulator is used to design and analyze a coordinate use of Distributed Energy Resources (DERs) for the voltage/var control (VVC) in distribution network. This thesis is focused control structure based on the use of phase measurement units (PMUs). In order to limit the required reinforcements of the communication infrastructures currently adopted by Distribution Network Operators (DNOs), the study is focused on leader-less MAS schemes that do not assign special coordinating rules to specific agents. Leader-less MAS are expected to produce more uniform communication traffic than centralized approaches that include a moderator agent. Moreover, leader-less MAS are expected to be less affected by limitations and constraint of some communication links. The developed co-simulator has allowed the definition of specific countermeasures against the limitations of the communication network, with particular reference to the latency and loss and information, for both the case of wired and wireless communication networks. Moreover, the co-simulation platform has bee also coupled with a mobility simulator in order to study specific countermeasures against the negative effects on the medium voltage/current distribution network caused by the concurrent connection of electric vehicles.

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5

Amaripadath, Deepak. "Development of Tools for Accurate Study of Supraharmonic Emissions in Smart Grids." Thesis, Bourgogne Franche-Comté, 2019. http://www.theses.fr/2019UBFCA016.

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Alors que la préoccupation mondiale pour le changement climatique et ses effets se multiplient, les gouvernements sont forcés de prendre des décisions fermes en faveur de la mise en place des réseaux électriques intelligents. Toutefois, le succès de ces actions dépend fortement de la satisfaction de certaines exigences du réseau électrique soulevées par la qualité de l’énergie fournie et les moyens de l’évaluer. Les réseaux électriques intelligents doivent relever les défis posés par l’utilisation croissante des sources d’énergie renouvelables, telles que le photovoltaïque (PV), le vent, etc. et les équipements, tels que les onduleurs photovoltaïques (PVI), les chargeurs de véhicules électriques (EVC), etc. Cela introduit un environnement opérationnel de dynamique complexe pour le système de distribution. Les distorsions provenant d’équipement de nouvelle génération et de charge sont généralement plus importantes et moins régulières que celles dues à l’équipement de génération traditionnelle et de charge, rendant les mesures de puissance et d’énergie difficiles à effectuer.Dans ce contexte, la thèse vise à quantifier et reproduire les émissions supra-harmoniques pour des fréquences de 2 à 150 kHz. Par conséquent, la littérature existante sur les émissions supra-harmoniques pour des fréquences de 2 à 150 kHz est étudiée. Le système de mesure à 4 voies est conçu et mis en œuvre pour la mesure des composantes fondamentales et supra-harmoniques des formes d’onde de tension et de courant pour des fréquences de 2 à 150 kHz dans le réseau électrique. Les mesures sont effectuées dans la plateforme Concept Grid. La caractérisation des équipements individuels et les tests du réseau électrique sont effectués ici. Les formes d’onde acquises durant les campagnes de mesure sont traitées mathématiquement à l’aide de l’algorithme de transformation rapide de Fourier (FFT) et statistiquement à l’aide de l’algorithme d’analyse de variance (ANOVA). Le traitement mathématique et statistique des formes d’onde acquises permet de déterminer les effets individuels et les interactions des différents paramètres dans la génération des émissions supra-harmoniques dans le réseau électrique. Les différents paramètres, tels que les émissions primaires et secondaires, les effets de la longueur du câble, les effets de l’ajout soudain et l’enlèvement de l’équipement de charge sont également étudiés.La thèse décrit la conception de la plateforme complexe d’onde, qui peut être utilisée pour des essais en laboratoire et la caractérisation des analyseurs de qualité de puissance (PQA) pour des fréquences de 2 à 150 kHz. Dans les réseaux électriques, la plateforme d’onde peut être utilisée pour mesurer les émissions supra-harmoniques pour des fréquences de 2 à 150 kHz. L’architecture logicielle de la plateforme d’onde est décrite ici. De plus, le document explique la conception matérielle de la plateforme d’onde. Il comprend également les applications de la plateforme d’onde du laboratoire et du réseau électrique. La configuration au laboratoire pour la caractérisation du PQA et le schéma de mesure pour les formes d’onde du réseau électrique sont également représentés ici. Le bilan d’incertitude pour la plateforme d’onde est calculé en tenant compte des différents facteurs, tels que la longueur du câble, le bruit, etc., sont discutés dans la thèse. Enfin, le PQA est caractérisé dans des fréquences de 2 à 150 kHz par rapport à la plateforme d’onde pour des amplitudes d’émission variables
As the worldwide concern for the climate change and its effects are growing, the governments are forced to make strong decisions in favour of the implementation of the smart electrical grids. However, the success of these actions strongly depends on meeting the certain requirements of the electricity system raised by the quality of the energy supplied and the means to assess it. The smart electrical networks have to tackle the challenges raised by the increasing uptake of the renewable energy sources, such as the photovoltaic (PV), wind, etc. and the equipment, such as photovoltaic inverters (PVI), electric vehicle chargers (EVC), etc. This introduces a complex dynamic operating environment for the distribution system. The distortions coming from the new generation and load equipment are generally larger and less regular than those due to the traditional generation and load equipment, making the power and energy measurements difficult to perform.In this context, the thesis aims to quantify and reproduce the supraharmonic emissions in the frequency range of 2 to 150 kHz. Therefore, the existing literature on the supraharmonic emissions in the frequency range of 2 to 150 kHz is studied. The 4-channel measurement system is designed and implemented for the measurement of the fundamental and supraharmonic components of the voltage and current waveforms in the frequency range of 2 to 150 kHz in the electrical network. The measurements are carried out in the Concept Grid platform. The individual equipment characterization and electrical network tests are carried out here. The waveforms acquired during the measurement campaigns are processed mathematically using the fast Fourier transform (FFT) algorithm and statistically using the analysis of variance (ANOVA) algorithm. The mathematical and statistical processing of the acquired waveforms helps to determine the individual effects and interactions of the different parameters in the generation of the supraharmonic emissions in the electrical network. The various parameters, such as the primary and secondary emissions, effects of the cable length, effects of the sudden addition and removal of the load equipment are also studied.The thesis describes the design of the complex waveform platform, which can be used for the laboratory testing and the characterization of the power quality analyzers (PQA) in the frequency range of 2 to 150 kHz. In the electrical networks, the waveform platform can be used to measure the supraharmonic emissions in the frequency range of 2 to 150 kHz. The software architecture of the waveform platform is described here. In addition, the paper explains the hardware design of the waveform platform. It also includes the laboratory and electrical network applications of the waveform platform. The laboratory setup for the characterization of the PQA and the measurement schema for the electrical network waveforms are also depicted here. The uncertainty budget for the waveform platform is calculated considering the various factors, such as the cable length, noise, etc. are discussed in the thesis. Finally, the PQA is characterized in the frequency range of 2 to 150 kHz with respect to the waveform platform for varying emission amplitudes

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6

Tinarwo, Loyd. "Development of methodologies for deploying and implementing local & medium area broadband PLC networks in office and residential electric grids." Thesis, University of Fort Hare, 2008. http://hdl.handle.net/10353/83.

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The use of electrical networks for telecommunications has a long history. It has been known since the beginning of the twentieth century [Ahola03]. The idea of using electrical networks for broadband communications arose in the 1990s [Hrasnica et al 04]. Recent and growing research interest has indicated that PowerLine Communications (PLC) is the threshold for achieving broadband delivery particularly in very dispersed and low teledensity areas. Currently, there are numerous PLC trials and commercial deployments underway inside and outside South Africa. Nevertheless, these PLC deployments are very isolated, done without clear methodology and performance remains bound to the physical layout of the electrical network. Because of that high bandwidth broadband PLC systems are prone to poor performance and this in turn limits the acceptance and deployment of this emerging alternative broadband technology. Though, PLC technical challenges are being addressed, there has been little analysis and research work that is focused on the “Development of Methodologies for Deploying and Implementing Local & Medium Area Broadband Power Line in Residential and Office Electric Grids” that would lead to broadband PLC being adopted and be of greater use to non-broadband communities of South Africa. PLC is a term describing several different systems using electrical grid distribution wires for simultaneous distribution of data by superimposing an analog signal [Hrasnica et al 04]. The research proposed and presented broadband PLC methodologies for typical medium voltage and local voltage PLC networks. These methodologieswere implemented and experimented with in configurations which closely mirrored residential and office settings through laboratory and multibuilding experiments using commercial 2nd Generation Mitsubishi Electric PLC technology. Research results presented not only serve to provide insight into broadband PLC but also how it handled broadband applications (communications), competed and compared with other technologies such as Ethernet LAN. In combination with networking communication theories, the research explored and analyzed the extent of PLC in providing broadband communication to residential and office electric grids at the University Fort Hare, Computer Science Department.

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7

Adekola, Olawale Ibrahim. "Design and development of a smart inverter system." Thesis, Cape Peninsula University of Technology, 2015. http://hdl.handle.net/20.500.11838/2195.

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Thesis (MTech (Electrical, Electronic and Computer Engineering))--Cape Peninsula University of Technology, 2015.
The growing interest in the use of solar energy to mitigate climate change, reduction in the cost of PV system and other favourable factors have increased the penetration of the PV(Photovoltaic) systems in the market and increase in the worldwide energy supply. The main component in a DG is a smart inverter connected in a grid-tied mode which serves as a direct interface between the grid and the RES (Renewable Energy System). This research work presents a three phase grid-tied inverter with active and reactive power control capabilities for renewable energy sources (RES) and distributed generators (DG). The type of the inverter to be designed is a Voltage Source Inverter (VSI). The VSI is capable of supplying energy to the utility grid with a well regulated DC link at its input. The solution this project proposes is an implementation of the designed filter to effectively reduce the harmonics injected into the grid to an acceptable value according to standards and also an approach to control the real and reactive power output of the inverters to help solve the problems of instability and power quality of the distribution system. The design, modelling and simulation of the smart inverter system is performed in MATLAB/SIMULINK software environment. A 10 kW three-phase voltage source inverter system connected to the utility grid was considered for this research. Series of simulations for the grid-connected inverter (GCI) model was carried out using different step changes in active and reactive power references which was used to obtain the tracking response of the set power references. The effectiveness of the control system which was designed to track the set references and supply improved power quality with reduced current ripples has been verified from the simulation results obtained.

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8

Musoni, Nkusi Emmanuel. "Analysis of the effect of renewable generation on the power quality of the grid, modelling and analysis of harmonic and voltage distortion." Thesis, Cape Peninsula University of Technology, 2018. http://hdl.handle.net/20.500.11838/2805.

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Thesis (Master of Engineering in Electrical Engineering)--Cape Peninsula University of Technology, 2018.
As the electric energy demand grows, there is a significant increase in the penetration of renewable generation (RG) in the existing electrical grid network. Interconnecting of renewable generation technologies to an existing distribution system has proven to provide various benefits such as meeting the growing load demand and its contribution to energy system decarbonisation, long-term energy security and expansion of energy access to new energy consumers in the developing urban and rural areas. However, the aim of this thesis is to conduct a study on the impacts of renewable generation on the power quality of electrical grid. Therefore, this work aims at assessing the potential effects of Distributed Generation (DG) on the operation of electric power system by modelling of harmonics and voltage distortion. With different types of renewable generation available at present, it is believed that some designs contribute significantly to electrical network’s Power Quality (PQ). After the analysis of harmonic currents (chapter 6 and 7 of this thesis) introduced by renewable generation technologies, their negative impact on the power quality of the grid is seen to be apparent at point of connection (POC) but only within controlled limits. Analytical method for modeling of harmonic interactions between the grid and aggregated distributed generation technologies are investigated using DIgSILENT Power Factory software and the results obtained are discussed.

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9

Gupta, Gunjan. "An analysis and improvement of selected features of power quality of grid-tied alternative energy systems." Thesis, Cape Peninsula University of Technology, 2018. http://hdl.handle.net/20.500.11838/2696.

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Thesis (PhD (Electrical Engineering))--Cape Peninsula University of Technology, 2018.
Electrical energy can be easily used and converted to other forms of energy for various applications. Technological advancement increases the dependency on electricity to a great extent. Various internal and external factors are responsible for the bad quality of power in power systems. The performance of the system is greatly affected by the presence of harmonics, as well as voltage and frequency variations, which leads to the malfunctioning of the device and decline of power quality and supply at load side. The reactive power compensation is carried out for better power quality. The literature survey is done to find the best and efficient scheme for reactive power compensation and mitigation of various power quality problems. The devices which are used to measure various power quality factors are discussed. Various mitigating schemes are surveyed in order to compensate reactive power and to improve the power quality at the distribution end. The integration of the most widely used renewable energy, wind energy in the distribution system creates technical issues like stability of the grid, harmonic distortion, voltage regulation, active and reactive power compensation etc. which are restricted to IEC and IEEE standards. One of the topics this thesis addresses is regulation in the reactive power generated along with voltage regulation by using an effective power electronics device known as a STATCOM. The main power quality factors like overvoltage and voltage flickers are mitigated by establishing STATCOMs in small wind farms. The wind farms are equipped with three wind turbines. These three wind turbines found in the wind farm can be operated together or one after another with an introduced delay. A glitch in even a little piece of a power grid can result in loss of efficiency, income and at times even life. In this manner, it is basic to outline a system which can distinguish the faults of the power system and take a faster response to recover it back to required reactive power. Two devices STATCOM and D-STATCOM are used for this purpose in this thesis. The D-STATCOM circuit and operating principle are also discussed in thesis. Different topologies of D-STATCOM discussed with their benefits and shortcomings. The voltage, current and hybrid technologies of D-STATCOM are also discussed.

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10

Osama, Hassan Eltayeb Khalid. "Development of the Simulation Model for the CoSES Laboratory Test Microgrid in Modelica." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.

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Evolution of the traditional consumer in a power system to a prosumer has posed many problems in the traditional uni-directional grid. This evolution in the grid model has made it important to study the behaviour of microgrids. This thesis deals with the laboratory microgrid setup at the Munich School of Engineering, built to assist researchers in studying microgrids. The model is built in Dymola which is a tool for the OpenModelica language. Models for the different components were derived, suiting the purpose of this study. The equivalent parameters were derived from data sheets and other simulation programs such as PSCAD. The parameters were entered into the model grid and tested at steady state, firstly. This yielded satisfactory results that were similar to the reference results from MATPOWER power flow. Furthermore, fault conditions at several buses were simulated to observe the behaviour of the grid under these conditions. Recommendations for further developing this model to include more detailed models for components, such as power electronic converters, were made at the end of the thesis.

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11

Melo, Lucas Silveira. "Development of a platform for implementing multi-agents systems for application to automatic restoration of electric power distribution systems." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=15234.

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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico
It is common the occurence of permanent faults in power distribution systems. In a typical radial power distribution system when the fault protection system operates, may cause power-off not only in the fault section, but also to all customers downstream the fault.Through disjunction devices normally closed along the feeder, and normaly open on its edges, is possible to isolate the faulty sector and reenergize the healthy ones, reducing the number of customers affected by a fault. Network operators normally do this procedure manually and in addition to demand a considerable ammount of time, is subject to errors on the part of the operator. In order to automate the analisys of the network and provided it of self-healing capacity, various methods have been proposed to solve this matter. Most of these approaches adopts a centralized strategy and do not address the aspect of electric power grid self-healing. In this work is proposed an approach that uses multi-agent systems for self-healing purposes of power distribution systems. Multi-agent are highly suitable for modelling distributed systems in the smart grid domain. For a safe recovery and without violation of operational restrictions the feeder agents perform an evaluation before device agents send any command to the network switches. The proposed multi-agent system is implemented in a agentâs development platform proposed in this work that uses the Python programming language. The platform is called PADE, Python Agent DEvelpment framework. The computer representation of the network, without simplifications, is accomplished by a data encoding based on the theory of graphs and named node-depth representation that serves as a basis for the development of an API of network representation that models each of the required components in the restoration analysis. The device agents communicate with IED that in turn control the switches in the network, by means of IEC 61850 protocols: GOOSE and MMS. To validate the proposed approach, computer simulations are performed using a simplified distribution power grid as a case study and a test platform with relay test case, protection and control IED, managed switch and embedded systems.
Ã comum a ocorrÃncia de faltas permanentes no sistema de distribuiÃÃo de energia elÃtrica. Por tratar-se de um sistema radial, a atuaÃÃo da proteÃÃo para estas faltas causa a desenergizaÃÃo nÃo sÃ do setor em falta, mas de todos os consumidores a jusante do setor onde ocorreu a falta. Fazendo uso dos dispositivos de disjunÃÃo normalmente fechados ao longo do alimentador e normalmente abertos nas suas bordas Ã possÃvel isolar o setor sob falta e re-energizar os setores sÃos, reduzindo o nÃmero de consumidores afetados por um defeito. Este procedimento Ã normalmente feito pelos operadores da rede, e alÃm de demandar um tempo considerÃvel, estÃ sujeito Ã erros por parte do operador. No sentido de tornar automÃtica as anÃlises de restauraÃÃo da rede e prover o sistema da capacidade de auto-cura, tÃm sido propostas diversas metodologias para o problema. A maioria destas abordagens adota uma estratÃgia centralizada e nÃo abordam o aspecto de auto-cura da rede elÃtrica. Neste trabalho, Ã proposta uma abordagem utilizando sistemas multiagentes para recomposiÃÃo de setores de alimentadores de distribuiÃÃo de energia elÃtrica. A tÃcnica de sistemas multiagentes vem se mostrando bastante promissora no desenvolvimento de sistemas distribuÃdos em um contexto de redes elÃtricas inteligentes. Para que a recomposiÃÃo ocorra sem a violaÃÃo das restriÃÃes operacionais e de forma coerente, sÃo feitas anÃlises pelos agentes alimentadores antes que qualquer comando seja enviado para as chaves do sistema por meio de agentes dispositivo. O sistema multiagente proposto Ã implementado em uma plataforma de desenvolvimento de agentes proposta neste trabalho e que utiliza a linguagem de programaÃÃo Python. A plataforma tem o nome de PADE, Python Agent DEvelpment framework. A representaÃÃo computacional sem simplificaÃÃes da rede Ã proporcionada por uma codificaÃÃo de dados apoiada na teoria de grafos e denominada RepresentaÃÃo NÃ-Profundidade, que serve de base para o desenvolvimento de uma API de representaÃÃo da rede-elÃtrica que modela cada um dos componentes necessÃrios nas anÃlises de recomposiÃÃo. Ao agente dispositivo Ã dada a possibilidade de comunicaÃÃo com IED, que controlam as chaves do sistema, por meio dos protocolos da norma IEC 61850: GOOSE e MMS. Para validar a metodologia proposta sÃo realizadas simulaÃÃes computacionais utilizando uma rede de distribuiÃÃo simples como caso base e uma plataforma de testes com: mala de testes de relÃs, IED de proteÃÃo e controle de mercado, switch gerenciÃvel e placas de desenvolvimento de sistemas embarcados.

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12

Alharbi, Mohammad. "Development of simplified power grid models in EU project Spine." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-285503.

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The electric power system is among the biggest and most complex man-made physical network worldwide. The increase of electricity demand, the integration of ICT technologies for the modernization of the electric grid and the introduction of intermittent renewable generation has resulted in further increasing the complexity of operating and planning the grid optimally. For this reason the analysis of large-scale power systems considering all state variables is a very complicated procedure. Thus, it is necessary to explore methods that represent the original network with smaller equivalent networks in order to simplify power system studies. The equivalent network should provide an accurate and efficient estimation of the behavior of the original power system network without considering the full analytical modelling of the grid infrastructure. This thesis investigates partitioning methods and reduction methodologies in order to develop a proper reduction model. The K-means and K-medoids clustering algorithms are employed to partition the network into numerous clusters of buses. In this thesis the Radial, Equivalent, and Independent (REI) method is further developed, implemented, and evaluated for obtaining a reduced, equivalent circuit of each cluster of the original power system. The basic idea of REI method is to aggregate the power injections of the eliminated buses to two fictitious buses through the zero power balance network. The method is implemented using Julia language and the PowerModels.jl package. The reduction methodology is evaluated using the IEEE 5-bus, 30-bus, and 118-bus systems, by comparing a series of accuracy and performance indices. Factors examined in the comparison include the chosen number of clusters, different assumptions for the slack bus as well as the effect of the imposed voltage limits on the fictitious REI buses.
Elsystemet är ett av de största och mest komplexa människotillverkade fysiskanätverken i världen. Ökad elförbrukning, integration av informationsteknik föratt modernisera elnäten samt införandet av varierande förnybar elproduktion harresulterat i ytterligare ökad komplexitet för att driva nätet optimalt. Därför ärdet mycket komplicerat att analysera storskaliga elsystem samtidigt som man tarhänsyn till alla tillståndsvariabler. Det är således nödvändigt att utforska metoderför att modellera det ursprungliga nätverket med ett mindre ekvivalent nätverk föratt underlätta studier av elsystem. Det ekvivalenta nätverket ska ge en noggrann ocheffektiv uppskattning av det ursprungliga systemets egenskaper utan att inkludera enkompletta analytisk modell av nätverkets stuktur.Den här rapporten undersöker metoder för att dela upp och reducera ett nätverkför att få fram en lämplig ekvivalent modell. Klusteranalysalgotmerna K-meansoch K-medoids används för att dela in nätverket i ett antal kluster av noder. Irapporten vidareutvecklas, implementeras och utvärderas REI-metoden för att ta framreducerade ekvivalenta nätverk för varje kluster i det ursprungliga systemet. Dengrundläggande idén med REI-metoden är att den aggregerar elproduktionen i deelminerade noderna i två fiktiva noder genom ett nolleffektbalansnätverk.Metoden är implementerad i programspråket Julia och programpaketetPowerModels.jl. Reduceringsmetoderna utvärderas på IEEE:s system med 5 noder,30 noder respektive 118 noder, genom att jämföra ett antal index för noggrannhetoch prestanda. De faktorer som undersäks i jämförelsen inkluderar det valda antaletkluster, olika antagande om slacknoden samt följderna av spänningsgränserna för defiktiva REI-noderna.v

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13

Raji, Atanda Kamoru. "Modelling and development of fuel cell off grid power converter system." Thesis, [S.l. : s.n.], 2008. http://dk.cput.ac.za/cgi/viewcontent.cgi?article=1039&context=td_cput.

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14

Li, Quan, and q. li@cqu edu au. "DEVELOPMENT OF HIGH FREQUENCY POWER CONVERSION TECHNOLOGIES FOR GRID INTERACTIVE PV SYSTEMS." Central Queensland University. School of Advanced Technologies & Processes, 2002. http://library-resources.cqu.edu.au./thesis/adt-QCQU/public/adt-QCQU20020807.152750.

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This thesis examines the development of DC-DC converters that are suitable for Module Integrated Converters, (MICs), in grid interactive photovoltaic (PV) systems, and especially concentrates on the study of the half bridge dual converter, which was previously developed from the conventional half bridge converter. Both hard-switched and soft-switched half bridge dual converters are constructed, which are rated at 88W each and transform a nominal 17.6Vdc input to an output in the range from 340V to 360Vdc. An initial prototype converter operated at 100kHz and is used as a base line device to establish the operational behaviours of the converter. The second hard-switched converter operated at 250kHz and included a coaxial matrix transformer that significantly reduced the power losses related to the transformer leakage inductance. The soft-switched converter operated at 1MHz and is capable of absorbing the parasitic elements into the resonant tank. Extensive theoretical analysis, simulation and experimental results are provided for each converter. All three converters achieved conversion efficiencies around 90%. The progressive increases in the operation frequency, while maintaining the conversion efficiency, will translate into the reduced converter size and weight. Finally different operation modes for the soft-switched converter are established and the techniques for predicting the occurrence of those modes are developed. The analysis of the effects of the transformer winding capacitance also shows that soft switching condition applies for both the primary side mosfets and the output rectifier diodes.

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15

Steel, Katherine Deaton. "Energy system development in Africa : the case of grid and off-grid power in Kenya." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43840.

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Анотація:

Thesis (Ph. D.)--Massachusetts Institute of Technology, Engineering Systems Division, 2008.
Includes bibliographical references.
This research used a combination of a grounded theory approach and system dynamics to study the electric power system in Kenya and to model the feedback at work in the development of the system. The ethnographic study revealed the challenges faced by consumers in choosing between grid and off-grid power options. Examination of this challenge leads to the hypothesis that competition between the grid and off-grid markets is contributing to the low growth in power consumption and that there is the potential for off-grid to become the dominant option in the future. This theory guided the construction of a system dynamics model focusing on consumers' decision-making and their interaction with the operation of the system. I then used the model to explore the dynamics of the system through scenario testing. There were two key outcomes from the model. The first showed that given the parameters chosen in most cases there is a clearly dominant option, although it changes over time. This finding points to the second key outcome the model, which is that there are realistic scenarios under which off-grid generation will become the dominant supply source. This shift could be induced by either reduced overhead on photovoltaic panels or high fuel prices. The outcomes from this research have implications for future electricity planning in Kenya and elsewhere in Africa. In particular, there is a need to decouple the system from external prices or account for the extreme uncertainty in fuel prices. Given the potential shift to large-scale off grid power generation, energy planners also need to look at options for managing a decentralized power system architecture and consider how to build in options for future reintegration if a large-scale centralized generation source comes online.
(cont.) This research has both academic and applied contributions. On the academic side, it extends the range of engineering systems modeling to include qualitative factors found in an African environment. These factors include the addition of reliability and availability of the electric power grid and the biases in decision-making, which differ from those in industrialized countries. While the model clearly has direct application in Kenya, it was designed with flexibility to be expanded to include other countries and regions and could be a useful tool for understanding policy trade-offs in African electrification planning.
by Katherine Deaton Steel.
Ph.D.

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16

Mataifa, Haltor. "Modeling and control of a dual-mode grid-integrated renewable energy system." Thesis, Cape Peninsula University of Technology, 2015. http://hdl.handle.net/20.500.11838/2190.

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Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2015.
From the electric power generation perspective, the last three decades have been characterized by sustained growth in the amount of Distributed Power Generation (DPG) systems integrated into the electric grid. This trend is anticipated to continue, especially in light of the widespread acceptance of the many benefits envisaged in the increase of renewable-based power generation. The potential for grid-integrated DPG systems to significantly contribute to electric power supply reliability has consistently attracted extensive research in recent times, although concerns continue to be raised over their adverse impact on the normal grid operation at high penetration levels. These concerns largely stem from the limited controllability of most DPG systems, which tend to exhibit large output impedance variation, and non-deterministic power output characteristics. There has therefore also been a growing need to develop effective control strategies that can enhance the overall impact of the DPG systems on the grid operation, thus improving their synergistic properties, and probably also enabling an even higher penetration level into the utility grid. In line with this identified need, this thesis discusses the modeling and controller design for an inverter-based DPG system with the capability to effectively operate both in grid-connected and autonomous (i.e. independent of the utility grid) operational modes. The dual-mode operation of the DPG is made possible by incorporating into the inverter interface control scheme the means to ensure seamless transition of the DPG between the grid-connected and autonomous modes of operation. The intention is to have a grid-integrated inverter-based DPG system whose operation approximates that of an online Uninterruptible Power Supply (UPS) system, in that it is able to sustain power supply to the local load in the absence of the grid supply, which would be desirable for critical loads, for which the level of power supply reliability guaranteed by the grid often falls short of the requirements. The work developed in this thesis considers three of the aspects associated with grid-integrated DPG systems that are equipped with autonomous-mode operation capability.

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17

Chisenga, Lesley. "Development of a low power photovoltaic inverter for connection to the utility grid." Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611257.

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18

Andersson, Karin. "Development of models for quantifying the environmental impact of demand response in electrical power distribution." Thesis, Uppsala universitet, Industriell teknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-263282.

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In this report some possible consequences of introducing demand response in the electric power grid are studied. Demand response is a part of the Smart Grid, which is a technology being developed to use our electric power grids more efficiently. Demand response programs aim to move people’s power usage over different times of the day, for example to distribute the power usage more evenly throughout the day or to permit a larger share of renewable, intermittent power sources in the system without making the delivery of electric power less stable. A distribution system operator (DSO) can encourage customers to shift their power usage between different hours by various tariffs, for example by using time-differentiated or power dependent tariffs. In this thesis, the change in power losses and possible environmental impact of introducing due to a power shift is studied. Power input curves from a DSO, Sala-Heby Energi AB, are studied and modified to simulate a power shift with an evened out electric power usage. The studies made show that in the best-case scenario, that is a electric power usage evened out to 100% each day, the power losses in the whole grid can be reduced with 2.6%. The environmental study shows that the result varies greatly with what method is chosen to do the calculations. The results are presented in kg CO2-equivalents (CO2e), and depending on method used they can either decrease or increase. The environmental study show that the environmental impact from the power usage is more dependent on the shift in power usage between hours than the decrease in electric power losses.

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19

Kimera, Raymond. "Consideration for a sustainable hybrid electric power mini-grid : case study for Wanale village in Uganda." Master's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/10679.

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In this study, a hybrid mini-grid system is designed to supply electricity to a rural village in Uganda. Renewable energy resources are identified, an estimation of the projected village short-term electricity demand is simulated, and using HOMER software, a hybrid mini-grid system is designed, components sized, and the system optimized in terms of cost, and efficient and reliable operation to meet the village demand.

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20

Borchers, Mark Louis. "A decision making tool for assessing grid electrification versus stand-alone power supply options for remote users." Master's thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/8291.

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Анотація:

Includes bibliography.
The objective of this study is to compile a micro-computer based tool to aid in the evaluation of power supply options for remote sites. The options considered are stand-alone photovoltaic, diesel generation, and grid extension power supplies. The basis on which the various options are compared is the unit cost of energy expected from the system. This is determined by combining all capital costs, running costs, and other payments on a present value basis over the project lifetime. The comparison of the unit energy cost expected from each option is only meaningful if the reliability of each supply system is known. The Loss of Energy Probability of each option is therefore established to provide a common ground on which to compare these costs. •

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21

Fernandez, Horcajuelo Alba. "Development of EMT components and reference grid in OpenModelica." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-293978.

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Power systems simulation tools enable to study and evaluate the performance of electrical power systems in different scenarios. This allows the development and implementation of new solutions to the challenges electrical grids face nowadays. In this sense, electromagnetic transient (EMT) simulation provides detailed information on the behaviour of the different components involved in the system. Moreover, among the wide range of existing tools, those based in Modelica language present certain advantages for power system simulation, such as equation- based modeling and the possibility of working in open- source environments. This project presents the development of components and reference grid in EMT formalism in the open- source environment OpenModelica, based on Modelica language. With the purpose of power system simulation, electrical components have been modeled in OpenModelica and gathered in a library for EMT simulation The performance of the different components has been validated by comparing the results of the EMT simulation of a 3buses reference grid in different case studies in OpenModelica and other EMT- based software. Furthermore, the comparison has been also established with phasor simulation in OpenModelica, enabling the evaluation of the differences between phasor and EMT simulation. The results show the main advantages and drawbacks of working with OpenModelica regarding other simulation tools and the lack of information provided by the phasor simulation, particularly in the case of a fault event. Additionally, certain difficulties encountered when working with OpenModelica have also been identified.
Simulering av kraftsystem gör det möjligt att studera och utvärdera prestandan i olika scenarion. Genom detta kan utveckling och implementering av nya lösningar på de utmaningar som elnäten står inför framöver ske. Elektromagnetisk transient (EMT)simulering ger detaljerad information om beteendet hos de olika komponenterna i systemet. Bland de många befintliga verktygen innehåller de som är baserade på Modelica- språket dessutom vissa fördelar för kraftsystemsimulering, såsom ekvationsbaserad modellering och möjligheten att arbeta i miljöer med öppen källkod. Den här uppsatsen presenterar en utveckling av komponenter och testelnät i EMT- formalism i öppen källkodsmiljö OpenModelica, baserat på programmeringsspråket Modelica. Elektriska komponenter har modellerats i OpenModelica och samlats i ett bibliotek för EMT- simulering. Målet är en detaljerad simulering av elkraftsystem. Komponenternas prestanda har validerats genom att jämföra resultatet av EMT- simuleringen av ett 3bussreferensnät i olika fallstudier i OpenModelica och annan EMT- baserad programvara. Sedan har jämförelsen även utförts med simuleringar i fasorformalism i OpenModelica. Den här jämförelsen har också möjliggjort utvärderingen av skillnaderna mellan fasor och EMT- simulering. Resultaten visar de största fördelarna och nackdelarna med att arbeta med OpenModelica njämfört med andra simuleringsverktyg. De visar också bristen på information om fasorsimuleringen, särskilt i fallet med ett elektriskt fel. Dessutom har vissa svårigheter identifierats med att arbeta med OpenModelica.

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22

Khan, Akrama. "Development of a power conditioner for a PMSG-based wind energy system integrated into a weak grid." Doctoral thesis, Faculty of Engineering and the Built Environment, 2020. http://hdl.handle.net/11427/32243.

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With the growing use of non-linear loads and due to their ever changing nature, electricity networks experience power imbalance continually. These non-linear asymmetrical loads draw distorted unbalanced currents and voltages at the point of common coupling (PCC) which propagate into the distribution network. Power quality has therefore become an important issue, which has resulted in the development of numerous control strategies and other interventions to maintain the integrity of the electric network. Recent advancements in power electronics have provided new ways to optimize power systems by regulating the active power transfer. These developments lead to opportunities for renewable energy systems to harness energy and at the same time inject optimized currents into the network by means of distributed units. An emerging problem with most such units is that they are located far from the PCC and are usually designed for the small linear loads. Moreover, the problem is exacerbated during overload conditions when the voltage level drops below the allowed minimum level due to the high network impedance which characterizes a weak grid. This thesis aims to study similar scenarios where a permanent magnet synchronous generator (PMSG) based wind energy conversion system (WECS) is integrated into a weak AC grid. The system comprises of a machine-side (MSC) and a grid-side (GSC) converter, which provides available ancillary services and is envisaged to augment existing power quality conditioners such as STATCOM devices. To represent a weak grid, a Thevenin equivalent model of the electric network is considered with unbalanced loads. The main objective of this project is to transform the traditional converter topology into a versatile system that can perform as a power conditioner. In particular, it monitors a distribution line, sense changes in the load, detects faults and redistributes the currents to ensure maximized power transfer into the network. The system under consideration possesses the capability of independent injection of active and reactive currents within the defined limits. Since the system under consideration is integrated v into a weak grid, the perceived load is always considered to be unbalanced. Under the specified condition, if a fault occurs at one or two phases, unbalanced voltages are observed at the PCC. Two scenarios are created to perform the case study. Firstly, a no-fault case is considered with symmetrical voltages at the PCC. To ensure maximum power transfer into the network with least losses, a set of currents is injected according to the optimal current injection technique. Secondly, asymmetrical faults are considered at the PCC and currents are injected according to the coordinated sequence current injection technique. This technique defines a new current injection limit which not only improves the power transfer but also enhances the power factor. Furthermore, the peak magnitude of the three phase currents is also kept within the rated current limit. For both scenarios described above, the MSC regulates the DC link voltage so as to limit the active power coming from the generator according to the grid condition. The GSC however performs two important functions. It implements small active/reactive power perturbations for the impedance estimation, and once the impedances are determined, magnitudes of the required currents are calculated and injected based on the proposed techniques. Validation of the analysis is done experimentally on a 3.3kW PMSG connected to a programmable regenerative power supply which emulates a weak grid. The MSC and GSC utilized in this project are conventional two-level converters which are controlled by means of a FPGA based controller.

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23

Salehi, Pour Mehr Vahid. "Development and Verification of Control and Protection Strategies in Hybrid AC/DC Power Systems for Smart Grid Applications." FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/804.

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Modern power networks incorporate communications and information technology infrastructure into the electrical power system to create a smart grid in terms of control and operation. The smart grid enables real-time communication and control between consumers and utility companies allowing suppliers to optimize energy usage based on price preference and system technical issues. The smart grid design aims to provide overall power system monitoring, create protection and control strategies to maintain system performance, stability and security. This dissertation contributed to the development of a unique and novel smart grid test-bed laboratory with integrated monitoring, protection and control systems. This test-bed was used as a platform to test the smart grid operational ideas developed here. The implementation of this system in the real-time software creates an environment for studying, implementing and verifying novel control and protection schemes developed in this dissertation. Phasor measurement techniques were developed using the available Data Acquisition (DAQ) devices in order to monitor all points in the power system in real time. This provides a practical view of system parameter changes, system abnormal conditions and its stability and security information system. These developments provide valuable measurements for technical power system operators in the energy control centers. Phasor Measurement technology is an excellent solution for improving system planning, operation and energy trading in addition to enabling advanced applications in Wide Area Monitoring, Protection and Control (WAMPAC). Moreover, a virtual protection system was developed and implemented in the smart grid laboratory with integrated functionality for wide area applications. Experiments and procedures were developed in the system in order to detect the system abnormal conditions and apply proper remedies to heal the system. A design for DC microgrid was developed to integrate it to the AC system with appropriate control capability. This system represents realistic hybrid AC/DC microgrids connectivity to the AC side to study the use of such architecture in system operation to help remedy system abnormal conditions. In addition, this dissertation explored the challenges and feasibility of the implementation of real-time system analysis features in order to monitor the system security and stability measures. These indices are measured experimentally during the operation of the developed hybrid AC/DC microgrids. Furthermore, a real-time optimal power flow system was implemented to optimally manage the power sharing between AC generators and DC side resources. A study relating to real-time energy management algorithm in hybrid microgrids was performed to evaluate the effects of using energy storage resources and their use in mitigating heavy load impacts on system stability and operational security.

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24

Bosi, Marco. "Development of a distributed measurement system for detection of high impedance faults in medium voltage power lines." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.

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The aim of this thesis is to propose a new method to detect High impedance Faults, which relies on measuring the phase currents on electrical transmission and distribution grids using a common time source for synchronization. The goal is to measure the residual currents both at the transformer side and at the load side of the network. The time synchronization allows synchronized real-time measurements of the two residual currents at the two ends of the grid. In normal operating conditions and in all load conditions (balanced or unbalanced), the residual currents will result almost equal at the two ends. When a High Impedance Fault occurs, the residual currents at the two ends will differ. The difference in magnitude of the residual currents are monitored in real time and used as a pick-up criteria.

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25

Rose, Robert W. "Defending electrical power grids." Thesis, Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion.exe/07Mar%5FRose.pdf.

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Анотація:

Thesis (M.S. in Operations Research)--Naval Postgraduate School, March 2007.
Thesis Advisor(s): Javier Salmeron. "March 2007." Includes bibliographical references (p. 51-52). Also available in print.

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26

Alvarez, Rogelio E. "Interdicting electrical power grids." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Mar%5FAlvarez.pdf.

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Анотація:

Thesis (M.S. in Operations Research)--Naval Postgraduate School, March 2004.
Thesis advisor(s): Javier Salmeron, R. Kevin Wood. Includes bibliographical references (p. 69-70). Also available online.

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27

Mazloomzadeh, Ali. "Development of Hardware in the Loop Real-Time Control Techniques for Hybrid Power Systems Involving Distributed Demands and Sustainable Energy Sources." FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1666.

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The future power grid will effectively utilize renewable energy resources and distributed generation to respond to energy demand while incorporating information technology and communication infrastructure for their optimum operation. This dissertation contributes to the development of real-time techniques, for wide-area monitoring and secure real-time control and operation of hybrid power systems. To handle the increased level of real-time data exchange, this dissertation develops a supervisory control and data acquisition (SCADA) system that is equipped with a state estimation scheme from the real-time data. This system is verified on a specially developed laboratory-based test bed facility, as a hardware and software platform, to emulate the actual scenarios of a real hybrid power system with the highest level of similarities and capabilities to practical utility systems. It includes phasor measurements at hundreds of measurement points on the system. These measurements were obtained from especially developed laboratory based Phasor Measurement Unit (PMU) that is utilized in addition to existing commercially based PMU’s. The developed PMU was used in conjunction with the interconnected system along with the commercial PMU’s. The tested studies included a new technique for detecting the partially islanded micro grids in addition to several real-time techniques for synchronization and parameter identifications of hybrid systems. Moreover, due to numerous integration of renewable energy resources through DC microgrids, this dissertation performs several practical cases for improvement of interoperability of such systems. Moreover, increased number of small and dispersed generating stations and their need to connect fast and properly into the AC grids, urged this work to explore the challenges that arise in synchronization of generators to the grid and through introduction of a Dynamic Brake system to improve the process of connecting distributed generators to the power grid. Real time operation and control requires data communication security. A research effort in this dissertation was developed based on Trusted Sensing Base (TSB) process for data communication security. The innovative TSB approach improves the security aspect of the power grid as a cyber-physical system. It is based on available GPS synchronization technology and provides protection against confidentiality attacks in critical power system infrastructures.

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28

Andersson, Jonas, Vendela Bernström, and Joacim Törnqvist. "Hosting Capacity of a Low-Voltage Grid : Development of a Simplified Model to be used in future Solar Roadmaps." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-325010.

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The purpose of this bachelor thesis is to assess whether it is possible to create a simplified model that estimates the hosting capacity of a low-voltage grid. The Simplified model is compared with a more elaborate model created by the Built Environment Energy Systems Group (BEESG) at Uppsala University. The Simplified model takes three easily obtainable variables into account. The model created by BEESG allows us to observe both the amount of photovoltaic (PV) power that is installed as well as the voltages in each bus in a grid. The hosting capacity is found by gradually increasing the amount of PV power installed in a low-voltage grid until overvoltage is reached. Simulations with BEESG’s model are done for a week in July when the PV generation has its peak and the load is generally low. The Simplified model is created using linear regression with the calculated values from the BEESG’s model as a reference. The report shows that the Simplified model will give an estimation of the low-voltage grid’s hosting capacity that is comparable to the value calculated with BEESG’s model. The results show that it is rarely the low-voltage grid that restricts the installation of PV facilities and that a high self-consumption is advantageous regarding to the grids hosting capacity.

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29

Ang, Chee Chien. "Optimized recovery of damaged electrical power grids." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2006. http://library.nps.navy.mil/uhtbin/hyperion/06Mar%5FAng.pdf.

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Анотація:

Thesis (M.S. in Operations Research)--Naval Postgraduate School, March 2006.
"March 2006." Thesis Advisor(s): Javier Salmeron, R. Kevin Wood. Includes bibliographical references (p. 33-34). Also available online.

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30

Flodström, Kristian, and Andersson Simon. "Automated regression testing in Power Grids applications." Thesis, Uppsala universitet, Elektricitetslära, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-385433.

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During development of any kind, the testing process is a big part in terms of time and money. Automating the testing procedure to run regression tests more frequent and in an effective manner makes the development phase a simpler and more development focused activity. This thesis will study the possibility of automating the release testing of new platforms by using statistical tolerances on ABB FACTS products. To do this, a research and literature study regarding tolerances within control systems and automated testing including regression testing is used. The result of the study presents a proof of concept that the release testing can be automated using statistical tolerances as verification.

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31

Livani, Hanif. "Intelligent Fault Location for Smart Power Grids." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/46788.

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Modernized and advanced electricity transmission and distribution infrastructure ensures reliable, efficient, and affordable delivery of electric power. The complexity of fault location problem increases with the proliferation of unusual topologies and with the advent of renewable energy-based power generation in the smart grid environment. The proliferation of new Intelligent Electronic Devices (IEDs) provides a venue for the implementation of more accurate and intelligent fault location methods. This dissertation focuses on intelligent fault location methods for smart power grids and it aims at improving fault location accuracies and decreasing the cost and the mean time to repair damaged equipment in major power outages subsequently increasing the reliability of the grid. The developed methods utilize wavelet transformation to extract the traveling wave information in the very fast voltage and current transients which are initiated immediately after a fault occurs, support vector machines to classify the fault type and identify the faulted branches and finally Bewley diagrams to precisely locate the fault. The approach utilizes discrete wavelet transformation (DWT) for analysis of transient voltage and current measurements. The transient wavelet energies are calculated and utilized as the input for support vector machine (SVM) classifiers. SVM learns the mapping between inputs (i.e. transient voltages and/or currents wavelet energies) and desired outputs (i.e. faulty phase and/or faulty section) through processing a set of training cases. This dissertation presents the proposed methodologies applied to three complex power transmission systems. The first transmission system is a three-terminal (teed) three-phase AC transmission network, a common topology in high- and extra high-voltage networks. It is used to connect three substations that are wide apart from each other through long transmission lines with a tee-point, which is not supported by a substation nor equipped with a measuring device. The developed method overcomes the difficulties introduced by the discontinuity: the tee point. The second topology is a hybrid high voltage alternative current (HVAC) transmission line composed of an overhead line combined with an underground cable. The proposed fault location method is utilized to overcome the difficulties introduced by the discontinuity at the transition point from the overhead line to the underground cable and the different traveling wave velocities along the line and the cable. The third topology is a segmented high voltage direct current (HVDC) transmission line including an overhead line combined with an underground cable. This topology is widely utilized to transmit renewable energy-based electrical power from remote locations to the load centers such as from off-shore wind farms to on-shore grids. This dissertation introduces several enhancements to the existing fault type and fault location algorithms: improvement in the concept of fault type classification and faulty section identification by using SVMs with smaller inputs and improvements in the fault location in the complex configurations by utilizing less measurements from the terminals.
Ph. D.

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Papalexandrou, Tryfon. "Integrated Energy Recovery Scenarios of Biomass Residues in the Non-interconnected Island of Crete : A Pre-Feasibility Study in Greece." Thesis, KTH, Industriell ekologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-174024.

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The cornerstone of our production system is based on the concept “take, make, waste”. Moreover, the manufacture of a product requires the input of energy and raw materials which produce waste and products. The latter ultimately end up becoming wastes. In other words, the root problem of this production system is that is designed on a linear, one-way cradle-to grave model (McDonough, W. and Braungart, M., 2002). This approach coupled with the population explosion and our thirst for growth has led to an unprecedented pressure to the environment. The consequences are multiple; climate change, dwindling energy resources and waste generation. This study lies in two pillars: the concept of sustainable development and the waste management hierarchy. The idea was how these two fundamental concerns (energy generation and waste production) could be tackled. This study assesses the availability of biomass residues and wastes in the off-grid island of Crete with the aim to ‘close the loop’ by converting waste to an energy resource. In addition, the exploration of the most sustainable energy generation solutions was attempted in order to drive forward the synergies between biomass waste production and energy generation. The collected information was extracted from the literature about agricultural, livestock, Municipal Solid Waste (MSW) and Industrial & Commercial (I&C) waste. It is also based on numerous interviews to waste management associations, the Greek Ministry of Rural Development & Food and all the Waste Water Treatment Plants in the island were analysed in order to shed light on the potential energy generation from all the aforementioned biomass sources and its contribution to the electric energy production system of Crete. It is considered that the biomass potential in Crete is a sleeping giant. There is considerable potential for biomass-to-energy technologies in Crete providing improved rural energy services based on agricultural residues. From the findings of this study it appears that the biomass potential is more than estimated in previous papers. Based on the findings it is concluded that the largest portion of Crete’s biomass potential is agricultural residues and animal wastes. The utilisation of low-cost biomass power in Crete could help provide cleaner, more efficient energy services and to reduce the island’s economic and environmental vulnerability. Biomass can provide both base load power and turn into liquid transportation fuels and contributes to reducing energy dependence due to import fuel from the mainland. In terms of the study’s goal to select the most sustainably viable biomass-to-energy technologies, that was based on the multi-criteria methodology. A number of integrated biomass-to-energy alternatives were assessed against technical, environmental, financial and social criteria with the aim to assist the regional authority’s decision making process of energy generation planning. From the final screening of the integrated biomass-to-energy alternatives it was concluded that the best in a descending order technologies from the regional authority’s standpoint are: F - Anaerobic digestion & Fuel cell; E – Anaerobic digestion & Gas engine; C - Gasification & Gas engine; A – Combustion & Steam turbine; and B – Gasification & Steam turbine.

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Протащик, Олег Валерійович. "Інформаційне забезпечення економіко-математичної моделі розвитку енергокомплексу України". Master's thesis, КПІ ім. Ігоря Сікорського, 2018. https://ela.kpi.ua/handle/123456789/28495.

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Актуальність теми полягає в заощадженні традиційних паливно-енергетичних ресурсів, покращення екологічного стану навколишнього середовища та зменшенні залежності країни від імпортних енергоносіїв. Наукові дослідження за темою дисертації відповідають стратегічним положенням Енергетичної стратегії України на період до 2035 року. Метою роботи є вдосконалення математичних моделей прогнозування розвитку електроенергетичної системи з використанням сучасних відновлюваних технологій виробництва теплової та електричної енергії і розробка відповідних програмно-інформаційних засобів їх реалізації з урахуванням капіталізації ринку в межах обраного часового горизонту прогнозування. Для досягнення поставленої мети використано оптимізаційну двопродуктову економіко-математичну модель розширення існуючого виробництва галузі з розподілом інвестованого капіталу, спрямованих на розвиток технологій виробництва теплової та електричної енергії: з біомаси та біогазу, з використанням теплоти геотермальних вод, малих ГЕС, енергії вітру та сонячного випромінювання. Обчислення максимально досяжних обсягів виробництва здійснено за умови обмежень на раціональне використання паливних і енергетичних ресурсів з урахуванням фондомісткості кожної технології. Об'єкт дослідження – електроенергетична система у процесі її невпинного вдосконалення в умовах конкурентного ринку, що здійснюється через прискорене впровадження перспективних альтернативних та відновлюваних технологій виробництва і споживання електричної і теплової енергії. Предметом дослідження інформаційне забезпечення економіко-математичної моделі розвитку електроенергетичної системи за умови розширеного використання відновлюваних технологій тепло- та електрогенерування. Методи дослідження. Наукові результати дисертаційної роботи були отримані на основі методології системного аналізу та з використанням математичних методів: техніко-економічного аналізу, лінійного програмування (класична оптимізаційна задача лінійного програмування із пошуком розв’язків шляхом модельних озрахунків на ЦВМ). Новизна і практична значимість. Пристосовано відомі методи розв’язання оптимізаційних техніко-економічних задач для отримання прогнозних обсягових оцінок вироблення електричної та теплової енергії за вірогідними сценаріями у розвитку паливно-енергетичного комплексу з використанням нових та відновлюваних технологій. Розроблено інформаційне забезпечення оптимізаційної моделі розвитку сектору генерування паливно-енергетичного комплексу України з визначенням нових конкурентних технологій відновлюваної енергетики (ТВЕ) – через показники фондомісткості, що відповідають сучасним досягненням науково-технічного прогресу в енергетиці. Отримано розрахункові оцінки максимізованих прогнозних обсягів вироблення енергії кінцевого споживання конкурентними ТВЕ у варіантах – за базовим та оптимістичним сценаріями розвитку енергосистеми України в межах обраного часового горизонту прогнозування.
The aim of the work is to improve the mathematical models of forecasting the development of the electric power system with the use of modern renewable technologies for the production of thermal and electric energy and the development of appropriate software and information tools for their implementation, taking into account market capitalization within the chosen time forecasting horizon. To achieve this goal, an optimization two-product economic and mathematical model of the expansion of the existing production of the industry with the distribution of invested capital aimed at the development of technologies for the production of thermal and electric energy: from biomass and biogas, using heat of geothermal waters, small hydropower plants, wind power and solar radiation. The calculation of the maximum achievable production volume was made subject to restrictions on the rational use of fuel and energy resources, taking into account the stock of each technology. The object of research is the electric power system in the process of its unceasing improvement in a competitive market, which is carried out through the accelerated introduction of promising alternative and renewable technologies of production and consumption of electric and thermal energy. The subject of research is data design of the economic-mathematical model of the development of the power system, provided that the use of renewable technologies of heat and power generation is expanded. The scientific and practical value of the work were obtained on the basis of the methodology of system analysis and using mathematical methods: technical and economic analysis, linear programming (classical optimization problem of linear programming with the search of solutions by model calculations on the central computer). Novelty and practical significance. Improvement of well-known methods and means of forecasting the development of electric and heat supply systems in the existing scientific and technological progress in the power industry. Study and development of information support for existing models of development of the fuel and energy complex generation sector on the basis of renewable energy technologies. Obtaining the forecasted results for the development of Ukraine's grid system taking into account market capitalization within the chosen time forecasting horizon.

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Mia, Gredelj. "DC micro-grids." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elkraftteknikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-27249.

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The conventional electrical system in place today sees our electrical devices powered by AC mains. But as renewable technologies such as solar photovoltaic and wind power become more prevalent at a household level, DC micro-grids could be a cheaper and more efficient alternative. New lighting devices (LED) can reduce the electricity consumption substantially. Two alternatives are envisioned in this paper: A stand-alone alternative in which there is no grid connection, that would require local storage (battery), and a grid-connection alternative. After reviewing and investigating relevant literature for this topic and writing theoretical part of thesis there were the fallowing tasks. One typical four member family household was described and hourly load curves for one year period, with typical summer and winter days, were made for this case. Next task that was completed was generating yearly energy production from solar panels, which the observed household contains, in INSEL software. With having those previously mentioned data, combined with necessary information about prices of all necessary components and prices from Croatian power system, it was possible to make feasibility and cost analysis where the two previously mentioned alternatives were investigated. With changing some parameters in that economical analysis several scenarios were observed. At the end conclusions were made about which one of those two options is more profitable and under what conditions. Also, suggestions were made for further work on this topic. This assignment is realized as a part of the collaborative project “Sustainable Energy and Environment in Western Balkans” that aims to develop and establish five new internationally recognized MSc study programs for the field of “Sustainable Energy and Environment”, one at each of the five collaborating universities in three different WB countries. The project is funded through the Norwegian Programme in Higher Education, Research and Development in the Western Balkans, Programme 3: Energy Sector (HERD Energy) for the period 2011-2014.

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Mauch, Brandon Keith. "Managing Wind Power Forecast Uncertainty in Electric Grids." Research Showcase @ CMU, 2012. http://repository.cmu.edu/dissertations/199.

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Electricity generated from wind power is both variable and uncertain. Wind forecasts provide valuable information for wind farm management, but they are not perfect. Chapter 2 presents a model of a wind farm with compressed air energy storage (CAES) participating freely in the day-ahead electricity market without the benefit of a renewable portfolio standard or production tax credit. CAES is used to reduce the risk of committing uncertain quantities of wind energy and to shift dispatch of wind generation to high price periods. Using wind forecast data and market prices from 2006 – 2009, we find that the annual income for the modeled wind-CAES system would not cover annualized capital costs. We also estimate market prices with a carbon price of $20 and $50 per tonne CO2 and find that the revenue would still not cover the capital costs. The implied cost per tonne of avoided CO2 to make a wind-CAES profitable from trading on the day-ahead market is roughly $100, with large variability due to electric power prices. Wind power forecast errors for aggregated wind farms are often modeled with Gaussian distributions. However, data from several studies have shown this to be inaccurate. Further, the distribution of wind power forecast errors largely depends on the wind power forecast value. The few papers that account for this dependence bin the wind forecast data and fit parametric distributions to the actual wind power in each bin. A method to model wind power forecast uncertainty as a single closed-form solution using a logit transformation of historical wind power forecast and actual wind power data is presented in Chapter 3. Once transformed, the data become close to jointly normally distributed. We show the process of calculating confidence intervals for wind power forecast errors using the jointly normally distributed logit transformed data. This method has the advantage of fitting the entire dataset with five parameters while also providing the ability to make calculations conditioned on the value of the wind power forecast. The model present in Chapter 3 is applied in Chapter 4 to calculate increases in net load uncertainty introduced from day-ahead wind power forecasts. Our analyses uses data from two different electric grids in the U.S. having similar levels of installed wind capacity with large differences in wind and load forecast accuracy due to geographic characteristics. A probabilistic method to calculate the dispatchable generation capacity required to balance day-ahead wind and load forecast errors for a given level of reliability is presented. Using empirical data we show that the capacity requirements for 95% day-ahead reliability range from 2100 MW to 5600 MW for ERCOT and 1900 MW to 4500 MW for MISO, depending on the amount of wind and load forecast for the next day. We briefly discuss the additional requirements for higher reliability levels and the effect of correlated wind and load forecast errors. Additionally, we show that each MW of additional wind power capacity in ERCOT must be matched by a 0.30 MW day-ahead dispatchable generation capacity to cover 95% of day-ahead uncertainty. Due to the lower wind forecast uncertainty in MISO, the value drops to 0.13 MW of dispatchable capacity for each MW of additional wind capacity. Direct load control (DLC) has received a lot of attention lately as an enabler of wind power. One major benefit of DLC is the added flexibility it brings to the grid. Utilities in some parts of the U.S. can bid the load reduction from DLC into energy markets. Forecasts of the resource available for DLC assist in determining load reduction quantities to offer. In Chapter 5, we present a censored regression model to forecast load from residential air conditioners using historical load data, hour of the day, and ambient temperature. We tested the forecast model with hourly data from 467 air conditioners located in three different utilities. We used two months of data to train the model and then ran day-ahead forecasts over a six week period. Mean square errors ranged from 4% to 8% of mean air conditioner load. This method produced accurate forecasts with much lower data requirements than physics based forecast models.

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Barakat, Mahmoud. "Development of models for inegrating renewables and energy storage components in smart grid applications." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMC217/document.

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Cette thèse présente un modèle unique du MASG (Modèle d’Architecture du Smart Grid) en considérant l 'état de l’art des différentes directives de recherche du smart grid. Le système hybride de génération d'énergie active marine-hydrogène a été modélisé pour représenter la couche de composants du MASG. Le système intègre l'électrolyseur à membrane d’échange de proton (à l’échelle de méga watt) et les systèmes de piles à combustible en tant que composants principaux du bilan énergétique. La batterie LiFePO4 est utilisée pour couvrir la dynamique rapide de l'énergie électrique. En outre, la thèse analyse le système de gestion de l'énergie centralisé et décentralisé. Le système multi-agents représente le paradigme du système décentralisé. La plate-forme JADE est utilisée pour développer le système multi-agents, en raison de son domaine d'application général, de ses logiciels à licence libre, de son interface avec MATLAB et de sa calculabilité avec les standards de la Fondation des Agents Physiques Intelligentes. Le système de gestion d'énergie basé sur JADE équilibre l'énergie entre la génération (système de conversion d'énergie marine-courant) et la demande (profil de charge résidentielle) pendant les modes de fonctionnement autonome et connecté au réseau. Le modèle proposé du MASG peut être considéré comme une étude de cas pilote qui permet l'analyse détaillée et les applications des différentes directions de recherche du smart grid
This thesis presents a unique model of the SGAM (Smart Grid Architecture Model) with considering the state of the art of the different research directions of the smart grid and. The hybrid marine-hydrogen active power generation system has been modeled to represent the component layer of the SGAM. The system integrates the MW scale PEM electrolyzer and fuel cell systems as the main energy balance components. The LiFePO4 battery is used to cover the fast dynamics of the electrical energy. Moreover, the thesis analyzes the centralized and the decentralized energy management system. The MAS (Multi-Agent Systems) represents the paradigm of the decentralized system. The JADE platform is used to develop the MAS due to its general domain of application, open source and free license software, interface with MATLAB and the computability with the FIPA (Foundation of Intelligent Physical Agent) standards. The JADE based energy management system balances the energy between the generation (marine-current energy conversion system) and the demand side (residential load profile) during the stand-alone and the grid-connected modes of operation. The proposed model of the SGAM can be considered as a pilot case study that enables the detailed analysis and the applications of the different smart grid research directions

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Häggblom, Johan, and Jonathan Jerner. "Photovoltaic Power Production and Energy Storage Systems in Low-Voltage Power Grids." Thesis, Linköpings universitet, Fordonssystem, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-156875.

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In recent years, photovoltaic (PV) power production have seen an increase and the PV power systems are often located in the distribution grids close to the consumers. Since the distributions grids rarely are designed for power production, investigation of its effects is needed. It is seen in this thesis that PV power production will cause voltages to rise, potentially to levels exceeding the limits that grid owners have to abide by. A model of a distribution grid is developed in MathWorks MATLAB. The model contains a transformer, cables, households, energy storage systems (ESS:s) and photovoltaic power systems. The system is simulated by implementing a numerical Forward Backward Sweep Method, solving for powers, currents and voltages in the grid. PV power systems are added in different configurations along with different configurations of ESS:s. The results are analysed, primarily concerning voltages and voltage limits. It is concluded that addition of PV power production in the distribution grid affects voltages, more or less depending on where in the grid the systems are placed and what peak power they have. It is also concluded that having energy storage systems in the grid, changing the power factor of the inverter for the PV systems or lowering the transformer secondary-side voltage can bring the voltages down.
På senare tid har det skett en ökning i antalet solcellsanläggningar som installeras i elnätet och dessa är ofta placerade i distributionsnäten nära hushållen. Eftersom distributionsnäten sällan är dimensionerade för produktion så behöver man utreda effekten av det. I det här arbetet visas det att solcellsproduktion kommer att öka spänningen i elnätet, potentiellt så mycket att de gränser elnätsägarna måste hålla nätet inom överstigs. En modell över lågspänningsnätet skapas i MathWorks MATLAB. Modellen innehåller transformator, kablar, hushåll, energilager och solcellsanläggningar. Systemet simuleras med hjälp av en numerisk Forward Backward Sweep-lösare som beräknar effekter, strömmar och spänningar i elnätet. Solcellanläggningarna placeras ut i elnätet i olika konfigurationer tillsammans med olika konfigurationer av energilager. Resultaten från simuleringarna analyseras främst med avseende på spänningen i elnätet utifrån dess gränser. De slutsatser som dras i arbetet är att solcellsproduktion kommer att påverka spänningen, mycket beroende på var i elnätet anläggningarna placeras och storleken hos dem. Det visas också att energilager, justering av effektfaktor hos solcellsanläggningarna eller en spänningssänkning på transformatorns lågspänningssida kan få ner spänningen i elnätet.

LiTH-ISY-EX--19/5194--SE

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Elyas, Seyyed Hamid 8045266. "Synthetic Modeling of Power Grids Based on Statistical Analysis." VCU Scholars Compass, 2017. http://scholarscompass.vcu.edu/etd/4888.

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The development of new concepts and methods for improving the efficiency of power networks needs performance evaluation with realistic grid topology. However, much of the realistic grid data needed by researchers cannot be shared publicly due to the security and privacy challenges. With this in mind, power researchers studied statistical properties of power grids and introduced synthetic power grid topology as appropriate methodology to provide enough realistic power grid case studies. If the synthetic networks are truly representative and if the concepts or methods test well in this environment they would test well on any instance of such a network as the IEEE model systems or other existing grid models. In the past, power researchers proposed a synthetic grid model, called RT-nested-smallworld, based on the findings from a comprehensive study of the topology properties of a number of realistic grids. This model can be used to produce a sufficiently large number of power grid test cases with scalable network size featuring the same kind of small-world topology and electrical characteristics found in realistic grids. However, in the proposed RT-nested-smallworld model the approaches to address some electrical and topological settings such as (1) bus types assignment, (2) generation and load settings, and (3) transmission line capacity assignments, are not sufficient enough to apply to realistic simulations. In fact, such drawbacks may possibly cause deviation in the grid settings therefore give misleading results in the following evaluation and analysis. To address this challenges, the first part of this thesis proposes a statistical methodology to solve the bus type assignment problem. This method includes a novel measure, called the Bus Type Entropy, the derivation of scaling property, and the optimized search algorithm. The second part of this work includes a comprehensive study on generation/Load settings based on both topology metrics and electrical characteristics. In this section a set of approaches has been developed to generate a statistically correct random set of generation capacities and assign them to the generation buses in a grid. Then we determine the generation dispatch of each generation unit according to its capacity and the dispatch ratio statistics, which we collected and derived from a number of realistic grid test cases. The proposed approaches is readily applied to determining the load settings in a synthetic grid model and to studying the statistics of the flow distribution and to estimating the transmission constraint settings. Considering the results from the first two sections, the third part of this thesis will expand earlier works on the RT-nested-smallworld model and develop a new methodology to appropriately characterize the line capacity assignment and improve the synthetic power grid modeling.

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Redander, Jessica, and Johanna Lenárd. "Development of a Real-Time Simulation Model in RSCAD of a STATCOM and its Control System." Thesis, Uppsala universitet, Elektricitetslära, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-447234.

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The development of interconnected power systems together with an increasing number of renewable non-synchronous power sources, create major challenges for the power system to meet the voltage stability and power quality requirements. One way to increase the voltage stability in a sustainable way is to locally implement a STATCOM. By enhancing grid voltage stability under varying network conditions, the active power transfer capability will increase. However, before a STATCOM can be deployed in the power system, the behavior of it needs tobe investigated for the specific network conditions at the point of interface. The thesis develops a software model in RSCAD of a STATCOM along with important control functions for real-time simulations in RTDS without hardware-in-the-loop. The model aims to be sufficient for representing the gross behavior of a STATCOM in real-time simulations in order to get a quick overview of the dynamic response of the system. The model’s overall performance is evaluated through simulations in RTDS. The results indicate that the main control functions are operating in a stable and sufficient way. Hence, the model can perform in different operation modes as well as handling unbalances that are introduced in the system without losing controllability. There is potential for improvements in order to obtain a model with a more sophisticated control system. The main area would be to introduce limiters and anti-windups at appropriate places as well as a fault-ride-through logic to ensure a safe and stable operation during disturbances.

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40

Einarsson, Mårten. "Power quality in low voltage grids with integrated microproduction." Thesis, Uppsala universitet, Elektricitetslära, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-136092.

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This report seeks to evaluate and predict possible power quality issues regarding Fortums engagement in the project of Stockholm Royal Seaport. Stockholm Royal Seaport is a city district planned by Stockholm Municipality to be constructed based on sustainable urban city principles. Fortum has, together with additional partners, engaged in the challenge to create a sustainable energy system. This is thought to be achieved through several measures. Energy saving actions are incorporated at several levels and there is a plan to create a “smart grid” for the electricity supply. A smart grid has no strict definition but in this case a key feature is “demand-response” which effectively means a way to optimize the consumption to have a more balanced consumption over the 24 hours of a day. One of the key components in the smart grid is the “active house” which is planned to have several specific features separating it from an ordinary house. It is planned to have its own contribution to electricity production using solar cells and an energy storage using batteries. Another feature is thought to be both automation and economic incentives measures to achieve peak load reduction. This thesis has taken the perspective of the end customer in the active house and has tried to evaluate the power quality to be experienced. An investigation regarding the different components has been carried out to get an overview from the mentioned perspective and identify possible problems or issues that may require attention in the realization of Stockholm Royal Seaport. It has been found that no major problems are to be expected but some smaller issues has arisen that might be worthwhile giving some attention.

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Formigli, Rodriguez Carlos Manuel <1976&gt. "Vulnerability and robustness indices against blackouts in power grids." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6502/.

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In this dissertation some novel indices for vulnerability and robustness assessment of power grids are presented. Such indices are mainly defined from the structure of transmission power grids, and with the aim of Blackout (BO) prevention and mitigation. Numerical experiments showing how they could be used alone or in coordination with pre-existing ones to reduce the effects of BOs are discussed. These indices are introduced inside 3 different sujects: The first subject is for taking a look into economical aspects of grids’ operation and their effects in BO propagation. Basically, simulations support that: the determination to operate the grid in the most profitable way could produce an increase in the size or frequency of BOs. Conversely, some uneconomical ways of supplying energy are shown to be less affected by BO phenomena. In the second subject new topological indices are devised to address the question of "which are the best buses to place distributed generation?". The combined use of two indices, is shown as a promising alternative for extracting grid’s significant features regarding robustness against BOs and distributed generation. For this purpose, a new index based on outage shift factors is used along with a previously defined electric centrality index. The third subject is on Static Robustness Analysis of electric networks, from a purely structural point of view. A pair of existing topological indices, (namely degree index and clustering coefficient), are combined to show how degradation of the network structure can be accelerated. Blackout simulations were carried out using the DC Power Flow Method and models of transmission networks from the USA and Europe.

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Givaki, Kamyab. "Integration of large wind farms to weak power grids." Thesis, University of Strathclyde, 2017. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=28878.

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Power grids are changing significantly with the introduction of large amounts of renewable energy (especially wind) into the system. Integration of wind energy into the grid is challenging as, firstly it increases penetration stresses when compared to conventional generation as the wind is intermittent and fluctuates in power output. Secondly, most of the wind farms are located in offshore or rural areas which have good wind conditions. The grid in these regions is not normally strong. Most of the modern variable speed wind turbines use voltage source converters (VSCs) for grid integration. However, integrating VSCs to weak power grids will cause instability when a large amount of active power is transferred to the grid. In this thesis, the integration of wind farms to very weak power grids is investigated. A multiple input, multiple output (MIMO) model of the grid side VSC of a wind turbine is developed in the frequency domain in which the d-axis of the synchronous reference frame (SRF) is aligned with the grid voltage. Then, this model has been used as the basis for modelling the multiple parallel converters in the frequency domain. In this thesis, to improve the stability of the very weak grid connected of VSCs, a control method based on the d- and q- axis current error is introduced. This controller compensates the output angle of the phase locked loop (PLL) and the voltage amplitude of the converter. Using this controller, full rated active power transfer and fault ride-through are achieved under very weak grid connection. Furthermore, a stabiliser controller based on virtual impedance is proposed in this thesis to achieve stable operation of a very weak grid connected VSC. This stabilising control method enables the VSC to operate at full power and to ride-through faults under very weak grid conditions. Based on this principle, an external device is proposed that can be utilised and connected to a weak point of the grid to allow a large amount of VSC interfaced power generation (e.g. wind power) to be connected to the grid without introducing stability issues.

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Wang, Chengwei. "Synchronisation in complex networks with applications to power grids." Thesis, University of Aberdeen, 2017. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=232252.

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In this thesis, we present several novel theoretical results in complex networks, most of which benefit from extensions of existing methods of analysis in electrical engineering. These results not only contribute to a better characterisation of the topology and structure of complex networks, but also provide a new way to study complex systems by modelling them as a flow network to determine how nodes nonlocally interact as a function of the adjacent physical laws. We also contribute towards a better understanding of how frequency synchronisation (FS) in coupled phase oscillator networks comes about by revealing the fundamental mechanisms and determinant conditions for nodes to become FS. Moreover, we design a scheme to control explosive synchronisation. Equipped with the theoretical knowledge obtained from the study of phase oscillator networks, we reveal the mechanism behind the onset of FS in realistic models of power grids and the causes behind frequency collapse. Furthermore, we put forward advanced control techniques and novel prediction methods to prevent blackouts from happening in those models. These results might help engineers to construct a stable, economic and efficient smart power grid in the near future. The breakthroughs in this thesis build up a bridge which, on the one hand, promotes the progress of the research in the fields of complex networks and synchronization by borrowing methods from electrical engineering and extending them to the treatment of complex networks, and on the other hand, aids engineers to efficiently solve some specific problems in smart grids based on the knowledge of approaches coming from the area of complex systems. Therefore, this thesis bridges the gap between engineering and physics by identifying, explaining and extending interdisciplinary approaches from these two disciplines to better understand models and networks considered within these fields.

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Shuker, Mamz, and Linn Nielsen. "Automatisering av produktionsprocess Kartläggning hos Hitachi ABB Power Grids." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-92308.

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The purpose of this thesis is to identify areas where the present production process can be more effective with the help of automation solutions and how this efficiency can contribute to improved productivity, quality, safety and ergonomics. Today, Hitachi ABB Power Grids has a manual manufacturing process for customized power transformers and seeks to meet a demand that requires a more automated approach. The research problem deals with five workstations for Hitachi ABB Power Grids production process of the internal components of power transformers. These workstations are connectors (A-donet), core stacking (including core cutting), winding, active part assembly and final assembly. The study's questions are, 1. how should Hitachi ABB Power Grids manually based production process be more effective through automation solutions? and 2. which automation solution meets the best requirements of increased productivity, quality, safety and ergonomics with acceptable profitability? To answer these questions and achieve the thesis purpose, the study was carried out in the form of a qualitative case study, which data was collected via documents, observations, interviews and literatures. Hitachi ABB Power Grids current production process was studied and a dialogue was held with the employees. Consequently, the obstacles that have prevented Hitachi ABB Power Grids from implementing automation were identified. Together with a market description, several concept proposals have been brainstormed. Core-laying machine is a potential automation solution in Hitachi ABB Power Grids production but is not taken into account based on the company's needs. The study resulted in Augmented Reality (AR) in the production process for increased communication. A complete solution is discussed to avoid a shifting effect that can occur when automating only one workstation. If the company implements the core-laying machine, the bottleneck will disappear at this workstation where pre-cut sheet metal is waiting to be used. Consequently, a new bottleneck would arise at the winding which would not be able to maintain the same speed, thus more cores can be manufactured than to be wound. To maintain the same productivity, the total workstation area of the winding should be widened and make room for more winding stations. The workforce that was previously at the core, can be trained to become a winding worker which can be made more efficient by letting the workers be trained in a mixed reality. The conclusion is that Microsoft's AR equipment, HoloLens 2 Remote Assist, is the automation solution that best meets the requirements of increased productivity, quality, safety and ergonomics. An investment in this information technology solution would result in a payback period of 12 months.
Syftet med detta examensarbete är att identifiera områden där den nuvarande produktionsprocessen kan effektiviseras med hjälp av automationslösningar och hur denna effektivisering kan bidra till förbättrad produktivitet, kvalitet, säkerhet och ergonomi. Idag har Hitachi ABB Power Grids en manuell tillverkningsprocess avseende kundanpassade krafttransformatorer och de försöker bemöta en efterfrågan som kräver ett mer automatiserat tillvägagångssätt. Studiens problemställning behandlar fem arbetsstationer för tillverkning av de inre komponenterna av krafttransformatorer. Dessa arbetsstationer är anslutningsdon (A-don), kärnläggning (inklusive kärnklippning), lindning, aktiv delmontage och slutmontage. Studiens frågeställningar är, 1. hur bör Hitachi ABB Power Grids manuellt baserade produktionsprocess effektiviseras genom automationslösningar? och 2. vilken automationslösning uppfyller bäst kraven på ökad produktivitet, kvalitet, säkerhet och ergonomi med godtagbar lönsamhet? För att besvara dessa frågeställningar och uppnå studiens syfte, genomfördes examensarbetet i form av en kvalitativ fallstudie, vilket medförde att data insamlades via dokument, observationer, intervjuer och litteraturer. Hitachi ABB Power Grids nuvarande process studerades och en dialog fördes med de anställda. Följaktligen identifierades hinder som har gjort att Hitachi ABB Power Grids ännu inte har implementerat automatisering. Tillsammans med en marknadsbeskrivning, har flertal konceptförslag brainstormats fram. Kärnläggningsmaskin är en potentiell automationslösning hos Hitachi ABB Power Grids produktion, men har selekterats bort utifrån företagets behov. Studien resulterade i förstärkt verklighet (AR) i produktionsprocessen för ökad kommunikation. Det diskuteras en helhetslösning för att undvika en förskjutningseffekt som kan uppstå vid automatisering av endast en arbetsstation. Om företaget implementerar kärnläggningsmaskinen, försvinner flaskhalsen vid denna arbetsstation där färdigklippt plåt väntar på att nyttjas. Följaktligen skulle en ny flaskhals uppstå vid lindningen som inte skulle kunna upprätthålla samma hastighet, därmed kan fler kärnor tillverkas än vad som hinner lindas. För att hålla samma produktivitet bör lindningens totala arbetsstationsyta vidgas och göra plats för fler lindningsstationer. Arbetskraften som tidigare befunnit sig vid kärnläggningen, kan läras upp till att bli lindare som i sin tur kan effektiviseras genom att låta arbetstagarna läras upp i en mixad verklighet. Slutsatsen är att Microsofts AR-utrustning, HoloLens 2 Remote Assist, är den lösning som uppfyller bäst kraven på ökad produktivitet, kvalitet, säkerhet och ergonomi. En investering i denna informationstekniska lösning skulle resultera i en återbetalningsperiod på 12 månader.

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Pahwa, Sakshi. "Dynamics on complex networks with application to power grids." Diss., Kansas State University, 2013. http://hdl.handle.net/2097/16891.

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Doctor of Philosophy
Department of Electrical and Computer Engineering
Caterina Scoglio
The science of complex networks has significantly advanced in the last decade and has provided valuable insights into the properties of real world systems by evaluating their structure and construction. Several phenomena occurring in real technological and social systems can be studied, evaluated, quantified, and remedied with the help of network science. The electric power grid is one such real technological system that can be studied through the science of complex networks. The electric grid consists of three basic sub-systems: Generation, Transmission, and Distribution. The transmission sub-system is of particular interest in this work because its mesh-like structure offers challenging problems to complex networks researchers. Cascading dynamics of power grids is one of the problems that can be studied through complex networks. The North American Electric Reliability Corporation (NERC) defines a cascading failure as the uncontrolled successive loss of system elements triggered by an incident at any location. In this dissertation, we primarily discuss the dynamics of cascading failures in the power transmission grid, from a complex networks perspective, and propose possible solutions for mitigating their effects. We evaluate the grid dynamics for two specific scenarios, load growth and random fluctuations in the grid, to study the behavior of the grid under critical conditions. Further, we propose three mitigation strategies for reducing the damage caused by cascading failures. The first strategy is intentional islanding in the power transmission grid. The aim of this method is to intentionally split the grid into two or more separate self- sustaining components such that the initial failure is isolated and the separated components can function independently, with minimum load shedding. The second mitigation strategy involves controlled placement of distributed generation (DG) in the transmission system in order to enhance robustness of the grid. The third strategy requires the addition of a link in the transmission grid by reduction of the average spectral distance, utilizing the Ybus matrix of the grid and a novel algorithm. Through this dissertation, we aim to successfully cover the gap present in the complex networks domain, with respect to the vulnerability analysis of power grid networks.

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Hu, Liang. "Dynamic state estimation for power grids with unconventional measurements." Thesis, Brunel University, 2016. http://bura.brunel.ac.uk/handle/2438/12692.

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State estimation problem for power systems has long been a fundamental issue that demands a variety of methodologies dependent on the system settings. With recent introduction of advanced devices of phasor measurement units (PMUs) and dedicated communication networks, the infrastructure of power grids has been greatly improved. Coupled with the infrastructure improvements are three emerging issues for the state estimation problems, namely, the coexistence of both traditional and PMU measurements, the incomplete information resulting from delayed, missing and quantized measurements due to communication constraints, and the cyber-attacks on the communication channels. Three challenging problems are faced when dealing with the three issues in the state estimation program of power grids: 1) how to include the PMU measurements in the state estimator design, 2) how to account for the phenomena of incomplete information occurring in the measurements and design effective state estimators resilient to such phenomena, and 3) how to identify the system vulnerability in state estimation scheme and protect the estimation system against cyber-attacks. In this thesis, with the aim to solve the above problems, we develop several state estimation algorithms which tackle the issues of mixed measurements and incomplete information, and examine the cyber-security of the dynamic state estimation scheme. • To improve the estimation performance of power grids including PMU measurements, a hybrid extended Kalman filter and particle swarm optimization algorithm is developed, which has the advantages of being scalable to the numbers of the installed PMUs and being compatible with existing dynamic state estimation software as well. • Two kinds of network-induced phenomena, which leads to incomplete information of measurements, are considered. Specifically, the phenomenon of missing measurements is assumed to occur randomly and the missing probability is governed by a random variable, and the quantized nonlinear measurement model of power systems is presented where the quantization is assumed to be of logarithmic type. Then, the impact of the incomplete information on the overall estimation performance is taken into account when designing the estimator. Specifically, a modified extended Kalman filter is developed which is insensitive to the missing measurements in terms of acceptable probability, and a recursive filter is designed for the system with quantized measurements such that an upper bound of the estimation error is guaranteed and also minimized by appropriately designing the filter gain. • With the aim to reduce or eliminate the occurrence of the above-mentioned network-induced phenomena, we propose an event-based state estimation scheme with which communication transmission from the meters to the control centre can be greatly reduced. To ensure the estimation performance, we design the estimator gains by solving constrained optimization problems such that the estimation error covariances are guaranteed to be always less than a finite upper bound. • We examine the cyber-security of the dynamic state estimation system in power grids where the adversary is able to inject false data into the communication channels between PMUs and the control centre. The condition under which the attacks cause unbounded estimation errors is found. Furthermore, for system that is vulnerable to cyber-attacks, we propose a system protection scheme through which only a few (rather than all) communication channels require protection against false data injection attacks.

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Wilkinson, Jeffrey Kenneth. "Uniting the Nation's Power Grids: Opening Markets to Integrate Large Scale Renewable Power." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/777.

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As renewable energy becomes increasingly cost competitive and Renewable Portfolio Standards (RPS) push states to produce more and more of their steadily growing power demands from renewable sources, the need to solve the problems associated with renewable penetration becomes a priority. The intermittent nature of solar and wind power generation require additional cost that inhibit their implementation as penetration levels grow. Reliability remains power utilities' top priority while they struggle to upgrade their systems. Old generation facilities will be decommissioned, renewable energy projects will come on line and transmission upgrades become inevitable. Variability on the grid is currently mitigated through the use of Operational Reserves. These units are costly and utilities are currently looking for ways to reduce the amount of reserves required. Balancing Area cooperation is currently being considered by many as the most economical and environmentally conscience method to mitigate variability. Many aspects of Balancing Area cooperation will be discussed along with the motivations for their implementation. A 22.5 square mile area of land in Clovis, NM will be the home of the Tres Amigas project designed to unite the three asynchronous grids of our Nation with the purpose of improving reliability and reducing cost through the exchange of power and ancillary services such as VAR support and Operating Reserves. This paper will investigate the implications of this project on the Operational Reserves required to mitigate variability due to increasing renewable energy penetration by enabling Balancing Areas to cooperate across regions that are currently not assessable.

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Palma, David João Nunes. "Design of future distribution grids." Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/11110.

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Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores
This work presents the concept of voltage control in power distribution systems with distributed generation and electric vehicles penetration. The impact of DG and EV in the voltage supply is investigated. DG provides more power into the system, which can cause the inversion of the load flow and an increase in the voltage supply when the demand is low. EVs on the other hand are additional load in distribution systems, increasing power demand and voltage drop. Both might be a cause of voltage problems in the power supply, when no voltage control is applied. Devices such as the tap-changer transformer or the voltage regulator which were not essential in the past are now important solutions to solve voltage variation issues. In this work, several different solutions for voltage control are analyzed, both technically and economically. Overall, the results show that different strategies have different outcomes, and some solutions provide better voltage control than others. In order to have a proper solution for a system, when choosing a control strategy, it is necessary to always take into account the cable ampacity, the technical limits of each device and the costs associated with it.

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de, Groot Martijn. "Development of a Plug and Play Solution for Commercial Off-grid Solar Refrigeration : Presenting a Battery Supported System Providing the AC Power Required to run a Coolfinity 300L Commercial Refrigerator." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-302991.

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In this report the design and testing of a plug and play system to run Coolfinity’s Icevolt 300 refrigerator on solar panels is discussed. Such a system will be able to provide adequate cooling for food & beverages in area’s with unreliable or no electricity available. Currently such systems are only available for small chest refrigerators, while the Icevolt 300 is a large standing commercial refrigerator with a glass door. This is ideal for shops, cafés restaurants and smaller distribution centres. The system contains a solar charge controller, a battery and an inverter. First the component specifications and required solar panels are calculated. From those calculations system components are evaluated. A custom casing is designed to fit the components. An OEM is chosen and the chosen Inverter is tested extensively. The tests show that the inverter does not have any problems starting the Icevolt 300 compressor at a reduced voltage. Many battery manufacturers are evaluated and samples from three different manufacturers are obtained and tested. Samples of one of the manufacturers match specifications and have no issues with the high start up power of the compressor. A full system test proofs that the system works, but also indicates that the original refrigerator consumption estimate was too low. This means more PV panels are needed than originally estimated. With the information from the tests a new model is build that estimates the performance more accurate. A program is written to estimate the performance and decide the PV panels required. The pilot series of the case showed a lot of improvements are needed in the case design, especially on cost. A test is prepared in Mali but no test data is obtained yet. Based on the work done it would be recommend to investigate DC direct refrigerators instead of continuing the path of PV to AC systems.
I denna rapport diskuteras design och testning av ett plug and play - system för att köra Coolfinity’s Icevolt 300 -kylskåp på solpaneler. Ett sådant system kommer att kunna tillhandahålla tillräcklig kylning för mat och dryck i områden med opålitlig eller ingen tillgänglig el. För närvarande är sådana system endast tillgängliga för små kylboxar, medan Icevolt 300 är ett stort stående kommersiellt kylskåp med en glasdörr. Detta är idealiskt för butiker, kaféer och mindre distributionscentra. Systemet innehåller en laddningsregulator för solpaneler, ett batteri och en växelriktare. Först beräknas komponentspecifikationerna och nödvändiga solpaneler. Utifrån dessa beräkningar utvärderas systemkomponenter. Ett anpassat hölje är utformat för att passa komponenterna. En OEM väljs och den valda växelriktaren testas utförligt. Testerna visar att växelriktaren inte har några problem att starta Icevolt 300 -kompressorn med reducerad spänning. Många batteritillverkare utvärderas och prover från tre olika tillverkare erhålls och testas. Prover från en av tillverkarna matchar specifikationerna och har inga problem med kompressorns höga starteffekt. Ett fullständigt systemtest bevisar att systemet fungerar, men indikerar också att den ursprungliga uppskattningen av kylförbrukningen var för låg. Det betyder att fler PV -paneler behövs än vad som ursprungligen beräknades. Med informationen från testerna byggs en ny modell som uppskattar prestandan mer exakt. Ett program skrivs för att uppskatta prestanda och bestämma vilka PV -paneler som krävs. Pilotserien för höljet visade att många förbättringar behöver göras vad beträffar höljets design, särskilt vad gäller kostnaden. Ett test förbereds i Mali men inga testdata har erhållits ännu. Baserat på det utförda arbetet skulle det rekommenderas att undersöka direkta DC -kylskåp istället för att fortsätta vägen för PV till AC-system.

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Larsson, Anders. "High frequency distortion in power grids due to electronic equipment." Licentiate thesis, Luleå : Luleå tekniska universitet/Tillämpad fysik, maskin- och materialteknik/Energiteknik, 2006. http://epubl.ltu.se/1402-1757/2006/63/LTU-LIC-0663-SE.pdf.

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