Teses / dissertações: "Micro distributed generation system"

1

Eliasstam, Hannes. "Design, Management and Optimization of a Distributed Energy Storage System with the presence of micro generation in a smart house". Thesis, Linköpings universitet, Institutionen för systemteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-86818.

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The owners of a house in today’s society do not know in real-time how much electricity they use. It could be beneficial for any residential consumer to have more control and overview in real-time over the electricity consumption. This could be done possible with a system that monitors the consumptions, micro renewables and the electricity prices from the grid and then makes a decision to either use or sell electricity to reduce the monthly electricity cost for the household and living a "Greener" life to reduce carbon emissions. In this thesis, estimations are made based on artificial neural network (ANN). The predictions are made for air temperature, solar insolation and wind speed in order to know how much energy will be produced in the next 24 hours from the solar panel and from the wind turbine. The predictions are made for electricity consumption in order to know how much energy the house will consume. These predictions are then used as an input to the system. The system has 3 controls, one to control the amount of sell or buy the energy, one to control the amount of energy to charge or discharge the fixed battery and one to control the amount of energy to charge or discharge the electric vehicle (EV). The output from the system will be the decision for the next 10 minutes for each of the 3 controls. To study the reliability of the ANN estimations, the ANN estimations (SANN) are compared with the real data (Sreal ) and other estimation based on the mean values (Smean) of the previous week. The simulation during a day in January gave that the expenses are 0.6285 € if using SANN, 0.7788 € if using Smean and 0.5974 € if using Sreal. Further, 3 different cases are considered to calculate the savings based on the ANN estimations. The first case is to have the system connected with fixed storage device and EV (Scon;batt ). The second and third cases are to have the system disconnected (without fixed battery) using micro generation (Sdiscon;micro) and not using micro generation (Sdiscon) along with the EV. The savings are calculated as a difference between Scon;batt and Sdiscon, also between Sdiscon;micro and Sdiscon. The saving are 788.68 € during a year if Scon;batt is used and 593.90 € during a year if Sdiscon;micro is used. With the calculated savings and the cost for the equipment, the pay-back period is 15.3 years for Scon;batt and 4.5 years for Sdiscon;micro. It is profitable to only use micro generation, but then the owner of the household loses the opportunity to be part of helping the society to become "Greener".

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Navarro, Espinosa Alejandro. "Low carbon technologies in low voltage distribution networks : probabilistic assessment of impacts and solutions". Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/low-carbon-technologies-in-low-voltage-distribution-networks-probabilistic-assessment-of-impacts-and-solutions(cc5c77df-54fe-4c1c-a599-3bbea8fbd0c1).html.

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The main outcome of this research is the development of a Probabilistic Impact Assessment methodology to comprehensively understand the effects of low carbon technologies (LCTs) in low voltage (LV) distribution networks and the potential solutions available to increase their adoption. The adoption of LCTs by domestic customers is an alternative to decreasing carbon emissions. Given that these customers are connected to LV distribution networks, these assets are likely to face the first impacts of LCTs. Thus, to quantify these problems a Monte Carlo-based Probabilistic Impact Assessment methodology is proposed in this Thesis. This methodology embeds the uncertainties related to four LCTs (PV, EHPs, µCHP and EVs). Penetration levels as a percentage of houses with a particular LCT, ranging from 0 to 100% in steps of 10%, are investigated. Five minute time-series profiles and three-phase four-wire LV networks are adopted. Performance metrics related to voltage and congestion are computed for each of the 100 simulations per penetration level. Given the probabilistic nature of the approach, results can be used by decision makers to determine the occurrence of problems according to an acceptable probability of technical issues. To implement the proposed methodology, electrical models of real LV networks and high resolution profiles for loads and LCTs are also developed. Due to the historic passive nature of LV circuits, many Distribution Network Operators (DNOs) have no model for them. In most cases, the information is limited to Geographic Information Systems (GIS) typically produced for asset management purposes and sometimes with connectivity issues. Hence, this Thesis develops a methodology to transform GIS data into suitable computer-based models. In addition, thousands of residential load, PV, µCHP, EHP and EV profiles are created. These daily profiles have a resolution of five minutes. To understand the average behaviour of LCTs and their relationship with load profiles, the average peak demand is calculated for different numbers of loads with and without each LCT.The Probabilistic Impact Assessment methodology is applied over 25 UK LV networks (i.e., 128 feeders) for the four LCTs under analysis. Findings show that about half of the studied feeders are capable of having 100% of the houses with a given LCT. A regression analysis is carried out per LCT, to identify the relationships between the first occurrence of problems and key feeder parameters (length, number of customers, etc.). These results can be translated into lookup tables that can help DNOs produce preliminary and quick estimates of the LCT impacts on a particular feeder without performing detailed studies. To increase the adoption of LCTs in the feeders with problems, four solutions are investigated: feeder reinforcement, three-phase connection of LCTs, loop connection of LV feeders and implementation of OLTCs (on-load tap changers) in LV networks. All these solutions are embedded in the Probabilistic Impact Assessment. The technical and economic benefits of each of the solutions are quantified for the 25 networks implemented.

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van, der Walt Rhyno Lambertus Reyneke. "Photovoltaic based distributed generation power system protection". Diss., University of Pretoria, 2017. http://hdl.handle.net/2263/62807.

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In recent years, the world has seen a significant growth in energy requirements. To meet this requirement and also driven by environmental issues with conventional power plants, engineers and consumers have started a growing trend in the deployment of distributed renewable power plants such as photovoltaic (PV) power plants and wind turbines. The introduction of distributed generation pose some serious issues for power system protection and control engineers. One of the major challenges are power system protection. Conventional distribution power systems take on a radial topology, with current flowing from the substation to the loads, yielded unidirectional power flow. With the addition of distributed generation, power flow and fault current are becoming bi-directional. This causes loss of coordination between conventional overcurrent protection devices. Adding power sources downstream of protection devices might also cause the upstream protection device to be blinded from faults. Conventional overcurrent protection is mainly based on the fault levels at specific points along the network. By adding renewable sources, the fault levels increase and become dynamic, based on weather conditions. In this dissertation, power system faults are modelled with sequence components and simulated with Digsilent PowerFactory power system software. The modeling of several faults under varying power system parameters are combined with different photovoltaic penetration levels to establish a framework under which protection challenges can be better defined and understood. Understanding the effects of distributed generation on three phase power systems are simplified by modeling power systems with sequence networks. The models for asymmetrical faults shows the limited affect which distributed generation has on power system protection. The ability of inverter based distributed generators to provide active control of phase current, irrespective of unbalanced voltage occurring in the network limits their influence during asymmetrical faults. Based on this unique ability of inverter based distributed generators (of which PV energy sources are the main type), solutions are proposed to mitigate or prevent the occurrence of loss of protection under increasing penetration levels of distributed generation. The solutions include using zero and negative sequence overcurrent protection, and adapting the undervoltage disconnection time of distributed generators based on the unique network parameters where it is used. Repeating the simulations after integrating the proposed solutions show improved results and better protection coordination under high penetration levels of PV based distributed generation.
Dissertation (MEng)--University of Pretoria, 2017.
Electrical, Electronic and Computer Engineering
MEng
Unrestricted

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Ibrahim, Sarmad Khaleel. "DISTRIBUTION SYSTEM OPTIMIZATION WITH INTEGRATED DISTRIBUTED GENERATION". UKnowledge, 2018. https://uknowledge.uky.edu/ece_etds/116.

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In this dissertation, several volt-var optimization methods have been proposed to improve the expected performance of the distribution system using distributed renewable energy sources and conventional volt-var control equipment: photovoltaic inverter reactive power control for chance-constrained distribution system performance optimisation, integrated distribution system optimization using a chance-constrained formulation, integrated control of distribution system equipment and distributed generation inverters, and coordination of PV inverters and voltage regulators considering generation correlation and voltage quality constraints for loss minimization. Distributed generation sources (DGs) have important benefits, including the use of renewable resources, increased customer participation, and decreased losses. However, as the penetration level of DGs increases, the technical challenges of integrating these resources into the power system increase as well. One such challenge is the rapid variation of voltages along distribution feeders in response to DG output fluctuations, and the traditional volt-var control equipment and inverter-based DG can be used to address this challenge. These methods aim to achieve an optimal expected performance with respect to the figure of merit of interest to the distribution system operator while maintaining appropriate system voltage magnitudes and considering the uncertainty of DG power injections. The first method is used to optimize only the reactive power output of DGs to improve system performance (e.g., operating profit) and compensate for variations in active power injection while maintaining appropriate system voltage magnitudes and considering the uncertainty of DG power injections over the interval of interest. The second method proposes an integrated volt-var control based on a control action ahead of time to find the optimal voltage regulation tap settings and inverter reactive control parameters to improve the expected system performance (e.g., operating profit) while keeping the voltages across the system within specified ranges and considering the uncertainty of DG power injections over the interval of interest. In the third method, an integrated control strategy is formulated for the coordinated control of both distribution system equipment and inverter-based DG. This control strategy combines the use of inverter reactive power capability with the operation of voltage regulators to improve the expected value of the desired figure of merit (e.g., system losses) while maintaining appropriate system voltage magnitudes. The fourth method proposes a coordinated control strategy of voltage and reactive power control equipment to improve the expected system performance (e.g., system losses and voltage profiles) while considering the spatial correlation among the DGs and keeping voltage magnitudes within permissible limits, by formulating chance constraints on the voltage magnitude and considering the uncertainty of PV power injections over the interval of interest. The proposed methods require infrequent communication with the distribution system operator and base their decisions on short-term forecasts (i.e., the first and second methods) and long-term forecasts (i.e., the third and fourth methods). The proposed methods achieve the best set of control actions for all voltage and reactive power control equipment to improve the expected value of the figure of merit proposed in this dissertation without violating any of the operating constraints. The proposed methods are validated using the IEEE 123-node radial distribution test feeder.

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Zhang, Zhipeng. "Contributions of distributed generation to electric transmission system". Thesis, University of Bath, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715266.

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Distributed generation (DG) refers to electricity generating plant that is connected to a distribution network rather than the transmission system. At present, small-scale DGs are mostly treated as ‘negative demand’ to the transmission system. However, if their contribution to transmission levels are fully understood and properly assessed, these generators can make into valuable assets to improve operational efficiency and substitute major infrastructure investment. This PhD research aims to addresses this challenge from three key aspects: 1. On assessment methodologies, our current industrial practices to evaluate DG-to- transmission-contribution reveal inherent defects. The method given in the transmission system (SQSS) is not sufficient to reflect today’s dispersed generation technologies; while the method for the distribution system (P2/6) fails to reflect and discriminate between different characteristics of distribution networks that DGs are connected. Overcoming these drawbacks, enhanced frameworks to evaluate DG contribution have been developed in this research. 2. On generator’s contribution, little attention has been paid to photovoltaic (PV) outputs characterization and their integration to the overall evaluation process. Neither SQSS nor P2/6 pays sufficient attantion to evaluating PV’s contribution to system. In this regard, an approach aiming at characterizing PV seasonal outputs is proposed. Integrating with the proposed frameworks, this part of the research completes the DG contribution evaluation architecture. 3. On commercial arrangements, conventional business models largely rely on network investment to meet customer demand. Earning a fixed rate of return on invested capital, incumbent distribution network operator (DNO) businesses are encouraged to invest in network assets, very little has been done to support third party service providers for more efficient network development. In the third part of this research, alternative DNO business models and market mechanisms are proposed to further unlock the potential of DG, substantially increase the potential of their contributions to the transmission system.

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Sahoo, Smrutirekha. "Impact Study: Photo-voltaic Distributed Generation on Power System". Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-32369.

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The grid-connected photo-voltaic (PV) system is one of the most promising renewable energy solutions which offers many benefits to both the end user and the utility network and thus it has gained the popularity over the last few decades. However, due to the very nature of its invariability and weather dependencies, the large scale integration of this type of distributed generation has created challenges for the network operator while maintaining the quality of the power supply and also for reliable and safe operations of the grids. In this study, the behavioral impact of large scale PV system integration which are both steady and dynamic in nature was studied. An aggregate PV model suited to study the impacts was built using MATLAB/Simulink. The integration impacts of PV power to existing grids were studied with focus on the low voltage residential distribution grids of Mälarenergi Elnät AB (10/0.4 kV). The steady state impacts were related to voltage profile, network loss. It was found that the PV generation at the load end undisputedly improves the voltage profile of the grid especially for the load buses which are situated at farther end of the grid. Further, with regard to the overvoltage issue, which is generally a concern during the low load demand period it was concluded that, at a 50% PV penetration level, the voltage level for the load buses is within the limit of 103% as prescribed by the regulator excepting for few load buses. The voltage level for load buses which deviate from the regulatory requirement are located at distance of 1200 meter or further away from the substation. The dynamic impact studied were for voltage unbalancing in the grid, which was found to have greater impact at the load buses which is located farther compared to a bus located nearer to the substation. With respect to impact study related to introduction of harmonics to the grid due to PV system integration, it was found that amount of harmonic content which was measured as total harmonic distortion (THD) multiplies with integration of more number of PV system. For a 50 % penetration level of PV, the introduced harmonics into the representative network is very minimal. Also, it was observed from the simulation study that THD content are be less when the grid operates at low load condition with high solar irradiance compared to lower irradiance and high load condition.

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7

Bakkar, Mostafa. "Sag effects on protection system in distributed generation grids". Doctoral thesis, Universitat Politècnica de Catalunya, 2022. http://hdl.handle.net/10803/673721.

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Distributed Generators (DGs) are sensible to voltage sags, so the protection devices must trip fast to disconnect the faulted part of the grid. The DG disconnection will not be desirable in the near future with a large penetration, so it will be necessary to lay down new requirements that should be based on avoiding unnecessary disconnections. Therefore, to prevent unnecessary tripping when inverter-based DGs are connected to the Medium Voltage (MV) grid, reliable and effective protection strategies need to be developed, considering the limited short-circuit current contribution of DG. The initial goal of this study is to employ different possible control strategies for a grid-connected inverter according to the Spanish grid code and to analyze the output voltage behavior during symmetrical and unsymmetrical voltage sags. The analytical development of the proposed strategies shows the impacts of the sag on currents, voltages, active and reactive powers. Another goal of this research is to propose a protection strategy based on Artificial Intelligence for a radial or ring distribution system with high DG penetration. The protection strategy is based on three different algorithms to develop a more secure, redundant, and reliable protection system to ensure supply continuity during disturbances in ring and radial grids without compromising system stability. In order to classify, locate and distinguish between permanent or transient faults, new protection algorithms based on artificial intelligence are proposed in this research, allowing network availability improvement disconnecting only the faulted part of the system. This research introduces the innovative use of directional relay based on a communication system and Artificial Neural Network (ANN). The first algorithm, Centralize algorithm (CE), collects the data from all the PDs in the grid in the centralized controller. This algorithm detects the power flow direction and calculates the positive-sequence current of all the PDs in the grid. Significant benefits of this system are that it consolidates the entire systems security into a single device, which can facilitate system security control. However, the CE will not pinpoint the exact location of the fault if there is any loss of information due to poor communication. Therefore, the systems redundancy can be improved by cooperating with a second algorithm, the Zone algorithm (ZO). ZO algorithm is based on zone control using peer-to-peer connectivity in the same line. The faulty line in that zone may be identified by combining the two PDs data on the same line. The most relevant advantage of this algorithm is its flexibility to adapt to any grid modification or disturbance, even if they are just temporary, unlike the CE, which is fixed to the existing grid configuration. The third protection algorithm, Local algorithm (LO), has been proposed without depending on the communication between the PDs; then, the protection system can work properly in case of a total loss of communication. Each PD should be able to detect if the fault is located in the protected line or another line by using only the local information of the PD. According to the type of fault and based on local measurements at each PD of abc voltages and currents, different algorithms will be applied depending on the calculation of the sequence components. The main advantage of this algorithm is the separate decision of each PD, and avoiding communication problems. In case of radial grids, both mechanical breakers and Solid State Relays (SSRs) are used to verify the protection strategies, and in the case of ring grids, mechanical breakers are used, due to the limitations in required voltage difference of SSR. The proposed protection algorithms are compared with conventional protections (Overcurrent and Differential) protections to validate the contribution of the proposed algorithms, especially in reconfigurable smart grids.
El objetivo inicial de este estudio es emplear diferentes estrategias de control posibles para un inversor conectado a la red segun el código de red español y analizar el comportamiento de la tensión de salida durante caídas de tensión simétricas y asimétricas. El desarrollo analítico de las estrategias propuestas muestra los impactos de los huecos de tensión en las corrientes, tensiones, potencias activas y reactivas. Otro objetivo de esta investigación es proponer una estrategia de protecclón basada en lnteligencia Artificial para una red del Sistema de Distribución, radial o en anillo, con elevada penetración de Generación Distribuida. La estrategia de protección se basa en tres algoritmos diferentes para desarrollar un sistema de protección más seguro, redundante, y fiable, que asegure la continuidad de suministro durante perturbaciones en redes radiales o en anillo sin comprometer la estabilidad del sistema. Para clasificar, localizar y distinguir entre faltas permanentes o transitorias, se proponen en este trabajo nuevos algoritmos de protección basados en inteligencia artificial, permitiendo la mejora de la disponibilidad de la red, al desconectar sólo la parte del sistema en falta. Esta investigación introduce la innovación del uso del rele direccional basado en un sistema de comunicación y Redes Neuronales Artificiales (ANN). El primer algoritmo, Algoritmo Central (CE), recibe los datos de todos los PDs de la red en un control central. Este algoritmo detecta la dirección de flujo de cargas y calcula la corriente de secuencia positiva de todos los PDs de la red. El entrenamiento de ANNs incluye variaciones en la corriente de cortocircuito y la dirección del flujo de potencia en cada PD. Los beneficios mas significativos de este sistema son que concentra la seguridad total del sistema en un único dispositivo, lo que puede facilitar el control de la seguridad del sistema. Sin embargo, el CE no determinara con precisión la localización exacta de la falta si hay alguna perdida de información debida a una pobre comunicación. Por lo tanto, la redundancia del sistema se puede mejorar cooperando con un segundo algoritmo, el algoritmo de Zona (ZO). El algoritmo ZO se basa en un control de zona usando la conectividad entre dispositivos de protección de una misma línea. La línea en falta en esa zona puede identificarse combinando los datos de los dos PDs de la misma línea.. La ventaja mas relevante de este algoritmo es su flexibilidad para adaptarse a cualquier modificación de la red o perturbación, incluso si sólo son temporales, a diferencia del CE, que se ha adaptado para la configuración de la red existente. El tercer algoritmo de protección, algoritmo Local (LO), ha sido propuesto sin dependencia de la comunicación entre PDs; por lo tanto, el sistema de protección puede operar correctamente en el caso de una pérdida total de comunicación. Cada PD debe poder detectar si la falta esta ubicada en la línea protegida o en otra línea, utilizando sóIo la información local del PD. Según el tipo de falta, y en base a medidas locales en cada PD, de tensiones y corrientes abc, se aplican diferentes algoritmos en función del cálculo de las componentes simétricas. La principal ventaja de este algoritmo es la actuación por separado de cada PD, evitando los problemas de comunicación. En el caso de las redes radiales, se utilizan tanto interruptores mecánicos como réles de estado sóIido (SSR) para verificar las estrategias de protección, y en el caso de las redes en anillo se utilizan interruptores mecánicos, debido a las limitaciones de tensión para su conexión. Los algoritmos de protección propuestos se comparan con protecciones convencionales (Sobrecorriente y Diferencial) para validar la contribución de los algoritmos propuestos, especialmente en redes inteligentes reconfigurables.
Enginyeria Elèctrica

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Abada, Hashim H. "Turboelectric Distributed Propulsion System for NASA Next Generation Aircraft". Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright1515501052742277.

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9

Luong, Tommy. "Smart Micro-Grid with Distributed Generation Using Renewable Energy for a Coastal City". Thesis, California State University, Long Beach, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10977986.

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This thesis presents a novel approach towards solving one of the nation’s electric and energy sustainability problems and will have a major impact on California’s energy policy in meeting its targets, regarding renewable energy and minimizing carbon footprint. The study focuses on examining the technical and economic feasibility of smart micro-grid with distributed generation (DG) system with renewable energy on a coastal city. It presents a method to increase power reliability, redundancy, efficiency and to decrease the greenhouse gases (GHG) emissions contributing to climate change and ensure environmental sustainability. This innovative idea of aggregating multiple micro-grids that encompasses renewable energy from solar and wind, and uses battery storage and natural gas turbine generation for grid stability is unprecedented, which has been demonstrated as part of the results of this study. The proposed system produces enough power to sustain a small city while selling its excess power to adjacent cities. Moreover, this system could adopt other energy sources, not constrained to solar and wind, to exploit an area’s particular renewable energy niche (micro-hydro, geothermal, tidal wave, etc.). It is important to note that this system is economically, socially and environmental friendly (pillars of sustainability), through energy resource diversification, while harnessing free and abundant energy. The results of this study can used in designing and implementing a smart micro-grid in any city to meet its renewable energy and sustainability goal.

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El-Feres, Rashid. "Development of adaptive voltage control system for distribution system with distributed generation". Thesis, University of Manchester, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.489512.

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Jn today's distribution system, voltage regulation is a big challenge. In fact, with more, inclusion of DG (Distributed Generation), managing Voltage to customer becomes more of a concern. Failure to maintain system voltage can result in unsatisfactory performance of customer's devices or complete failure resulting in damage.

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Mondal, Abrez. "ANALYSIS AND MITIGATION OF FREQUENCY DISTURBANCES IN AN ISLANDED MICROGRID". The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492563068162654.

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12

Simhadri, Arvind. "Impact of distributed generation of solar photovoltaic (PV) generation on the Massachusetts transmission system". Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98604.

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Thesis: S.M., Massachusetts Institute of Technology, Engineering Systems Division, 2015. In conjunction with the Leaders for Global Operations Program at MIT.
Thesis: M.B.A., Massachusetts Institute of Technology, Sloan School of Management, 2015. In conjunction with the Leaders for Global Operations Program at MIT.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 73-76).
After reaching 250 megawatt direct current (MW dc) of solar photovoltaic (PV) generation installed in Massachusetts (MA) in 2013, four years ahead of schedule, Governor Deval Patrick in May of 2013 announced an increase in the MA solar PV goal to 1,600 MW by 2020 ([13]). However, integration of such significant quantities of solar PV into the electric power system is potentially going to require changes to the transmission system planning and operations to ensure continued reliability of operation ([14]). The objective of this project is to predict the distribution of solar PV in MA and to develop a simulation framework to analyze the impact of solar generation on the electric power system. To accomplish this objective, we first developed a prediction model for solar PV aggregate and spatial long term distribution. We collected solar PV installation data and electricity consumption data for 2004 to 2014 for each ZIP code in MA. Additional information such as population, land availability, average solar radiance, number of households, and other demographic data per ZIP code was also added to improve the accuracy of the model. For example, ZIP codes with higher solar radiance are more likely to have solar PV installations. By utilizing machine learning methods, we developed a model that incorporates demographic factors and applies a logistic growth model to forecast the capacity of solar PV generation per ZIP code. Next we developed an electrically equivalent model to represent the predicted addition of solar PV on the transmission system. Using this model, we analyzed the impact of solar PV installations on steady-state voltage of the interconnected electric transmission system. We used Siemens PTI's PSS/E software for transmission network modeling and analysis. Additionally, we conducted a sensitivity analysis on scenarios such as peak and light electricity consumption period, different locations of solar PV, and voltage control methods to identify potential reliability concerns. Furthermore, we tested the system reliability in the event of outages of key transmission lines, using N-1 contingency analysis. The analysis identified that the voltage deviation on transmission system because of adding 1,600 MW dc of distributed solar PV is within +/- 5% range. Based on the analysis performed in this thesis, we conclude that the current MA transmission system can operate reliably after the addition of the expected 1,600 MW dc of solar PV. As National Grid acquires information on solar installations, new data will improve the ability and accuracy of the prediction model to predict solar PV capacity and location more accurately. The simulation framework developed in this thesis can be utilized to rerun the analysis to test the robustness of the electric transmission system at a future date.
by Arvind Simhadri.
S.M.
M.B.A.

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Moreira, Dilvan de Abreu. "Agents : a distributed client/server system for leaf cell generation". Thesis, University of Kent, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262372.

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Abusief, Fatihe Ramadan. "Islanded Distribution Networks Supplied by Distributed Generation". Doctoral thesis, Università degli studi di Padova, 2017. http://hdl.handle.net/11577/3424572.

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The modern power systems have recently increased the interest in distributed generation (DG) technologies due to, fuel cost uncertainties, environmental constraints, and increasing power consumption with shortage of transmission capacities. Distributed generation (DG) using clean and renewable energy in power supply system have attracted serious attention. Many developing countries are adopting distributed generation (DG) technologies for their power systems expansion planning. Solar Energy is one of the most promising, nonpolluting, free source of energy. The enormous development of the exploitation of renewable energy throughout the territory leads to rethink the paradigm of traditional power grid. In particular, the possibility of operating of small networks in islanded configuration in remote villages, along with several benefits that we can glimpse. In some countries, electrical distribution lines have to cross areas where the installation cost could be very high and carrying out maintenance could become extremely difficult (e.g. desert areas). As a result, frequent power disconnections and blackout heavily affect the quality of supply of end-users. Conversely, the renewable energy sources exploitation in supplying portions of the distribution network during system disconnections is very interesting, both for reducing fossil fuel use and as backup power generator. In case the islanded local electrification makes use of discontinuous and unpredictable energy sources such as photovoltaic, a Battery Energy Storage System is required to regulate the system, supplying power balance and voltage stability. This requires, however, the development of appropriate control strategies to allow a continuous balance between the load and the generation. In this thesis, a control strategy implementing Battery Energy Storage System (BESS) and PV generation plants has been developed and tested for electrification of modeled remote distribution network. In the proposed (SMO) master/slave control strategy, the BESS operates as a slack node, while PV are controlled as PQ generators. The ability of the developed control strategy to preserve energy balance and system stability was extensively investigated. To minimize the BESS size, a use of Synchronous Generators was introduced to supply base load during night period. Furthermore, for efficiency improvement of the BESS and further reduction in batteries size especially under peak load conditions, a Battery Supercapacitor Hybrid Energy Storage System (ESS) was developed and investigated.
I moderni sistemi di alimentazione hanno recentemente aumentato l'interesse per la generazione distribuita (DG) a causa di tecnologie, le incertezze sui costi di carburante, i vincoli ambientali e l'aumento il consumo di energia con carenza di capacità di trasmissione. La generazione distribuita (DG) utilizzando energia pulita e rinnovabile nel sistema di alimentazione ha attirato l'attenzione. Molti paesi in via di sviluppo stanno adottando le tecnologie di generazione distribuita (DG) per la loro pianificazione di espansione dei sistemi di energia. L'energia solare è uno delle più promettenti, non inquinante, fonte gratuita di energia. L'enorme sviluppo dello sfruttamento delle energie rinnovabili in tutto il territorio porta a ripensare il paradigma tradizionale della rete elettrica. In particolare, la possibilità di operare su piccole reti in configurazione islanded in villaggi remoti, insieme a diversi benefici che possiamo intravedere. In alcuni paesi, le linee di distribuzione elettrica devono attraversare aree in cui i costi di installazione potrebbero essere molto elevati e effettuare la manutenzione potrebbe diventare estremamente difficile (ad esempio nel deserto). Come risultato, frequenti disconnessioni elettriche e blackout influenzano fortemente la qualità di fornitura degli utenti finali. Al contrario, sfruttare le fonti di energia rinnovabili nella fornitura della rete di distribuzione durante le disconnessioni è molto interessante, sia per ridurre l'uso di combustibili fossili che generatori di corrente. Nel caso in cui il locale islanded fa uso di fonti di energia discontinua e imprevedibile come il fotovoltaico, un sistema di batterie Energy Storage è necessario per regolare il sistema, fornendo equilibrio di energia e stabilità di tensione. Ciò richiede, tuttavia, lo sviluppo di appropriate strategie di controllo per consentire un continuo equilibrio tra il carico e la generazione. In questa tesi, una strategia di controllo dell'applicazione del sistema di batterie Energy Storage (BESS) e impianti di generazione fotovoltaica è stato sviluppato e testato per l'elettrificazione di una rete di distribuzione remota. Nella strategia di controllo master / slave proposta (SMO), il BESS opera come un nodo di gioco, mentre PV sono controllati come generatori PQ. La capacità della strategia di controllo sviluppato per preservare l'equilibrio energetico e la stabilità del sistema è stato ampiamente studiato. Per ridurre al minimo le dimensioni Bess, l'uso di generatori sincroni è stato introdotto per la fornitura di carico di base durante il periodo notturno. Inoltre, per migliorare l'efficienza della riduzione BESS e ulteriormente in batterie di tipo soprattutto sotto carico di picco condizioni, un sistema di storage ibrido di energia della batteria Supercapacitor (ESS) è stato sviluppato e indagato.

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Dewadasa, Jalthotage Manjula Dinesh. "Protection of distributed generation interfaced networks". Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/43681/1/Jalthotage_Dewadasa_Thesis.pdf.

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With the rapid increase in electrical energy demand, power generation in the form of distributed generation is becoming more important. However, the connections of distributed generators (DGs) to a distribution network or a microgrid can create several protection issues. The protection of these networks using protective devices based only on current is a challenging task due to the change in fault current levels and fault current direction. The isolation of a faulted segment from such networks will be difficult if converter interfaced DGs are connected as these DGs limit their output currents during the fault. Furthermore, if DG sources are intermittent, the current sensing protective relays are difficult to set since fault current changes with time depending on the availability of DG sources. The system restoration after a fault occurs is also a challenging protection issue in a converter interfaced DG connected distribution network or a microgrid. Usually, all the DGs will be disconnected immediately after a fault in the network. The safety of personnel and equipment of the distribution network, reclosing with DGs and arc extinction are the major reasons for these DG disconnections. In this thesis, an inverse time admittance (ITA) relay is proposed to protect a distribution network or a microgrid which has several converter interfaced DG connections. The ITA relay is capable of detecting faults and isolating a faulted segment from the network, allowing unfaulted segments to operate either in grid connected or islanded mode operations. The relay does not make the tripping decision based on only the fault current. It also uses the voltage at the relay location. Therefore, the ITA relay can be used effectively in a DG connected network in which fault current level is low or fault current level changes with time. Different case studies are considered to evaluate the performance of the ITA relays in comparison to some of the existing protection schemes. The relay performance is evaluated in different types of distribution networks: radial, the IEEE 34 node test feeder and a mesh network. The results are validated through PSCAD simulations and MATLAB calculations. Several experimental tests are carried out to validate the numerical results in a laboratory test feeder by implementing the ITA relay in LabVIEW. Furthermore, a novel control strategy based on fold back current control is proposed for a converter interfaced DG to overcome the problems associated with the system restoration. The control strategy enables the self extinction of arc if the fault is a temporary arc fault. This also helps in self system restoration if DG capacity is sufficient to supply the load. The coordination with reclosers without disconnecting the DGs from the network is discussed. This results in increased reliability in the network by reduction of customer outages.

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Hall, Joseph Edward. "Distributed control system for demand response by servers". Thesis, University of Iowa, 2015. https://ir.uiowa.edu/etd/1971.

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Within the broad topical designation of “smart grid,” research in demand response, or demand-side management, focuses on investigating possibilities for electrically powered devices to adapt their power consumption patterns to better match the availability of intermittent renewable energy sources, especially wind. Devices such as battery chargers, heating and cooling systems, and computers can be controlled to change the time, duration, and magnitude of their power consumption while still meeting workload constraints such as deadlines and rate of throughput. This thesis presents a system by which a computer server, or multiple servers in a data center, can estimate the power imbalance on the electrical grid and use that information to dynamically change the power consumption as a service to the grid. Implementation on a testbed demonstrates the system with a hypothetical but realistic usage case scenario of an online video streaming service in which there are workloads with deadlines (high-priority) and workloads without deadlines (low-priority). The testbed is implemented with real servers, estimates the power imbalance from the grid frequency with real-time measurements of the live outlet, and uses a distributed, real-time algorithm to dynamically adjust the power consumption of the servers based on the frequency estimate and the throughput of video transcoder workloads. Analysis of the system explains and justifies multiple design choices, compares the significance of the system in relation to similar publications in the literature, and explores the potential impact of the system.

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Musa, Idris. "Stochastic power system optimisation algorithm with applications to distributed generation integration". Thesis, University of Newcastle upon Tyne, 2015. http://hdl.handle.net/10443/2999.

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The ever increasing level of penetration of Distributed Generation (DG) in power distribution networks is not without its challenges for network planners and operators. Some of these challenges are in the areas of voltage regulation, increase of network fault levels and the disturbance to the network protection settings. Distributed generation can be beneficial to both electricity consumers and if the integration is properly engineered the energy utility. Thus, the need for tools considering these challenges for the optimal placement and sizing of DG units cannot be over emphasized. This dissertation focuses on the application of a soft computing technique based on a stochastic optimisation algorithm (Particle Swarm Optimisation or PSO) for the integration of DG in a power distribution network. The proposed algorithm takes into consideration the inherent nature of the control variables that comprise the search space in the optimal DG sizing/location optimisation problem, without compromising the network operational constraints. The developments of the proposed Multi-Search PSO algorithm (MSPSO) is described, and the algorithm is tested using a standard, benchmarking 69-bus radial distribution network. MSPSO results and performance are compared with that of a conventional PSO algorithm (and other analytical and stochastic methods). Both single-objective (minimising network power loss) and multi-objective (considering nodal voltages as part of the cost function) optimisation studies were conducted. When compared with previously published studies, the proposed MSPSO algorithm produces more realistic results since it accounts for the discrete sizes of commercially available DG units. The new MSPSO algorithm was also found to be the most computationally efficient, substantially reducing the search space and hence the computational cost of the algorithm compared with other methods, without loss of quality in the obtained solutions. As well as the size and location of DG units, these studies considered the operation of the generators to provide ancillary voltage support to the network (i.e. with the generators operating over a realistic range of lagging power factors, injecting reactive power into the network). The algorithm was also employed to optimise the integration of induction generation based DG into the network, considering network short-circuit current ratings and line loading constraints. A new method for computing the reactive power requirement of the Abstract V induction generator (based on the machine equivalent circuit) was developed and interfaced with the MSPSO to solve the optimization problem, including the generator shunt compensation capacitors. Finally, the MSPSO was implemented to carry out a DG integration problem for a real distribution network and the results validated using a commercial power system analysis tool (ERACS).

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El, Chehaly Mohamed. "Power system stability analysis with a high penetration of distributed generation". Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=92399.

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The operation and structure of distribution system is changing with the integration of distributed generation, based on alternative energy sources, including renewable energy sources (wind, solar). Among the new issues, there is the question of stability of distribution systems in the presence of a large penetration of distributed generation (DG).
With power systems operating near their loadability limits, voltage stability becomes an important issue. Many utilities have implemented long-term solutions to counter this problem, such as adding transmission lines and new power plants in order to improve the reliability of the power system. An alternative solution consists in increase of generation at the distribution level. This is also a way of meeting growing economical, technical and environmental constraints. The size, the technology and the placement of DG play an important role in the operation of distribution systems.
For long-term voltage stability analysis, bus-based voltage indices are implemented using Power-Voltage curves (PV curves) to analyze the contribution of DG. Large-penetration of DG also has an impact on the short-term stability (voltage stability and transient stability) of the system. Indices are developed to rank contingencies and show how different DG interconnections affect the system during faults. Time-domain simulations are used to perform those studies. For short-term voltage stability, voltage dips at load buses are monitored following a large disturbance. The maximum rotor speed deviations of centralized synchronous generators are used to study the transient stability of the overall system.
All of the indices defined above are tested on three commonly used test systems: the IEEE RTS-96 24-bus system, the IEEE 39-bus New England system and the IEEE 118 bus system. The studies conclude that, regardless of its technology, DG mostly improves the long-term voltage stability particularly when located in areas near large loads. With DG injecting reactive power, the voltage security margin is increased. Synchronous machine based DG has the greatest impact on the short-term stability when located near large centralized generators. For short-term voltage stability, the contribution of DG is most noticeable when it absorbs reactive power, thus lowering the voltage dips.
La pénétration de la production décentralisée (DG) ne cesse de croître dans les réseaux électriques. La structure des réseaux conventionnels est modifiée à cause de la présence des sources de puissance alternatives localisées au niveau de la distribution. La stabilité du système est donc étudiée afin de déterminer les conséquences de la grande pénétration de DG.
La stabilité de tension devient une préoccupation majeure de la plupart des utilités dont leur capacité de charge approche les limites. Plusieurs utilités ont mis en uvre des solutions à long terme pour contrer ce problème, telles que l'implémentation de nouvelles lignes de transmission et de nouvelles centrales électriques afin de garantir la fiabilité du réseau électrique. D'autres utilités ont opté à des solutions plus modernes telles que la production décentralisée qui satisfait les contraintes économiques, techniques et environnementales.
Concernant l'analyse de la stabilité de tension à long terme, des indices basés sur la tension sont implémentés à l'aide des courbes PV pour analyser la contribution de la DG. La haute pénétration de la DG a également un impact sur la stabilité à court terme du système. Les indices sont mis au point pour classifier les défauts et exposer les effets des différentes interconnexions de la DG sur le réseau. Ces études ont été performées à l'aide de plusieurs simulations. Concernant la stabilité de tension à court terme, les creux de tension qui apparaissent à la charge lors d'un défaut sont utilisés pour déterminer la stabilité du système. Les plus grands écarts de vitesse du rotor des générateurs synchrones centralisés aident à déterminer la stabilité transitoire du réseau.
Ces indices sont testés en utilisant trois réseaux électriques. Indépendamment de la technologie, les DGs améliorent la stabilité de tension à long terme quand elles sont situées proches des grosses charges. La stabilité de tension est augmentée lorsque les DG opèrent avec un facteur de puissance inductif. Les DGs basées sur des machines synchrones améliorent le plus la stabilité à court terme, lorsqu'elles sont situées proche des grands générateurs centralisés. Pour la stabilité de tension à court terme, la contribution de la DG est plus visible quand elle opère avec un facteur de puissance capacitif.

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Hayes, Barry Patrick. "Distributed generation and demand side management : applications to transmission system operation". Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/7884.

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Electricity networks are undergoing a period of rapid change and transformation, with increased penetration levels of renewable-based distributed generation, and new influences on electricity end-use patterns from demand-manageable loads and micro-generation. This creates a number of new challenges for the delivery of a reliable supply of electrical energy. The main aim of this PhD research is to provide a methodology for a more detailed and accurate assessment of the effects of wind-based distributed generation (DG) and demand side management (DSM) on transmission network operation. In addition, the work investigates the potential for co-ordinated implementation and control of DG and DSM to improve overall system performance. A significant amount of previous literature on network integration of DG and DSM resources has focused on the effects at the distribution level, where their impact is direct and often easily observed. However, as penetration levels increase, DG and DSM will have a growing influence on the operation and management of the bulk transmission system. Modelling and analysis of the impact of embedded and highly-dispersed DG and DSM resources at transmission voltage levels will present a significant challenge for transmission network operators in the future. Accordingly, this thesis presents a number of new approaches and methodologies allowing for a more accurate modelling and aggregation of DG and DSM resources in power system studies. The correct representation of input wind energy resources is essential for accurate estimation of power and energy outputs of wind-based DG. A novel modelling approach for a simple and accurate representation of the statistical and temporal characteristics of the wind energy resources is presented in the thesis. An "all-scale" approach to modelling and aggregation of wind-based generation is proposed, which is specifically intended for assessing the impact of embedded wind generation on the steady state performance of transmission systems. The methodology allows to include in the analysis wind-based generation at all scales and all levels of implementation, from micro and small LV-connected units, through medium-size wind plants connected at MV, up to large HV-connected wind farms. The thesis also presents an assessment of the potential for DSM in the UK residential and commercial sectors, based on the analysis and decomposition of measured demands at system bulk supply points into the corresponding load types. Using a section of the Scottish transmission network as a case study, a number of DG and DSM scenarios are investigated in detail. These results demonstrate the importance of accurately modelling the interactions between the supply system and various DG and DSM schemes, and show that the aggregated effects of highly-distributed DG and DSM resources can have significant impacts on the operation of the bulk transmission system.

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Souto, Laiz de Carvalho. "Fault location in power distribution networks with distributed generation". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/3/3143/tde-28062016-151847/.

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This research presents the development and implementation of fault location algorithms in power distribution networks with distributed generation units installed along their feeders. The proposed algorithms are capable of locating the fault based on voltage and current signals recorded by intelligent electronic devices installed at the end of the feeder sections, information to compute the loads connected to these feeders and their electric characteristics, and the operating status of the network. In addition, this work presents the study of analytical models of distributed generation and load technologies that could contribute to the performance of the proposed fault location algorithms. The validation of the algorithms was based on computer simulations using network models implemented in ATP, whereas the algorithms were implemented in MATLAB.
Esta pesquisa apresenta o desenvolvimento e a implementação de algoritmos para localização de faltas em redes primárias de distribuição de energia elétrica que possuem unidades de geração distribuída conectadas ao longo dos seus alimentadores. Esses algoritmos são capazes de efetuar a localização de faltas utilizando registros dos sinais de tensões e correntes realizados por dispositivos eletrônicos inteligentes, instalados nas saídas dos alimentadores de distribuição, além de informações que permitam determinar os valores das cargas conectadas nesses alimentadores, características elétricas, e o estado operativo da rede de distribuição. Ademais, este trabalho apresenta o estudo de modelos analíticos de unidades de geração distribuída e de cargas que poderiam contribuir positivamente com o desempenho dos algoritmos propostos. A validação dos algoritmos foi realizada através de simulações computacionais, utilizando modelos de rede implementados em ATP e os algoritmos foram implementados em MATLAB.

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Li, Fangxing. "A Software Framework for Advanced Power System Analysis: Case Studies in Networks, Distributed Generation, and Distributed Computation". Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/28124.

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This work presents a software framework for power system analysis, PowerFrame. It is composed of four layers. This four-layer architecture is designed for extensibility and reusability so that more complex power system problems can be tackled within the architecture. In the context of PowerFrame, this work explores complex power system problems. Included in these problems are parallel-placed cables with multiple conductors, and distributed resources operating in unbalanced power distribution systems. Mathematical models are derived. Errors between more exact models and conventional approaches are presented. PowerFrame is also designed to handle distributed computation for intensive power system calculations on multiple, networked computers. Distributed power flow algorithms are presented. Tests on Ethernet LANs show the feasibility of distributed computation under current computer network bandwidth.
Ph. D.

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Jones, Gavin Wesley. "Distribution system operation and planning in the presence of distributed generation technology". Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.umr.edu/thesis/pdf/Jones_09007dcc803b193d.pdf.

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Thesis (M.S.)--University of Missouri--Rolla, 2007.
Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 16, 2007) Includes bibliographical references (p. 71-74).

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Nieh, Tsu-Yuan. "Renewable energy, distributed generation and their application in modern electrical energy system". Thesis, City University London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492348.

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This thesis presents a new approach)o the various kind of renewable technologies, \: especially in wind energy, together with Distribut~d Generation (DG) and how there .. ' ~.- regulation and application in the modern power industry and market. The modern power market is growing in the fastest rate in the last decade, mainly because of the deregulation of the power market. The deregulation induced the competitive, which is supposed to reduce the cost and improve the power quality. However, it is like every other growing industry, there are always flaws exist inside the system or mechanism that compromises the original ta, rget. To ma.ke matters more complex, the environmental and energy exhausting concern produce more issues that required immediately attention, such as insertion of renewable energy,' eHP and DG techllologies that helps to reduce pollution and improve power quality. There are many barriers for applying newly development technologies that stated above, one main barrier is that even though population may understand the importance of energy saving and environmental friendly energy source, they may not know where or how to acquire those energy source. Secondly, applying new technologies on the old power system design will increase additional costs such as new wiring system, new design of control and security, and new expertise opinion on the new technologies to ensure their reliability and consistence. All the additional costs will catch participants' attention and some may think they are not worth of investment. Thirdly, DG will seem to be a favourable technologies for renewable energy to use because their characteristics of small in size and feasible to co-operate with traditional energy sources. However, it will create additional load on the existing distribution system that causes the electrical power to flow back to electrical energy grid, which is not original design of the electrical energy gird. To solve the problem may require redesign of the system, which will have negative effect on investor's decision.

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Cai, Hui. "Enhancement of power system dynamic stability using electric vehicles and distributed generation". Thesis, Queen's University Belfast, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.602450.

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This thesis proposes a method to establish the accurate parameters of stabilisers in the context of power systems with increasing penetration of Doubly Fed Induction Generators (DFIGs), Solid Oxide Fuel Cells (SOFCs) and Photovoltaic (PVs) using a hierarchical coordinated strategy and localised design. The performance of the tuned stabilisers is verified using modal analysis results and non-linear simulation. This thesis proposes that by using regulated stabilisers, the dynamic stability of a power system with large-scale Distributed Generation (DG) integration can be maintained. SmartParks have been proposed in published literature to support emergent electric vehicle charging. In practice, a SmartPark can be configured as an adjustable load, in charging mode, or a regulated generator, in a discharging mode using a voltage control strategy. In this thesis, damping torque analysis (DTA) has been used to investigate the impact on dynamic stability of the joint operation of SmartParks in power systems with conventional synchronous machines. The analysis reveals that in terms of the local damping ratio, optimal charging and local capacity is best considered during SmartPark design. According to a Phillips-Heffron model developed for a multi-machine system with SmartPark, active and reactive power stabiliser can be incorporated into the SmartPark control loops to improve the damping of the system. Finally, this thesis considers the economic operation of micro-grids by proposing a combined EV charging/discharging model which incorporates stochastic uncertainties in vehicle travel patterns and initial battery state of charge (SOC). The model includes provision of energy storage and renewable generation infeed is used to establish an economic basis for micro-grid operation based on market revenues.

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Bauknecht, Dirk. "Transforming the Grid : electricity system governance and network integration of distributed generation". Thesis, University of Sussex, 2011. http://sro.sussex.ac.uk/id/eprint/7443/.

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The thesis analyses how the standard model of liberalised electricity markets that was developed to increase the efficiency of electricity supply can deal with new objectives. While the liberalisation literature argues that additional objectives can be incorporated in the market framework through price signals, a large body of literature based on evolutionary economics argues that innovation and systemic transformation require governance mechanisms that complement the price mechanism of the market to overcome the lock-in of the existing system and coordinate innovation processes. The thesis focuses on the integration of distributed generation (DG) into electricity networks. In the standard model the governance of networks is mainly based on incentive regulation by independent regulators. Thus, the main question is how DG can be integrated into this regime and whether and how it needs to evolve. The research question is broken down according to both different governance issues (connection, integration, innovation, transformation) and different governance levels on which they can be addressed. This is analysed from two angles: Firstly, there is a mainly theoretical discussion of network regulation. Various approaches to amending the standard model are discussed. Secondly, this is complemented by country case studies of the UK and Denmark. The conceptual analysis shows how incentive regulation can accommodate the efficient integration of DG as an additional objective. There is also scope for this model to incorporate governance mechanisms that are geared towards infrastructure transformation. The UK case study shows the practical implementation of this approach and corresponding difficulties. As for Denmark – a DG and network transformation pioneer – the standard model plays a marginal role and economic issues are mainly dealt with outside regulation. The same is true for mechanisms beyond economic incentives. The thesis shows the potential of the standard model to pursue new objectives as well as the need to broaden the scope beyond governance based on economic incentives.

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Balachandran, Nandu. "Utilization of Distributed Generation in Power System Peak Hour Load Shedding Reduction". ScholarWorks@UNO, 2016. http://scholarworks.uno.edu/td/2124.

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An approach to utilize Distributed Generation (DG) to minimize the total load shedding by analyzing the power system in Transactive energy framework is proposed. An algorithm to optimize power system in forward and spot markets to maximize an electric utility’s profit by optimizing purchase of power from DG is developed. The proposed algorithm is a multi-objective optimization with the main objective to maximize a utility’s profit by minimizing overall cost of production, load shedding, and purchase of power from distributed generators. This work also proposes a method to price power in forward and spot markets using existing LMP techniques. Transactive accounting has been performed to quantify the consumer payments in both markets. The algorithm is tested in two test systems; a 6-bus system and modified IEEE 14-bus system. The results show that by investing in DG, utility benefits from profit increase, load shedding reduction, and transmission line loading improvement.

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Vijayarengan, Manoaj Srikumar. "Coordinated operations of distributed wind generation in a distribution system using PMUs". Thesis, Kansas State University, 2012. http://hdl.handle.net/2097/15039.

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Master of Science
Department of Electrical and Computer Engineering
Noel N. Schulz
Wind energy is becoming one of the most widely implemented forms of renewable energy worldwide. Traditionally, wind has been considered a non-dispatchable source of energy due to the uncertainty of wind speed and hence the variable availability of wind power. Advances in technology allow the consideration of the impact of distributed wind turbines and farms on distribution systems. It is possible to combine the clean energy attributes of wind with the quickly dispatchable nature of a storage facility in order to provide the maximum amount of locally available power economically to the loads present on the distribution feeder. However, a monitoring and control system needs to be provided that is capable of detecting the changes associated with the distribution feeder load and also the variable generation output from the wind farms. This task can be accomplished using a Phasor Measurement Unit (PMU) which has very high sampling rates and hence can measure very rapid and dynamic changes in power levels associated with distribution feeder load and wind generation. The data which is obtained from these PMUs can be used to calculate the amount of distributed generation and storage that can be dispatched locally at the distribution feeder, thus resulting in a reduction in the peak load levels associated with the distribution feeder as seen by the substation monitoring system. Simulations will work to balance load requirements, wind generation output, and distributed storage providing a stable system utilizing maximum renewable resources. The standard IEEE 37-node distribution test feeder is used in the study. Probabilistic models are implemented for distribution feeder load, and the models are analyzed through simulations. Four different combinations of charging and discharging methods have been investigated. Two analytically different algorithms have been used for wind and battery dispatch, one based on forecasted load information and the other based on historical measurements obtained from PMUs. The strategies being investigated can also be used to implement other important applications such as distribution system state estimation, protection and instability prediction.

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Aljadid, Abdolmonem Ibrahim. "Control and protection analysis for power distribution in a distributed generation system". Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2192.

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Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology.
Distributed Generation systems based on renewable energy sources, such as wind or solar are mostly intermittent sources, due to their dependency on the weather, whereas those based on other primary energy sources are non-intermittent. All of them are specially designed to be integrated into distribution systems, in order to improve the power demand of consumers. In the last few decades of the twentieth century, several different factors have played a key role in increasing interest in systems. Distributed Generation (DG) is gaining more and more attention worldwide as an alternative to large-scale central generating stations. The aim of this research project is to investigate the contribution of distributed generation in fault current level in a power distribution system. The simulation results indicate that DG can have a positive or negative impact, on the fault current level in distribution network systems. The DG location and size affect the fault level. The second aim of this research was to suggest a model-based method for design, and implementation of a protection scheme for power distribution systems, by establish algorithms in a hardware environment. The overcurrent relay was chosen for the model development because it is considered a simple and popular protection scheme, and it is a common scheme in relaying applications. The proposed relay model was tested for fault conditions applied on a simple power system in different scenarios. The overcurrent relay model was implemented in MATLAB/Simulink, by using MATLAB programming languages and the SimPowerSystem (SPS) Tool. MATLAB/SIMULINK software is applicable to the modelling of generation, transmission, distribution and industrial grids, and the analysis of the interactions of these grids. This software provides a library of standard electrical components or models such as transformers, machines, and transmission lines. Therefore, the modelling and simulations are executed using MATLAB/Simulink version 2014b

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Yang, Yumeng. "MIMO radio-over-fibre distributed antenna system for next generation wireless communication". Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/270865.

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This thesis introduces low-cost implementations for the next generation distributed antenna system (DAS) using analogue radio over fibre. A multiple-input-multiple-output (MIMO) enabled radio over fibre (RoF) system using double sideband (DSB) frequency translation system is proposed. In such a system, the 2x2 MIMO signals can be transmitted to the remote antenna units (RAUs) from the base station via a single optical link. By using the DSB frequency translation, the original single-input-single-output (SISO) DAS can be upgraded into the MIMO DAS without implementing parallel optical links. Experimentally, the DSB frequency translation 2x2 MIMO RoF system transmits 2x2 LTE MIMO signals with 20MHz bandwidth in each channel via a 300m MMF link. The condition number of the system is < 10dB within the power equaliser bandwidth which means the MIMO system is well-conditioned and the crosstalk between the channels can be compensated by the MIMO signal processing. To install the DSB frequency translation system in a wideband service-agnostic DAS, the original MIMO signals need to be translated into unoccupied frequency bands over the DAS, which are usually occupied by specific applications that are not to be transmitted over the DAS. The frequency spectrum allocation of the wireless services is analysed showing that by choosing a particular LO frequency (2.2GHz in the UK), in the DSB frequency translation system, the original MIMO signals can always be translated into unoccupied frequency bands so that the same infrastructure can support multiple services. The idea of DSB frequency translation system can not only support MIMO radio over fibre but can also improve the SFDR of a general radio over fibre system. Because when the upper sideband and the lower sideband of the signal after translation are converted back to the original frequency band, the noise adds incoherently but the signals add-up coherently, this gives the system theoretically 2dB 3rd order SFDR improvement. If the idea of the DSB frequency translation is extended into a higher number of sidebands, the system SFDR can be further improved. Experimentally, the system 3rd order SFDR can be improved beyond the intrinsic optical link by 2.7dB by using quadruple sideband (QSB) frequency translation. It means the optical bandwidth in a general RoF system can be traded for the electrical SFDR. By integrating the analogue and the digital RoF systems, a hybrid DAS has been demonstrated, showing that the EVM dynamic range for the 4G LTE service (using digital RoF link) can be improved to be similar to the 3G UMTS service (using analogue RoF link), so that fewer number of RAUs for the LTE services are needed.

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30

Azad, Vikas. "Modeling a distributed energy system for California electricity production through 2050". Scholarly Commons, 2012. https://scholarlycommons.pacific.edu/uop_etds/837.

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Recent research shows that combining distributed generation (DG) with renewable resources will reduce fossil fuel dependency and carbon dioxide (C02) emissions. This thesis presents a framework to evaluate the benefits of DG in terms of C02 emission and transmission line losses with respect to the use of centralized power production through 2050. Due to availability of complete data, Sacramento Municipal Utility District (SMUD) in California is the main focus of this thesis; however other utility companies such as PG&E, SDG&E and SCE are also discussed. The test results based on SMUD show a decrease of about 11% to 4% in line losses when a 500 MW DG is placed at the consumption site. This thesis also shows that by adding a 40 MW DG at the central location, C02 can be reduced by 71% when compared to current standard business practices. By adding 40 MW DG every year near consumers, SMUD can eliminate inhouse electricity generation thus completely eliminating C02 emissions by 2034.

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31

Knazkins, Valerijs. "Stability of power systems with large amounts of distributed generation". Doctoral thesis, KTH, Electrical Systems, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-46.

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This four-part dissertation is essentially concerned with some theoretical aspects of the stability studies of power systems with large penetration levels of distributed generation. In particular, in Parts I and II the main emphasis is placed upon the transient rotor angle and voltage stability. The remaining two parts are devoted to some system-theoretic and practical aspects of identification and modeling of aggregate power system loads, design of auxiliary robust control, and a general qualitative discussion on the impact that distributed generation has on the power systems.

One of the central themes of this dissertation is the development of analytical tools for studying the dynamic properties of power systems with asynchronous generators. It appears that the use of traditional tools for nonlinear system analysis is problematic, which diverted the focus of this thesis to new analytical tools such as, for example, the Extended Invariance Principle. In the framework of the Extended Invariance Principle, new extended Lyapunov functions are developed for the investigation of transient stability of power systems with both synchronous and asynchronous generators. In most voltage stability studies, one of the most common hypotheses is the deterministic nature of the power systems, which might be inadequate in power systems with large fractions of intrinsically intermittent generation, such as, for instance, wind farms. To explicitly account for the presence of intermittent (uncertain) generation and/or stochastic consumption, this thesis presents a new method for voltage stability analysis which makes an extensive use of interval arithmetics.

It is a commonly recognized fact that power system load modeling has a major impact on the dynamic behavior of the power system. To properly represent the loads in system analysis and simulations, adequate load models are needed. In many cases, one of the most reliable ways to obtain such models is to apply a system identification method. This dissertation presents new load identification methodologies which are based on the minimization of a certain prediction error.

In some cases, DG can provide ancillary services by operating in a load following mode. In such a case, it is important to ensure that the distributed generator is able to accurately follow the load variations in the presence of disturbances. To enhance the load following capabilities of a solid oxide fuel plant, this thesis suggests the use of robust control. This dissertation is concluded by a general discussion on the possible impacts that large amounts of DG might have on the operation, control, and stability of electric power systems.

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32

Hadji, Leila. "A Unified Load Generator for Geographically Distributed Generation ofNetwork Traffic". Thesis, Högskolan Dalarna, Datateknik, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:du-2375.

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During the last decade, the Internet usage has been growing at an enormous rate which has beenaccompanied by the developments of network applications (e.g., video conference, audio/videostreaming, E-learning, E-Commerce and real-time applications) and allows several types ofinformation including data, voice, picture and media streaming. While end-users are demandingvery high quality of service (QoS) from their service providers, network undergoes a complex trafficwhich leads the transmission bottlenecks. Considerable effort has been made to study thecharacteristics and the behavior of the Internet. Simulation modeling of computer networkcongestion is a profitable and effective technique which fulfills the requirements to evaluate theperformance and QoS of networks. To simulate a single congested link, simulation is run with asingle load generator while for a larger simulation with complex traffic, where the nodes are spreadacross different geographical locations generating distributed artificial loads is indispensable. Onesolution is to elaborate a load generation system based on master/slave architecture.

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33

Yasin, Aysar Mahmoud Masoud. "Distributed Generation Systems Based on Hybrid Wind/Photovoltaic/Fuel Cell Structures". Doctoral thesis, Università di Catania, 2012. http://hdl.handle.net/10761/995.

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The distributed generation (DG) today attracts a large interest due to an even increasing demand of energy and the growth of awareness about the impact of conventional energy sources on the environment. Photovoltaic (PV) and wind power are two of the most promising renewable energy technologies. Fuel cell (FC) systems also show enormous potential in future DG applications, due to a fast technology development, high efficiency, environment friendliness and modularity. Hybrid systems encompassing wind, photovoltaic and FC generators are today revised as a viable solution to overcome the inner unreliability of renewable energy sources. The modelling and control of a hybrid wind/PV/FC DG system is addressed in this dissertation. Dynamic models for the main system components, namely: wind and PV energy generators, fuel cell, electrolyser, power electronic interfaces, battery, hydrogen storage tank, gas compressor, are developed and verified by experimental tests and simulation studies. Five different architectures of stand-alone hybrid power systems are considered, exploiting connections through DC and AC buses. Each configuration is managed through a specific control methodology. Based on suitable dynamic models, the five proposed stand-alone hybrid energy system configurations have been simulated using the MATLAB/Simulink/SimPowSysTM software environment. A comparison among those configurations has been performed on the basis of purposely developed performance indexes. According to obtained results the high voltage DC bus (HVDC) configuration reaches the best score among the five configurations. A Fuzzy logic based management of a stand-alone hybrid generator based on high voltage DC bus configuration has been developed to dynamically optimize the power flows among the different energy sources. The performances of the proposed strategy are evaluated by simulation in different operating conditions. The results confirm the effectiveness of the proposed strategy. A further goal of the thesis has been the development of a probabilistic approach to size step-up transformers for grid-connected wind farms. This approach is mainly based on the evaluation of the Loss of Produced Power Probability index (LPPP); the costs of the wind farm equipments are also taken into consideration.

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34

Mao, Yiming Mui Karen. "Protection system design for power distribution systems in the presence of distributed generation /". Philadelphia, Pa. : Drexel University, 2005. http://dspace.library.drexel.edu/handle/1860/501.

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35

Kurt, Burcak. "Impact Of High-level Distributed Generation Penetration On The Transmission System Transient Stability". Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12611199/index.pdf.

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This thesis investigates the impact of high-level penetration of distributed generation especially from the renewable energy sources on the transient stability of the transmission system. Distributed generation is a source of electric power connected to the distribution network or on the consumer side. It is expected that distributed generation grows significantly by the increasing environmental concerns and deregulation in the market. As soon as the increasing penetration level, distributed generation starts to influence the distribution system as well as the transmission system. To investigate the impact of distributed generation with different penetration levels on the transmission system transient stability, simulation scenarios are created and simulations are run on the basis of these scenarios by the implementation of the different distributed generation technologies to the &ldquo
New England&rdquo
test system. Stability indicators are observed to assess the impact on the transient stability. Results are presented throughout the thesis and the impact of the different distributed generation technologies and the different penetration levels on the transient stability is discussed by comparing the stability indicators.

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36

Alrayes, Ali Said. "Transmission system overvoltage mitigation through the use of distributed generation (DG) smart inverters". Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/126993.

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Thesis: M.B.A., Massachusetts Institute of Technology, Sloan School of Management, in conjunction with the Leaders for Manufacturing Program at MIT, May, 2020
Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, in conjunction with the Leaders for Manufacturing Program at MIT, 2020
Cataloged from the official PDF of thesis.
Includes bibliographical references (pages 63-65).
The objective of this project is to demonstrate the technical ability and cost-effectiveness of reducing electric transmission system overvoltage violations using distributed generation (DG) smart inverters connected to the electric distribution system. Overvoltage violations are situations when the system exhibits voltage levels outside of the acceptable range set by the American National Standards Institute (ANSI) of 105% of nominal system voltage. The challenge that Atlantic Electric could potentially face from the rapid deployment of DG across its distribution system - driven by new additional renewable energy incentive programs in the US State in which it operates - is the underloading of its high voltage (69kV and 115kV) transmission lines causing overvoltage violations at the ends of the transmission lines. The traditional response to this challenge is to install system upgrades on the transmission system in the form of shunt reactors.
However, these system upgrades are expensive and time-consuming to install, which could de-incentivize and delay the deployment of DG projects. The solution we propose is to utilize the reactive power absorption capability of the DG inverters to absorb excessive reactive power from the transmission system. In this work, we investigate feeders' maximum capability of reactive power absorption through distributed generation (DG) smart inverters by modeling two "representative" Atlantic Electric distribution feeders under different PV deployment scenarios based on the feeders' load and generation levels, among other factors. We then perform a cost-benefit analysis to compare against installing shunt reactors. Our findings show that implementing an inverter-based solution has a range of significant cost-savings of up to $300,000/year when compared with installing shunt reactors on the transmission system.
This arrangement, however, is one that hinges on the utility's ability to review regulatory and commercial with all stakeholders involved.
by Ali Said Alrayes.
M.B.A.
S.M.
M.B.A. Massachusetts Institute of Technology, Sloan School of Management
S.M. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science

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37

Montero, Carrero Marina. "Decoupling heat and electricity production from micro gas turbines: numerical, experimental and economic analysis of the micro humid air turbine cycle". Doctoral thesis, Universite Libre de Bruxelles, 2018. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/271492.

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We all take for granted that if we press the switch, the lights turn on; that to charge our phone we just need to plug-in the charger and that food is always safely stored in our fridge. but what would happen in the event of a blackout? are we really conscious of how much we rely on electricity? could we survive without it, even for a few days?The current electricity network is strongly centralised, with electricity generated in large power plants and distributed through transmission networks to the final consumers. With increasing energy demand and renewable energies entering the scene, centralised systems have proven to be very stiff: lacking the flexibility to adapt to sudden demand fluctuations and being unable to deal with strong peaks, with the consequent risk of blackouts.Small, decentralised energy systems can be placed closed to the consumers, avoiding distribution losses and adding flexibility to the network. In particular, small cogeneration units can simultaneously generate heat and electricity; thus, also fulfilling our heating requirements and increasing energy efficiency. However, when there is no or little heat demand (e.g. during the summer), the heat produced by the cogeneration engines cannot be utilised and they need to be shut down. This is the reason why small-scale cogeneration cycles are rarely seen and have not been widely adopted yet.This PhD focuses on the injection of water in a specific small-scale cogeneration technology, the micro gas turbine (mGT) cycle. Thanks to water injection, the production of heat and electricity is decoupled; therefore, the operation of the units is not anymore dependant on the heating demand and they can be used any time during the year. The objective of this thesis is to analyse the numerical, experimental and economic aspects of the so-known micro Humid Air Turbine cycle. The aim is to bring mGTs closer to the market so as to contribute to a more secure, future energy network, where blackouts are avoided at all times.
Doctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished

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38

Golsorkhi, Esfahani Mohammad Sadegh. "Coordinated Control of Distributed Energy Resources in Islanded Microgrids". Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/15829.

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As the penetration of the distributed energy resources (DERs) in the power grid increases,new challenges are revealed, including: stability issues, frequency fluctuations, voltage control, protection system coordination, etc. A systematic approach for dealing with those issues is to view the DERs and associated loads as a subsystem or a microgrid (MG). MGs can operate either in the grid connected or islanded modes. As opposed to the grid connected mode, the voltage and frequency regulation and load/generation balancing during islanded mode is solely dependent on the local generation units. Therefore, stable and reliable operation of islanded MGs requires a real time coordinated control scheme. Conventionally, such coordination is achieved by means of the active power-frequency and reactive powervoltage droop control schemes. The conventional droop method, which is based on P-f droop concept in power systems, lacks compatibility with the resistive nature of networks as well as the low inertia of electronically interfaced DER units in MGs. As a result, it features a slow dynamic response but also a low power quality due to frequency and voltage fluctuations. This PhD research proposes a novel droop concept based on the global positioning system (GPS) and voltage-current (V-I) droop characteristics for coordination of inverter-based DER units in islanded MGs. The concept of V-I droop control is introduced in Chapter 2. In this control approach, each DER is equipped with a GPS receiver, which produces a pulse at frequency of 1Hz (1PPS). Since all GPS receivers are locked to atomic clocks of the GPS satellites, the 1PPS signal can be utilized to synchronize the time reference of the DER units. Using the common time reference and fixing the frequency at the nominal value, all of the units can share a common synchronous rotating reference frame (SRRF). Furthermore, proportional load sharing is achieved by drooping the d and q axis components of the reference voltage with respect to the d and q axis components of current, respectively. The proposed scheme not only circumvents the issue of frequency fluctuations but also is in accordance with the fast dynamics of inverter-based DER units and resistive nature of the networks in islanded MGs. The V-I droop scheme, in its basic form, relies on availability of GPS signals at each of the DER units. With the intention of improving the MG robustness with respect to GPS signal failure, a new control strategy based on V-I droop concept is presented Chapter 3. In this method, an adaptive reactive power-frequency droop scheme is used as a backup for the V-I droop controller to ensure synchronization in case of a GPS signal failure. Droop control schemes in general, and the proposed V-I droop strategy in particular are characterized by non-ideal sharing of current among the DER units due to the variations of voltage along the MGs. In order to improve the sharing accuracy of the V-I droop scheme iv while regulating the average voltage at the nominal value, a new distributed secondary control method based on consensus protocol is proposed in Chapter 4. In this method, the daxis droop characteristics is altered so as to regulate the average microgrid voltage to the rated value but also guarantee proper sharing of active power among the DERs. Additionally, the q-axis component of voltage is adjusted to perform proper sharing of current. Generally, DERs might be supplied from different energy sources, including renewables and storage systems. The intermittency of renewable energy resources on one hand and the limited capacity of the energy storage systems on the other hand, necessitate modification of droop characteristics based on an energy management plan. In Chapter 5, a novel distributed secondary control strategy is introduced for power management of integrated photovoltaicbattery DER units in islanded MGs. The distributed secondary controllers are coordinated based on a leader-follower framework, where the leader restores the MG voltage to the rated value and the followers pursue energy management. Unbalanced and nonlinear loads, which are quite common in MGs, adversely affect the power quality and sharing accuracy. In order to mitigate those issues, two new solutions are proposed in this thesis. In the first approach (Chapter 6), a new supplementary droop control scheme is added to the V-I droop controller to reduce the voltage unbalance while preventing current and power overload under unbalanced loading conditions. In the second approach (Chapter 7), a hierarchical control scheme, consisting of primary (modified V-I droop) and distributed secondary control levels is introduced to mitigate harmonic distortions and prevent overcurrent stresses under nonlinear and unbalanced loading conditions. Finally, the conclusions and possible future work are addressed in Chapter 8.

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39

Piña, Alexander L. "Applying epoch-era analysis for homeowner selection of distributed generation power systems". Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/90721.

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Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, Engineering Systems Division, System Design and Management Program, 2014.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 161-164).
The current shift from centralized energy generation to a more distributed model has opened a number of choices for homeowners to provide their own power. While there are a number of systems to purchase, there are no tools to help the homeowner determine which system they should select. The research investigates how an Epoch-Era Analysis formulation can be used to select the appropriate distributed generation system for the homeowner. Ten different distributed generation systems were successfully analyzed and resulted in the average homeowner selecting the solar photovoltaic system. Additionally, the research investigated how using an "average" homeowner compared to an individual homeowner might result in a different distributed generation selection. Two randomly selected homeowners were analyzed and there were noticeable differences with the average homeowner results, including one of the homeowners selecting the geothermal system instead. Suggestions for how the research can be expanded - including individual homeowner parameterization, distributed generation systems inclusion, and epoch/era expansion - are covered at the end.
by Alexander L. Piña.
S.M. in Engineering and Management

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40

Ruini, Fabio. "Distributed control for collective behaviour in micro-unmanned aerial vehicles". Thesis, University of Plymouth, 2013. http://hdl.handle.net/10026.1/1549.

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The work presented herein focuses on the design of distributed autonomous controllers for collective behaviour of Micro-unmanned Aerial Vehicles (MAVs). Two alternative approaches to this topic are introduced: one based upon the Evolutionary Robotics (ER) paradigm, the other one upon flocking principles. Three computer simulators have been developed in order to carry out the required experiments, all of them having their focus on the modelling of fixed-wing aircraft flight dynamics. The employment of fixed-wing aircraft rather than the omni-directional robots typically employed in collective robotics significantly increases the complexity of the challenges that an autonomous controller has to face. This is mostly due to the strict motion constraints associated with fixed-wing platforms, that require a high degree of accuracy by the controller. Concerning the ER approach, the experimental setups elaborated have resulted in controllers that have been evolved in simulation with the following capabilities: (1) navigation across unknown environments, (2) obstacle avoidance, (3) tracking of a moving target, and (4) execution of cooperative and coordinated behaviours based on implicit communication strategies. The design methodology based upon flocking principles has involved tests on computer simulations and subsequent experimentation on real-world robotic platforms. A customised implementation of Reynolds’ flocking algorithm has been developed and successfully validated through flight tests performed with the swinglet MAV. It has been notably demonstrated how the Evolutionary Robotics approach could be successfully extended to the domain of fixed-wing aerial robotics, which has never received a great deal of attention in the past. The investigations performed have also shown that complex and real physics-based computer simulators are not a compulsory requirement when approaching the domain of aerial robotics, as long as proper autopilot systems (taking care of the ”reality gap” issue) are used on the real robots.

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41

Puranik, Sachin V. "Control of Fuel Cell Based Green Energy Systems for Distributed Generation Applications". The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1253476960.

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42

Sabir, Omar O. "Distributed power generation and energy storage : potential effects of extending tax incentives". Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122430.

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Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, System Design and Management Program, 2019
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 66-69).
Solar PV penetration has been increasing rapidly in the U.S. in recent years. This growth can be attributed to multiple factors; one of which is financial incentives in the form of tax credit programs. One of the most effective tax credit programs in the U.S. is a federal tax program known as the Investment Tax Credit (ITC). The ITC program has been extended in recent years, and is currently set to expire in the early 2020s. This work conducts scenario analysis to evaluate the effects extending the ITC will have on the Levelized Cost of Energy (LCOE) as opposed to allowing it to expire as it is currently set to. Particular attention is paid to the effects on LCOE as this helps evaluate whether solar PV will stay economically competitive compared to other sources of electricity and thus provides some guidance on the role of the ITC in accelerating the adoption of solar PV.
by Omar O. Sabir.
S.M. in Engineering and Management
S.M.inEngineeringandManagement Massachusetts Institute of Technology, System Design and Management Program

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43

Du, Rand Carel Petrus. "Optimising the power quality control of a distributed generation power system / C.P. du Rand". Thesis, North-West University, 2004. http://hdl.handle.net/10394/468.

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Nguyen, Ngo Minh Thang. "Test case generation for Symbolic Distributed System Models : Application to Trickle based IoT Protocol". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLC092.

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Les systèmes distribués sont composés de nombreux sous-systèmes distants les uns des autres. Afin de réaliser une même tâche, les sous-systèmes communiquent à la fois avec l’environnement par des messages externes et avec d’autres sous-systèmes par des messages internes, via un réseau de communication. En pratique, les systèmes distribués mettent en jeu plusieurs types d’erreurs, propres aux sous-systèmes les constituant, ou en lien avec les communications internes. Afin de s’assurer de leur bon fonctionnement, savoir tester de tels systèmes est essentiel. Cependant, il est très compliqué de les tester car sans horloge globale, les sous-systèmes ne peuvent pas facilement synchroniser leurs envois de messages, ce qui explique l’existence des situations non déterministes. Le test à base de modèles (MBT) est une approche qui consiste à vérifier si le comportement d’un système sous test (SUT) est conforme à son modèle, qui spécifie les comportements souhaités. MBT comprend deux étapes principales: la génération de cas de test et le calcul de verdict. Dans cette thèse, nous nous intéressons à la génération de cas de test dans les systèmes distribués. Nous utilisons les systèmes de transition symbolique temporisé à entrées et sorties (TIOSTS) et les analysons à l’aide des techniques d’exécution symbolique pour obtenir les comportements symboliques du système distribué. Dans notre approche, l’architecture de test permet d’observer au niveau de chaque soussystème à la fois les messages externes émis vers l’environnement et les messages internes reçus et envoyés. Notre framework de test comprend plusieurs étapes: sélectionner un objectif de test global, défini comme un comportement particulier exhibé par exécution symbolique, projeter l’objectif de test global sur chaque sous-système pour obtenir des objectifs de test locaux, dériver des cas de test unitaires pour chacun des sous-systèmes. L’exécution du test consiste à exécuter des cas de test locaux sur les sous-systèmes paramétrés par les objectifs de tests en calculant à la volée les données de test à soumettre au sous-système en fonction de données observées. Enfin, nous mettons en œuvre notre approche sur un cas d’étude décrivant un protocole utilisé dans le contexte de l’IoT
Distributed systems are composed of many distant subsystems. In order to achieve a common task, subsystems communicate both with the local environment by external messages and with other subsystems by internal messages through a communication network. In practice, distributed systems are likely to reveal many kinds of errors, so that we need to test them before reaching a certain level of confidence in them. However, testing distributed systems is complicated due to their intrinsic characteristics. Without global clocks, subsystems cannot synchronize messages, leading to non-deterministic situations.Model-Based Testing (MBT) aims at checking whether the behavior of a system under test (SUT) is consistent with its model, specifying expected behaviors. MBT is useful for two main steps: test case generation and verdict computation. In this thesis, we are mainly interested in the generation of test cases for distributed systems.To specify the desired behaviors, we use Timed Input Output Symbolic Transition Systems (TIOSTS), provided with symbolic execution techniques to derive behaviors of the distributed system. Moreover, we assume that in addition to external messages, a local test case observes internal messages received and sent by the co-localized subsystem. Our testing framework includes several steps: selecting a global test purpose using symbolic execution on the global system, projecting the global test purpose to obtain a local test purpose per subsystem, deriving unitary test case per subsystem. Then, test execution consists of executing local test cases by submitting data compatible following a local test purpose and computing a test verdict on the fly. Finally, we apply our testing framework to a case study issued from a protocol popular in the context of IoT

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45

Menon, Suraj S. "Supporting Distributed Fault Tolerance In A Real-Time Micro-Kernel". Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/35463.

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Research into modular approaches for constructing power electronics control systems has provided a number of benefits, as well as new opportunities. Control systems composed of an interconnected collection of standardized parts makes distributed processing a realistic possibility. Unfortunately, current strategies to supporting software on such systems have a number of critical drawbacks. Many existing approaches rely on centralized control strategies, fail to support fault tolerance in the face of failures among processing nodes or communications links, and fail to robustly support live addition or removal of nodes from a running network. In this context, failure of a single element means failure of the entire system. This thesis describes research to extend the Dataflow Architecture Real-time Kernel (DARK) to support distributed, fault-tolerant execution of control algorithms for power electronics control systems. An appropriate scheme for fault-tolerant scheduling of processes on distributed processing nodes is described, added to DARK, and evaluated. Literature indicates that fault-tolerant multiprocessor scheduling for hard real-time tasks with task precedence constraints is an NP-hard problem. The new system is based on an off-line fault-tolerant scheduling strategy that generates a static schedule of tasks for each processing unit to follow. This algorithm handles both the task precedence constraints and the constraints imposed by the underlying network protocol(DRPESNET). Modifications to the underlying daisy-chained, packet-switched, time-triggered ring network protocol to support communications fault tolerance and plug-and-play addition or removal of live nodes from an existing control system are also described.
Master of Science

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46

Widén, Joakim. "System Studies and Simulations of Distributed Photovoltaics in Sweden". Doctoral thesis, Uppsala universitet, Fasta tillståndets fysik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-132907.

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Grid-connected photovoltaic (PV) capacity is increasing worldwide, mainly due to extensive subsidy schemes for renewable electricity generation. A majority of newly installed systems are distributed small-scale systems located in distribution grids, often at residential customers. Recent developments suggest that such distributed PV generation (PV-DG) could gain more interest in Sweden in the near future. With prospects of decreasing system prices, an extensive integration does not seem impossible. In this PhD thesis the opportunities for utilisation of on-site PV generation and the consequences of a widespread introduction are studied. The specific aims are to improve modelling of residential electricity demand to provide a basis for simulations, to study load matching and grid interaction of on-site PV and to add to the understanding of power system impacts. Time-use data (TUD) provided a realistic basis for residential load modelling. Both a deterministic and a stochastic approach for generating different types of end-use profiles were developed. The models are capable of realistically reproducing important electric load properties such as diurnal and seasonal variations, short time-scale fluctuations and random load coincidence. The load matching capability of residential on-site PV was found to be low by default but possible to improve to some extent by different measures. Net metering reduces the economic effects of the mismatch and has a decisive impact on the production value and on the system sizes that are reasonable to install for a small-scale producer. Impacts of large-scale PV-DG on low-voltage (LV) grids and on the national power system were studied. Power flow studies showed that voltage rise in LV grids is not a limiting factor for integration of PV-DG. Variability and correlations with large-scale wind power were determined using a scenario for large-scale building-mounted PV. Profound impacts on the power system were found only for the most extreme scenarios.
Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 711

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47

Sun, Jun-Jie, e 孫峻傑. "Operation of Micro-Grid with Distributed Generation and Energy Storage Systems". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/88861106994356429824.

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碩士
義守大學
電機工程學系碩士班
99
To study the feasibility of Kinmen micro-grid with diesel generator power system and wind generation (WG) analysis of normal and emergency operation, Changes of wind speed the effects of wind speed change to the changes and critical clearing time during feeder and the system fault contingency, finally, the improvement by adding battery energy storage (BES) system. In the first part, explore the operating characteristics of WG and micro-grid structure, and simulation by PSS / E. Simulation wind changes and constant speed and system failure analysis of transient stability with models of double-fed inductive generator (DFIG), and compare the impact on the system in parallel with WG. Finally, parallel storage system at the enetwork, and explore the output power on the system voltage and frequency for BES.

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48

Mohamed, Yasser. "New Control Algorithms for the Distributed Generation Interface in Grid-Connected and Micro-grid Systems". Thesis, 2008. http://hdl.handle.net/10012/4112.

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Driven by economic, technical, and environmental reasons, the energy sector is moving into an era where large portions of increases in electrical energy demand will be met through widespread installation of distributed resources or what's known as distributed generation (DG). DG units can operate in parallel to the main grid or in a micro-grid mode. The later is formed by a cluster of DG units connected to a distribution network to maintain the reliability of critical loads, mainly when the grid supply is not available. Distributed resources include variable frequency sources, high frequency sources, and direct energy conversion sources producing dc voltages or currents. The majority of distributed resources are interfaced to the utility grid or to the customer load via dc-ac pulse-width-modulated (PWM) voltage source inverter (VSI) systems. However, these interfaces introduce new issues, such as the absence of the physical inertia, wide-band of dynamics, limited overload capability, susceptibility to parameters variation, and switching harmonics generation. In addition, the uncertain and dynamic nature of the distribution network challenges the stability and control effectiveness of a grid-connected inverter-based DG interface. Generally, difficulties appear in the form of grid impedance and interfacing parameter variations, fast and slow grid-voltage disturbances, grid distortion and unbalance, and interactions between the inverter ac-side filter and the grid. On the other hand, a micro-grid system will be dominated by inverter-based DG units. Unlike conventional power system generators, inverter-based DG units have no physical inertia. This fact makes the micro-grid system potentially susceptible to oscillations resulting from system disturbances. Severe and random disturbances might be initiated in a micro-grid system, due to load changes, the power sharing mechanism of the inverters and other generators, and interactions between the DG interface and the network. Motivated by the aforementioned difficulties, this thesis presents new control algorithms for the DG interface that guarantee stable and high power quality injection under the occurrence of network disturbances and uncertainties, in both the grid-connected and micro-grid systems. The control architecture of the proposed DG interface relies on the following subsystems. First, a newly designed deadbeat current regulation scheme is proposed. The proposed design guarantees high power quality current injection under the presence of different disturbing parameters such as grid voltage distortion, interfacing parameter variation, and inverter system delays. Further, it utilizes the maximum dynamic performance of the inverter in a way that provides a high bandwidth and decoupled control performance for the outer control loops. Different topologies of the ac-side filter are considered for the current control design. Second, a novel adaptive discrete-time grid-voltage sensorless interfacing scheme for DG inverters is proposed. The adaptive interface relies on a new interface-monitoring unit that is developed to facilitate accurate and fast estimation of the interfacing impedance parameters and the grid voltage vector (magnitude and position) at the point of common coupling. The estimated grid voltage is utilized to realize a grid-voltage sensorless interfacing scheme, whereas the interfacing parameters are utilized for the self-tuning control and interface-parameter monitoring. Further, a simple and robust synchronization algorithm and a voltage-sensorless average power control loop are proposed to realize an adaptive voltage-sensorless DG interface. The voltage-sensorless interface positively contributes to the elimination of the residual negative sequence and voltage feed-forward compensation errors, and to the robustness of the power sharing mechanism in paralleled inverter systems, where the power-sharing mechanism is generally based on open-loop controllers. Third, a new voltage control scheme for the DG interface featuring fast load voltage regulation and effective mitigation of fast voltage disturbances is proposed. The proposed voltage control scheme targets the problem of fast and large-signal-based voltage disturbances, which is common in typical distribution feeders. A hybrid voltage controller combining a linear with a variable-structure-control element is proposed for the DG interface. Positive and dual-sequence versions of the proposed voltage controller are developed to address the issue of unbalanced voltage disturbances. The proposed voltage controller successfully embeds a wide band of frequency modes through an equivalent internal model. Subsequently, wide range of balanced and unbalanced voltage perturbations, including capacitor-switching disturbances, can be effectively mitigated. Fourth, to constrain the drift of the low frequency modes in a conventional droop-controlled micro-grid, a new transient-based droop controller with adaptive transient-gains is proposed. The proposed power-sharing controller offers an active damping feature that is designed to preserve the dynamic performance and stability of each inverter unit at different loading conditions. Unlike conventional droop controllers, the proposed droop controller yields two-degree of freedom tunable controller. Subsequently, the dynamic performance of the power-sharing mechanism can be adjusted, without affecting the static droop gain, to damp the oscillatory modes of the power-sharing controller. The overall robust DG interface facilitates a robust micro-grid operation and safe plug-and-play integration of DG units on existing distribution systems; hence increasing the system penetration of DG. The direct result of this development is huge financial saving for utilities by capturing the salient features of deploying DG into existing utility networks. Further, these developments are significant to the industry as they provide the blue print for reliable control algorithms in future DG units, which are expected to operate under challenging system conditions.

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49

Gonçalves, João Pedro Leitão. "Alternativas integradas para sistemas elétricos isolados mais sustentáveis - O caso de Porto Santo". Master's thesis, 2018. http://hdl.handle.net/10316/86753.

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Dissertação de Mestrado Integrado em Engenharia Electrotécnica e de Computadores apresentada à Faculdade de Ciências e Tecnologia
A disseminação da geração distribuída nos sistemas de energia elétrica é aos dias de hoje uma realidade. Este fenómeno está relacionado com a crescente procura de energia elétrica, com o desenvolvimento tecnológico ao longo dos últimos anos da geração dispersa que lhe permite competir com a tradicional geração centraliza e com questões ambientais.A operação de sistemas de energia elétrica com elevada penetração de geração distribuída, especialmente em sistemas de mais reduzida dimensão e com ausência de interligação, é mais complexa devido à maior dificuldade em manter o equilíbrio entre geração e procura. Na busca de soluções para este problema surgiram as micro-redes, definidas como uma tecnologia que agrega todos os seus componentes numa unidade singular controlável o que facilita o equilíbrio entre geração e procura através de uma gestão local otimizada de recursos.O presente trabalho foi elaborado no âmbito da Dissertação de Mestrado Integrado em Engenharia Eletrotécnica e de Computadores, lecionada no Departamento de Engenharia Eletrotécnica e de Computadores da Faculdade de Ciências e Tecnologia da Universidade de Coimbra, no ano letivo 2017/2018, tendo com objetivo de analisar alternativas integradas para sistemas isolados mais sustentáveis. Para tal, foi necessário recorrer a uma ferramenta de simulação computacional, o software computacional Homer Pro. Esta ferramenta permitiu a parametrização do sistema elétrico da ilha do Porto Santo, escolhido por se tratar de um sistema insular de pequenas dimensões e sem interligação a outros sistemas. Tal parametrização permitiu avaliar o impacto do reforço da geração renovável dispersa num sistema de energia elétrica com tais características. Após a análise dos resultados obtidos verificou-se um aumento muito significativo no excesso de geração de energia, causado pelo desequilíbrio entre a geração e a procura. Como solução do problema foram propostas duas abordagens, a primeira foi a identificação de recursos no lado da procura através da implementação de carga deferível, a segunda abordagem passou pela introdução de armazenamento de energia, tendo sido testadas três tecnologias diferentes. Após a análise dos resultados obtidos, verificou-se uma melhor adequação entre os perfis de geração e de carga, conduzindo a menores valores de excesso de geração. Assim, este trabalho permitiu concluir que uma abordagem baseada em micro-redes pode facilitar a exploração e funcionamento de sistema de energia elétrica, com características idênticas às do sistema do Porto Santo.
Nowadays the dissemination of distributed generation in electric power systems is a reality. This phenomenon is associated with the increasing demand for electric power, with the technological development over the last years of the dispersed generation that allows it to compete with the traditional centralized generation and with environmental issues.The operation of electricity systems with high penetration of distributed generation, especially in systems of smaller size and lack of interconnection, is more complex due to the greater difficulty in maintaining the balance between generation and demand. By searching for solutions to this problem microgrids have emerged, defined as a technology that aggregates all its components into a single controllable unit, which facilitates the balance between generation and demand through optimized local management of resources.The present work was elaborated in the scope of the Dissertation of Integrated Masters Degree in Electrotechnical Engineering and of Computers, taught in the Department of Electrical and Computer Engineering of the Faculty of Sciences and Technology of the University of Coimbra, in the academic year 2017/2018, aiming to analyze integrated alternatives for more sustainable isolated systems. For this, it was necessary to use a computer simulation tool, the computer software Homer Pro. This tool allowed the parameterization of the electrical system of the island of Porto Santo, chosen because it is an insular system of small dimensions and without interconnection to other systems. This parameterization allowed to evaluate the impact of the reinforcement of dispersed renewable generation in an electric power system with such characteristics. After the analysis of the results, it was verified a very significant increase in the excess of power generation, caused by the imbalance between generation and demand. As a solution to the problem, two approaches were proposed, the first was the identification of resources on the demand side through the implementation of chargeable load and the second approach was the introduction of energy storage and three different technologies were tested. After the analysis of the results obtained, a better adaptation between generation and load profiles was verified, leading to lower values of excess generation. Thus, this work allowed to conclude that an approach based on microgrids can facilitate the exploration and operation of an electric power system, with characteristics similar to those of the Porto Santo system.

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50

Salve, Rima. "PV Based Converter with Integrated Battery Charger for DC Micro-Grid Applications". Thesis, 2014. http://hdl.handle.net/1805/6108.

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Indiana University-Purdue University Indianapolis (IUPUI)
This thesis presents a converter topology for photovoltaic panels. This topology minimizes the number of switching devices used, thereby reducing power losses that arise from high frequency switching operations. The control strategy is implemented using a simple micro-controller that implements the proportional plus integral control. All the control loops are closed feedback loops hence minimizing error instantaneously and adjusting efficiently to system variations. The energy management between three components, namely, the photovoltaic panel, a battery and a DC link for a microgrid, is shown distributed over three modes. These modes are dependent on the irradiance from the sunlight. All three modes are simulated. The maximum power point tracking of the system plays a crucial role in this configuration, as it is one of the main challenges tackled by the control system. Various methods of MPPT are discussed, and the Perturb and Observe method is employed and is described in detail. Experimental results are shown for the maximum power point tracking of this system with a scaled down version of the panel's actual capability.

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