Thèses : « Virtual power »

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Newman, Guy. « Characterisation of virtual power plants ». Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/characterisation-of-virtual-power-plants(5e647750-5a44-40f0-8a33-763361d3a50b).html.

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The growing number of micro generation devices in the electrical network is leading many to consider that these devices can no longer be considered as fit and forget, but should instead be considered as having a demonstrable network impact which should be predicted and utilised. One of the techniques for considering the impacts of these devices is the Virtual Power Plant (VPP). The VPP is the aggregation of all the Distributed Generation (DG) connected into the network up to and including the connection voltage of the VPP, such that the cumulative power up the voltage levels can be seen in the single VPP unit, rather than across a broad spread of devices. One of the crucial tasks in characterising the VPP, developed in this work, is the ability to correctly predict and then aggregate the behaviour of several technology types which are weather driven, as a large proportion of DG is weather driven. Of this weather driven DG, some can only typically be dispatched with modification and the rest cannot be dispatched at all. The aggregation of the VPP as part of the electrical network is also developed, as the constraints of the network and the reliability of the network cannot be overlooked when considering the aggregation of the VPP. From a distribution network operator's (DNO) perspective, these characterisation models can be used to highlight problems in the network introduced by the addition of DG, but are also generally utilitarian in their role of predicting the power output (or negative load) found throughout the network due to DG. For a commercial agent interested in selling energy, these models allow for accurate predictions of energy to be determined for the trading period. A VPP agent would also be adversely affected by line failure in the network, leading to the development of an N-1 analysis based upon reliability rates of the network, which is used as the basis for a discussion on the impacts of single line failure and the mitigation available through feedback from the DNO.

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Tai, Sio Un. « Power quality study in Macau and virtual power analyzer ». Thesis, University of Macau, 2012. http://umaclib3.umac.mo/record=b2586277.

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Squillaci, Carmen. « Gestione dell’energia in Virtual Power Plants ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.

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I conﬁni delle risorse di energia distribuita sono in continua espansione negli ultimi anni con conseguenti cambiamenti nella gestione ottimizzata di energia nelle Smart Grid per soddisfare la domanda di energia, apportare miglioramenti alle condizioni ambientali e minimizzare i prezzi. Per raggiungere questo obiettivo si utilizza un Virtual Power Plant con al suo interno un gestore di energia che coordina le unit`a distribuite relative al sistema di energia elettrico. Questo lavoro di tesi sviluppa un modello per la gestione energetica all’interno di un Virtual Power Plant per decidere come e con quali fonti energetiche soddisfare la domanda di energia elettrica. Le decisioni riguardanti le quantita` ed il tipo di risorse energetiche utilizzate ad intervalli orari nell’arco di una giornata avvengono dinamicamente e dipendono da fattori variabili provenienti dalla disponibilit`a delle risorse di energia rinnovabili, dal costo dell’energia elettrica acquistata dalla rete esterna, dal costo del diesel, dai carichi associati ad utenze domestiche e dalla possibilit`a di immagazzinare o rilasciare energia all’interno dell’unit`a di storage. La soluzione `e calcolata mediante l’utilizzo di una funzione costo minimizzata la quale prende in considerazione solo i costi diretti relativi all’impianto VPP. Le conclusioni teoriche e le aspettative sono veriﬁcate mediante una simulazione di uno scenario reale.

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Setiawan, Eko Adhi. « Concept and controllability of virtual power plant ». Kassel : Kassel Univ. Press, 2007. http://www.uni-kassel.de/hrz/db4/extern/dbupress/publik/abstract.php?978-3-89958-309-0.

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Chen, Zhenwei. « Virtual Power Plant Simulation and Control Scheme Design ». Thesis, KTH, Industriella informations- och styrsystem, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-116752.

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Virtual Power Plant (VPP) is a concept that aggregate Distributed Energy Resources (DER) together, aims to overcome the capacity limits of single DER and the intermit-ted natural characteristics of renewable energy sources like wind and solar. The whole system can be viewed as a single large-capacity power plant from the system‘s point of view. In this project, the literature review of VPP concept, architecture, existed project and the survey of VPP in Sweden are being conducted first. Secondly, the simplified VPP model is built on MATLAB/Simulink software. The simplified system contains a wind farm, a hydro power plant, a dynamic system load and an infinite bus representing the large transmission grid. During the simulation process, the generation and consump-tion unites are running according to the real history data located in external database. In the third place, optimized control schemes for the hydro unit in VPP model to decrease its effects on transmission grid are implemented in Simulink model. At the same time, hydro turbine should be controlled in an optimized way that without large turbulence. Basically, the hydro power plant is responsible for balancing the active power between the wind farm and dynamic load. Since there is a limit for the hydro turbine output, the rest of either power shortage or surplus power need to be com-pensated by the grid. This is the fundamental control scheme, so called run time con-trol scheme. The advanced control schemes here are based on the moving average control method and forecast compensation control method. The forecast compensa-tion control method use the 24 hours ahead load forecasting data generated by Artifi-cial Neural Network. Later on, analysis of those three control schemes will be pre-sented. The last part of the project is the conclusion of the different control schemes according to comparison of their control results.

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Khalsa, N. S. « Virtual Cables at the Nevada Test Site ». International Foundation for Telemetering, 1996. http://hdl.handle.net/10150/611425.

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International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California
Shrinking budgets and labor pools have impacted our ability to perform experiments at the Nevada Test Site (NTS) as we did previously. Specifically, we could no longer run heavy cables to remote data acquisition sites, so we replaced the cables with RF links that were transparent to the existing system, as well as being low-cost and easy to deploy. This paper details how we implemented the system using mostly commercial off-the-shelf components.

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Setiawan, Eko Adhi [Verfasser]. « Concept and controllability of virtual power plant / Eko Adhi Setiawan ». Kassel : Kassel Univ. Press, 2007. http://d-nb.info/989833518/34.

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Gillie, Mary. « Operation and regulation of a 'virtual wind/gas' power plant ». Thesis, University of Strathclyde, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405322.

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Dong, Xuzhu. « Study of Power Transformer Abnormalities and IT Applications in Power Systems ». Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/26034.

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With deregulation, diagnosis and maintenance of power equipment, especially power transformers, become increasingly important to keep power systems in reliable operation. This dissertation systematically studied two kinds of transformer failure and abnormality cases, and then developed a new Internet based Virtual Hospital (VH) for power equipment to help power equipment diagnosis and maintenance. A practical case of generator-step-up (GSU) transformer failures in a pumped storage plant was extensively studied. Abnormal electrical phenomena associated with GSU transformers, including switching transients and very fast transients (VFT), and lightning, were analyzed. Simulation showed that circuit breaker restriking could be a major cause of transformer successive failures, and current surge arrester configuration did not provide enough lightning protection to GSU transformers. Mitigation of abnormal electrical phenomena effects on GSU transformers was proposed and discussed. The study can be a complete reference of troubleshooting of other similar transformer failures. Geomagnetically induced current (GIC) is another possible cause of transformer abnormality. A simplified method based on the equivalent magnetizing curve for transformers with different core design was developed and validated to estimate harmonic currents and MVar drawn by power transformers with a given GIC. An effective indicator was proposed using partial harmonic distortion, PHD, to show when the transformer begins saturating with the input GIC. The developed method has been applied to a real time GIC monitoring system last year for a large power network with thousands of transformers. A new Internet based Virtual Hospital (VH) for Power Equipment was conceptually developed to share experience of power equipment diagnosis and maintenance, and update the existing diagnostic techniques and maintenance strategies, and a comprehensive information model was developed for data organization, access, and archiving related to equipment diagnosis and maintenance. An Internet based interactive fault diagnostic tool has been launched for power transformers based on dissolved gas analysis (DGA). The above results and findings can help improving power equipment diagnosis and utility maintenance strategies.
Ph. D.

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Le, Louarn Theobald. « Optimization Of A Virtual Power Plant In The German Electricity Market ». Thesis, KTH, Elkraftteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-217380.

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Distributed energy sources are becoming more and more important in the German electricitynetwork. One solution to manage this growing number of distributed assets liesin the Virtual Power Plant concept. A Virtual Power Plant aggregates decentralizedgenerators and loads to behave like a large power plant. Based on new technologies, ituses advanced communication technologies to provide different services (generation ofenergy, steering of power systems, balancing services ...). This thesis proposes a mixedintegerstochastic model of a Virtual Power Plant. The participation to different productsis being studied: selling power on day-ahead basis on the spot market, providingflexibility to the secondary and tertiary reserve market. The particularity of this modelis to consider the revenue generated by the stochastic activation of the reserve market.An operational tool named AlocaBid is implemented in Python, based on the developedmathematical model. The performance of the model is being evaluated using four studycases, representing typical market situations. The results demonstrate the advantage ofthe proposed model over state-of-the-art method for bids’ allocation.
Distribuerade energik¨allor blir allt viktigare i det tyska eln¨atverket. En l¨osning f¨or atthantera det v¨axande antalet distribuerade tillg°angar ¨ar Virtual Power Plant-konceptet.Ett virtuellt kraftverk styr decentraliserade generatorer och laster f¨or att efterlikna ettnormalt kraftverk. Baserat p°a ny teknik anv¨ander det avancerad kommunikationsteknikf¨or att tillhandah°alla olika tj¨anster (generering av energi, styrning av kraftsystem, balanseringstj¨anster ...). Denna avhandling f¨oresl°ar en stokastisk blanda heltalsmodell avett virtuellt kraftverk. Deltagandet i olika produkter studeras: F¨ors¨aljning av maktp°a daglig basis p°a spotmarknaden, vilket ger flexibilitet till den sekund¨ara och terti¨arareservmarknaden. Det speciella med denna modell ¨ar att den tar h¨ansyn till de int¨aktersom genereras av den stokastiska aktiveringen av reservmarknaden. Ett operationsverktygmed namnet AlocaBid implementeras i Python, baserat p°a den utvecklade matematiskamodellen. Modellens prestanda utv¨arderas med fyra studiefall, som representerartypiska marknadssituationer. Resultaten visar f¨ordelen med den f¨oreslagna modelleframf¨or den senaste tekniken f¨or budgivningens f¨ordelning.

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Recasens, Bosch Joan. « Key Factors for a Successful Utility-scale Virtual Power Plant Implementation ». Thesis, KTH, Energiteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-277846.

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The high penetration of renewable energies (RE) in power systems is increasing the volatile production on the generation side and the presence of distributed energy resources (DER) over the territory. On the other hand, Virtual Power Plants (VPPs) are an aggregation of DER managed as a single entity to promote flexibility services to power systems. Therefore, VPPs are a valid approach to cope with the arising challenges in the power system related to RE penetration. This report defines the concept of a utility-scale VPP, as a tool to stabilize the grid and increase the flexibility capacity in power systems. For this purpose, the report places special emphasis in the use cases that can be developed with a utility-scale VPP. Nevertheless, implementing a utility-scale VPP is a complex procedure, as VPP solutions are highly customizable depending on the scope and the conditions of each project. For this reason, this report analyses the main factors that must be taken into account when implementing a VPP solution. The report concludes that the two most critical factors that define the viability of a VPP project are, first, the energy market design and regulatory framework and second, the technical requirements. These two must always align with the scope of the project and the use cases intended to be developed. Further, other minor factors, including a cost estimate for a VPP solution, are also considered in the report.
Den höga penetrationen av förnybara energier i kraftsystem ökar den flyktiga produktionen på produktionssidan och närvaron av distribuerade energiresurser över territoriet. Å andra sidan är virtuella kraftverk en sammanställning av distribuerade energiresurser som hanteras som en enda enhet för att främja flexibilitetstjänster till kraftsystem. Därför är virtuella kraftverk: er en giltig strategi för att hantera de uppkomna utmaningarna i kraftsystemet relaterat till förnybara energier genomslag. I denna rapport definieras konceptet med en virtuella kraftverk verktygsskala som ett verktyg för att stabilisera nätet och öka flexibilitetskapaciteten i kraftsystem. För detta ändamål lägger rapporten särskild tonvikt på användningsfall som kan utvecklas med en virtuella kraftverk-nytta. Trots det är implementering av en virtuella kraftverknyckelskala en komplex procedur, eftersom virtuella kraftverk-lösningar är mycket anpassningsbara beroende på omfattning och villkor för varje projekt. Av denna anledning analyserar denna rapport de viktigaste faktorerna som måste beaktas vid implementering av en VPP-lösning. Rapporten drar slutsatsen att de två mest kritiska faktorerna som definierar ett virtuella kraftverk projekts livskraft är, dels energimarknadens utformning och regelverk och för det andra de tekniska kraven. Dessa två måste alltid anpassa sig till projektets omfattning och användningsfall som är avsedda att utvecklas. Vidare beaktas även andra mindre faktorer, inklusive en kostnadsuppskattning för en virtuella kraftverk lösning, i rapporten.

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Li, Qiong. « Developing Modeling and Simulation Methodology for Virtual Prototype Power Supply System ». Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/27462.

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This dissertation develops a modeling and simulation methodology for design, verification, and testing (DVT) power supply system using a virtual prototype. The virtual prototype is implemented before the hardware prototyping to detect most of the design errors and circuit deficiencies that occur in the later stage of a standard hardware design verification and testing procedure. The design iterations and product cost are reduced significantly by using this approach. The proposed modeling and simulation methodology consists of four major parts: system partitioning, multi-level modeling of device/function block, hierarchical test sequence, and multi-level simulation. By applying the proposed methodology, the designer can use the virtual prototype effectively by keeping a short simulation CPU time as well as catching most of the design problems. The proposed virtual prototype DVT procedure is demonstrated by simulating a 5 V power supply system with a main power supply, a bias power supply, and other protection, monitoring circuitry. The total CPU time is about 8 hours for 780 tests that include the basic function test, steady stage analysis, small-signal stability analysis, large-signal transient analysis, subsystem interaction test, and system interaction test. By comparing the simulation results with the measurements, it shows that the virtual prototype can represent the important behavior of the power supply system accurately. Since the proposed virtual prototype DVT procedure verifies the circuit design with different types of the tests over different line and load conditions, many circuit problems that are not obvious in the original circuit design can be detected by the simulation. The developed virtual prototype DVT procedure is not only capable of detecting most of the design errors, but also plays an important role in design modifications. This dissertation also demonstrates how to analyze the anomalies of the forward converter with active-clamp reset circuit extensively and facilitate the design and improve the circuit performances by utilizing the virtual prototype. With the help of the virtual prototype, it is the first time that the designer is able to analyze the dynamic behavior of the active-clamp forward converter during large-signal transient and optimize the design correspondingly.
Ph. D.

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ALI, JIBRAN. « Virtual Power Plant Concepts for Ancillary Market - Demonstration, Development, and Validation ». Doctoral thesis, Università degli studi di Genova, 2020. http://hdl.handle.net/11567/1006270.

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The increased penetration of distributed energy resources and renewables open up issues in power systems as a whole. Chapter 1 discusses these issues, and highlights the literature solutions. The concept of VPP is highlighted, different options are explored, and the use of VPP is motivated. The chapter further discusses different ancillary services, with both technical and market perspectives. It makes a clear demarcation amongst transmission and distribution level VPPs, and their economic and technical aspects. Different components within VPP are also highlighted in this chapter. The models of VPP, based on SGAM, are presented in Chapter 2, with detailed test cases. The models characterize VPP as an aggregator at TSO, VPP as DER-Aggregator/DERMS at DSO-DMS, and VPP as business case for flexibility to DSO-DMS. It includes the VPP actors, their characteristics, and a compact architecture based on SGAM. It further splits VPP participants in different software: MATLAB/Simulink, DIgSILENT, and LabVIEW for defined test cases. These are further elaborated in detail in the next chapters, and all are discussed w.r.t regulatory, technical, and economic aspects. Chapter 3 co-simulates VPP-DERMS (Distributed Energy Resource Management System as a Virtual Power Plant) based customers' DR through LabVIEW. It develops interface to customers' meters for reactive power visibility, and then develops a HMI and recording tool at VPP controller. The performance of the tool is analyzed in the chapter, which is in fact the modeling of Modbus based customers' interaction for reactive power. Chapter 4 co-simulates effects of DER on a distribution grid in DIgSILENT. A distribution grid is modelled in DIgSILENT, and then DERs are added to the network. Node voltages and line loading are analyzed in the absence and presence of unplanned DERs. Then the network is seen from two perspectives – flexibility that can be provided to TSO with STATCOM at transmission node, and flexibility that can be provided to DSO with planned DGs at distribution node. Chapter 5 co-simulates storage model in MATLAB/Simulink. It starts with the techno-economic analysis of potential storage systems, and then to realize the storage model for simulation. The model of selected storage system is implemented in MATLAB/Simulink, and then a explicit service test case is developed within VPP-aggregator to analyze the flexibility margin by storage. Next step is the integration of these co-simulators within different service platform levels. The objective of Chapter 6 is to develop an interface amongst co-simulators to simulate the VPP chain. At first step, the co-simulators are realized within tags: wind farm tags are created in DIgSILENT, customers' based tags are built in LabVIEW, and storage tags are located inside MATLAB/Simulink. Then communication amongst the co-interfaces is done by the development of Matrikon OPC server and explorer platform. The master platform is implemented in LabVIEW-RT tool. Then test cases are defined for the validation of platform, which is performed in Chapter 7. Chapter 7 is dedicated to the validation of the formulated VPPs – DERMS, business VPP, and aggregator. DERMS based model is validated within DIgSILENT, by using a portion of the Italian distribution grid. Aggregator based model is validated within DIgSILENT, by using the IEEE 9 bus transmission test model. Business VPP model is validated using IEC 61850 compliant feature of DIgSILENT for the same distribution grid in a translational manner. The validated VPP is used as an application for power system reliability, which is presented in Chapter 8. It describes the conventional schemes for power system protection, and the issues with DER penetration. It then models a VPP, and verifies its functionality for power system protection. Chapter 9 concludes the thesis.

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Möller, Cecilia. « Design and Experiments with High Power Microwave Sources : The Virtual Cathode Oscillator ». Doctoral thesis, KTH, Rymd- och plasmafysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-104794.

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High-Power Microwaves (HPM) can be used to intentionally disturb or destroy electronic equipment at a distance by inducing high voltages and currents.This thesis presents results from simulations and experiments with a narrow band HPM source, the vircator. The high voltages needed to generate HPM puts the vircator under great stress, especially the electrode materials. Several electrode materials have been tested for endurance and their influence on the characteristics of the microwave pulse. With the proper materials the shot-to-shot variations are small and the geometry can be optimized in terms of e.g. output power or frequency content. Experiments with a resonant cavity added to the vircator geometry showed that with proper tuning of the cavity, the frequency content of the microwave radiation is very narrow banded and in this case the highest fields are generated. The vircator can be built in different geometries. Four different vircator types are investigated and the coaxial vircator is found to have advantages as a high radiated power and the possibility to vary the polarization during operation.Since HPM pulses are very short and have high field strengths, special field probes are needed. An HPM pulse may shift in frequency during the pulse and therefore it is very important to be able to compensate for the frequency dependence of the entire measurement system. The development and use of a far-field measurement system is described.

QC 20121122

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Hinz, Mauro. « Virtual power : um modelo de custo baseado no consumo de energia do processador por máquina virtual em nuvens IaaS ». Universidade do Estado de Santa Catarina, 2015. http://tede.udesc.br/handle/handle/2051.

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Made available in DSpace on 2016-12-12T20:22:53Z (GMT). No. of bitstreams: 1 Mauro Hinz.pdf: 2658972 bytes, checksum: 50ee82c291499d5ddc390671e05329d4 (MD5) Previous issue date: 2015-09-29
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The outsourcing of computing services has been through constant evolutions in the past years, due to the increase of demand for computing resources. Accordingly, data centers are the main suppliers of computing service and cloud-based computing services provide a new paradigm for the offer and consumption of these computing resources. A substantial motivator for using cloud computing is its pricing model, which enables to charge the customer only for the resources he used, thus adopting a pay-as-you-use cost model. Among cloud-based computing services, the service type Infrastructure-as-a-Service (IaaS) is the one mostly used by companies that would like to outsource their computing infrastructure. The IaaS service, in most cases, is offered through virtual machines. This paper revisits the cost models used by data centers and analyses the costs of supply of virtual machines based on IaaS. This analysis identifies that electricity represents a considerable portion of this cost and that much of the consumption comes from the use of processors in virtual machines, and that this aspect is not considered in the identified cost models. This paper describes the Virtual Power Model, a cost model based on energy consumption of the processor in cloud-based, virtual machines in IaaS. The model is based on the assumptions of energy consumption vs. processing load, among others, which are proven through experiments in a test environment of a small data center. As a result, the Virtual Power Model proves itself as a fairer pricing model for the consumed resources than the identified models. Finally, a case study is performed to compare the costs charged to a client using the cost model of Amazon for the AWS EC2 service and the same service charged using the Virtual Power Model.
A terceirização dos serviços de computação tem passado por evoluções constantes nos últimos anos em função do contínuo aumento na demanda por recursos computacionais. Neste sentido, os data centers são os principais fornecedores de serviço de computação e os serviços de computação em nuvem proporcionam um novo paradigma na oferta e consumo desses recursos computacionais. Um considerável motivador do uso das nuvens computacionais é o seu modelo de tarifação que possibilita a cobrança do cliente somente dos recursos que ele utilizou, adotando um modelo de custo do tipo pay-as-you-use. Dentre os serviços de computação em nuvem, o serviço do tipo IaaS (Infrastructure-as-a-Service) é um dos mais utilizados por empresas que desejam terceirizar a sua infraestrutura computacional. O serviço de IaaS, na grande maioria dos casos, é ofertado através de instâncias de máquinas virtuais. O presente trabalho revisita os modelos de custos empregados em data centers analisando a formação dos custos no fornecimento de máquina virtuais em nuvens baseadas em IaaS. Com base nesta análise identificasse que a energia elétrica possui uma parcela considerável deste custo e que boa parte deste consumo é proveniente do uso de processadores pelas máquinas virtuais, e que esse aspecto não é considerado nos modelos de custos identificados. Este trabalho descreve o Modelo Virtual Power, um modelo de custo baseado no consumo de energia do processador por máquina virtual em nuvens IaaS. A constituição do modelo está baseada nas premissas de consumo de energia vs. carga de processamento, entre outros, que são comprovados através de experimentação em um ambiente de testes em um data center de pequeno porte. Como resultado o Modelo Virtual Power mostra-se mais justo na precificação dos recursos consumidos do que os modelos identificados. Por fim, é realizado um estudo de caso comparando os custos tarifado a um cliente empregando o modelo de custo da Amazon no serviço AWS EC2 e o mesmo serviço tarifado utilizando o Modelo Virtual Power.

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Sen, Ramen. « A framework for the development of generic virtual reality systems ». Thesis, University of Sheffield, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327650.

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Bäcke, Maria. « Power Games : Rules and Roles in Second Life ». Doctoral thesis, Karlskrona : Blekinge Institute of Technology, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-00496.

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This study investigates how the members of four different role-playing communities on the online platform Second Life perform social as well as dramatic roles within their community. The trajectories of power influencing these roles are my main focus. Theoretically I am relying primarily on performance studies scholar Richard Schechner, sociologist Erving Goffman, and post-structuralists Michel Foucault, Gilles Deleuze and Felìx Guattari. My methodological stance has its origin primarily within literature studies using text analysis as my preferred method, but I also draw on the (cyber)ethnographical works of primarily T.L. Taylor, Celia Pearce, and Mikael Jakobsson. In this dissertation my focus is the relationship of the role-player to their chosen role especially in terms of the boundary between being in character, and as such removed from ”reality,” and the popping out of character, which instead highlights the negotiations of the social, sometimes make-belief, roles. Destabilising and problematising the dichotomy between the notion of the online as virtual and the offline as real, as well as the idea that everything is ”real” regardless of context, my aim is to understand role-play in a digital realm in a new way, in which two modes of performance, dramatic and social, take place in a digital context online — or inworld as many SL residents call it.

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Perera, Aravinda. « Virtual Synchronous Machine-based Power Control in Active Rectifiers for Micro Grids ». Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elkraftteknikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-19202.

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This dissertation presents an analytical study on virtual synchronous machine-based power control in active rectifiers for micro grids supported by prototype modelling, simulation results and discussions.Popularity and demand of the distributed energy resources and renewable energy sources are increasing due to their economic and environmental friendliness. Concept of micro grid with an active rectifier (AR) interface has been found to be promising for smart integration of such distributed generation units. Having the presence of a synchronous generator (SG) in a micro grid introduces several advantages in terms of stability and reliability in the power system. This is mainly owed to the inertia, damping and load sharing properties of SG. This in return, gives rise to the question if an AR of a micro grid can imitate the behaviour of a synchronous generator, can the stability and reliability introduced by SG be replicated in a micro grid. A research on the state-of-the-art for uninterruptible power supplies (UPS) has been carried out to identify the implementation and the control strategies of redundancy and parallel operation as UPS has been an established technology over the last decades. The theoretical study on virtual synchronous machine (VSM) concept in the fall, 2011, has been extended in developing a model with classical inner current control and outer voltage control loops based on the synchronous reference frame.The complete active rectifier model has been able to emulate the inertia, damping and load sharing properties of a SG and redundancy and expandability of parallel UPS systems. It must be emphasized that due to the flexibility of the virtual machine parameters and the absence of magnetic saturation and eddy current losses, a much improved performance have been achieved with a VSM compared to a synchronous generator.Simulations have been carried out for single and parallel operation of active rectifiers in island and grid-tied modes with satisfactory stability, damping and power sharing features.Key words – Active rectifier, virtual synchronous machine, micro grid, uninterruptible power supply, load sharing, redundancy, island mode, grid-tied mode, synchronous reference frame

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Fu, Hao. « Market-oriented micro virtual power prosumers operations in distribution system operator framework ». Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7516/.

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As the European Union is on track to meet its 2020 energy targets on raising the share of renewable energy and increasing the efficiency in the energy consumption, considerable attention has been given to the integration of distributed energy resources (DERs) into the restructured distribution system. This thesis proposes market-oriented operations of micro virtual power prosumers (J.lVPPs) in the distribution system operator framework, in which the J.lVPPs evolve from home-oriented energy management systems to price-taking prosumers and to price-making prosumers. Considering the diversity of the DERs installed in the residential sector, a configurable J.l VPP is proposed first to deliver multiple energy services using a fuzzy logic-based generic algorithm. By responding to the retail price dynamics and applying load control, the J.lVPP achieves considerable electricity bill savings, active utilisation of energy storage system and fast return on investment. As the J.lVPPs enter the distribution system market, they are modelled as price-takers in a two-settlement market first and a chance-constrained formulation is proposed to derive the bidding strategies. The obtained strategy demonstrates its ability to bring the J.l VPP maximum profit based on different composition of DERs and to maintain adequate supply capacity to meet the demand considering the volatile renewable generation and load forecast. Given the non-cooperative nature of the actual market, the J.l VPPs are transformed into price-makers and their market behaviours are studied in the context of electricity market equilibrium models. The resulted equilibrium problems with equilibrium constraints (EPEC) are presented and solved using a novel application of coevolutionary approach. Compared with the roles of home-oriented energy management systems and price-taking prosumers, the J.lVPPs as price making prosumers have an improved utilisation rate of the installed DER capacity and a guaranteed profit from participating in the distribution system market.

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Roslan, Nurul Fazlin. « Control strategy of grid connected power converter based on virtual flux approach ». Doctoral thesis, Universitat Politècnica de Catalunya, 2021. http://hdl.handle.net/10803/673388.

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Distributed Generation (DG) provides an alternative to the Centralized Generation (CG) by means of generating electricity near to the end user of power with the employment of small-scale technologies to produce electricity, mainly using Renewable Energy Sources (RES). The prospects of renewable energy integration during the next years are still very optimistic. This PhD dissertation is made to provide an alternative control framework for the grid connected power converter by adopting the virtual flux concept in the control layer. This dissertation can be divided into three main topics. The 1st topic presents the voltage sensorless control system for the grid-connected power converter. The control system presented is done without depending on AC-voltage measurement where the grid synchronization is based on the Virtual Flux (VF) estimation. In this regard, the Frequency Locked Loop (FLL) is used in conjunction with the estimation scheme to make the system fully adaptive to the frequency changes. This voltage sensorless application is useful for reducing cost and complexity of the control hardware. It is also can be utilized in case of limited reliability or availability of voltage measurements at the intended point of synchronization to the grid. Considering that most previous studies are based on the VF estimation for the case of power converter connected to the grid through the L-filter or LC-filter, this dissertation is focused on the power converter connected to the grid through the LCL filter. The Proportional Resonant (PR) current controller is adopted in the inner loop control of the power electronics-based converter to test the performance of such system. Another control method based on VF synchronization that permits to control the active and reactive power delivery in a remote point of the grid is also presented in this dissertation. This is due to the fact that the VF is implemented that the voltage in a remote point of the line can be estimated. As it will be shown in simulations and experiments, the proposed control scheme provides a good tracking and dynamic performance under step changes in the reference power. The fast synchronization and the smooth reference tracking achieved in transient conditions have demonstrated the effectiveness of the Dual Second Order Generalized Integrator controlled as Quadrature Signal Generator (DSOGI-QSG) and also the current controller used in the proposed system. In addition to the power control itself, this study could also benefit the frequency and the voltage regulation methods in distributed generation applications as for instance in microgrid. Considering the fact that the grid connected power converter can be controlled as a virtual synchronous generator where the flux is a variable to be used for controlling its operation, this dissertation also presents a Virtual Synchronous Flux Controller (VSFC) as a new control framework of the grid connected power converter. In this regard, a new control strategy in the inner loop control of the power converter will be proposed. The main components of the outer loop control of VSFC are based on the active and reactive power control. The results presented show that the VSFC works well to control the active and reactive power without considering any synchronization system. The inner loop control is able to work as it is required, and the measurement flux is able to track the reference flux without any significant delays. All the work presented in this dissertation are supported by mathematical and simulation analysis. In order to endorse the conclusions achieved, a complete experimental validations have been conducted before wrapping this dissertation with a conclusion and recommendation for future enhancement of the control strategies that have been presented.
Sistemes d'energia elèctrica

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Ren, Zizheng. « Multi-Period Dynamic Reward Structures For Prosumers Participating In Virtual Power Plants ». Thesis, The University of Sydney, 2022. https://hdl.handle.net/2123/29336.

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At present, conventional fossil fuels such as coal, petroleum and natural gas still remain dominant in electricity generation. Therefore, distributed energy resources (DERs) attract people's attention for being renewable and environmentally friendly and hence promotes the utilisation of DERs in electric power systems. This offers an opportunity to aggregate prosumers into virtual power plants (VPPs) operated as a single dispatchable resource. Yet that raises the question of how to financially reward prosumers for participating in VPPs. Against this backdrop, this thesis explores dynamic export tariffs based on the dual variables of the optimisation problem used for aggregation. In contrast to the existing approaches, we use a multi-period optimisation model to account for inter-temporal coupling introduced by battery storage systems, which can reflect prosumers' energy consumption behaviours and hence, have better performance to reward prosumers for exporting energy surplus back to the grid. The work begins with an introductory chapter, aiming to demonstrate the motivation, outline, and contribution of the research. Then, a literature review follows to demonstrate the necessity of the research. The thesis continues by presenting mathematical formulations for the VPP models and the proposed multi-period dynamic export tariff. Then, we use AMPL-MATLAB platform to simulate a VPP test system under the given operating parameters, aiming to investigate the efficacy of dynamic export tariffs on prosumers' electricity cost-saving participating in those VPPs from both financial and electrical aspects. Furthermore, the sensitivity analysis for the dynamic export tariff is implemented. The results demonstrate that the proposed multi-period dynamic export tariff can effectively reduce the current electricity cost of prosumers participating in VPPs.

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LABELLA, ALESSANDRO GIUSEPPE. « Advanced Primary Controllers for Inverter Based Power Sources : Microgrids and Wind Power Plants ». Doctoral thesis, Università degli studi di Genova, 2020. http://hdl.handle.net/11567/1009797.

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The aim of this doctoral thesis is to present the research activity fulfilled during the Ph.D. studies. The research project of the candidate was focused on two main cores. The first core is centred in the microgrid area; in particular in islanded microgrid modelling and control. Firstly, the model was compared with experimental results collected in some facilities available at University of Genoa. Then traditional controllers for islanded microgrid are analysed and explored, proposing a new stability estimation procedure for droop controlled microgrid. Finally, a new control strategy based on Model Predictive Control (MPC) is proposed in order to collect many functionalities in just one control layer. MPC is widely used in MG environment, but just for power and energy management at tertiary level; instead here it is here proposed with an inedited use. Some experimental validations about this new methodology are obtained during a research period in Serbia and Denmark. The second core is related with synthetic inertia for wind turbine connected to the main grid, i.e. frequency support during under-frequency transients. This aspect is very important today because it represents a way to increase grid stability in low inertia power systems. The importance of this feature is shared by all the most important Transmitter System Operators (TSO) all over the world.

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Simoni, Chiara. « Ottimizzazione offline/online in condizioni di incertezza con applicazione su Virtual Power Plant ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20079/.

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Le centrali elettriche virtuali (Virtual Power Plant) sono sistemi energetici che integrano diversi tipi di fonti rinnovabili e non, carichi e dispositivi di accumulo. Un tipico VPP è un grande impianto industriale con elevati carichi elettrici e termici (parzialmente shiftabili), generatori di energia rinnovabili e depositi elettrici e termici. Il lavoro oggetto di questa tesi implementa un modello di ottimizzazione in due fasi per la generazione di flussi energetici. L'ottimizzazione avviene in due fasi: la prima, offline, consiste in un approccio robusto per la modellazione dell'incertezza basata su scenari, che cerca di minimizzare il valore della funzione obiettivo lungo l'orizzonte temporale considerando diverse tipologie di funzioni obiettivo. La fase seguente, online, è costituita da un algoritmo greedy che utilizza i valori ottimizzati della domanda di carica ottenuti dalla fase offline e genera i valori dei flussi energetici. Tramite un'interfaccia appositamente realizzata è possibile personalizzare l'intero processo di ottimizzazione selezionando i componenti, lo step (offline, online), se e dove applicare l'incertezza, quale funzione obiettivo utilizzare. Tali scelte determinano risoluzioni diverse del modello elaborato in base alle quali il comportamento dei VPP si adatta. Il procedimento complessivo simula la fase decisionale dell’EMS, ovvero il centro decisionale nella gestione del VPP.

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Evans, Paul Leonard. « Fast multidisciplinary analysis and virtual prototyping of multi-chip power module based systems ». Thesis, University of Nottingham, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.555336.

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Virtual prototyping is a relatively new concept in the field of power electronics that intends to allow the integrated electrical, mechanical and thermal design of power electronic systems. Virtual prototyping uses coupled, multidisciplinary simulations to evaluate potential designs and aims to allow a designer to easily arrive at the optimum system design for any given set of performance targets and design space constraints using an iterative design approach. This work explores the current, established simulation options and identities advantages and weaknesses of these approaches and subsequently a set of requirements that must be met for an improved simulation approach suitable for virtual prototyping of power electronic systems. This required approach is determined to be based around coupled simulation of a number of compact, reduced order models and a fundamental weakness in all similar existing approaches is identified: the lack of a suitable method for the systematic extraction of the compact dynamic thermal models. This is then addressed by the proposal of novel method for the automatic extraction of compact thermal models of multi chip power modules from design data that would be readily available in a virtual prototyping design process. This thermal model extraction method is validated through simulation and experimental results and is implemented as a software tool for later use. A software design framework is then developed. centred on the thermal extraction utility, which implements the previously highlighted virtual prototyping approach in the form or a systematic design methodology suitable for the coupled, multidisciplinary simulation and evaluation 01" multi-chip power module based systems. The operation of the methodology is validated using design examples which demonstrate the ability of the thermal extraction utility, and the framework in which it is implemented, for use in virtual prototyping and highlight their potential weaknesses and limitations.

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MUSIO, MAURA. « Management and modelling of battery storage systems in microGrids and virtual power plants ». Doctoral thesis, Università degli Studi di Cagliari, 2016. http://hdl.handle.net/11584/266749.

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In the novel smart grid configuration of power networks, Energy Storage Systems (ESSs) are emerging as one of the most effective and practical solutions to improve the stability, reliability and security of electricity power grids, especially in presence of high penetration of intermittent Renewable Energy Sources (RESs). This PhD dissertation proposes a number of approaches in order to deal with some typical issues of future active power systems, including optimal ESS sizing and modelling problems, power ows management strategies and minimisation of investment and operating costs. In particular, in the first part of the Thesis several algorithms and methodologies for the management of microgrids and Virtual Power Plants, integrating RES generators and battery ESSs, are proposed and analysed for four cases of study, aimed at highlighting the potentialities of integrating ESSs in different smart grid architectures. The management strategies here presented are specifically based on rule-based and optimal management approaches. The promising results obtained in the energy management of power systems have highlighted the importance of reliable component models in the implementation of the control strategies. In fact, the performance of the energy management approach is only as accurate as the data provided by models, batteries being the most challenging element in the presented cases of study. Therefore, in the second part of this Thesis, the issues in modelling battery technologies are addressed, particularly referring to Lithium-Iron Phosphate (LFP) and Sodium-Nickel Chloride (SNB) systems. In the first case, a simplified and unified model of lithium batteries is proposed for the accurate prediction of charging processes evolution in EV applications, based on the experimental tests on a 2.3 Ah LFP battery. Finally, a dynamic electrical modelling is presented for a high temperature Sodium-Nickel Chloride battery. The proposed modelling is developed from an extensive experimental testing and characterisation of a commercial 23.5 kWh SNB, and is validated using a measured current-voltage profile, triggering the whole battery operative range.

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ABDUL, SALAM HUMAIRA. « Power Modeling and Resource Optimization in Virtualized Environments ». Doctoral thesis, Università degli studi di Genova, 2020. http://hdl.handle.net/11567/998108.

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The provisioning of on-demand cloud services has revolutionized the IT industry. This emerging paradigm has drastically increased the growth of data centers (DCs) worldwide. Consequently, this rising number of DCs is contributing to a large amount of world total power consumption. This has directed the attention of researchers and service providers to investigate a power-aware solution for the deployment and management of these systems and networks. However, these solutions could be beneﬁcial only if derived from a precisely estimated power consumption at run-time. Accuracy in power estimation is a challenge in virtualized environments due to the lack of certainty of actual resources consumed by virtualized entities and of their impact on applications’ performance. The heterogeneous cloud, composed of multi-tenancy architecture, has also raised several management challenges for both service providers and their clients. Task scheduling and resource allocation in such a system are considered as an NP-hard problem. The inappropriate allocation of resources causes the under-utilization of servers, hence reducing throughput and energy eﬃciency. In this context, the cloud framework needs an eﬀective management solution to maximize the use of available resources and capacity, and also to reduce the impact of their carbon footprint on the environment with reduced power consumption. This thesis addresses the issues of power measurement and resource utilization in virtualized environments as two primary objectives. At ﬁrst, a survey on prior work of server power modeling and methods in virtualization architectures is carried out. This helps investigate the key challenges that elude the precision of power estimation when dealing with virtualized entities. A diﬀerent systematic approach is then presented to improve the prediction accuracy in these networks, considering the resource abstraction at diﬀerent architectural levels. Resource usage monitoring at the host and guest helps in identifying the diﬀerence in performance between the two. Using virtual Performance Monitoring Counters (vPMCs) at a guest level provides detailed information that helps in improving the prediction accuracy and can be further used for resource optimization, consolidation and load balancing. Later, the research also targets the critical issue of optimal resource utilization in cloud computing. This study seeks a generic, robust but simple approach to deal with resource allocation in cloud computing and networking. The inappropriate scheduling in the cloud causes under- and over- utilization of resources which in turn increases the power consumption and also degrades the system performance. This work ﬁrst addresses some of the major challenges related to task scheduling in heterogeneous systems. After a critical analysis of existing approaches, this thesis presents a rather simple scheduling scheme based on the combination of heuristic solutions. Improved resource utilization with reduced processing time can be achieved using the proposed energy-eﬃcient scheduling algorithm.

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Rakhshani, Elyas. « Analysis and control of multi–area HVDC interconnected power systems by using virtual inertia ». Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/404614.

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Virtual inertia is known as an inevitable part of the modern power systems. Recent trend of research is oriented in different methods of emulating virtual inertia in different part of the systems. This dissertation is focused on modelling, analysing and application of virtual inertia concept in frequency control and Automatic Generation Control (AGC) issue in high level control AC/DC interconnected power systems. Since the virtual inertia is provided by advanced control concepts of power electronic based components, the HVDC links are the main focus of this dissertation for emulating inertia. AGC in a multi-area power system during load and resource variation is known as a very important mechanism that could facilitate various tasks like: frequency restoration, tie-line power control between authority areas and economic dispatch of generation units. The AGC concept is known as higher level control at the transmission level. This higher level control will generate the set-points for all the local components, like generators or power converter stations, which are under control by their local controllers. In this thesis two different methods for emulating virtual inertia are proposed and introduced in AGC modelling and control of AC/DC interconnected power systems. The first method which is one of the common methods for emulating inertia in various filed of applications, is derivative control technique. In this thesis, derivative control technique is used for higher level application of inertia emulation. This method of inertia emulation is developed for two-area AGC system which is connected by parallel AC/DC transmission lines. Based on the proposed technique, the dynamic effect of inertia emulated for frequency and active power control of interconnected systems are evaluated. The effects of frequency measurements delay and Phase Locked Loop (PLL) effects are also considered by introducing a second-order function. Simulations performed by Matlab software demonstrate how virtual inertia emulation can effectively improve the performance of the power system. A detailed eigenvalue and sensitivity analyses have been also performed to support the positive effects of the proposed method. Since the first method is based on derivation for grid frequency, the measurement of frequency is very important and application of different method for frequency measurements like PLL will bring some limitations for this method. Therefore, as an ultimate solution, the second method for virtual inertia emulation is introduced in this thesis. The second method is based on Virtual Synchronous Power (VSP) concept. The concept of VSP to simulate the dynamic effects of inertia emulations by HVDC links for higher level control applications is introduced and reflected in the multi-area AGC model. By using this proposed combination in AGC model, the dynamic performance of the systems shows a significant improvement. The active power loop control on VSP based HVDC link has second-order characteristic which make a simultaneous enabling of damping and inertia emulations into the system. Trajectory sensitivities and eigenvalue analyses are used to analyse the effects of VSP on the system stability. The effectiveness of proposed concept on dynamic improvements is tested through Matlab simulation of multi-area test system. Finally, it became clear that virtual inertia will add additional degree of freedom to the system dynamics which makes a considerable improvement in first overshoot in addition to damping characteristics of HVDC links. Comparing the results of these two different methods of inertia emulation shows that VSP technique has better performance with several advantages for emulating the inertia. In the VSP technique, PLL and frequency estimation are not required. Also considering the fact that simultaneous damping and inertia could be emulated, a powerful method based on VSP for improving the system dynamics during the contingencies is proposed.
El concepto de inercia virtual se está convirtiendo en una parte imprescindible de los sistemas de energía modernos y en la actualidad hay diferentes líneas de investigación orientadas a estudiar diferentes métodos de emulación de inercia virtual en diferentes partes del sistema.Esta tesis doctoral se centra en el modelado, análisis y aplicación del concepto de inercia virtual en el control de frecuencia y en el control automático de generación (AGC), los cuales son elementos clave en el control de alto nivel de los sistemas eléctricos interconectados AC / DC.Dada la evolución tanto en las topologías, como en las prestaciones de control de los convertidores electrónicos de potencia, los enlaces HVDC y el control a alto nivel de los dispositivos implicados para emular inercia constituirán el foco principal de esta tesis doctoral.El AGC es un mecanismo muy útil en un sistema de potencia multi-zona durante, sobre todo cuando hay variaciones en la carga o en la generación, ya que puede facilitar diversas tareas como: la restauración de frecuencia, control de potencia de líneas de enlace entre las áreas y el despacho económico de los sistemas de generación. En este contexto en AGC, dada su condición de control a alto nivel, generará las consignas para todos los elementos locales, tales como generadores o estaciones de conversión de energía, que están bajo el control de sus controladores locales.En esta tesis se proponen dos métodos diferentes para emular inercia virtual, los cuales se introducirán, se modelarán y se aplicarán al control de sistemas de potencia AC / DC interconectados. El primer método, que es uno de los métodos más comunes para la emulación de inercia en otras aplicaciones, es la técnica del control derivativo. En esta tesis, esta técnica se utiliza para llevar a cabo la emulación de inercia a alto nivel. Éste método de emulación de inercia se ha desarrollado para un sistema AGC de dos área que está interconectado mediante líneas de transmisión de CA / CC en paralelo. Sobre la base de la técnica propuesta, el efecto dinámico de la inercia emulada sobre el control de frecuencia y potencia activa será formulado y evaluado. Los efectos del retardo mediciones de frecuencia y los efectos del bucle de sincronización (PLL) también se consideran en el análisis y posterior ensayo. Las simulaciones llevadas a cabo demostrarán cómo la emulación de inercia virtual puede mejorar efectivamente el rendimiento del sistema de potencia.Dado que el primer método se basa en la derivación de la frecuencia de red, la medición de la frecuencia es muy importante y la aplicación de los métodos de medida de la misma, como las PLL, conlleva algunas limitaciones en la aplicación y respuesta del mismo. Por lo tanto, como una solución definitiva, se introduce el segundo método para la emulación de inercia virtual en esta tesis. El segundo método se basa en el concepto de energía síncrona virtual (VSP). El concepto de VSP, el cual permite simular los efectos dinámicos de las emulaciones de inercia por enlaces HVDC, se presentará y aplicará en sistemas de control de alto nivel, aplicándolo finalmente en el modelo AGC multi-zona. Tal y como se demostrará, mediante el uso de esta combinación propuesta en el modelo de AGC, el comportamiento dinámico de los sistemas muestra una mejora significativa. El control de bucle de potencia activa en el enlace HVDC basado en el VSP tiene una característica de segundo orden que genera una respuesta instantánea y permite controlar la amortiguación y la inercia en el sistema. La eficacia de concepto propuesto en las mejoras dinámicas se probará en plataformas de simulación que representarán un sistema multi-zona. Por último, se demostrará que la inercia virtual añade un grado de libertad adicional a la dinámica del sistema, lo cual ayuda a controlar el sobre pico así como el amortiguamiento en los transitorios en los enlaces HVDC.

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Chandrasekaran, Vetrivel. « Virtual Modeling and Optimization of an Organic Rankine Cycle ». The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1408456065.

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Kusic, Dara Kandasamy Nagarajan. « Combined power and performance management of virtualized computing environments using limited lookahead control / ». Philadelphia, Pa. : Drexel University, 2008. http://hdl.handle.net/1860/2999.

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Moreira, Alexandre Candido 1981. « Uso de instrumentação virtual para a analise da qualidade da energia eletrica ». [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259913.

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Orientadores: Sigmar Maurer Deckmann, Fernando Pinhabel Marafão
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e Computação
Made available in DSpace on 2018-08-07T06:01:54Z (GMT). No. of bitstreams: 1 Moreira_AlexandreCandido_M.pdf: 4879981 bytes, checksum: 6aa206d50e7569915efea8d3f32bd2c3 (MD5) Previous issue date: 2006
Resumo: O presente trabalho avalia a possibilidade da aplicação de instrumentação virtual para a análise de problemas da qualidade da energia elétrica (QEE). Aproveitando-se da grande flexibilidade, elevada capacidade de processamento e da facilidade de reconfiguração oferecida por tal tipo de instrumento, são desenvolvidos algoritmos para medição digital e análise de grandezas elétricas. No modo de medição, é feita uma análise comparativa entre os dois principais métodos apresentados na literatura, para o cálculo de potência e fator de potência em sistemas trifásicos com condutor de retorno (neutro). Para comparar esses métodos, foram implementadas sub-rotinas para identificação das componentes fundamentais, de seqüência positiva das tensões e correntes, potências ativa e não-ativa, além de algoritmos para calcular o fator de desequilíbrio da componente fundamental e o nível de distorção harmônica total. No modo de análise, foi implementado um algoritmo que realiza uma varredura nos indicadores de QEE, calculados de minuto em minuto e salvos em arquivos, através do instrumento de medição para uma análise estatística diária (baseada na função de distribuição de amostras).Tal algoritmo permite identificar os principais distúrbios que ocorrem em determinada instalação como também permite avaliar a duração das violações dos limites pré-fixados
Abstract: This work explores the possibility of applying virtual instrumentation to analyze power quality problems. Based on the great flexibility, increased processing capacity and the possibility of reconfiguration, offered by such type of instrumentation, several digital algorithms have been developed for digital measurement and analysis of electrical quantities. In the case of measurement mode, a comparison is made between the two main methods reported in the literature concerning power and power factor calculation in three-phase systems with return conductor (neutral). To compare those methods, sub-routines have been implemented to identify the fundamental components, positive sequence of voltages and currents, active and non-active powers, as well as to calculate the unbalanced factor of the fundamental component and the total harmonic distortion. In the case of analysis mode, an algorithm was implemented that realizes a sweeping of the power quality indices, obtained minute by minute, and automatically stored in files by the instrument, for daily statistical analysis (based on distribution function). Such algorithm helps to identify the main disturbing causes in a specific installation, and permits to evaluate the violation time of the prescribed limits
Mestrado
Energia Eletrica
Mestre em Engenharia Elétrica

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Edwall, Bill. « Virtual Power Plant Optimization Utilizing the FCR-N Market : A revenue maximization modelling study based on building components and a Battery Energy Storage System. Based on values from Sweden's first virtual power plant, Väla ». Thesis, KTH, Skolan för industriell teknik och management (ITM), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-279520.

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Renewable energy resources are projected to claim a larger part of the Swedish power mix in coming years. This could potentially increase frequency fluctuations in the power grid due to the intermittency of renewable power generating resources. These fluctuations can in turn cause issues in the power grid if left unchecked. In order to resolve these issues, countermeasures are employed. One such countermeasure is for private actors to regulate power; in exchange they are financially compensated through reserve markets. The reserve market studied in this thesis is called Frequency Containment Reserve – Normal (FCR-N). Currently hydroelectric power provides almost all regulated power within this market. As the need for power regulation is expected to increase in the coming years, there exists a need to study other technologies capable of power regulation. This thesis focuses on one such technology called, virtual power plants. While virtual power plants are operating in other parts of the world, there were no virtual power plants operating in Sweden. As a result, the nature of an optimized virtual power plant and the economic benefits of optimization had not been previously investigated. To answer such questions, this thesis modelled and optimized the revenue of a virtual power plant. The examined virtual power plant consisted of cooling chillers, lighting, ventilation fans and a battery energy storage system. Where varying their total power demand allowed for them to provide power regulation. With the virtual power plant market in Sweden being in its infancy, this thesis serves as a first look into how an optimized virtual power plant using these components could function. To put the economic results of the optimization into context, a comparative model was constructed. The comparative model was based on a semi-static linear model. This is what the thesis’s industry partner Siemens currently uses. For the simulated scenarios, the optimized model generated at least 85% higher net revenues than the semi-static linear model. The increase in revenue holds potential to increase the uptake of virtual power plants on the Swedish market, thus increasing stability in the power grid and easing the transition to renewable energy.
Då förnyelsebara energiresurser antas omfatta en större roll av den svenska elproduktionen inom kommande år, så kan detta leda till att frekvensfluktueringar i elnätet ökar. Detta sker på grund av att den oregelbundna elproduktionen från förnyelsebara energiresurser inte matchas med konsumtion. Om dessa fluktueringar inte hanteras kan det i sin tur leda till skadliga störningar inom elnätet. För att motverka detta och således stabilisera elnätet används diverse lösningar. Ett sätt att åstadkomma ökad stabilisering i elnätet är att låta privata aktörer kraftreglera. De privata aktörerna som står för kraftregleringen gör detta i utbyte mot ekonomisk kompensation, genom att delta i reservmarknader. Den reservmarknad som studerades inom detta examensarbete kallas Frequency Containment Reserve – Normal (FCR-N). I nuläget står vattenkraft för nästan all reglerad kraft inom den här marknaden. Men då behovet av kraftreglering antas öka inom kommande år så behövs nya teknologier studeras som kan bistå med kraftregleringen. Den studerade teknologin inom detta examensarbete var ett virtuellt kraftverk. Då inga virtuella kraftverk var i bruk i Sverige då denna uppsats skrevs fanns det osäkerheter kring hur man optimalt styr ett virtuellt kraftverk och de ekonomiska fördelarna som detta skulle kunna leda till. Detta examensarbete modellerade och optimerade ett virtuellt kraftverk ur ett vinstperspektiv. Det virtuella kraftverket var uppbyggt utav kylmaskiner, ljus, ventilationsfläktar och ett batterisystem. Deras kraftkonsumtion styrdes på ett sådant sätt som lätt de bidra till kraftreglering på reservmarknaden. För att kunna analysera de ekonomiska resultaten från det optimerade virtuella kraftverket, så byggdes en jämförelsemodell. Denna jämförelsemodell är baserad på en semistatisk linjär modell, vilket är det som examensarbetets industripartner Siemens använder. Den ekonomiska jämförelsens resultat påvisade att inkomsten från den optimerade modellen var minst 85% högre än den semistatiskt linjära modellen, inom de studerade scenarierna. Denna inkomstökning skulle potentiellt kunna öka användningen av virtuella kraftverk på den svenska reservmarknaden vilket i sin tur skulle medföra högre stabilitet på elnätet. Genom att öka stabiliteten på elnätet kan således förnyelsebara energiresurser i sin tur lättare implementeras.

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Alsafran, Ahmed Sulaiman. « Consensus Control for Power Sharing in an Islanded Microgrid Using an Adaptive Virtual Impedance Approach ». University of Dayton / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1607607802396011.

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Arabi, Samaneh. « Virtual vibration testing of body and power unit mounted components (diesel engine EGR coolant rail) ». Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6692/.

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As a part of the sign-off procedure for body and power unit mounted components, random vibration testing is carried out to original equipment manufacturer (OEM) specification which the components must survive without damage. With the current move to minimise design and development costs and time-scales in the development of new vehicles, the use of CAE to validate system design through the use of virtual testing is becoming ever more important. The desire is therefore to develop computer aided analysis/numerical techniques that will replicate the vibration testing of body and power unit mounted components. The research demonstrates the development of numerical analysis to replicate the vibration testing of a Diesel Engine EGR Coolant Rail. A Finite element model of the coolant rail with rubber hoses was developed. The rubber material properties were derived from a series of tests (tensile test, relaxation test and DMA test) and were modelled using visco-hyperelastic constitutive equations. In order to check the validity of the simulation results, a test rig was designed and developed. In this research, the influence of the fluid dynamics on the vibration of a mechanical structure is also presented using the FSI method. A FE analysis was conducted to simulate the vibration behaviour of an EGR coolant rail consisting of a metal tube and rubber tubes at both ends of the metal tube with water inside it. The correlation study suggests a close agreement between the test and simulation results in terms of the prediction of the natural frequencies. This analysis enables design engineers to extract the natural modes and frequencies of vibrating parts with flowing fluid in order to investigate the failure modes and redesign brackets, supports, and fittings for desired strength.

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Behi, Behnaz. « Bidding strategy for a virtual power plant for trading energy in the wholesale electricity market ». Thesis, Behi, Behnaz (2022) Bidding strategy for a virtual power plant for trading energy in the wholesale electricity market. PhD thesis, Murdoch University, 2022. https://researchrepository.murdoch.edu.au/id/eprint/65657/.

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Virtual power plants (VPPs) are an effective way to increase renewable integration. In this PhD research, the concept design and the detailed costs and benefits of implementing a realistic VPP in Western Australia (WA), comprising 67 dwellings, are developed. The VPP is designed to integrate and coordinate an 810kW rooftop solar PV farm, 350kW/700kWh vanadium redox flow batteries (VRFB), heat pump hot water systems (HWSs), and smart appliances through demand management mechanisms. This research develops a robust bidding strategy for the VPP to participate in both load following ancillary service (LFAS) and energy market in the wholesale electricity market in WA considering the uncertainties associated with PV generation and electricity market prices. Using this strategy, the payback period can be improved by 3 years (to a payback period of 6 years) and the internal rate of return (IRR) by 7.5% (to an IRR of 18%) by participating in both markets. The daily average error of the proposed robust method is 2.7% over one year when compared with a robust mathematical method. The computational effort is 0.66 sec for 365 runs for the proposed method compared to 947.10 sec for the robust mathematical method. To engage customers in the demand management schemes by the VPP owner, the gamified approach is adopted to make the exercise enjoyable while not compromising their comfort levels. Seven gamified applications are examined using a developed methodology based on Kim’s model and Fogg’s model, and the most suitable one is determined. The simulation results show that gamification can improve the payback period by 1 to 2 months for the VPP owner. Furthermore, an efficient and fog-based monitoring and control platform is proposed for the VPP to be flexible, scalable, secure, and cost-effective to realise the full capabilities and profitability of the VPP.

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Águila, Grandez Roger del, Romero Liliana Padilla et Cosio Naydith Terrazas. « Plan de marketing para el lanzamiento de una plataforma nutricional de asesoramiento en comida saludable : Power Food ». Master's thesis, Universidad del Pacífico, 2018. http://hdl.handle.net/11354/2260.

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El principal objetivo del presente trabajo de investigación es proponer un plan de marketing para el lanzamiento de una nueva plataforma nutricional llamada Power Food, una aplicación que permitirá conectar rápidamente a los nutricionistas con los interesados en mejorar su salud. Mediante esta herramienta las personas que desean bajar de peso, pero están muy ocupados para ir a un nutricionista, podrán obtener este asesoramiento fácilmente. Los nutricionistas se basarán en los datos de la persona interesada para elaborar un plan nutricional que le permita lograr sus objetivos. Se utilizará gamification1 para mantener motivado al usuario y generar mayor frecuencia de uso. En este sentido, el trabajo de investigación se inicia con el análisis del macro y microentorno, resaltando las oportunidades y amenazas que afectan al proyecto Power Food, así como las fortalezas y debilidades. Como todo plan de marketing, se detallan las estrategias que el equipo de Power Food utilizará para conseguir los objetivos. También se muestran las vistas que tendrán el prototipo de la aplicación y el link a la página web del proyecto. Este proyecto cubre la necesidad de los nutricionistas independientes por atraer nuevos clientes; a su vez, para Power Food, los nutricionistas son un elemento muy importante en el modelo de negocio, por tanto, se han elaborado estrategias y tácticas para captarlos y fidelizarlos. Como menciona Rosario Sheen, en su libro “El employer Brand en el Perú” (2018), las plataformas digitales están transformando el trabajo independiente y han hecho que prolifere un nuevo mercado de trabajo con nuevos modelos de negocio.

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Ireland, Jessica. « "Democracy" in a virtual world| EVE Online's Council of Stellar Management and the power of influence ». Thesis, The University of Wisconsin - Milwaukee, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1538532.

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Interest in virtual worlds has grown within academia and popular culture. Virtual worlds are persistent, technologically-mediated, social spaces. Academic literature focuses on issues such as identity, sociality, economics, and governance. However studies of governance focus on internal or external modes of control; less attention has been paid to institutions of governance that operate within both the virtual and real worlds.

In EVE Online, the Council of Stellar Management (CSM) represents a joint venture between developers and users to shape the direction of EVE's virtual society. As a group of elected representatives, the CSM represents societal interests to the game's developer, Crowd Control Productions (CCP). The CSM structures the relationship between CCP and the player base, and shapes how these institutions manage the development process. At the same time, cultural and political conventions of EVE's players at times work against these structures as CCP and the CSM seek to attend to their own interests.

In this thesis, I examine the intersection of culture, power, and governance, and illustrate the consequences these negotiations of power have for the inhabitants of EVE Online. The historical circumstances that led to the CSM's creation shape its reception among the community. As a model of governance, the CSM was designed as a deliberative democracy to generate community consensus. This feedback is channeled to developers through elected representatives. However, these channels of information hindered discussions necessary for true democracy. I examine how power is generated, leveraged, and mediated by the two cultures in which the CSM is embedded: EVE and Icelandic cultures. I also illustrate the authority and legitimacy of the CSM from the standpoint of its constituents. The CSM is understood within the same cultural frameworks as in-game power structures.

Primary research was carried out during a one-year period in 2012. During this time, I joined SKULL SQUADRON, a large corporation with a neutral diplomatic mission. Snowball sampling was used to find informants. Three main methods were used to interview participants: face-to-face interviews, text-based interviews through EVE's communication channels, and voice interviews conducted over Skype, an internet-based communications program.

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Roberts, Sean. « Dominant-power politics and ‘virtual’ party hegemony : the role of United Russia in the Putin period ». Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/952/.

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This case study examines the role of the political party United Russia in the rise of ‘dominant-power politics’, also termed ‘electoral authoritarianism’, that characterises the Putin period (2000-2008). Comparative literature identifies parties as important independent or explanatory variables in a range of regime outcomes, including the successful consolidation of democracy, but also in the establishment and consolidation of authoritarian rule. The impressive rise of United Russia in the Russian political system from late 2001 onwards, together with its co-occurrence with the growing strength of the Putin regime, suggests that the party was a factor in the outcome of the latter. This research first develops a theoretical framework to understand the role of parties in modern political systems and then applies this framework to explore the Russian case. Although a component of power in the Putin period, this research argues that the origins of United Russia in the ‘party of power’ phenomenon limit its value as an explanatory variable. Rather than a principal power in the emerging post-Yeltsin political order, United Russia is an agent of a powerful civilian executive, which remains beyond the control of any party. In this sense, the rise of United Russia in the Putin period is misleading. United Russia is an example of ‘virtual’ party hegemony; a reflection of the intentions and ability of non-party power-holders to project their power onto party-agents. This research contributes to existing literature on party politics in the post-Soviet space and Russian politics in the Putin period. In comparative terms, this study contributes to existing notions of party dominance and emerging literature on divergent regime trajectories in the post-Cold War period.

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Irigoyen, Tineo Aralar. « A study on the profitability of Virtual Power Plants and their potential for compensation of imbalances ». Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-270724.

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In the current climate crisis, there is an increasing need for the integration of renewableenergy in higher penetration indexes, which is boosting innovation not only in the technology but also in new business models. Virtual Power Plants (VPPs) are an aggregation model for generation that is said to be able to decrease imbalances from renewable generation while improving economic performance. While the regulation in some countries still does not allow this type of activity there are also many others in which aggregation of demand and even VPPs are growing in numbers. This study aims to prove the previous statement and quantify the amount of imbalances that can be offset and the consequent penalties avoided for a VPP located in the north of Portugal composed of a pumped-storage hydro plant and onshore wind generation. In order to do so, two case studies have been compared: a baseline case in which each unit is operated independently and another in which all the units are aggregated under the VPP model. With this aim, a simplified bidding strategy has been simulated for both cases and three different error levels, to finally compare the results through four key performance indicators (KPIs): increase in profit, increase revenues, decrease in imbalance and decrease in penalty cost. The optimization problem was formulated as a mixed-integer linear programming (MILP) problem and it was carried out in two steps: one for the day ahead session and a second for the intraday market. It aims to diversify the generation port- folio of the hydro power plant and divide it among the available products: energy sold in the day ahead market, capacity reserves for the secondary reserves, and energy sold as tertiary reserves. It was decided to follow a deterministic approach, considering in the strategy a tree of scenarios and their associated probabilities. In order to formulate this scenarios historical data was used, due to the high dependence between the market variables. The results show that an average annual 16% decrease in energy deviations could be achieved which implies a 16.3% decrease in the penalty costs. Moreover, it was also found that the combined oper- ation of the assets in the intraday market, together with the penalty reduction, would lead to a 1% increase in profit with a 0.1% decrease in revenues, concluding that a more detailed and data intensive model would be required to analyse the full advantage of the VPP modelwhen operating the assets together also during the day ahead session.
I den nuvarande klimatkrisen finns det ett ökande behov av integration av en högre andel förnybar energi, vilket ökar behovet av innovationer inte bara inom tekniken utan också i nya affärsmodeller. Virtuella kraftverk (Virtual Power Plants VPP) är en aggregeringsmodell för produktion som sägs kunna minska obalansen från förnybar produktion samtidigt somden förbättrar det ekonomiska utfallet. Ä ven om förordningen i vissa länder fortfarande intetillåter denna typ av verksamhet finns det också många andra där aggregering av efterfrågan och till och med VPP växer i antal. Denna studie syftar till att visa på nyttan av VPP och kvantifiera mängden obalanser som kan kompenseras och de orsakade obalans-kostnader som undviks för en VPP som ligger i norra Portugal som består av ett vattenkraftverk med pumplagring och vindkraft på land. För att göra det har två fallstudier jämförts: ett basfall där varje enhet drivs oberoende och en annan där alla enheterna är aggregerade enligt VPPmodellen. Med detta syfte har en förenklad budstrategi simulerats för båda fallen och tre olika nivåer på fel i prognoser för att slutligen kunna jämföra resultaten genom fyra olika indikatorer (KPI:er): vinstökning, ökning av intäkter, minskning av obalans och minskning av obalanskostnader. Optimeringsproblemet formulerades som ett mixed-linear-integer programmeringsproblem (MILP) och det genomfördes i två steg: ett för dagenföremarknaden och ett andra för intradagsmarknaden. Detta syftar till att diversifiera produktionsportföljen för vattenkraftverket och dela den mellan de tillgängliga produkterna: energi som säljs i den kommande marknaden, kapacitetsreserver för sekundära reserver och energi som säljs som tertiära reserver. I studien har vi valt en deterministisk strategi med beaktande av ett scenarioträd med respektive sannolikheter. För att formulera dessa scenarier användes historiska data på grund av den stora korrelationen mellan marknadsvariablerna. Resultaten visar att en genomsnittlig årlig minskning av energiavvikelserna med 16% skulle kunna uppnås vilket innebär en minskning av obalanskostnaderna med 16,3%. Dessutom konstaterades det att den kombinerade driften av tillgångarna på intradagsmarknaden, tillsammans med minskningen av obalanser, skulle leda till en vinstökning på 1% med en minskning av intäkterna på 0,1%, från vilket vi drar slutsatsen att en mer detaljerad och datakrävande modell skulle krävas för att analysera VPP-modellens fulla potential när mananvänder tillgångarna tillsammans även under dagenföremarknaden.

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Ching-Shiu, Tseng. « Low Power Design for Java Virtual Machine ». 2005. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-1507200516020900.

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Lin, Wei-Min, et 林為閔. « Power Efficient Strategy for Deploying Virtual Clusters ». Thesis, 2013. http://ndltd.ncl.edu.tw/handle/vkrt2s.

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碩士
中華大學
資訊工程學系碩士在職專班
101
Virtualization and scalability of resource management has become an important subject in cloud computing. In this study, the relationship between CPU power consumption of virtual machines and the number of virtual machines is analyzed. A power prediction model for optimizing resource allocation in virtualized environments has been also developed. Our study shows that the number of virtual machine running on a physical host is inversely proportional to the CPU power consumption of each virtual machine. In addition, different hardware specifications were tested to verify the correctness of the proposed models. In the preliminary analysis, power consumption of virtual machines under different circumstances, such as physical machine loading as well as quantity of virtual machines, is completely reported. According to these preliminary tests, we proposed an algorithm named PEVCD (Power-Efficient Virtual Cluster Deployment), a power efficient strategy for deploying virtual clusters. PEVCD is proved applicable for enterprise, scientific applications and individual requirements, and presents significant improvement in terms of power consumption, resulting in reduce of the usage of physical resources and energy loss of virtual clusters.

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Tseng, Ching-Shiu, et 曾清旭. « Low Power Design for Java Virtual Machine ». Thesis, 2004. http://ndltd.ncl.edu.tw/handle/73166792270398679279.

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碩士
國立臺灣大學
資訊工程學研究所
93
Memory system is a main concern to embedded system engineers since it dominates the cost, power and performance of mobile embedded systems. In particular, emerging memory technology, the flash memory is becoming an indispensable component in mobile embedded systems due to its versatile features: non-volatility, solid-state reliability, low power consumption. NAND flash has the nature of high density and low cost. With the shadowing technique support, NAND flash will replace NOR flash for the embedded memory system code storage in nearly future. The more advanced solution is NAND+RAM. Neither NOR flash memory nor mask ROM is used in this architecture; it uses NAND flash memory for code storage. Copying the whole software executable binary code into RAM offers the best performance possible at run time. With the advantage of portability, it is more important to implement Java system for embedded devices. The performance is a major drawback of Java system, especially for resource-limited embedded devices. Therefore, if becomes an interesting topic to improve the Java performance for embedded devices. In our thesis, we present three KVM interpreter optimization schemes based on the NAND+RAM memory architecture and the drawback of NAND page sequential access latency. By reducing of page fault ratio from NAND to RAM, the J2ME execution performance and the NAND flash energy consumption will both be decreased.

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Chiung-I, Huang, et 黃瓊儀. « Power--between the virtual and the reality ». Thesis, 2001. http://ndltd.ncl.edu.tw/handle/09350860754911376988.

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碩士
南華大學
教育社會學研究所
89
Power acts everywhere,from the individual to the whole global.When we enter into the cyber space,what kinds of power relationship between virtual and reality will be? In this text,we''ll discuss how the individual gets the power through exchange between virtual and reality. The power elites establish a new class system in the information society.What is the different between the old class system and the new one? When the virtual invades the reality,the autocratic countries will be challeaged.It may be bringing the democracy to the people.The culture hegemony is also the important issue in this discussion. The cyber space is built by the technology,so the technopower is playing a very important role.We''ll discuss this in the text. Anyway,this article is talking about the power between the virtual and the reality.

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Matos, João Miguel Bico Alves. « Commercial Demand Response in Virtual Power Plants ». Master's thesis, 2021. https://hdl.handle.net/10216/133033.

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Global economy growth, continuous development and the extensive use of technologies by consumers is increasing the demands of consumers for a reliable and efficient energy supply. Along with the rising energy consumption in the world, new technologies will influence the way we generate, distribute and consume energy. Alongside others, distributed energy generation is expected to become a major trend in many countries. The fast upward penetration of Distributed Energy Resources (DER) and the ongoing trend towards a more competitive electricity market requires new technologies and policies to handle emerging technical and economic issues. In order to handle distributed generation and to increase its participation within power markets, the idea of a Virtual Power Plant (VPP) has emerged. The concept of a VPP is recognized as an effective option to aggregate and operate DER and allowing for wholesale energy market participation to provide the required flexibility services to the local grid. Also, many DERs are available in urban areas and exploiting the flexibility of a VPP and developing a robust business case requires advanced considerations on their technical and commercial constraints and trade-offs in developing the VPP's operations regarding flexibility when simultaneously participating in the market. Considering the potential of activating commercial consumers in demand response programs, this paper proposes a new framework for energy scheduling of a distribution grid based on the concept of a technical virtual power plant (TVPP). This concept aims to enhance the flexibility of the grid, while contributing to an increase in the quality and reliability of the system, which also brings economic benefits. In this paper, a stochastic mixed-integer linear programming (MILP) optimization model was developed, which guarantees that the global optimum solution is obtained, in this case, maximizing the total profit of a TVPP. Regarding operational constraints, the TVPP allows the presence of commercial buildings and other distributed energy resources a day-ahead (DA) electricity market, as a price maker agent. In this context, this paper presents a comprehensive, integrated techno-economic approach that assesses the technical constraints and commercial flexibility opportunities. The case study includes the VPP's energy scheduling, improving system reliability by improving the voltage profile, and demand response and main commercial customers' assets (electric vehicles (EVs) parking lots and Heating Ventilation and Air Condition (HVAC) systems) aggregation and management. The model is tested using the IEEE 119-Bus test system, and results show that with the optimal management of DER, EVs parking lots and HVAC systems in commercial buildings allows the TVPP to increase its profit, by a percentage of 49,23%.

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Matos, João Miguel Bico Alves. « Commercial Demand Response in Virtual Power Plants ». Dissertação, 2021. https://hdl.handle.net/10216/133033.

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Global economy growth, continuous development and the extensive use of technologies by consumers is increasing the demands of consumers for a reliable and efficient energy supply. Along with the rising energy consumption in the world, new technologies will influence the way we generate, distribute and consume energy. Alongside others, distributed energy generation is expected to become a major trend in many countries. The fast upward penetration of Distributed Energy Resources (DER) and the ongoing trend towards a more competitive electricity market requires new technologies and policies to handle emerging technical and economic issues. In order to handle distributed generation and to increase its participation within power markets, the idea of a Virtual Power Plant (VPP) has emerged. The concept of a VPP is recognized as an effective option to aggregate and operate DER and allowing for wholesale energy market participation to provide the required flexibility services to the local grid. Also, many DERs are available in urban areas and exploiting the flexibility of a VPP and developing a robust business case requires advanced considerations on their technical and commercial constraints and trade-offs in developing the VPP's operations regarding flexibility when simultaneously participating in the market. Considering the potential of activating commercial consumers in demand response programs, this paper proposes a new framework for energy scheduling of a distribution grid based on the concept of a technical virtual power plant (TVPP). This concept aims to enhance the flexibility of the grid, while contributing to an increase in the quality and reliability of the system, which also brings economic benefits. In this paper, a stochastic mixed-integer linear programming (MILP) optimization model was developed, which guarantees that the global optimum solution is obtained, in this case, maximizing the total profit of a TVPP. Regarding operational constraints, the TVPP allows the presence of commercial buildings and other distributed energy resources a day-ahead (DA) electricity market, as a price maker agent. In this context, this paper presents a comprehensive, integrated techno-economic approach that assesses the technical constraints and commercial flexibility opportunities. The case study includes the VPP's energy scheduling, improving system reliability by improving the voltage profile, and demand response and main commercial customers' assets (electric vehicles (EVs) parking lots and Heating Ventilation and Air Condition (HVAC) systems) aggregation and management. The model is tested using the IEEE 119-Bus test system, and results show that with the optimal management of DER, EVs parking lots and HVAC systems in commercial buildings allows the TVPP to increase its profit, by a percentage of 49,23%.

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Lee, Jin-Chang, et 李錦昌. « A PC-Based Virtual Instrument for Power Analyzers ». Thesis, 2001. http://ndltd.ncl.edu.tw/handle/30864318475076647954.

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碩士
義守大學
電機工程學系
89
Three PC-based Virtual Instruments (VI) for power analyzers are developed in the thesis. The proposed VI is based on LabVIEW (Laboratory Virtual Instrument Engineering Workbench) language under the workbench of the MS Windows 95/98 operating system. Instead of theoretical research, some practical sub-VIs, such as the harmonic analyzer, power factor and power measurement, TCP/IP read and TCP/IP write etc., are developed first. By using those developed sub-VIs, three VI including the power analyzer, power quality recorder and internet-based power quality recorder can be designed. The capability of the proposed system can be expanded according to the requirements of users. One of the most attractive facts is that a well-developed VI can be considered as a software IC and used to design a large-scale or complex system. The reuse of the existed sub-VIs makes the development of a new VI easier.

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Chi-Yuan, Chen, et 陳啟元. « Physical Channel and Virtual Channel Power Model Comparison ». Thesis, 2009. http://ndltd.ncl.edu.tw/handle/68996101214061792467.

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碩士
亞洲大學
經營管理學系碩士班
97
In today's society, often have the channel predominant the marketing. Application of science and technology network in the commercial prosperity of increasing competition in the business has changed the structure of the end of the 20th century, from which the electronic commerce (E-commerce) is produced, providing an alternative channel model for selling products. With the development of the E-commerce, enterprises have to face a new business model, and supply chain management (SCM) is the optimal solution to implement and integrate E-commerce and competitive advantage of outsourcing. However, in retailer channel industry, among the upstream and downstream there generally exists unequal channel power, there is no confidence and power imbalances, and the conflicts among channel members impact on the cooperation and growth between both the manufacturers and channel retailers, which also trouble all practitioners in channel industry. This study aimed at the channel power source and the channel power itself in the channel power of Taiwan’s physical channel and virtual channel clothing industry to explore the causal relationship of the degree of satisfaction of the channel members. This study discovered that both the channel power sources and the channel power have positive direct impact on the degree of satisfaction, because the competition is fierce in the channel retailer market of Taiwan’s clothing industry. Therefore the channel distributors and the channel retailers can take and maintain mutually beneficial cooperative model, hoping by such a power model so that the both sides are able to reap greater benefits.

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Lu, Kuei-Wan, et 呂奎宛. « An Integrated Environmental Assessment of Virtual Power Plant ». Thesis, 2010. http://ndltd.ncl.edu.tw/handle/01195249843923802627.

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碩士
臺灣大學
環境工程學研究所
98
Virtual power plant (VPP) is contemplated in this research, which considers electricity supply and electricity final demand, to decrease the environmental impact by changing of the electricity consumption patterns. The electricity consumption varied with electricity final demand is analyzed by the electricity input-output analysis (EIOA), and the environment impact is quantified by life cycle assessment (LCA), including human toxicity (carcinogenic and non-carcinogenic), respiratory, photochemical oxidation, terrestrial ecotoxicity, aquatic ecotoxicity, aquatic acidification, aquatic eutrophication and global warming. According to EIOA in 2008, the electricity consumptions of industries account for 80% total electricity consumption in Taiwan, and the electricity consumptions of industries are provided to household consumption, export, and other demands. Export is the main demand, which accounts for 58% of the industrial electricity consumption. Besides, sensitive industries of electricity consumption in Taiwan are divided by EIOA into 11 industries, including chemical material, textiles mills, pulp paper and paper products, chemical products, plastic products, non-metallic mineral products, iron and steel, fabricated metal products, electronic parts & components, computers electronic & Optic Prod and electrical equipment. Compared with EIOA in 2008, VPP is conducted in electricity strategy by adjusting electricity efficiency and electricity supply structure. On one hand, increasing 30% electricity efficiency in sensitive industries and insensitive industries reduce 16.38% and 13.62% industrial electricity consumption, respectively. On the other hand, electricity supply structure of sensitive industries is modified by using liquid nature gas (LNG) as an alternative fuel for the cogeneration system and installing decentralized generation system (DES). The fomer reduces 9-17% environmental impact in human toxicity (carcinogenic), respiratory, terrestrial ecotoxicity and aquatic acidification; the latter reduces 6-10% environmental impact in human toxicity (non-carcinogenic), aquatic ecotoxicity and aquatic eutrophication; and both reduce 7-9% environmental impact in photochemical oxidation and global warming. In summary, owing to reduction of environmental impact categorically, VPP is revealed enough as the electricity consumption pattern to decrease environmental impact.

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48

Wu, Ming-Zhi, et 吳銘智. « Power Saving of Virtual Machine Assignment Research based on Different Performance of Virtual Machine Distribution ». Thesis, 2013. http://ndltd.ncl.edu.tw/handle/04922861301072052465.

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碩士
淡江大學
電機工程學系碩士班
101
MapReduce is a kind of distributed computing system, and also many people use it nowadays. In this paper, the Green Master based on MapReduce is proposed to solve the problem between load balance and power saving. There are three mechanism proposed by this paper to improve the MapReduce system efficiency. First, a brand new architecture called Green Master is designed in the system. Second, Benchmark Score is added to each service in the cluster. In the last, an algorithm about how to distinguish the high score service and the low score service, and explain how to use them effectively. The algorithm in this paper will be used to improve the system efficiency based on MapReduce of Hadoop. Hadoop is a kind of open source software that develop from Google MapReduce, and it can will create a cluster that connects each services. The cluster is used to make more computing resources called computing pool, and it can be expanded more and more. In the end, we can decide what we want to get or how to execute the program through coding the Map Function and Reduce Function. As usual, in order to make the maximum computing resources, the services must keep the high-speed state, but it also has a lot of unnecessary waste. For example, service performance are not the same, some of them are very high, but some of them are very low. if we allocate the same amount of work to all service, it must cause a part of service will complete the work early, but it still have to wait other service that performance is poor, and the waiting time means resources wastes. We will talk about how to make the service off if the performance is too low that seriously affects the system performance.

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49

Chia, An, et 夏安. « Low Power and Access Delay for Virtual Cache Design ». Thesis, 2010. http://ndltd.ncl.edu.tw/handle/31997155525584143514.

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碩士
逢甲大學
資訊工程所
98
In recent years, the demand of user are increasing, and the application are more and more complex, many embedded device start used operation system and virtual memory to help manage. However, when virtual memory is used, there are two kind of cache architecture: 1) physical cache and 2) virtual cache. For the first, the cache is access by physical address, therefore, cache before the access must be translation the virtual address to physical address, however, the translation is a waste of time and limit the capacity of cache. For the second design, virtual address can access the virtual cache immediate without translation to reduce the time; however, the virtual cache will access the wrong data by the synonym problem. Therefore, how to design the virtual cache architecture can reduce time, no capacity limited and no synonym problem will be focus of our design. In this paper, we will present two virtual cache designs, respectively, for the performance and power. In the experimental simulation, in the performance, taking into consideration the design of the virtual cache, the overall structure of performance improvement of about 31%, and energy considerations in the design, it can save about 27% of energy consumption. We design the virtual cache is more suitable for embedded systems.

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Lin, Sheng-kai, et 林聖開. « Operation Planning of Virtual Power Plant with Demand Response ». Thesis, 2015. http://ndltd.ncl.edu.tw/handle/22681905795746090713.

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碩士
國立中山大學
電機工程學系研究所
103
Owing to the increase of power demand and rising awareness of environmental protection, people start to adopt clean power. Many countries enact codes to promote the development of renewable energy, including photovoltaic, wind turbine and hydro generator. The growing demand has been a heavy burden on the power system. In order to meet the demand, the concept of virtual power plant has been proposed. The concept integrates the operation of supply-side and demand-side assets to meet customer demand for energy services in both the short-term and long-term. In short-term, virtual power plant makes extensive and sophisticated use of information technology, smart meter, automated control capabilities and electricity storage to match load fluctuations. The concept also treats long-term load reduction achieved through energy efficiency investments, distributed generation, and demand response. Using real-time pricing and demand response schemes, customer energy usage can be charged according to tariff structure to move the non-critical demand to off-peak periods, such as washing machines, dehumidifiers and dish driers. Demand response is one of demand side management schemes. Through adequate incentive offers to customers, peak load demand can be reduced at rush hours, and customer bills can be reduced. In this thesis, we build a virtual power plant model and use the concept of demand response and time of use pricing to control the distributed energy resources, such as battery energy storage system, to maximize the profits. A demand response contract is designed and different factors are taken into account in operation scheduling.

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