Dissertations / Theses: 'Active Distribution Networks'

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Cobelo, I. "Active control of distribution networks." Thesis, University of Manchester, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.685442.

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Zhou, Lin. "Active network management and uncertainty analysis in distribution networks." Thesis, University of Bath, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.675697.

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In distribution networks, the traditional way to eliminate network stresses caused by increasing generation and demand is to reinforce the primary network assets. A cheaper alternative is active network management (ANM) which refers to real-time network control to resolve power flow, voltage, fault current and security issues. However, there are two limitations in ANM. First, previous ANM strategies investigated generation side and demand side management separately. The generation side management evaluates the value from ANM in terms of economic generation curtailment. It does not consider the potential benefits from integrating demand side response such as economically shifting flexible load over time. Second, enhancing generation side management with load shifting requires the prediction of network stress whose accuracy will decrease as the lead time increases. The uncertain prediction implies the potential failure of reaching expected operational benefits. However, there is very limited investigation into the trade-offs between operational benefit and its potential risk. In order to tackle the challenges, there are two aspects of research work in this thesis. 1) Enhanced ANM. It proposes the use of electric vehicles (EVs) as responsive demand to complement generation curtailment strategies in relieving network stress. This is achieved by shifting flexible EV charging demand over time to absorb excessive wind generation when they cannot be exported to the supply network. 2) Uncertainty management. It adopts Sharpe Ratio and Risk Adjust Return On Capital concepts from financial risk management to help the enhanced ANM make operational decisions when both operational benefit and its associated risk are considered. Copula theory is applied to further integrate correlations of forecasting errors between nodal power injections (caused by wind and load forecasting) into uncertainty management. The enhanced ANM can further improve network efficiency of the existing distribution networks to accommodate increasing renewable generation. The cost-benefit assessment informs distribution network operators of the trade-off between investment in ANM strategy and in the primary network assets, thus helping them to make cost-effective investment decisions. The uncertainty management allows the impact of risks that arise from network stress prediction on the expected operational benefits to be properly assessed, thus extending the traditional deterministic cost-benefit assessment to cost-benefit-risk assessment. Moreover, it is scalable to other systems in any size with low computational burden, which is the major contribution of this thesis.

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Sansawatt, Thipnatee Punim. "Adaptive control for active distribution networks." Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/6268.

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Rise of the global environmental awareness and climate change impacts caused by greenhouse gases emissions brings about a revolution in the power and energy industries to reduce fossil fuels and promote low-carbon and renewable distributed generation (DG). The new dimensions, mainly encouraged by the governments’ legislative targets and incentives, have allowed the development of DG worldwide. In the U.K., renewable DG especially wind is being connected on distribution networks and ranges widely in scales. Despite the growing number of potential DG sites, the surplus generation present on the passive networks can lead to some technical problems. In particular, rural networks where wind farms exist are prone to voltage rise and line thermal constraints. In order to accommodate new DG and ensure security of supply and network reliability, active management to mitigate these issues are required. In addition, the duties to provide cost-effective DG connections at avoided expensive investment incurred from conventional solutions, e.g., reinforcement and maintain robust network are a major challenge for Distribution Network Operators (DNOs). This thesis endeavours to develop an adaptive control scheme that provides local and real-time management against voltage variations and line capacity overload at the point of wind connections on rural distribution networks. Taking into account maximising power exports and providing an economically-viable control scheme, the wind turbine’s capability, comprising reactive power control and active power curtailment, is used. Whilst the thesis concentrates on the decentralised control applying several different algorithms, in addition, semi-coordinated and centralised approaches that adopt on-load tap changing transformers’ regulation and Optimal Power Flow tool are developed. Comparisons of these approaches based upon measures, i.e., economics, DG penetration and performance are determined. As an outcome, the developed scheme can enable growing integration of renewable DG on distribution networks and can be seen as an interim solution for the DNOs towards Smart Distribution Networks.

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Campillo, Javier. "From Passive to Active Electric Distribution Networks." Doctoral thesis, Mälardalens högskola, Framtidens energi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-31592.

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Large penetration of distributed generation from variable renewable energy sources, increased consumption flexibility on the demand side and the electrification of transportation pose great challenges to existing and future electric distribution networks. This thesis studies the roles of several actors involved in electric distribution systems through electricity consumption data analysis and simulation models. Results show that real-time electricity pricing adoption in the residential sector offers economic benefits for end consumers. This occurs even without the adoption of demand-side management strategies, while real-time pricing also brings new opportunities for increasing consumption flexibility. This flexibility will play a critical role in the electrification of transportation, where scheduled charging will be required to allow large penetration of EVs without compromising the network's reliability and to minimize upgrades on the existing grid. All these issues add significant complexity to the existing infrastructure and conventional passive components are no longer sufficient to guarantee safe and reliable network operation. Active distribution networks are therefore required, and consequently robust and flexible modelling and simulation computational tools are needed for their optimal design and control. The modelling approach presented in this thesis offers a viable solution by using an equation-based object-oriented language that allows developing open source network component models that can be shared and used unambiguously across different simulation environments.

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Conner, Steven. "Automated distribution network planning with active network management." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/28818.

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Renewable energy generation is becoming a major part of energy supply, often in the form of distributed generation (DG) connected to distribution networks. While growth has been rapid, there is awareness that limitations on spare capacity within distribution (and transmission) networks is holding back development. Developments are being shelved until new network reinforcements can be built, which may make some projects non-viable. Reinforcements are costly and often underutilised, typically only loaded to their limits for a few occasions during the year. In order to accommodate new DG without the high costs or delays, active network management (ANM) is being promoted in which generation and other network assets are controlled within the limits of the existing network. There is a great deal of complexity and uncertainty associated with developing ANM and devising coherent plans to accommodate new DG is challenging for Distribution Network Operators (DNOs). As such, there is a need for robust network planning tools that can explicitly handle ANM and which can be trusted and implemented easily. This thesis describes the need for and the development of a new distribution expansion planning framework that provides DNOs with a better understanding of the impacts created by renewable DG and the value of ANM. This revolves around a heuristic planning framework which schedules necessary upgrades in power lines and transformers associated with changes in demand as well as those driven by the connection of DG. Within this framework a form of decentralised, adaptive control of DG output has been introduced to allow estimation of the impact of managing voltage and power flow constraints on the timing and need for network upgrades. The framework is initially deployed using simple scenarios but a further advance is the explicit use of time series to provide substantially improved estimates of the levels of curtailment implied by ANM. In addition, a simplified approach to incorporating demand side management has been deployed to facilitate understanding of the scope and role this may play in facilitating DG connections.

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Thornley, Vincent Paul. "State estimation and control of active distribution networks." Thesis, University of Manchester, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.682241.

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Renewable power is often connected as distributed generation within distribution networks. A common limiting factor is the potential for the network voltage to exceed operational limits as a result of such generation. One method of overcoming this is the application of improved methods of voltage control to allow better use of the existing network assets. A segment controller is proposed which combines state estimation with a limit› based control algorithm to maintain the voltage at all nodes of a distribution network within operational limits, allowing increased generation to be safely introduced. A key feature is to minimise additional infrastructure required, therefore real measurements from around the network are restricted to the generation sites. The requirements and implementation for two field trials in the UK have been defined and are described. A state estimator is developed and the results from the site trials are presented. The accuracy of the estimator is, in some cases, poor. Investigations demonstrate that accuracy can be improved through careful selection of measurement parameters. The sparseness of real measurements is complemented by pseudo› measurements of load. Three existing load models (termed Half Rated Load, Allocation of Load by Rating and Allocation of Load by Profile) are presented and a new load model, Allocation of Load by Profile with Diversity, is developed. Studies show that load models based on allocation of load can significantly improve the accuracy of the state estimates. The AVRS control algorithm is described and adapted for practical implementation. Results from the site trials show that it is capable of maintaining the voltage across the network within limits. Additional requirements for commercial application of the technique are described. It is concluded that the combination of state estimation and a limit-based control algorithm are capable of maintaining a network within its operation voltage limits, allowing increased generation to be introduced to it.

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Coppo, Massimiliano. "Modeling and management of active electric distribution networks." Doctoral thesis, Università degli studi di Padova, 2016. http://hdl.handle.net/11577/3424471.

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In modern electricity distribution networks the vertically integrated grid paradigm is rapidly changing due to the ever growing presence of generation sources connected at lower voltage levels. These units, although having each a small size respect to the main generation plants connected to the bulk grid, in the last years are becoming more and more relevant due to their high number. If on one hand the connection of distributed generators is encouraged by the reduction of their cost and the incentives for renewable energy policies, on the other hand this process is resulting in serious concerns on the power system's stability and security. From the bulk grid standpoint, for example, the increasing share of distributed generation in the power generation mix is becoming a key issue as regards the system's frequency regulation. Concerning the operation of the distribution system, the presence of renewable intermittent generation resources (e.g. photovoltaic) and new storage-capable loads (e.g. plug-in hybrid electric vehicles), commonly referred to as Distributed Energy Resources (DERs) is often cause of undesired voltage and current unbalances and higher network losses. To face the mentioned issues, several national and international standard bodies stated new technical requirements for the generators connected to the distribution network with the aim of improving their integration in the grid regulation. A remarkable share of generators being connected to the distribution grid use static converters as an interface to the system: with the new standards these units need to be capable of changing their operating point supporting the grid regulation either on a local basis (e.g. frequency and Volt/Var control), as a response to remote signals from the DSO or remaining connected in presence of transient fault conditions (fault-ride-through). As clearly appears from the decisions being taken updating the grid codes, the integration of DGs and in general of distributed energy resources (DERs) will have a key role in the future electrical grids, both for security reasons and to improve the system's efficiency. For this reason, other than the technical requirements for the grid regulation support, decisions at regulatory level are going to be taken in order to path the way towards the ``smart-grid''. The mentioned challenges related with the integration of distributed resources in the grid operation highlight the importance of modelling with higher detail a distribution network in order to represent correctly all the active users which may participate to its regulation. Having suitable simulation tools, scenarios of integration of these resources may be studied proposing strategies for their management. These aspects are addressed in this thesis in which active distribution networks are studied both from the representation and management points of view. This thesis presents a methodology to represent distribution systems and, in general, multi-conductor networks enabling the consideration of asymmetrical systems, even in presence of specific grounding options and of circuits with different number of phases. From the management point of view, this thesis proposes a decentralised energy management system suitable for Medium Voltage networks aiming at involving DERs in the network's regulation. A coordinated control is also presented for the management of DERs connected in Low Voltage distribution networks, aiming both at limiting the voltage unbalance and aggregating services to be provided to the upstream MV grid. Both the modelling methodology and the management strategies are simulated in several case studies to demonstrate the applicability of the proposed tools to different power systems.
Nelle attuali reti elettriche di distribuzione, la struttura verticalmente integrata sta rapidamente cambiando a causa della crescente presenza di fonti di generazione connesse ai più bassi livelli di tensione. Queste unità, pur avendo dimensioni ridotte rispetto alle centrali tradizionali connesse alla rete di alta tensione, negli ultimi anni stanno diventando sempre più rilevanti a causa del loro elevato numero. Se da un lato la connessione di generatori distribuiti è incoraggiata dalla riduzione del loro costo e gli incentivi per politiche a sostegno delle energie rinnovabili, d'altra parte questo processo si ripercuote sulla stabilità e la sicurezza del sistema elettrico. Dal punto di vista della rete di trasmissione, la crescente percentuale di energia prodotta nelle reti di distribuzione rispetto ai quella proveniente dalle centrali elettriche tradizionali sta diventando una questione di importanza fondamentale nel risolvere problemi come la regolazione di frequenza. Per quanto riguarda il funzionamento del sistema di distribuzione, la presenza di risorse di generazione rinnovabile e intermittente (ad esempio fotovoltaico) e nuovi utenti in grado di accumulare energia (ad esempio veicoli elettrici connessi alla rete), comunemente indicati come Distributed Energy Resources (DER) è spesso causa di squilibri indesiderati di tensione e corrente e incremento delle perdite di rete. Per affrontare i suddetti problemi, diversi enti normativi nazionali e internazionali hanno aggiornato i requisiti tecnici per i generatori connessi alla rete di distribuzione, con l'obiettivo di favorire la loro integrazione nella regolazione di rete. Una quota rilevante di questi generatori connessa alla rete di distribuzione utilizza convertitori statici per interfacciarsi con il sistema elettrico: con le nuove norme, queste unità devono prevedere la possibilità di modificare il proprio funzionamento per contribuire alla regolazione di rete attraverso controlli basati su logica locale (ad esempio controllo di frequenza e tensione), sulla base di segnali inviati da remoto dal Distributore e rimanendo connessi in presenza di condizioni di guasto transitorie (fault-ride-through). Come appare evidente dalle decisioni prese sul piano normativo per aggiornare i codici di rete, l'integrazione dei DER avrà un ruolo predominante nella futura gestione delle reti elettriche, sia da un punto di vista della sicurezza che nel migliorare l'efficienza energetica. Per questo motivo, oltre all'aggiornamento dei requisiti di connessione per la partecipazione al supporto di rete, decisioni a livello regolatorio dovranno essere prese per favorire il passaggio alle cosiddette ``smart-grid''. Le suddette problematiche associate all'integrazione delle risorse distribuite nella gestione delle reti elettriche evidenziano l'importanza di rappresentare con elevato livello di dettaglio la rete di distribuzione, in modo da includere modelli di generatori distribuiti che possono partecipare alla regolazione. Avendo strumenti di simulazione adeguati, scenari di integrazione di queste risorse possono essere studiati, proponendo strategie per la loro gestione. Questa tesi affronta emntrambi i temi, trattando sia la rappresentazione della rete che la sua gestione. Questa tesi presenta una metodologia per la rappresentazione di reti di distribuzione e, in generale, di reti multi-conduttore, includendo sistemi asimmetrici anche in presenza di particolari configurazioni di messa a terra e di sezioni con diverso numero di conduttori. Dal punto di vista della gestione del sistema, in questa tesi viene proposta una strategia decentralizzata per la gestione di reti di media tensione con l'obiettivo di coinvolgere i DER nella regolazione di rete. Un controllo coordinato viene proposto anche per la gestione di DER connessi alla rete di bassa tensione, con il duplice obiettivo di limitare lo squilibrio di tensione e aggregare i contributi delle risorse distribuite per fornire servizi ancillari. I criteri di rappresentazione e gestione delle reti di distribuzione sono stati applicati ad alcuni casi studio per dimostrarne l'applicabilità in diversi sistemi elettrici.

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Lyons, Padraig Fionnbharr. "Experimental investigation and evaluation of future active distribution networks." Thesis, Durham University, 2010. http://etheses.dur.ac.uk/273/.

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The UK government’s policy to achieve a 20% renewable energy generation target by 2020, will require significant amounts of SSEG (Small-Scale Embedded Generation) to be connected. In addition to the expected economic and environmental benefits, the anticipated growth in SSEG brings with it numerous challenges for the operation of low voltage and medium voltage distribution networks. At present, there are a number of competing active network management concepts being considered to overcome these challenges and at Durham University a concept defined as the Small Scale Energy Zone (SSEZ) has been proposed and is investigated as part of this research. To further this, a bespoke active low voltage distribution network emulator known as the Experimental SSEZ has been developed by the author. Controllable emulated SSEG, controllable energy storage and controllable emulated load are incorporated into this laboratory. A transformation system has been developed to relate the operation of this system to that of low voltage distribution networks. Centralised and distributed network control systems have been developed for the Experimental SSEZ. These systems were used to evaluate, in conjunction with the relevant literature, the implementation of similar systems on future low voltage distribution networks. Both centralised and distributed control system architectures were found to have their merits. This research should therefore be useful in informing design decisions when developing and implementing active distribution network management systems on LV networks.

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Manitsas, Efthymios. "State estimation and active management in power distribution networks." Thesis, Imperial College London, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.550819.

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This thesis develops solutions that accommodate the introduction of state estimation in High Voltage (HV) power distribution networks, and proposes methodologies that further enhance the value of state estimation in distribution network operation. Furthermore, it investigates the impact of Distributed Generation (DG) and Active Management (AM) on the infrastructure development of typical European distribution networks. In HV distribution networks, measurements are very limited and normally available at the main substation only. Thus, it is essential to introduce appropriately modelled pseudo measurements. This is necessary not only for the state estimation mathematical models to be established but also for state estimation to generate estimates of sufficient quality. Two approaches, one based on correlation coefficients and regression analysis and one based on Artificial Neural Networks (ANNs), are proposed. Distribution networks are not static. Faults, maintenance and emergencies constantly change their topology; sudden changes in major power injections significantly change their power flows and voltages. For the Distribution Management System (DMS) to be reliable, it is important that changes significantly changing the state of the network are immediately identified and taken into consideration before control actions are issued. A methodology for detection of network changes using state estimation and the Bayes theorem of conditional probability is introduced. Finally, the future infrastructure development of typical distribution networks of Germany, the Netherlands and Poland is examined. The technical, economic and environmental aspects of Passive Management (PM), AM and DG are assessed and quantified while the technical and economic efficiency of different AM strategies is evaluated.

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Coffele, Federico. "Adaptive protection solutions for future active power distribution networks." Thesis, University of Strathclyde, 2012. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=18682.

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Power distribution networks are undergoing a continuous evolution from being passive to active in nature, with increasing penetration of distributed generation and the introduction of active network management schemes to facilitate increased distributed generation connections, automatically manage and reconfigure the network, optimise voltages and power losses and improve power supply reliability. The purpose of the research presented in this dissertation is to investigate the protection challenges that this evolution will introduce to the functions of protecting distribution networks, to develop new solutions and implement and demonstrate them in the laboratory. To analyse the potential problems that may be introduced to traditional protection systems, a detailed analysis of the impact of distributed generation, network automation and islanded operation has been undertaken using a hardware in the loop simulation of a network model representative of typical UK rural distribution networks. This analysis has demonstrated certain protection challenges (and disproved others) associated with overcurrent and loss of mains protection of future active power distribution networks. Two solutions to the demonstrated challenges have been developed: a new adaptive overcurrent protection system with automatic settings calculation, which overcomes the demonstrated sensitivity, selectivity and coordination problems associated with overcurrent protection; and a novel adaptive inter-tripping scheme with back-up passive loss of mains protection, which overcomes the demonstrated sensitivity and stability problems associated with loss of mains protection. The developed protection solutions have been implemented on commercially available hardware and tested using an hardware in the loop simulation environment. The performance of both solutions has been compared to traditional overcurrent and loss of mains protection systems, which are configured in accordance with UK distribution network operator protection policy. The results of this comparison have shown the effectiveness of the developed solutions in overcoming the demonstrated protection problems associated with future active power distribution networks.

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Singh, Narender. "Feeder Dynamic Rating Application for Active Distribution Networks using Synchrophasors." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187665.

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There is an ever increasing demand of electricity and to meet this demand, installation of new transmission and distribution lines is required. This task requires a significant investment and consent from the respective authorities. An alternative is to utilize maximum capability of the existing lines. Static line ratings are based on a conservative estimate, which means that on most occasions, the actual capacity of lines is much higher than the static line ratings. In order to provide a solution to this problem, this thesis introduces an approach that has been developed to utilize real time weather conditions, conductor sag data and the actual line loading of the conductor from PMU to provide dynamic line ratings for active distribution networks. The application has been developed in LabVIEW environment which provides a user friendly front panel where real-time ampacity can be seen as a waveform while being compared to the actual line loading. The developed application has been tested on the reference grid created for IDE4L project. The ampacity calculation method introduced here makes use of real-time data available through a real-time simulator in SmarTS lab at KTH, Sweden.
Det är ett ökande behov av elektricitet och för att möta detta behövet, installation av nya transmission och distributionsledningar behövs. Denna utbyggnad kräver ett stort engagemang och förståelse från ansvariga grupper. Ett alternativ är att utnyttja max-kapaciteten på redan befintliga ledningar. Installerade ledningar har räknats på ett konservativt sätt, vilket innebär att det vid vissa tillfällen går att öka belastingen på på dessa. För att ge en lösning på detta problem, introducerar den här avhandlingen en metod för att använda realtids-väderdata, tabeller för ledningarnas utvidgning och realtids-belastningsdata från PMU för att framställa dynamisk data för aktiva distributions-nätverk. Applikationen har utvecklas i LabVIEW-miljön som har ett användarvänligt GUI, där “Real-time ampacity” kan ses som en vågform medans den jämförs mot den faktiska belastningen på ledningen. Den utvecklade appliktionen har testats på referens-miljön som skapts för IDE4L projektet. “Ampacity calculation metoden” som introduceras här använder sig av realtidsdata som görs tillgänglig igenom en realtids-simulator i SmarTSlab på Kungliga Tekniska Högskolan i Sverige.

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Trichakis, Pavlos. "Multi agent systems for the active management of electrical distribution networks." Thesis, Durham University, 2009. http://etheses.dur.ac.uk/57/.

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This Thesis presents an investigation on the technical impacts caused by the steady state operation of Small-Scale Embedded Generators (SSEGs) and also introduces the Small Scale Energy Zone (SSEZ) concept which aims to remove the technical barriers associated with SSEGs through intelligent coordination of large numbers of customerowned SSEGs, energy storage units and controllable loads. This approach represents a move away from the conventional passive, “fit-and-forget” philosophy under which the majority of Low Voltage (LV) distribution networks are currently operated and towards a higher degree of network operational management. The employment of a distributed management and control approach for an SSEZ, realised through the Multi Agent Systems (MAS) technology, is proposed due to the advantages that can potentially be realised in the areas of: (i) scalability and openness, (ii) reliability and resilience and (iii) communications efficiency. A FIPA-compliant MAS-based control approach is designed, developed and evaluated based on the specific SSEZ control requirements. The MAS is composed of three types of agents: direct control agents, indirect control agents and utility agents, exchanging information through the employment of a common ontology. In addition, a relational database management system is also designed and developed in order to be coupled with the developed MAS for data management purposes.

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Azuatalam, Donald. "Technical and Economic Assessments of Electricity Distribution Networks with Active Customers." Thesis, The University of Sydney, 2020. https://hdl.handle.net/2123/21791.

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With a deepening penetration of distributed energy resources (DERs), distribution network service providers (DNSP) in most jurisdictions are faced with the challenge of designing tariff structures that are reflective of forward-looking network capacity costs, while ensuring a non-discriminatory, secure and reliable network for all end-users. Nonetheless, most electricity users seek to minimise their energy expenditure by participating in demand response programs or by actively managing their energy use through a home energy management system. Thus, DNSPs need to send accurate price signals to customers if they must achieve the desired peak demand targets. However, with inefficient pricing in place, DNSP loss in revenue and unfair cost allocation between customers may result. This thesis aims to address these challenges through a systematic technical and economic assessment of distribution networks with DER-enabled customers. To begin, a review of the performance of the state-of-the-art energy management methods is done in view of practicality and computational requirements while critiquing the modelling assumptions of each method. Next, a techno-economic assessment of grid defection is performed, based on the trade-off between the reliability and the levelised cost of electricity of residential PV-battery systems. Afterwards, the techno-economic impacts of different network tariffs, on low voltage networks are evaluated considering grid-connected customers, under various PV-battery penetration levels. Lastly, a benchmark for measuring the cost-reflectivity of network tariffs using cooperative game theory is proposed, which fairly apportions network costs to several customers with minimal error and computational burden. In brief, this thesis provides tools and analyses to guide DNSPs in designing DER-specific network tariffs which better signals network cost drivers, thus fostering customer participation while improving the equity of network cost allocations even with high DER penetration levels.

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Procopiou, Andreas. "Active management of PV-rich low voltage networks." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/active-management-of-pvrich-low-voltage-networks(acbb021f-c1ae-4235-b632-d4b4e15563fd).html.

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The increased penetration of residential-scale photovoltaic (PV) systems in European-style low voltage (LV) networks (i.e., long feeders with high number of connected customers) is leading to technical issues such as voltage rise and thermal overload of the most expensive network assets (i.e., transformer, cables). As these issues significantly limit the ability of LV networks to accommodate higher PV penetrations, Distribution Network Operators (DNOs) are required to proceed with expensive and time-consuming investments in order to reinforce or replace these assets. In contrast to this traditional approach of network reinforcement, which potentially leads to massive capital expenditure, the transition towards active LV networks where controllable elements, existing (i.e., PV systems) and likely to be adopted (i.e., battery energy storage systems, LV on-load tap changer transformers), can be managed in real-time, poses an attractive alternative. Although several active network management schemes have been recently proposed to increase the hosting capacity of PV-rich LV networks, they are mostly based on managing voltage issues only; and, in general, aim to solve technical issues separately. Integrated solutions aiming at managing simultaneously voltage and thermal issues are required, as recent studies demonstrate that both issues can coexist in PV-rich LV networks. More importantly the majority of studies, which commonly neglect the characteristics of real LV networks (e.g., unbalanced, three-phase, radial, multiple feeders with several branches, different types of customers), use complex optimisation techniques that require expensive communication infrastructure and extensive or full network observability (currently not available in LV networks). However, considering the extensiveness of LV networks around the world, practical, cost-effective and scalable solutions that use limited and already available information are more likely to be adopted by the industry. Considering the above gaps in the literature, this Thesis contributes by proposing innovative and scalable active network management schemes that use limited network monitoring and communication infrastructure to actively manage (1) Residential-scale PV systems, (2) Residential-scale Battery Energy Storage (BES) systems and (3) LV on-load tap changer (OLTC)-fitted transformers. The adoption of the proposed active network management schemes, which makes use of already available devices, information and requires limited monitoring (i.e., secondary distribution substation), allows making the transition towards active LV networks more practical and cost-effective. In addition, to tackle the challenges related to this research (i.e., lack of realistic LV network modelling with high resolution time-series analyses), this Thesis, being part of the industrial project 'Active Management of LV Networks' (funded by EDF R&D) and having access to French data, contributes by considering a fully modelled typical real residential French LV network (three-phase four-wire) with different characteristics and number of customers. Moreover, realistic (1-min resolution) daily time-series household (from real smart meter data) and PV generation profiles are considered while a stochastic approach (i.e., Monte Carlo) is adopted to cater for the uncertainties related to household demand as well as PV generation and location.

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Ng, Chong H. "Control of active filters to attenuate harmonic resonance in power distribution networks." Thesis, Northumbria University, 2007. http://nrl.northumbria.ac.uk/1440/.

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Harmonic resonance occurs when the network equivalent shunt harmonic capacitive reactance is associated with the network series harmonic inductive reactance. When such resonance occurs, it amplifies harmonic components with frequency close to the resonance point. Solutions used to solve harmonic resonance problems can be divided into two main categories. One is to reduce the content of harmonic components in the network (e.g. by using active or passive harmonic filters, etc.) and the other is to remove the resonance stimulating factor by shifting away the resonance frequency to a non-critical frequency range (e.g. detuning PFC capacitors, redesigning feeder transformers, etc.). Studies show that these techniques are not adequate to solve harmonic resonance problems in power distribution networks which are dynamic by their nature and with complex interconnections. Due to this, solutions in the category one are designed for localised harmonic distortion compensation, while solutions in the category two lack real-time operation feature. Therefore, it was identified that there is a need for real-time harmonic resonance attenuation that is suitable for power distribution networks. In this thesis, a new real-time Harmonic Resonance Attenuation (HRA) technique is proposed. This technique may be used with ordinary shunt harmonic filters to make them behave like a virtual shunt capacitor or inductor. Thus, looking from the harmonic current source side, the filter alters the network harmonic impedance and hence results in harmonic resonance attenuation. In order to implement the HRA technique, fast measurement of system harmonics in real-time is required. Therefore, in this work, a fast individual harmonic extraction (FIHE) technique is developed to enhance the desired real-time operation of the HRA. The proposed FIHE needs only one sixth of the fundamental cycle to extract any individual harmonic component which is faster than other methods currently available. In addition to the speed, the proposed FIHE provides overshoot free, oscillation free and ripple free extraction characteristics. The proposed HRA and FIHE techniques are described in this thesis with detailed analysis to illustrate their operating principles. A series of simulations and experiments are conducted to evaluate their functionality and performance. Results of the evaluation are presented and discussed in this thesis together with details of the experimental HRA model developed to verify the theoretical and simulation results.

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Zhao, Jinping. "Active congestion quantification and reliability improvement considering aging failure in modern distribution networks." Thesis, Zhao, Jinping (2022) Active congestion quantification and reliability improvement considering aging failure in modern distribution networks. PhD thesis, Murdoch University, 2022. https://researchrepository.murdoch.edu.au/id/eprint/66345/.

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The enormous concerns of climate change and traditional resource crises lead to the increased use of distributed generations (DGs) and electric vehicles (EVs) in distribution networks. This leads to significant challenges in maintaining safe and reliable network operations due to the complexity and uncertainties in active distribution networks, e.g., congestion and reliability problems. Effective congestion management (CM) policies require appropriate indices to quantify the seriousness and customer contributions to congested areas. Developing an accurate model to identify the residual life of aged equipment is also essential in long-term CM procedures. The assessment of network reliability and equipment end-of-life failure also plays a critical role in network planning and regulation. The main contributions of this thesis include a) outlining the specific characteristics of congestion events and introducing the typical metrics to assess the effectiveness of CM approaches; b) proposing spatial, temporal and aggregate indices for rapidly recognizing the seriousness of congestion in terms of thermal and voltage violations, and proposing indices for quantifying the customer contributions to congested areas; c) proposing an improved method to estimate the end-of-life failure probabilities of transformers and cables lines taking real-time relative aging speed and loss-of-life into consideration; d) quantifying the impact of different levels of EV penetration on the network reliability considering end-of-life failure on equipment and post-fault network reconfiguration; and e) proposing an EV smart charging optimization model to improve network reliability and reduce the cost of customers and power utilities. Simulation results illustrate the feasibility of the proposed indices in rapidly recognizing the congestion level, geographic location, and customer contributions in balanced and unbalanced systems. Voltage congestion can be significantly relieved by network reconfiguration and the utilization of the proposed indices by utility operators in CM procedures is also explained. The numerical studies also verify that the improved Arrhenius-Weibull can better indicate the aging process and demonstrate the superior accuracy of the proposed method in identifying residual lives and end-of-life failure probabilities of transformers and conductors. The integration of EV has a great impact on equipment aging failure probability and loss-of-life, thus resulting in lower network reliability and higher cost for managing aging failure. Finally, the proposed piecewise linear optimization model of the EV smart charging framework can significantly improve network reliability by 90% and reduce the total cost by 83.8% for customers and power utilities.

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Usman, Muhammad. "Novel Methodologies for the Analysis and Management of Low Voltage Active Distribution Networks." Doctoral thesis, Università degli studi di Padova, 2019. http://hdl.handle.net/11577/3424891.

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The continuous proliferation of renewable Distributed Energy Resources (DERs) in Medium Voltage (MV) and Low Voltage (LV) Distribution Networks (DNs) is playing a prominent role in reducing the carbon footprint of fossil-fuel-based electricity generation plants. However, the rapid integration of these resources has also changed the passive nature of these networks, and consequently, special attention is required to ensure their optimal, secure and reliable operation. Moreover, the installed DERs cannot be simply operated on the basis of a fit-and-forget policy due to the emergence of several technical problems caused by their interconnection. Issues such as voltage unbalance, reverse power flow, unintentional islanded operation etc. are frequently occurring in these networks which, in turn, require novel control and management schemes to ensure the continuous supply of electricity to end-users. In this context, several countries and network operators have updated their grid codes which put additional constraints on renewable DERs to participate in the provision of ancillary services in the context of maintaining network stability. In view of this, multi-phase analysis of MV and, especially, LV networks gains unprecedented attention due to the non-capability of single-phase equivalent representation-based network analysis approach in depicting the true picture of system’s operating conditions and state variables. Such a detailed network analysis, in turn, sets the path for innovative solutions to effectively manage these networks. Furthermore, concerning LV DNs, neutral conductor must be treated like phases conductors due to the significant presence of current in it under highly unbalanced network loading scenario. Resultantly, the application of the Kron reduction methodology to these networks must be avoided because of its reliance upon the unrealistic assumption of an equipotential neutral conductor. Since LV active DNs will become a central pillar of a decentralized electrical grid in near-future, it is, therefore, incumbent to analyse and manage them by taking into account each aspect of their structure. With a special emphasis and focus on LV active DNs, this thesis presents novel analysis and management techniques for such networks by taking into account the explicit representation of both phases and neutral conductors in the context of losses management, which includes both losses minimization and losses allocation concepts in its scope. Regarding the latter notion, a novel multi-phase losses allocation procedure is proposed which avoids allocating neutral losses to phases conductors and, consequently, provides explicit information about phase- and neutral-losses allocation factors. The proposed approach successfully takes into account the impact of unbalanced loading through self- and mutualvariable losses coefficients while allocating losses to end-users. Based on the information provided by positive neutral losses allocation factors, a novel unbalance reduction strategy is further developed which allows the commutation of loads from heavily loaded phases of a critical node to its lightly loaded phases and, therefore, improves network balancing significantly. In the framework of losses reduction, a multi-phase Optimal Power Flow (OPF) model based on Semi-Definite Programming (SDP) technique is formulated which successfully incorporates neutral conductors as well as wye- and delta-connected loads in its formulation. Moreover, a novel complex voltage variable-based approach is proposed for the incorporation of a complete ZIP load in the proposed relaxation. However, due to excessively high computational requirements of this relaxation in the case of medium- and large-size DNs, a cheap SDP-based OPF model is additionally proposed and three novel propositions are developed in this context for the modelling of constant current loads. The proposed cheap relaxation can be practically realized due to its low computational requirements and provision of exact solution under a range of ZIP load parameters. However, due to the dominance of multi-phase SDP-based approach over cheap SDP-based relaxation, the latter relaxation is further tightened by imposing additional constraints in the form of convex envelopes. As a result, a tight solution is obtained without making any compromise on the computational benefits of cheap SDP-based OPF relaxation. Finally, all the proposed strategies are simulated on several test cases to demonstrate their positive potential in the context of LV active DNs management.

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Han, Xue. "Quantitative Analysis of Distributed Energy Resources in Future Distribution Networks." Thesis, KTH, Industriella informations- och styrsystem, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-98484.

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There has been a large body of statements claiming that the large scale deployment of Distributed Energy Resources (DERs) will eventually reshape the future distribution grid operation in numerous ways. However, there is a lack of evidence specifying to what extent the power system operation will be alternated. In this project, quantitative results in terms of how the future distribution grid will be changed by the deployment of distributed generation, active demand and electric vehicles, are presented. The quantitative analysis is based on the conditions for both a radial and a meshed distribution network. The input parameters are on the basis of the current and envisioned DER deployment scenarios proposed for Sweden. The simulation results indicate that the deployment of DERs can significantly reduce the power losses and voltage drops by compensating power from the local energy resources, and limiting the power transmitted from the external grid. However, it is notable that the opposite results (e.g., severe voltage uctuations, larger power losses) can be obtained due to the intermittent characteristics of DERs and the irrational management of different types of DERs in the DNs. Subsequently, this will lead to challenges for the Distribution System Operator (DSO).

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Waite, Michael James. "Active power filter for unbalanced distribution networks using a flying-capacitor multi-level inverter." Thesis, University of Leeds, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.549738.

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Widespread growth of the consumer electronics market and the upward trend in harnessing electrical power from renewable sources has increased the number of power electronic converters connected to utility distribution systems. Power electronic converters offer flexibility in voltage and current control as well as improved energy efficiency, but generate harmonic currents which have detrimental effects on the power system. A particular challenge appears in 4-wire networks where zero-sequence harmonics exist; such currents accumulate in the neutral conductor and pose threats of overheating and failure. This work investigates harmonic compensation using shunt active power filters with specific application to unbalanced distribution networks. Owing to its increased availabil- ity of switching states, the flying-capacitor multi-level inverter (FCMI) is explored; how- ever an additional challenge exists in the balancing of capacitor voltages. Furthermore, synthesis of unbalanced inverter output volt ages necessitates a three-dimensional pulse- width-modulation (3D-PWM) strategy. This work proposes a new modulation scheme, specifically suited to 4-limb FCMIs, which combines 3D-PWM and natural flying-capacitor voltage control. To develop an optimal harmonic compensation strategy, it is important to understand the nature of harmonic distortion experienced in typical distribution systems. New data on harmonics generated by common single-phase appliances are presented and a compre- hensive power-quality study is performed on a typical 4-wire network. Findings are used to develop a computer model which emulates realistic harmonic load current waveforms. The final contribution in this work lies in the development of an unbalanced harmonic extraction technique based on synchronous reference frame theory and a new modified deadbeat controller which compensates delays and improves reference current tracking. In conjunction with the proposed 3D-PWM scheme, the complete control strategy pro- vides compensation of positive, negative and zero-sequence harmonic currents in addition to alleviating phase load imbalance. A bespoke FCMI test rig is developed, providing experimental validation of the proposed system.

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Robertson, James George. "New optimal power flow techniques to improve integration of distributed generation in responsive distribution networks." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/10528.

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Climate change has brought about legally-binding targets for Scotland, the U.K. and the E.U. to reduce greenhouse gas emissions and source a share of overall energy consumption from renewable energy resources by 2020. With severe limitations in the transport and heating sectors the onus is on the electricity sector to provide a significant reduction in greenhouse gas emissions and introduce a substantial increase in renewable energy production. The most attractive renewable energy resources are located in the geographic extremes of the country, far from the large population densities and high voltage, high capacity transmission networks. This means that the majority of renewable generation technologies will need to connect to the conventionally passive, lower voltage distribution networks. The integration of Distributed Generation (DG) is severely restricted by the technical limitations of the passively managed lower voltage infrastructure. Long lead times and the capital expenditure of traditional electricity network reinforcement can significantly delay or make the economics of some renewable generation schemes unviable. To be able to quickly and cost-effectively integrate significant levels of DG, the conventional fit-and-forget approach will have to be evolved into a ‘connect-and-manage’ system using active network management (ANM) techniques. ANM considers the real-time variation in generation and demand levels and schedules electricity network control settings to alleviate system constraints and increase connectable capacity of DG. This thesis explores the extent to which real time adjustments to DG and network asset controller set-points could allow existing networks to accommodate more DG. This thesis investigates the use of a full AC OPF technique to operate and schedule in real time variables of ANM control in distribution networks. These include; DG real and reactive power output and on-load-tap-changing transformer set-points. New formulations of the full AC OPF problem including multi-objective functions, penalising unnecessary deviation of variable control settings, and a Receding-Horizon formulation are assessed. This thesis also presents a methodology and modelling environment to explore the new and innovative formulations of OPF and to assess the interactions of various control practices in real time. Continuous time sequential, single scenario, OPF analyses at a very short control cycle can lead to the discontinuous and unnecessary switching of network control set-points, particularly during the less onerous network operating conditions. Furthermore, residual current flow and voltage variation can also gave rise to undesirable network effects including over and under voltage excursion and thermal overloading of network components. For the majority of instances, the magnitude of constraint violation was not significant but the levels of occurrence gave occasional cause for concern. The new formulations of the OPF problem were successful in deterring any extreme and unsatisfactory effects. Results have shown significant improvements in the energy yield from non-firm renewable energy resources. Initial testing of the real time OPF techniques in a simple demonstration network where voltage rise restricted the headroom for installed DG capacity and energy yield, showed that the energy yield for a single DG increased by 200% from the fit-and-forget scenario. Extrapolation of the OPF technique to a network with multiple DGs from different types of renewable energy resources showed an increase of 216% from the fit-and-forget energy yield. In a much larger network case study, where thermal loading limits constrained further DG capacity and energy yield, the increase in energy yield was more modest with an average increase of 45% over the fit-and-forget approach. In the large network where thermal overloading prevailed there was no immediate alternative to real power curtailment. This work has demonstrated that the proposed ANM OPF schemes can provide an intelligent, more cost effective and quicker alternative to network upgrades. As a result, DNOs can have a better knowledge and understanding of the capabilities and technical limitations of their networks to absorb DG safely and securely, without the expense of conventional network reinforcement.

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Cintuglu, Mehmet Hazar. "Wide-Area Time-Synchronized Closed-Loop Control of Power Systems And Decentralized Active Distribution Networks." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/3031.

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The rapidly expanding power system grid infrastructure and the need to reduce the occurrence of major blackouts and prevention or hardening of systems against cyber-attacks, have led to increased interest in the improved resilience of the electrical grid. Distributed and decentralized control have been widely applied to computer science research. However, for power system applications, the real-time application of decentralized and distributed control algorithms introduce several challenges. In this dissertation, new algorithms and methods for decentralized control, protection and energy management of Wide Area Monitoring, Protection and Control (WAMPAC) and the Active Distribution Network (ADN) are developed to improve the resiliency of the power system. To evaluate the findings of this dissertation, a laboratory-scale integrated Wide WAMPAC and ADN control platform was designed and implemented. The developed platform consists of phasor measurement units (PMU), intelligent electronic devices (IED) and programmable logic controllers (PLC). On top of the designed hardware control platform, a multi-agent cyber-physical interoperability viii framework was developed for real-time verification of the developed decentralized and distributed algorithms using local wireless and Internet-based cloud communication. A novel real-time multiagent system interoperability testbed was developed to enable utility independent private microgrids standardized interoperability framework and define behavioral models for expandability and plug-and-play operation. The state-of-theart power system multiagent framework is improved by providing specific attributes and a deliberative behavior modeling capability. The proposed multi-agent framework is validated in a laboratory based testbed involving developed intelligent electronic device prototypes and actual microgrid setups. Experimental results are demonstrated for both decentralized and distributed control approaches. A new adaptive real-time protection and remedial action scheme (RAS) method using agent-based distributed communication was developed for autonomous hybrid AC/DC microgrids to increase resiliency and continuous operability after fault conditions. Unlike the conventional consecutive time delay-based overcurrent protection schemes, the developed technique defines a selectivity mechanism considering the RAS of the microgrid after fault instant based on feeder characteristics and the location of the IEDs. The experimental results showed a significant improvement in terms of resiliency of microgrids through protection using agent-based distributed communication.

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Fila, Maciej. "Modelling, evaluation and demonstration of novel active voltage control schemes to accomodate distributed generation in distribution networks." Thesis, Brunel University, 2010. http://bura.brunel.ac.uk/handle/2438/5516.

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Voltage control in distribution networks is becoming more challenging due to the growing amount of distributed generation that is being connected to the distribution networks in addition to increasing load. The output of the distributed generation can radically change power flows and voltage profiles in distribution networks, creating conditions that adversely affect the performance of automatic voltage control schemes and in addition cause unacceptable voltage rise. On the other hand, inherent limitations and current operational policies of AVC schemes very often restrict the output of DG or even prevent its connection. This thesis investigates and analyses voltage control in terms of the shift from passive to active distribution networks. The thesis also reviews the performance of AVC schemes under varying load and generation output conditions, investigates effective utilisation of distribution network assets and methods to accommodate active voltage control schemes into existing infrastructure. A range of active voltage control and management schemes based on coordinated voltage control is presented and assessed. These schemes can be used to improve the voltage profile in distribution networks and increase their ability to accommodate distributed generation. The functionality of each scheme is assessed based on a number of factors such as the ability of the scheme to increase network capacity, reliability and accuracy. Simulation software to accurately evaluate the performance of an active voltage control scheme in a particular distribution network scenario is essential before the scheme can be deployed. Formal assessment of advanced AVC models and SuperTAPP n+ functionality is performed using simulation software as developed and presented in this thesis. The accuracy of the software results and performance of the SuperTAPP n+ scheme is validated based on network trials carried out in EDF Energy Networks.

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RUGGERI, SIMONA. "Centralised and decentralised control of active distribution systems: models, algorithms and applications." Doctoral thesis, Università degli Studi di Cagliari, 2015. http://hdl.handle.net/11584/266574.

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Power system were traditionally planned and designed by assuming unidirectional power flows from power stations to loads. Nowadays, several factors (e.g., liberalization of the electricity market, need of increased reliability, and environmental issues) lead to a situation where electricity is produced also downstream the transmission level. Connecting generators to the distribution networks could provide several benefits to the whole system, but also technical and safety problems that must be faced. On the other hand, the loads are changing: new loads like electric vehicles and electric pumps are appearing in the network and they are going to modify the electricity consumption; while traditional loads are designed in order to be more efficient, but with additional functions or special features that require more energy. For all these reasons, since 2005, the interest on Smart Grid (electricity network that can intelligently integrate the actions of all users connected to it – generators, consumers – in order to efficiently deliver sustainable, economic and secure electricity supplies) increased. In this framework different techniques to control, operate and thereby integrate distributed energy resources into the network have been analysed and developed. The first technique designed is a centralised control, characterised by a central controller (Distribution Management System) that gathers information like the measures of the main electric parameters, energy price and indicates to DERs (Active Loads, Generators, Energy Storage) the optimal set points minimizing the system cost, subject to technical and economical constraints. The second technique developed is a decentralised control using Multi Agent Systems (MAS). This type of control has been designed and developed for the direct control of active demand and plug-in electric vehicles, managed by the Aggregator, entrusted by the end users to change their consumption habits according to their needs. Moreover, the proposed decentralised MAS, with the active participation of small consumers in the electricity system, support the integration of the Electric Vehicles in the LV distribution network and reduce its harmful impact on voltage regulation. The techniques and the algorithms proposed by the author are analysed and applied in representative Italian Distribution networks, by taking into account the development of the distribution system according to the load profile evolution, providing several examples to underline the importance of the Active Management for deferring the reinforcement of the existing grid infrastructures, increasing the hosting capacity of the network

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Danzerl, Daniel. "Maximising wind farm connections : an investigation of novel voltage management and principles of access techniques in active distribution networks." Thesis, University of Strathclyde, 2018. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=30917.

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Power production from stochastic wind generators connected at the lower voltage levels on the distribution network where weak strength of the network prevails, can make voltage management particularly challenging for network operators. Distribution network operators (DNO's) tend to manage their networks conservatively by imposing stricter operational limits when deciding whether to allow generators to connect or not. Voltage rise limitation is a major barrier and impacts significantly on the capacities of generators that can be connected at lower voltage and weak distribution networks. This thesis develops and presents novel voltage control techniques which involves a coordination of active network management (ANM) technological solutions and principles of access (PoA) arrangements specific for wind farm connections managed under voltage constraint conditions. The proposed coordinated voltage control and PoA techniques effectively mitigate the voltage rise limitation and enhance the capacity of the network to connect more wind generation. The research presented assesses the performance of the strategy and it quantifies the benefit to the wind generators by using time-series optimal power flow methods on a realistic UK 11 kV distribution network. The proposed ANM solution provides DNO's alternative control options to address the voltage rise problem to facilitate cheaper and faster DG connections, deferring the need for costly and time-consuming reinforcement. It offers wind farm owners, exible options to minimise excessive curtailment by controlling their voltage at the point of connection. It provides a guide for suitable locations for future wind farm investment. It quantifies the risks and uncertainties associated with the different commercial arrangements and proposes alternative PoA suitable for voltage constrained networks.

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Horta, José Luis. "Innovative paradigms and architecture for future distribution electricity networks supporting the energy transition." Thesis, Paris, ENST, 2018. http://www.theses.fr/2018ENST0022/document.

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Les futurs réseaux de distribution d’électricité devront héberger une part importante et croissante de sources d’énergies renouvelables intermittentes. De plus, ils devront faire face à une part croissante de véhicules électriques. Ces tendances induisent le besoin de nouveaux paradigmes et architectures d’exploitation du réseau de distribution, afin de fiabiliser les réseaux et d'assurer la qualité de fourniture d’électricité. Dans cette thèse nous proposons une nouvelle architecture capable de favoriser la collaboration entre les acteurs du marché de gros, les gestionnaires de réseau de distribution et les clients finaux, afin de tirer parti des ressources énergétiques distribuées tout en prenant en compte les contraintes des réseaux de distribution. L’architecture est conçue pour fournir des services innovants de gestion de la demande résidentielle, dans le cadre de l'autoconsommation individuelle et collective (à l'échelle d'un quartier). La thèse apporte trois contributions principales. D'abord, sur la base de l'internet des objets et de la technologie blockchain, la thèse fournit les éléments de base pour les futures architectures de gestion de l'énergie au niveau du réseau de distribution. Ensuite, en focalisant sur les services rendus par de telles architectures, nous proposons un marché intra-journalier au pas horaire pour l'échange local de l'énergie renouvelable entre maisons, associé à un mécanisme d'allocation dynamique des phases afin d'améliorer la qualité de fourniture. Finalement, nous proposons un mécanisme de contrôle en temps réel pour l'ajustement des transactions du marché vers des échanges finaux d'électricité qui respectent les restrictions posées par le gestionnaire du réseau électrique
Future electricity distribution grids will host an important and growing share of variable renewable energy sources and local storage resources. Moreover, they will face new load structures due for example to the growth of the electric vehicle market. These trends raise the need for new distribution grid architecture and operation paradigms to keep the grid stable and to ensure quality of supply. In addition, these new paradigms will enable the provision of advanced new services. In this thesis we propose a novel architecture capable of fostering collaboration among wholesale market actors, distribution system operators and end customers, to leverage flexible distributed energy resources while respecting distribution system constrains. The architecture is designed for providing innovative residential demand side management services, with a special focus on services enabled by self-consumption at the household and neighborhood level. Following these general objectives, the thesis provides three main contributions. First, based on internet of things and blockchain technology, we propose the building blocks for future distribution grid energy management architectures. Then, focusing on the services enabled by such architectures, we propose hour-ahead markets for the local exchange of renewable energy among households together with dynamic phase allocation mechanism to improve the quality of electricity supply. Finally, we propose a real time control mechanism for the adjustment of market decisions to satisfy distribution system operator constraints

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Swaminathan, Bhargav Prasanna. "Gestion prévisionnelle des réseaux actifs de distribution - relaxation convexe sous incertitude." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAT039/document.

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Les réseaux électriques subissent deux changements majeurs : le taux croissant de générateurs d’énergie distribuée (GED) intermittents et la dérégulation du système électrique. Les réseaux de distribution et leurs gestionnaires (GRD) sont plus particulièrement touchés. La planification, construction et exploitation des réseaux de la plupart des GRD doivent évoluer face à ces change- ments. Les réseaux actifs de distribution et la gestion intelligente de associée est une solution potentielle. Les GRD pourront ainsi adopter de nouveaux rôles, interagir avec de nouveaux acteurs et proposer de nouveaux services. Ils pourront aussi utiliser la flexibilité de manière optimale au travers, entre autres, d’outils intelligents pour la gestion prévisionnelle de leurs réseaux de moyenne tension (HTA). Développer ces outils est un défi, car les réseaux de distribution ont des spécificités techniques. Ces spécificités sont la présence d’éléments discrets comme les régleurs en charge et la reconfiguration, les flexibilités exogènes, la non-linéarité des calculs de répartition de charge, et l’incertitude liée aux prévisions des GED intermittents. Dans cette thèse, une analyse économique des flexibilités permet d’établir une référence commune pour une utilisation rentable et sans biais dans la gestion prévisionnelle. Des modèles linéaires des flexibilités sont développés en utilisant des reformulations mathématiques exactes. Le calcul de répartition de charge est “convexifié” à travers des reformulations. L’optimalité globale des solutions obtenues, avec ce modèle d’optimisation exact et convexe de gestion prévisionnelle, sont ainsi garanties. Les tests sur deux réseaux permettent d’en valider la performance. L’incertitude des prévisions de GED peut pourtant remettre en cause les solutions obtenues. Afin de résoudre ce problème, trois formulations différentes pour traiter cette incertitude sont développées. Leurs performances sont testées et comparées à travers des simulations. Une analyse permet d’identifier les formulations les plus adaptées pour la gestion prévisionnelle sous incertitude
Power systems are faced by the rising shares of distributed renewable energy sources (DRES) and the deregulation of the electricity system. Distribution networks and their operators (DSO) are particularly at the front-line. The passive operational practives of many DSOs today have to evolve to overcome these challenges. Active Distribution Networks (ADN), and Active Network Management (ANM) have been touted as a potential solution. In this context, DSOs will streamline investment and operational decisions, creating a cost-effective framework of operations. They will evolve and take up new roles and optimally use flexibility to perform, for example, short-term op- erational planning of their networks. However, the development of such methods poses particular challenges. They are related to the presence of discrete elements (OLTCs and reconfiguration), the use of exogenous (external) flexibilities in these networks, the non-linear nature of optimal power flow (OPF) calculations, and uncertainties present in forecasts. The work leading to this thesis deals with and overcomes these challenges. First, a short-term economic analysis is done to ascertain the utilisation costs of flexibilities. This provides a common reference for different flexibilities. Then, exact linear flexibility models are developed using mathematical reformulation techniques. The OPF equations in operational planning are then convexified using reformulation techniques as well. The mixed-integer convex optimisation model thus developed, called the novel OP formulation, is exact and can guarantee globally optimal solutions. Simulations on two test networks allow us to evaluate the performance of this formulation. The uncertainty in DRES forecasts is then handled via three different formulations developed in this thesis. The best performing formulations under uncertainty are determined via comparison framework developed to test their performance

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Carradore, Loredana. "Modeling and Management of Smart Energy Networks." Doctoral thesis, Università degli studi di Padova, 2011. http://hdl.handle.net/11577/3427462.

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"Smart grids'' identifies what future electrical network would represent: an intelligent integrated system where every device available to modify their generation/absorption is responsive, awaken of its role, eco-sensitive, flexible and interconnected with others. In this scenario, smart technologies, such as Information and Communication Technologies and smart meters, will allow interconnections and interactions among these devices that are available to participate in ancillary services; whereas a smart management system would ensure quality, reliability, efficiency, effectiveness in the supply service and the free participation in services for the grid support of these new customers. However, even if the smart grid scenario seems to be clearly defined, investigation on the management system is still required, in order to efficiently co-ordinate all distributed resources in distribution networks and to exploit the potentiality of new possible participants in the network regulation, such us energy storage devices and electrical vehicles. By the way, energy markets seem to be ideally suited to support the system operator in the co-ordination of different energy resources, also allowing the exploitation of synergy among different energy carries to increase the overall efficiency and reliability of the system. In fact, energy markets could create suitable price signals able to make responsive devices available to modify their generation/absorption to network requirements. For this reason, it seems reasonable to refer to these devices as customers. Investigations on smart management procedures for the co-ordination of different resources in energy networks is the main thread of this thesis. In particular, the importance of price signals to obtain a virtuous behavior of customers has been exploited, focusing on co-ordinated management procedures, in order to ensure the management of the complex electrical network system. In the first chapter a brief introduction to smart grids, energy markets and storage devices is provided, in order to present general background and motivation of this work. The modeling basis of the software environment developed during the PhD and used to investigate management issues in smart energy network are presented in chapter 2. Chapter 3 presents preliminary investigations on energy hub, a generation, conversion and storage center, management based on suitable price signals to optimally manage exchanges of flows among different energy vectors, in order to exploit synergy properties. In chapter 4, investigation on the management of a multi-energy vector systems through price coefficients is presented. In particular, price coefficients proportional to reference signals, that represents network requirements, have been analyzed in a decoupled management procedure between network and energy hubs with storage devices. In chapter 5, it is described how to exploit this decoupled optimisation procedure, considering aggregators of EVs as flexible distributed storage devices. In chapter 6, an innovative management procedure based on token ring philosophy, aimed to co-ordinate distributed resources, ensuring their free participation in services for the grid support is proposed. The thesis ends with chapter 7, where the most important achievements and suggests in possible future work are summarizes and discusses.
Con "smart grids'' si può identificare quello che rappresenteranno le reti elettriche del futuro, ovvero un sistema integrato ed intelligente, dove ogni dispositivo disponibile a modificare la propria generazione e il proprio assorbimento, è reattivo, attento ai segnali di prezzo, consapevole del proprio ruolo, sensibile agli aspetti ambientali, flessibile e interconnesso con gli altri. In questo scenario, tecnologie intelligenti, come i sistemi ICT (Information and Communication Technologies) e gli smart meter, permetteranno le interconnesioni e le interazioni tra questi dispositivi disponibili a partecipare nei servizi ancillari; mentre un sistema di gestione intelligente dovrebbe essere in grado di assicurare qualità, affidabilità, efficienza, efficacia nel servizio di fornitura e la libera partecipazione nei servizi per il supporto della rete di questi nuovi clienti. Sebbene lo scenario identificato dal termine "smart grids'' sembri essere chiaramente definito, risulta ancora necessario lo studio relativo al sistema di gestione fondamentale per coordinare in maniera efficiente le risorse distribuite nelle reti di distribuzione e le potenzialità introdotte da nuovi possibili participanti nella regolazione della rete, come per esempio i sistemi di accumulo e i veicoli elettrici. A questo proposito, i mercati energetici sembrano ideali per aiutare l'operatore di sistema a coinvolgere tutte le risorse energetiche nella regolazione della rete, permettendo anche lo sfruttamento della singergia tra differenti vettori energetici, allo scopo di incrementare l'efficienza e l'affidabilità generale di tutto il sistema. Infatti, i mercati energetici possono creare appropriati segnali di prezzo in grado di rendere sensibili alle esigenze della rete quei dispositivi disponibili a modificare la loro generazione e il loro assorbimento. È per questo motivo che sembra opportuno identificare questi dispositivi come clienti. Il principale filo conduttore di questa tesi è stato la ricerca di procedure intelligenti di gestione per la coordinazione di differenti risorse nelle future reti energetiche intelligenti. In particolare, è stata sfruttata l'idea chiave dell'importanza dei segnali di prezzo per ottenere un comportamento virtuoso dei clienti, concentrandosi su metodi di coordinamento in grado di assicurare con meccanismi semplici la gestione di un complesso sistema come quello della rete elettrica. Nel primo capitolo di questa tesi è presente una breve introduzione alle smart grids, ai mercati energetici e ai sistemi di accumulo, al solo scopo di presentare background e motivazioni di questo lavoro. Il capitolo 2 raccoglie le basi teoriche della modellizzazione dell'ambiente software sviluppato durante il dottorato e usato per studiare la gestione in reti energetiche intelligenti. Il capitolo 3 presenta le prime indagini sulla gestione di un energy hub, un centro di generazione, conversione e assorbimento, basata su segnali di prezzo adeguati a permettere una gestione ottima di flussi tra differenti vettori energetici, in modo da sfruttare la loro sinergia. Il capitolo 4 riporta quanto studiato per la gestione di un sistema multi-vettore energetico attraverso coefficienti di prezzo. In particolare, è stata analizzata la possibilità di utilizzare termini di prezzo proporzionali ad un segnale di riferimento che rappresenti la richiesta della rete in una gestione disaccoppiata di rete ed energy hub con sistemi di accumulo. Questa precudura di ottimizzazione disaccoppiata è stata applicata nel capitolo 5 a degli agglomerati di veicoli elettrici, intesi come sistemi di accumulo flessibili e distribuiti. Nel capitolo 6, infine, viene presentata un'innovativa procedura di gestione, basata sulla filosofia del token ring, mirata a coordinare risorse distribuite assicurando la loro libera partecipazione nei servizi per il supporto della rete. La tesi si chiude con il capitolo 7, che riassume e discute i più importanti traguardi raggiunti e suggerendo possibili lavori futuri.

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Robitzky, Lena [Verfasser]. "Analysis of long-term voltage stability in electric power systems under consideration of active distribution networks and novel emergency control systems / Lena Robitzky." Aachen : Shaker, 2018. http://d-nb.info/1188548182/34.

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Nanchian, Sara. "State estimation for active distribution network." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/58215.

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The requirement of accommodating more distributed generations (DGs) at distribution voltage level has encouraged distribution network operators to utilize their feeder capacity more effectively. This requires the availability of the various network measurements such as voltages, currents, loads, voltage control settings and DG outputs. However these quantities are not directly available in the distribution network control centre. Therefore, to control voltage and power flow in the network, the estimations of these quantities are required. This consists of the monitoring and control of the network operation by application of modern distribution management system (DMS) at the primary substation. The state estimator takes all the available network measurement information, together with a parameterized network model and estimates state of the system in operational time scale. The estimator outputs are then fed into the main control functions and other asset management tools. Although the application of State Estimation (SE) is very common task at transmission system, the practical application are not common at distribution level. This is due to the fact that the operation, topology and design at distribution level differ from those at transmission level. The untransposed three-phase circuits, unbalanced loads, shorter lines with higher ratio of R/X, and the existence of discrete control options such as transformer tap positions illustrates some of those differences. These specificities have motivated this piece of research to consider some of the key issues in distribution system state estimation and to develop algorithms to tackle them. This thesis investigated in detail the criterion for identifying suitable solvers for the distribution system state estimation (DSSE) while considering the specific characteristic of the distribution network such as discrete tap position by exploring new optimization methods which are likely to be useful for practical implementation. Some of the research findings have already been disseminated through invited conference panel and IEEE journal.

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Ahmadi, Ali Reza. "Distribution network optimisation for an active network management system." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/6341.

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The connection of Distributed Generators (DGs) to a distribution network causes technical concerns for Distribution Network Operators (DNOs) which include power flow management, loss increase and voltage management problems. An Active Network Management System can provide monitoring and control of the distribution network as well as providing the infrastructure and technology for full integration of DGs into the distribution network. The Optimal Power Flow (OPF) method is a valuable tool in providing optimal control solutions for active network management system applications. The research presented here has concentrated on the development of a multi-objective OPF to provide power flow management, voltage control solutions and network optimisation strategies. The OPF has been shown to provide accurate solutions for variety of network topologies. It is possible to apply time-series of load and generation data to the OPF in a loop, generating optimal network solutions to maintain the network within thermal and voltage limits. The OPF incorporates not only the DG real power output maximisation, but also network loss minimisation as well as minimising the dispatch of DG reactive power. This investigation uses a direct Interior Point (IP) method as the solution methodology which is speed efficient and converges in polynomial time. Each objective function has been assigned a weighting factor, making it possible to favour one objective function and ignore the others. Contributions to enhance the performance of the IP OPF algorithm include a new generic barrier parameter formulation and a new swing bus formulation to model energy export/import in the main optimisation routine. A Terminal Voltage Regulator Mode (TVRM) and Power Factor Regulation Mode (PFRM) for DG were incorporated in the main optimisation routine. The main motivation is to compare these two decentralised DG control methods in terms of the achieving the maximum DG real power generation. The DG operation methods of TVRM and PFRM are compared with the optimisation results obtained from centralised dispatch in terms of the DG capacity achieved as it produces the optimum overall network solution. A suitable value of the droop and local voltage regulator dead-bands were determined for particular DGs. Furthermore, the effect of these decentralised DG control methods on distribution network losses are considered in a measure to assess the financial implications from a DNO's perspective.

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NGUYEN, Ngoc Trung. "Study and development of innovative measurement methods and systems for anti-islanding protection in smart grids." Doctoral thesis, Università degli Studi di Palermo, 2014. http://hdl.handle.net/10447/90786.

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Nikola, Vojnović. "Proračun tokova snaga neuravnoteženih mreža sa energetskim resursima priključenim na mrežu preko uređaja energetske elektronike." Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2018. https://www.cris.uns.ac.rs/record.jsf?recordId=107612&source=NDLTD&language=en.

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U disertaciji je obrađen problem proračuna nesimetričnih tokovasnaga neuravnoteženih prenosnih i aktivnih distributivnih mrežavelikih dimenzija, naročito onih sa energetskim resursimazasnovanim na uređajima energetske elektronike. Pri tome je dat dokazda tradicionalna klasifikacija čvorova nije dovoljna da se preciznomodeluju i rešavaju nesimetrični tokovi snaga navedenih mreža.Zatim je predložena nova klasifikacija čvorova sa odgovarajućimmetodima tokova snaga. Time je omogućena vrlo precizna formulacijai proračun modela nesimetričnih tokova snaga navedenih mreža. Tapreciznost metoda tokova snaga je rezultat toga što su novomklasifikacijom čvorova obuhvaćene sve praktično primenjeneupravljačke strategije tradicionalnih naizmeničnih mašina, anaročito energetskih resursa koji su zasnovani na energetskojelektronici.
This thesis deals with power flow calculations of unbalanced large scaletransmission networks and active distributive networks, especially oneswith electronically interfaced resources. The proof that the traditional busclassification is not sufficient for precise modeling and calculation of powerflow of these networks is given first. Then, a new bus classification andcorresponding very precise power flow model and calculation ofaforementioned networks are proposed. This precision of power flowcalculation is the result of encompassing of all control strategies of modernenergy resources by the new bus classification.

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Laverty, D. M. "Synchrophasor Measurement and Wireless Telecommunications in the Active Distribution Network." Thesis, Queen's University Belfast, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527827.

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Dolan, Michael James. "The application and assessment of active network management techniques for distribution network power flows." Thesis, University of Strathclyde, 2012. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=17815.

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The UK Government regards renewable energy technology deployment to be crucial in successfully meeting reduced greenhouse gas emission targets. As such, incentives promoting the connection of clean energy sources to the UK's electricity infrastructure are influencing a significant increase of distributed generation (DG) planning applications. With an abundance of the UK's indigenous energy resources being either rural or coastal large volumes of DG are seeking connection at the lower voltage distribution networks. Connecting large quantities of intermittent generation, to distribution networks, presents significant problems to the planning and operation of these traditionally passive networks due to bi-directional power flows creating voltage fluctuations and uncertainty in power flow magnitudes. In addition, conventional planning methods results in financial barriers that are preventing DG connections due to the high cost of reinforcing the existing infrastructure. One method of avoiding, or at least deferring, this high capital costs is to adopt an Active Network Management (ANM) approach. This thesis presents and evaluates two novel ANM approaches that manage the real power output of multiple DG units, in real-time, such that distribution networks operate within thermal limits. Studies are conducted in a closed-loop simulation environment, with actual hardware, on two topologically different networks to demonstrate the flexibility of the novel application of the Optimal Power Flow (OPF) and the Constraint Satisfaction Problem (CSP) when applied to the Power Flow Management (PFM) problem. The performance of these model-based algorithms is assessed against their ability to detect thermal excursions, their solution computation time, their resilience to measurement error, their real power curtailment, their ability to conform to current DG commercial connection agreements and their ability to adapt to changes in network topology. Results reported in this thesis demonstrate the feasibility of these novel ANM approaches for PFM, and their applicability in terms of incorporating intelligence into the UK's future smart grids.

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Hay, Stephanie Louise. "Integration of active network management into the distribution control room environment." Thesis, University of Strathclyde, 2012. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=19081.

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The way in which distribution networks are operated and managed from the control room is changing as a result of a number of external factors, most prominently the mounting interest in renewable generation technologies and growing trends of connecting small scale generation plants at distribution level voltages in decentralised locations. Growing interest in distributed generation (DG) presents a challenge to the validity of existing distribution control room procedures and supporting tools. To accommodate large penetrations of DG, a more active approach to control is necessary and extensive research and development is currently underway in this area. Active network management (ANM) is one of the enabling strategies that will allow DG to connect, whilst potentially postponing the need for costly and time consuming network reinforcements and upgrades, by operating the network closer to its limits through real-time monitoring and control of system parameters. Parameters such as power flow and voltage, and embedded resources such as responsive demand and DG can all be controlled in a more active manner such that network resources can be used more efficiently. The management of future active distribution networks is a concern as such changes will impact the control room in various ways. This thesis describes the changes that will occur on networks and how they will affect the control room in different ways, as well as the uncertainties associated with DG and ANM deployment. A Control Room Demonstration Suite (CoRDS) provides a comprehensive view of future networks and their operational issues, allowing preparatory measures to be taken by Distribution Network Operators (DNO). The CoRDS is also used to study the required behavioural changes of distribution control engineers in the way they will interact with ANM schemes.

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Schittekatte, Tim. "Distribution network tariff design and active consumers : a regulatory impact analysis." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS054/document.

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La diffusion des panneaux solaires photovoltaïques à prix abordables nous amène à repenser à la manière avec laquelle les coûts des réseaux de distribution sont récupérés auprès des consommateurs. Historiquement, les consommateurs étaient facturés pour l'utilisation du réseau de distribution principalement sur la base de leur volume (net) d'électricité consommé. Avec tel type de tarif de réseau, les consommateurs qui installent des panneaux photovoltaïques contribuent beaucoup moins à la récupération du coût d’investissement réseau. Cependant, ces consommateurs (prosummeurs) dépendent autant du réseau qu’avant. La question examinée dans cette thèse est de savoir comment définir le tarif du réseau de distribution dans ce contexte changeant. Des différents modèles de théorie des jeux sont développés pour faire cette analyse. Dans ces modèles, en plus des investissements dans l’énergie solaire photovoltaïque, des investissements dans les batteries du côté des consommateurs sont aussi considérés. Ce rapport de thèse consiste en un bref aperçu suivi de quatre chapitres indépendants et d'une conclusion
The uptake of affordable solar PV panels challenges the way in which costs of distribution networks are recuperated from consumers. Historically, consumers were charged for the use of the distribution network mainly according to their (net) volume of electricity consumed over a period of time. With such volumetric network charges, consumers installing PV panels contribute a lot less towards the recuperation of network costs. However, these consumers (prosumers) still rely on the network as much as they did before. The question investigated in this thesis is how to re-design the distribution network tariff in this changing context. Different game-theoretical models are developed to conduct this analysis. In the models, not only investments in solar PV but also investments in batteries at the consumer-side are considered. The thesis consists of a brief overview followed by four standalone chapters and a conclusion

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Chaitanya, Deshpande. "Multi-Agent Based Fault Localizationand Isolation in Active DistributionNetworks." Thesis, KTH, Industriella informations- och styrsystem, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-169221.

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Liberalized electricity markets, increased awareness of clean energy resources and theirdecreasing costs have resulted in large numbers of distributed power generators beinginstalled on distribution network. Installation of distributed generation has altered thepassive nature of distribution grid. A concept of Active Distribution Network is proposedwhich will enable present day infrastructure to host renewable energy resources reliably.Fault management that includes fault localization, isolation and service restoration ispart of active management of distribution networks.This thesis aims to introduce a distributed protection methodology for fault localizationand isolation. The objective is to enhance reliability of the network. Faults are identifiedbased on root mean square values of current measurements and by comparing thesevalues with preset thresholds. The method based on multi-agent concept can be usedto locate the faulty section of a distribution network and for selection of faulty phases.The nodal Bus Agent controls breakers that are associated with it. Based on indicationof fault, adjacent bus Agents communicate with each other to identify location of fault.A trip signal is then issued to corresponding Breakers in adjacent Bus Agents, isolatingthe faulty section of line. A case study was carried out to verify suitability of the proposedmethod. A meshed network model and multi-agent based protection scheme wassimulated in Simulink SimPowerSystems. Considering nature of Distribution Network,separate breakers for each phase are considered. The distribution network protectionsystem identified fault introduced in the network correctly along with interrupting thefault current.Keywords

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Constante, Flores Gonzalo Esteban. "Conservation Voltage Reduction of Active Distribution Systems with Networked Microgrids." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1531861356445195.

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Ding, Jiansong. "Optimisation of a power distribution network's active power loss and reliability performance." Thesis, University of Strathclyde, 2013. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=20299.

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The deregulation of UK power distribution market started in 1990. Due to the drivers from the regulator, DNOs need to invest appropriately and optimise network operation by innovations to satisfy the targets set by the industry regulator, the Office of Gas and Electricity Markets (Ofgem). Reduction of network losses and improvement of reliability of supply to customers are extremely important for distribution network operators (DNOs) to take into account when designing and operating their networks. They are important because of the need to minimise wasted energy and carbon emissions and to provide customers with an adequate level of service. Moreover, in Great Britain, Ofgem has implemented financial incentives with respect to these things. This thesis describes an investigation of methods these have been developed to help DNOs improve their performance with respect to two particular incentives. The first relates to network losses; the second relates to reliability of supp ly to consumers. A new loss optimisation algorithm by feeder reconfiguration based on graph theory and topology search techniques is developed in this thesis. By means of a directed exhaustive search of network configurations (and unlike a number of previous methods in the literature that rely on heuristics), this algorithm can find the global optimal result. In addition the results of the algorithm can be readily used in the solution of a multiobjective optimisation problem (optimisation both of P loss and reliability in this thesis). A new reliability evaluation and optimisation algorithm developed in this thesis is based on topology search techniques. This algorithm can not only calculate the reliability indices but, unlike previous approaches emerging from the academic literature, also determines the restoration method of each fault affected bus for a specific fault which is critical to determining the restoration time following a fault. The loss and reliability optimisation is developed to optimise both network's P loss and reliability performance. It can also provide a number of options regarding the configuration of the network, and suggests which are optimal with respect to either incentive or to both of them combined. An analytical tool developed to perform these algorithms is described. Case studies are presented to illustrate how DNOs can use the analytical methods and tool developed in this thesis to accurately calculate the impacts of design or operation decisions on losses and reliability and thereby help in the identification of cost-effective network operation actions and longer-term investments.

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Ainah, Priye. "Coordinated active power reduction strategy for voltage rise mitigation in LV distribution network." Thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/28351.

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Integration of renewable energy systems by the utility, customers, and the third party into the electric power system, most especially in the MV and LV distribution networks grew over the last decade due to the liberalization of the electricity market, rising energy demand, and increasing environmental concern. The distributed rooftop PV system contributes to relieve the overall load, reduce losses, avoid conventional generation upgrade, and better matching of demand on the LV distribution network. Originally, the LV distribution network is designed for unidirectional current flow, that is from the substation to customers. However, a high penetration of rooftop solar PVs (with power levels typically ranging from 1 – 10 kW) may lead to the current flowing in the reverse direction and this could result in a sudden voltage rise. These negative impacts on the network have discouraged the distribution network operators (DNOs) to allow increased PV penetration in the LV distribution network because some customers load, and equipment are sensitive to voltage perturbation. Presently, the most applied voltage rise mitigation strategy for high rooftop solar PV penetration is the total disconnect from the LV distribution network when the voltage at the point of common coupling (PCC) goes above statutory voltage limits. However, the sudden disconnection of the PV system from the grid can cause network perturbation and affect the security of the network. This action may also cause voltage instability in the network and can reduce the lifetime of grid equipment such as voltage regulators, air conditioner etc. Due to this negative impact, different voltage rise mitigation strategies such as the active transformer with on load tap changers (OLTC), distributed battery energy storage system and reactive power support (D-STATCOM, etc.) have been used to curtail voltage rise in the distribution network. However, the implementation of D-STATCOM device on a radial LV distribution network results in high line current and losses. This may be detrimental to the distribution network. Therefore, in this thesis, a coordinated active power reduction (CAPR) strategy is proposed using a modified PWM PI current control strategy to ramp down the output power and voltage of a grid-tied voltage source inverter (VSI). In the proposed strategy, a reactive reference is generated based on the measured voltage level at the PCC using a threshold voltage algorithm to regulate the amplitude of the modulating signal to increase the off time of the high frequency signal which shut down the PV array momentary in an extremely short time and allow the VSI to absorb some reactive power through the freewheeling diode and reduce voltage. The proposed CAPR strategy was designed and simulated on a scaled down simple radial LV distribution network in MATLAB®/Simulink® software environment. The results show that the CAPR can ramp down the PV output power, reduce reverse power flow and reduce the sudden voltage rise at the point of common coupling (PCC) within ±5% of the standard voltage limit. The study also compares the performance of the proposed CAPR strategy to that of the distributed static compensator (D-STATCOM) and battery energy storage system (BESS) with respect to response time to curtail sudden voltage rise, losses and reverse power flow. The investigation shows that the D-STATCOM has the faster response time to curtail voltage rise. However, the voltage rise reduction is accompanied by high current, losses and reverse active power flow. The introduction of the BESS demonstrates better performance than the D- STATCOM device in terms of reverse power flow and losses. The CAPR strategy performs better than both D-STATCOM and BESS in terms of line losses and reverse power flow reduction.

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Mat, Zali Samila Binti. "Equivalent dynamic model of distribution network with distributed generation." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/equivalent-dynamic-model-of-distribution-network-with-distributed-generation(f4dc9bba-ed4a-4c74-a727-735f3addb6b2).html.

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Today’s power systems are based on a centralised system and distribution networks that are considered as passive terminations of transmission networks. The high penetration of Distributed Generation (DG) at the distribution network level has created many challenges for this structure. New tools and simulation approaches are required to address the subject and to quantify the dynamic characteristics of the system. A distribution network or part of it with DG, Active Distribution Network Cell (ADNC), can no longer be considered as passive. An equivalent dynamic model of ADNC is therefore extremely important, as it enables power system operators to quickly estimate the impact of disturbances on the power system’s dynamic behaviour. A dynamic equivalent model works by reducing both the complexity of the distribution network and the computation time required to run a full dynamic simulation. It offers a simple and low-order representation of the system without compromising distribution network dynamic characteristics and behaviour as seen by the external grid. This research aims to develop a dynamic equivalent model for ADNC. It focuses on the development of an equivalent model by exploiting system identification theory, i.e. the grey-box approach. The first part of the thesis gives a comprehensive overview and background of the dynamic equivalent techniques for power systems. The research was inspired by previous work on system identification theory. It further demonstrates the theoretical concept of system identification, system load modelling and the modelling of major types of DG. An equivalent model is developed, guided by the assumed structure of the system. The problem of equivalent model development is then formulated under a system identification framework, and the parameter estimation methodology is proposed. The validation results of the effectiveness and accuracy of the developed model are presented. This includes the estimation of the parameter model using a clustering algorithm to improve the computational performance and the analysis of transformer impedance effects on the ADNC responses. The evaluation of probability density function, eigenvalue analysis and parameter sensitivity analysis for the model parameters are also presented. Typical model parameters for different network topologies and configurations are identified. Finally, the developed equivalent model is used for a large power system application. The accuracy and robustness of the developed equivalent model are demonstrated under small and large disturbance studies for various types of fault and different fault locations.

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Zubo, Rana H. A. "Distribution Network Operation with High Penetration of Renewable Energy Sources. Joint Active/Reactive Power Procurement: A Market-Based Approach for Operation of Distribution Network." Thesis, University of Bradford, 2019. http://hdl.handle.net/10454/18267.

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Distributed generators (DGs) are proposed as a possible solution to supply economic and reliable electricity to customers. It is adapted to overcome the challenges that are characterized by centralized generation such as transmission and distribution losses, high cost of fossil fuels and environmental damage. This work presents the basic principles of integrating renewable DGs in low voltage distribution networks and particularly focuses on the operation of DG installations and their impacts on active and reactive power. In this thesis, a novel technique that applies the stochastic approach for the operation of distribution networks with considering active network management (ANM) schemes and demand response (DR) within a joint active and reactive distribution market environment is proposed. The projected model is maximized based on social welfare (SW) using market-based joint active and reactive optimal power flow (OPF). The intermittent behaviour of renewable sources (such as solar irradiance and wind speed) and the load demands are modelled through Scenario-Tree technique. The distributed network frame is recast using mixed-integer linear programming (MILP) that is solved by using the GAMS software and then the obtained results are being analysed and discussed. In addition, the impact of wind and solar power penetration on the active and reactive distribution locational prices (D-LMPs) within the distribution market environment is explored in terms of the maximization of SW considering the uncertainty related to solar irradiance, wind speed and load demands. Finally, a realistic case study (16-bus UK generic medium voltage distribution system) is used to demonstrate the effectiveness of the proposed method. Results show that ANM schemes and DR integration lead to an increase in the social welfare and total dispatched active and reactive power and consequently decrease in active and reactive D-LMPs.
Ministry of Higher Education and Scientific Research - Iraq
The selected author's publications, the published versions of which were attached at the end of the thesis, have been removed due to copyright.

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Wu, Xiang [Verfasser], Antonello [Akademischer Betreuer] Monti, and Albert [Akademischer Betreuer] Moser. "New approaches to dynamic equivalent of active distribution network for transient analysis / Xiang Wu ; Antonello Monti, Albert Moser." Aachen : Universitätsbibliothek der RWTH Aachen, 2017. http://d-nb.info/1162845902/34.

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Numair, M., D.-EA Mansour, and Geev Mokryani. "A Proposed IoT Architecture for Effective Energy Management in Smart Microgrids." IEEE, 2020. http://hdl.handle.net/10454/18491.

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yes
The current electricity grid suffers from numerous challenges due to the lack of an effective energy management strategy that is able to match the generated power to the load demand. This problem becomes more pronounced with microgrids, where the variability of the load is obvious and the generation is mostly coming from renewables, as it depends on the usage of distributed energy sources. Building a smart microgrid would be much more economically feasible than converting the large electricity grid into a smart grid, as it would require huge investments in replacing legacy equipment with smart equipment. In this paper, application of Internet of Things (IoT) technology in different parts of the microgrid is carried out to achieve an effective IoT architecture in addition to proposing the Internet-of-Asset (IoA) concept that will be able to convert any legacy asset into a smart IoT-ready one. This will allow the effective connection of all assets to a cloud-based IoT. The role of which is to perform computations and big data analysis on the collected data from across the smart microgrid to send effective energy management and control commands to different controllers. Then the IoT cloud will send control actions to solve microgrid's technical issues such as solving energy mismatch problem by setting prediction models, increasing power quality by the effective commitment of DERs and eliminating load shedding by turning off only unnecessary loads so consumers won't suffer from power outages. The benefits of using IoT on various parts within the microgrid are also addressed.

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Mnie, Filali Imane. "Distribution multi-contenus sur Internet." Thesis, Université Côte d'Azur (ComUE), 2016. http://www.theses.fr/2016AZUR4068/document.

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Dans cette thèse, nous nous sommes intéressés aux protocoles pair-à-pair (P2P), qui représentent une solution prometteuse pour la diffusion et le partage de données à faible coût sur Internet. Nous avons mené, dans un premier temps, une étude comportementale de différents protocoles P2P pour le partage de fichier (distribution de contenus sans contrainte de temps) puis le live. Dans la première étude centréesur le partage de fichier, nous avons montré l’impact d’Hadopi sur le comportement des utilisateurs et discuté l’efficacité des protocoles en fonction du contenu et l’efficacité protocolaire, en se basant sur les choix des utilisateurs. BitTorrent s’est nettement démarqué au cours de cette étude, notamment pour les grands contenus. En ce qui concerne le live, nous nous sommes intéressés à la qualité de servicedu réseau de distribution live Sopcast, car plus de 60% des événements live diffusés en P2P le sont sur ce réseau. Notre analyse approfondie de ces deux modes de distribution nous a fait nous recentrer sur BitTorrent, qui est à la base de tous les protocoles P2P Live, et est efficace en partage de fichier et complètement open source. Dans la seconde partie de la thèse, nous avons proposé et implémenté dansun environnement contrôlé un nouveau protocole sur la base de BitTorrent avec des mécanismes protocolaires impliquant tous les pairs dans la gestion du réseau. Ces nouveaux mécanismes permettent d’augmenter l’efficacité du protocole via une meilleure diffusion, tant pour le live que le partage de fichier, de métadonnées (la pièce la plus rare) et via une méthode dite de push, par laquelle un client va envoyer du contenu aux pairs les plus dans le besoin
In this study, we focused on peer-to-peer protocols (P2P), which represent a promising solution for data dissemination and content delivery at low-cost in the Internet. We performed, initially, a behavioral study of various P2P protocols for file sharing (content distribution without time constraint) and live streaming. Concerning file sharing, we have shown the impact of Hadopi on users’ behavior and discussed the effectiveness of protocols according to content type, based on users’ choice. BitTorrent appeared as the most efficient approach during our study, especially when it comes to large content. As for streaming, we studied the quality of service of Sopcast, a live distribution network that accounts for more than 60% of P2P broadcast live events. Our in-depth analysis of these two distributionmodes led us to focus on the BitTorrent protocol because of its proven efficiency in file sharing and the fact that it is open source. In the second part of the thesis, we proposed and implemented a new protocol based on BitTorrent, in a controlled environment. The modifications that we proposed allow to increase the efficiency of the protocol through improved dissemination of metadata (the rarest piece), both for live and file sharing. An enhanced version is introduced with a push method, where nodes that lag behind receive an extra service so as to improve the overall performance

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Korniienko, Anton. "Réseau de PLLs distribuées pour synthèse automatique d'horloge de MPSOCs synchrones." Phd thesis, Ecole Centrale de Lyon, 2011. http://tel.archives-ouvertes.fr/tel-00676933.

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Les arbres classiques de distribution du signal d'horloge au sein des microprocesseurs synchrones présentent un certain nombre de limitations : skew, jitter, limitation de la fréquence, influence de perturbations et de dispersions quelles que soient leurs natures. Ces facteurs, critiques pour les microprocesseurs modernes complexes, sont devenus la raison principale qui a poussé à la recherche d'autres types d'architecture de génération et de distribution du signal d'horloge. Un exemple d'un tel système alternatif est le réseau de PLLs couplées, où les PLLs sont géographiquement distribuées sur la puce, et génèrent des signaux d'horloge locaux qui sont ensuite synchronisés, en temps réel, par un échange d'information entre les PLLs voisines et une rétroaction locale réalisé par leur correcteurs. La nature active du réseau de PLLs de génération et de distribution du signal d'horloge, qui peut permettre de surpasser les limitations mentionnées plus tôt, oblige à sortir du cadre classique des outils et des méthodes de la Microélectronique habituellement appliqués à l'étude et à la conception de ce type de systèmes. En effet, les aspects dynamiques de bouclage et de transformation de signaux au sein de tels systèmes complexes rendent leur conception extrêmement difficile voire parfois impossible. La difficulté principale consiste en un changement des propriétés d'un sous-système local indépendant par rapport aux propriétés du même sous-système faisant partie du réseau. Effectivement, il existe beaucoup de méthodes et d'outils de conception d'une PLL isolée garantissant un comportement et des propriétés locales désirés. Néanmoins, ces propriétés désirées locales, selon la topologie d'interconnexion considérée, ne sont pas forcément conservées quand il s'agit d'un réseau de PLLs interconnectées et de son comportement global. Le but principal de cette thèse est ainsi de développer une méthode de synthèse de la loi de commande décentralisée réalisée au sein de chaque sous-système (tel qu'une PLL) assurant le comportement désiré pour le réseau global. Une méthode de transformation du problème de synthèse globale en un problème équivalent de synthèse d'une loi de commande locale est proposée en se basant sur l'hypothèse des sous-systèmes identiques interconnectés en réseau. Le lien entre les propriétés locales et globales est établi grâce aux approches d'Automatique avancée telles que les approches entrée-sortie et la dissipativité. Ce choix de méthode permet non seulement de réduire considérablement la complexité du problème initial mais aussi de ramener le problème de synthèse à une forme proche des méthodes de conception locale utilisées en Microélectronique, ce qui garantit une continuité logique de leur évolution. Ensuite la méthode proposée est combinée avec la commande H∞ et l'optimisation sous contraintes LMIs conduisant au développement d'algorithmes efficaces de résolution du problème posé. Elles sont à la fois particulièrement bien adaptées à l'application considérée, c'est-à-dire à la synchronisation d'un réseau de PLLs, et sont facilement généralisables aux autres types de problèmes de commande de systèmes de grande dimension. Le premier aspect permet une intégration naturelle et aisée de la méthode dans le flux de conception existant en Microélectronique, très riche et mature à ce jour, alors que le deuxième offre une solution à d'autres problèmes de commande de systèmes interconnectés en réseau, un champ d'application aujourd'hui en plein essor.

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Fournie, Sandrine. "Construction sociotechnique et relationnelle d'une gouvernance alimentaire territoriale." Thesis, Paris, Institut agronomique, vétérinaire et forestier de France, 2016. http://www.theses.fr/2016IAVF0014/document.

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Les Systèmes Agroalimentaires Localisés représentent des formes d'organisation de productionet de consommation particulières. Ils se différencient des systèmes agro-industriels dans larelation singulière qui unit les hommes, les produits et le territoire, dans la valorisation deressources spécifiques et dans des modalités de coordination géographiquement et socialementsituées. Un nombre croissant d'initiatives cherchent à les mettre en œuvre au travers descircuits courts, des circuits de proximité ou des projets alimentaires territoriaux.Nos travaux proposent d'éclairer d'un regard sociologique les mécanismes de construction deces systèmes alimentaires à partir de l'étude fine d'expériences pionnières. Nous mobilisons lescadres d'analyse déployés par la sociologie de l'innovation et de l'acteur-réseau d'une part, etpar la sociologie des réseaux d'autre part. L'expérience de la coopérative agricole Fermes deFigeac témoigne des processus d'activation du lien entre l'agriculture, l'alimentation et leterritoire, et de valorisation des ressources spécifiques. Ils se matérialisent dans les réseauxsociotechniques qui portent les circuits alimentaires territorialisés. Inspirés du modèle de lacoopération agricole, les responsables de l'organisation soutiennent l'expérimentation d'unedémarche de gouvernance alimentaire afin de coordonner les stratégies individuelles dans desstratégies coopératives pour répondre aux enjeux collectifs de développement.Les analyses révèlent les processus de traduction, de transformation et de médiation quiinterviennent au sein des organisations et à leurs frontières. Ces opérations s'avèrentnécessaires aux constructions collectives et aux coordinations des acteurs (humains et objets,individus et collectifs). Nous montrons le rôle des positions intermédiaires dans l'articulationdes stratégies et les capacités d'adaptation et d'innovation. Nous rendons également compte dela diversité et la variabilité des formes relationnelles qui accompagnent ces dynamiques.Menés dans le cadre d'une recherche-action, nos travaux s'inscrivent dans la volonté de coproductionthéorique et empirique. D'un point de vue opérationnel, nous attirons l'attentionsur l'importance des médiations (animations, documents, échanges…) dans les processuscollectifs et coopératifs et de l'indétermination (imprévisibilité) des dynamiques de changement.Nous proposons de tenir compte des réseaux secondaires et d'identifier les acteursintermédiaires (au-delà des représentants formels) dans les analyses de gouvernance alimentaireterritoriale
Local Agri-Food System (SYAL) represents a particular form of organization of production andconsumption. SYAL differs from agro-industrial system as it encompass the singular web ofrelationship which unit people, the qualification of products and territory through the valuationof specific resources and the types of coordination that are geographically and socially situated.An increasing number of initiatives try to implement them, through short food circuits,proximity supply chains or local food projects.Our work proposes an empirical journey and a sociological theorizing of the mechanismsthrough which a particular local agri-food system has been enhanced. We mobilize theframeworks of Actor-Network-Theory (ANT) on one hand and by the Social Network Analysis(SNA) on the other hand. We took the opportunity of an in depth study of an agriculturalcooperative named “Fermes of Figeac” to decipher processes of structuration of associationbetween farming practices, food provisioning, territorial human agency and valuation'sprocesses of the specific resources. Those associations are materialized in socio-technicalnetworks, which supported territorialized food supply chain. Inspired by the foundationalmodel of agricultural cooperation, the managerial core set of the organization has experimentedan approach of food provision governance in order to transform individual strategies in cooperativestrategies with the aim to answer sustainable challenge at the local level.Analyses based on ANT and SNA methodology assess translation's, transformation's andmediation's processes that intervene within organizations and on their borders. Going beyond afunctional analysis, we also analyze the collective construction and the coordination of humanagency and objects, at both individual and collective levels. We particularly shed light on therole of intermediation positions in strategic articulations and of the capacities of adaptation andinnovation. We also report the diversity and the variability of the relational forms that sustaindynamics of change.Released in an action-research approach, our work intends to articulate theoretical andempirical production. From an operational point of view, we draw attention to mediations(animations, documents, exchanges…) in the collective and co-operative processes and to theunpredictability of dynamics of change. This leads to take into account secondary networks andto identify intermediaries (beyond the formal core set of managers) in the analysis of territorialfood governance

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Харевич, Віктор Ігорович, and Viktor Harevych. "Використання нерегульованих конденсаторних батарей в мережах 10 кВ." Master's thesis, Тернопільський національний технічний університет імені Івана Пулюя, кафедра електричної інженерії,Тернопіль, Україна, 2021. http://elartu.tntu.edu.ua/handle/lib/36658.

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Розвиток сучасної енергетики ґрунтується на поліпшенні технічних і економічних параметрів силового обладнання, підвищення їх надійності, рівня автоматизації та пропускної спроможності лінії електропередачі при постійному підвищенні якості електричної енергії і, відповідно, зменшенням втрат. Одним із найважливіших на сьогоднішній день питань при зростанні споживаної потужності залишається проблема зниження втрат та підвищення пропускної здатності, що в свою чергу вимагає розробки заходів щодо оптимізації параметрів режиму мережі з відповідним їх технічним і економічним обґрунтуванням. Зазначені проблеми оптимізації роботи міських розподільчих мереж не є чимось новим – вони розглядається вже на протязі довгого часу [1]. Зазвичай поставлені задачі оптимізації параметрів і режимів роботи потрібно вирішувати ще на стадії проектування, розвитку або реконструкції таких електричних мереж. На даний час усі міські розподільні мережі виконані у вигляді замикаючої ланки в енергетичній системі, яка забезпечує споживачів потрібною електричною енергією [2]. Варто відмітити, що сучасні міські поселення на теперішній час харак-теризуються доволі високою густиною електричних навантажень з питомою часткою споживання електричної енергії на малій території, що обумовлює збільшення втрат електричної енергії. В результаті доволі значного застосу-вання електричних приймачів нового покоління, які споживають з мережі також і значну частку реактивної потужності поряд з активною потужністю, мають місце значні втрати електричної енергії в електромережах 10/0,4 кВ.
У даній кваліфікаційній роботі було розглянуто проблеми зниження втрат електричної енергії в міських електричних мережах, виконано оптимізаційний розрахунок розміщення нерегульованих батарей статичних конденсаторів на шинах трансформаторних пунктів напругою 10/0,4 кВ та розрахунок наванта¬жу¬вальних втрат типової схеми без компенсації реактивної потужності і з вста-новленням нерегульованих батарей на шинах ТП 10 кВ і 0,4 кВ. Отримані розрахунки за допомогою типової схеми розміщення нерегу¬льо¬ваних конденсаторних батерей на шинах трансформаторних пунктів 10 кВ і 0,4 кВ розподільчої електромережі показали, що максимальне зниження річних втрат можна отримати при їх встановленні на шинах ТП 0,4 кВ, що дозволяє отримати кращий ефект від компенсації реактивної потужності у розподільній мережі та значно знизити втрати електричної енергії і, відповідно, відтермі¬нувати будівництво нових силових потужностей, що є надзвичайно актуаль¬ною проблемою на сьогоднішній день
In this qualification work the problems of reduction of electric energy losses in city electric networks were considered, optimization calculation of placement of unregulated batteries of static capacitors on busbars of transformer points with voltage 10 / 0,4 kV and calculation of loading losses of the standard scheme without compensation of reactive power and with installation of unregulated batteries on 10 kV and 0.4 kV busbars. The calculations obtained using a typical scheme of placement of unregulated capacitor banks on the busbars of transformer points 10 kV and 0.4 kV of the distribution network showed that the maximum reduction of annual losses can be obtained by installing them on busbars 0.4 kV, which allows to obtain better effect of reactive power compensation in the distribution network and significantly reduce electricity losses and, accordingly, delay the construction of new power plants, which is an extremely important issue today
ЗМІСТ ВСТУП 6 1 АНАЛІТИЧНИЙ РОЗДІЛ 10 1.1 Аналіз втрат електроенергії в розподільних мережах 10/0,4 кВ 10 1.2 Аналіз режимів роботи в розподільних мережах 10/0,4 кВ 13 1.3 Заходи щодо зниження втрат в мережах 10/0,4 кВ 17 1.4 Способи компенсації реактивної потужності в мережах 10/0,4 кВ 20 1.5 Проблеми компенсації реактивної потужності в міських мережах 23 1.6 Висновки до розділу 1 26 2 ПРОЕКТНО-КОНСТРУКТОРСЬКИЙ РОЗДІЛ 27 2.1 Визначення вхідних даних 27 2.2 Вибір потужності конденсаторних батарей 30 2.3 Вибір місця встановлення конденсаторної батареї 34 2.4 Висновки до розділу 2 36 3 РОЗРАХУНКОВО-ДОСЛІДНИЦЬКИЙ РОЗДІЛ 37 3.1 Визначення вихідних даних для проведення розрахунку 37 3.2 Розрахунок втрат потужності у нормальному режимі 47 3.3 Вибір нерегульованих батарей статичних конденсаторів 50 3.4 Втрати електроенергії на шинах ТП 0,4 кВ при встановленні НБСК 51 3.5 Втрати електроенергії на шинах ТП 10 кВ при встановленні НБСК 54 3.6 Використання нерегульованих конденсаторних батарей на шинах трансформаторних пунктів 0,4 кВ 57 3.7 Висновки до розділу 3 59 4 ОХОРОНА ПРАЦІ ТА БЕЗПЕКА В НАДЗВИЧАЙНИХ СИТУАЦІЯХ 60 4.1 Заходи безпеки при експлуатації пристроїв компенсації реактивної потужності 60 4.2 Захист персоналу у діючих електроустановках 63 ЗАГАЛЬНІ ВИСНОВКИ 67 ПЕРЕЛІК ПОСИЛАНЬ 69

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49

Fiala, Martin. "Elektrické sítě využívající stejnosměrné napětí do 1000 V." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-241980.

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This master´s thesis deals with the proposal of DC low voltage network at a voltage level of 1000 V DC in Praskolesy u Mrakotina village. Direct distribution will be realized only at the terminal, which will power the village. Next part of this thesis is theoretical and its main focus is description of both DC and AC distribution systems. The proposed DC grid will use existing distribution grid. The thesis further describes the problems of long terminals in low voltage distribution systems and electrical installation in buildings. The result of this work is a comparison of the losses between AC and the proposed DC system. The last part deals with economical evaluation and technical solution for the proposed network variant, including their advantages and disadvantages.

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Magne, Pierre. "Contribution à l'étude de la stabilité et à la stabilisation des réseaux DC à récupération d'énergie." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0119/document.

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Ce mémoire est consacré à l'étude du phénomène d'instabilité pouvant apparaître sur les bus continus des réseaux DC. En effet, l'interaction entre les différents sous-systèmes électriques (source, charge, filtre) composant le réseau DC peut conduire, sous certaines conditions, à l'instabilité du système. A partir de la modélisation des charges sous forme de "Charge à Puissance Constante" (notée CPL), des méthodes d'études permettant l'analyse de la stabilité "petit-signal" et "grand-signal" des systèmes électriques sont présentées. Celles-ci permettent de mettre en évidence le fait qu'un réseau DC ne peut pas fournir n'importe quelle puissance à ses charges sans devenir instable. Ces puissances limites dépendent à la fois de la structure du réseau et des valeurs de ses éléments passifs et de sa tension de bus. Afin de pouvoir augmenter l'amortissement/les marges de stabilité du système, des méthodes de stabilisation sont présentées dans ce mémoire. Elles proposent d'adapter les commandes des charges de manière à assurer sa stabilité. Ceci se fait grâce à l'addition d'un signal stabilisant sur la référence de chaque charge. Ce signal n'est visible que durant les régimes transitoires de la charge afin de ne pas modifier le point de fonctionnement demandé. Néanmoins, plus on voudra stabiliser une charge et plus son signal stabilisant sera important. Un bon compromis doit donc être trouvé afin d'assurer la stabilité du système sans altérer les performances dynamiques des charges. Deux approches différentes sont proposées afin de générer ces commandes stabilisantes. La première se base sur la mise en place d'un stabilisateur centralisé. Deux méthodes centralisées sont alors proposées : la première s'appuie sur la théorie des multimodèles de Takagi-Sugeno alors que la seconde s'appuie sur la théorie de Lyapunov. Cette dernière permettra d'orienter les efforts de stabilisation sur les charges souhaitées pour par exemple, les diriger principalement vers les organes de récupération d'énergie. La seconde approche se base sur la mise en place d'un système de stabilisation multi-agent. Celui-ci présente une structure décentralisée où chaque agent correspond à un bloc de stabilisation. Ceux-ci vont compenser localement les impacts déstabilisants de leur charge respective et leurs actions combinées permettront d'assurer la stabilité du système. De plus, on propose d'utiliser un algorithme d'optimisation sous contraintes qui permettra de donner un dimensionnement du système minimisant les efforts de stabilisation tout en considérant des cas de défaut tels que la perte de l'un des agents ou la reconfiguration du réseau
This thesis is devoted to the analysis of the instability phenomenon that may appear on the DC bus of DC microgrids. Indeed, interaction between the different electrical subsystems of the grid (source, load, filters) can lead, under certain conditions, to the system instability. From the "Constant Power Load" (CPL) hypothesis for the loads, this thesis presents studying methods for "small-signal" and "large-signal" stability analysis of electrical systems. This highlights that a DC microgrid cannot power the loads more than a maximum limit without becoming unstable. This power limitation depends on the structure of the grid, the value of its passive components, and its bus voltage. In order to improve the microgrid stability, stabilization methods are presented in this thesis. They propose to adapt the loads control to ensure the system stability. This is achieved by the addition of a stabilizing signal to the reference of each load. This signal is only visible during the load power transient mode to not change the requested operating point. However, a good trade-off must be found to ensure system stability without affecting the dynamic performance of its loads. Two approaches are investigated to generate the stabilizing commands. The first one is based on the establishment of a centralized stabilization block. Two centralized methods have been developed: the first one is based on the Takagi-Sugeno theory while the second is based on the Lyapunov theory. This latest permits to guide the stabilizing effort on the desired loads. For example, stabilizing effort can be oriented on the energy storage device. The second approach is based on the establishment of a multi-agent stabilizing system. It consists of a decentralized structure in which each agent corresponds to a stabilization block. These will locally compensate the destabilizing impact of their respective load on the microgrid, and their combined actions ensure the system stability. To design the system, the use of a constrained optimization algorithm is proposed. This permits to minimize stabilization efforts while considering faulty events such as the failure of one of the agents or a reconfiguration of the microgrid

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Dissertations / Theses on the topic 'Active Distribution Networks'

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