Дисертації з теми "Interconnected distribution networks"

Large scale penetration of distributed generation is one of the most important challenges that Smartgrids will need to deal with. Among the possible solutions to increase the amount of distributed generation, there is one that consists in meshing the existing looped (but radially operated) distribution-grid topologies. In order to migrate towards meshed and actively operated topologies, this PhD proposes:- The study a solution that is able to modulate power-flow (active and reactive powers independently) in the ties between distribution grids.- The analyzed solution must also be able to improve power-quality or to avoid propagation of power quality disturbances from one grid to the other.In order to satisfy the double challenge of controlling power-flow and power quality simultaneously, this PhD proposes the use of a Unified Power Line Conditioner (UPLC). Considering the outstanding functionalities of UPLC, the main ambition of the PhD is to explore the potential and the interest of using such an apparatus for interconnecting MV distribution grids.It must nevertheless consider that UPLC is not the only a device capable of combining these functions. A device named Medium Voltage Direct Current (MVDC) can also deal with these multiple objectives. One part of the PhD is thus committed to a comprehensive comparison between both apparatus.

CMOS is well known for its ability to scale. This fact is reflected in the aggressive scaling on a continual basis from the invention of CMOS up to date. As devices are scaled, device performance improves due to shorter channel lengths and more densely packed functions for the same amount of area. In recent years, however, the performance gain obtained through scaling has begun to suffer under the degradation of the associate interconnect performance. As devices become smaller, interconnects need to follow. Unlike transistors, the scaling of interconnects results in higher capacitances and resistances, thereby limiting overall system performance. Trying to alleviate the delay effects results in increased power consumption, especially in global structures such as clock distribution networks. A possible solution to this problem is the use of optical interconnects, which are fast and much less lossy than the electrical equivalents. This dissertation describes an investigation on what future technology nodes will entail in terms of power consumption of clock networks, and what is required for an optical alternative to become feasible. A common clock configuration is used as a basis for comparison, where both electrical and optical networks are designed to component level. Optimisation is done on both to ensure a reasonable comparison, and the results of the respective power consumption components are then compared in order to find the criteria for a feasible optical clock distribution scheme. Copyright
Dissertation (MEng)--University of Pretoria, 2009.
Electrical, Electronic and Computer Engineering
unrestricted

Thesis (Ph. D.)--University of Missouri--Rolla, 2007.
Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 16, 2007) Includes bibliographical references (p. 134-136).

Cette thèse porte sur la construction des algorithmes distribués pour l’optimisation de la production et du partage de ressources au sein d’un réseau de large dimension. Notamment, on se concentre sur les réseaux électriques et les réseaux cellulaires 5G. On considère dans le cas des réseaux électriques le problème OPF (Optimal Power Flow) dans lequel on vise à faire la gestion et l’optimisation de la production de l’énergie électrique d’une manière distribuée. On se concentre sur une version linéarisée du problème, la DC-OPF (Direct-Current Optimal Power Flow). Comme le problème d’optimisation est convexe dans ce cas, on vise à minimiser le coût de production de l’énergie tout en respectant les limites des lignes de transmission et les contraintes caractéristiques du système. Dans le cas des réseaux cellulaires, on formule un problème de Caching. On a pour but de réduire l’utilisation du backhaul liant les stations de base et le contrôleur du réseau. Les stations de base sont équipées d’une capacité de stockage limitée. Ils visent à trouver d’une manière optimale les fichiers à stocker dans le but de réduire une certaine fonction de coût sur l’utilisation du backhaul et sur le partage des fichiers avec les autres stations de base. L’approche adoptée dans cette thèse consiste à appliquer l’ADMM (Alternating Direction Method of Multipliers), une méthode d’optimisation de manière itérative, à un problème d’optimisation que l’on a préalablement reformulée de façon adéquate. Ce problème permet à la fois de décrire le DC-OPF et le problème de Caching. On démontre la convergence de cette méthode quand elle est appliquée noeud par noeudd’une manière totalement distribuée. Ainsi que dans le cas où le réseau est divisé en plusieurs zones. Ces zones peuvent se chevaucher mais aussi elles peuvent être séparées ou indépendantes. De plus, dans le contexte d’un réseau à zones, on démontre que l’application de l’ADMM d’une manière aléatoire par une seule zone converge aussi vers la solution optimale du problème
This thesis focuses on the construction of distributed algorithms for optimizing resource production in a large interconnected system. In particular, it focuses on power grid and 5G cellular networks. In the case of power grid networks, we consider the OPF (Optimal Power Flow) problem in which one seeks to manage and optimize the production of electrical energy in a distributed manner. We focus on a linearized version of the problem, the DC-OPF (Direct- Current Optimal Power Flow) problem. This optimization problem is convex; the aim is to minimize the cost of energy generation while respecting the limits of the transmission line and the power flow constraints. In the case of 5G cellular networks, we formulate a caching problem. We aim to offload the backhaul link usage connecting the small bases stations (SBSs) to the central scheduler (CS). The SBSs are equipped with a limited storage capacity. We seek to find the optimal way to store files so as to reduce the cost on the use of backhaul and sharing files with other SBSs. The approach adopted in this thesis is to apply the ADMM (Alternating Direction Method of Multipliers), an optimization method that is applied iteratively, to an optimization problem that we adequately formulated previously. This problem can both describe the DC-OPF problem and the Caching problem. We prove the convergence of the method when applied node by node in a fully distributed manner. Additionally, we prove its convergence in the case where the network is divided into multiple areas or nations that may or may not overlap. Furthermore, in the context of a network with multiple areas, we show that the application of ADMM in a random manner by a single randomly chosen area also converges to the optimal solution of the problem

Integrated systems with billions of transistors on a single chip are a now reality. These systems include multi-core microprocessors and are built today using deca-nanometer devices organized into synchronous digital circuits. The movement of data within such systems is regulated by a set of predictable timing signals, called clocks, which must be distributed to a large number of sequential elements. Collectively, these clocks have a significant impact on the frequency of operation and, consequently, on the performance of the systems. The clocks are also responsible for a large fraction of the power consumed by these systems. The objective of this dissertation is to better understand clock distribution in order to identify opportunities and strategies for improvement by analyzing the conditions under which the optimal tradeoff between power and performance can be achieved, by modeling the constraints associated with local and global clocking, by evaluating the impact of noise, and by investigating promising new design strategies for future integrated systems.

Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2005.
Madhavan Swaminathan, Committee Chair ; Sung Kyu Lim, Committee Member ; Abhijit Chatterjee, Committee Member ; David C. Keezer, Committee Member ; C. P. Wong, Committee Member. Vita. Includes bibliographical references.

碩士
建國科技大學
電機工程系暨研究所
102
Abstract The main purpose of this thesis is to simulate and analyze the power flow and short-circuit fault of photovoltaic power generation system interconnected into distribution networks. Firstly, the related studies of distributed renewable energy resources were serveyed; next, the sample system was designed referred to Taipower distribution system, and the commercial power system analysis package, ETAP Power Station, was used for system analysis before and after photovoltaic power generation system interconnected into distribution networks. In this thesis, the system impact analysis of two types of distribution feeder arrangement, which is radial and normally closed-loop, were performed under different generations and loadings. Finally, the simulatiuon results were summarized, and the outcomes of this thesis are helpful for distribution engineer to plan, design, and operate the distribution systems. Keywords：distribution system, power flow, fault analysis, distributed energy resources, Photovoltaic.

碩士
國立臺灣科技大學
電機工程系
100
The main purpose of this thesis is to investigate the planning, design, and operation problems of the Clustered Renewable Energy Systems (CRESs) interconnected with low-voltage distribution networks. First of all, the operating rules and correlative regulations for renewable energy systems, and the typical configuration of low-voltage distribution systems in Taiwan were explored, the key problems and research topics of CRESs were discussed in detail as well. Next, a sample system containing a typical Taiwan low-voltage distribution system and CRES were modeled by using the MATLAB®/Simulink®. Based on the sample system, simulation, analysis and discussion were carried out by considering the local regulations for steady voltage variation. More, an assessment methodology was proposed to evaluate the maximum allowable capacity of CRESs per customer. In addition, the system impact analysis of CRES on the low-voltage distribution system were also performed and discussed by considering the maximum possible installed capacity of Photovoltaic system, which is calculated by the typical roof area of a dwelling unit in Taiwan. The outcomes of this thesis can be applied as a reference for design, planning, and operation of CRESs and is of value to the promotion policy for renewable energy development in Taiwan.

碩士
建國科技大學
電機工程系暨研究所
100
The main purpose of this thesis is to explore the impact of the PV systems interconnected onto the distribution networks. First of all, the PV system structure, operation control mode, and related regulations for distributed energy generation systems were collected and discussed in detailed. Secondly, two Taipower distribution networks in the southern region of Taiwan were employed as the sample systems, and then the system-impact analysis were accomplished by theoretical analysis, simulation, and rigorous calculation using ETAP (Electric Transient Analysis Program) PowerStation and Matlab. Finally, the outcomes of this thesis are helpful for the distribution engineer and related study to realize the system impact of the PV systems interconnected onto distribution networks.

Power system operation is undergoing rapid changes due to market deregulations and interconnection of Distributed Energy Resources (DERs) such as wind power and solar panels. The power flow complexities arising from interconnection of DERs into the distribution network have adverse effect on protection systems which can degrade the reliability and power quality in power systems and lead to cascading failures or blackouts. However, with the prospect of integrating Information and Communication Technologies (ICT) infrastructures into power system operation, the ability to utilize advanced protection strategies has become realizable. Given the size and complexities in operation of the future power systems the need for distributed and resilient protection system is inevitable to address the difficulties and inaccuracies introduced in protection settings. Multi-Agent Systems (MAS), as a branch of Distributed Artificial Intelligence (DAI) are capable to deal with complex and large scale systems such as power distribution networks. Moreover, in MAS agents can be deployed in power system to engage with interdependencies between various components while pursuing global goals through supervisory function or behaviours specific to each agent types. In this research, a Multi-Agent Protection System (MAPS) consists of different agent types with certain tasks has been developed to effectively cooperate with other Intelligent Electronic Devices (IEDs) within the protection communication network. A heuristic approach based on exchanging information between different IEDs in the system is utilized to adjust the IED settings according to fault current level in the protected zone. Additionally, to validate the outcomes of the research under real-world scenario, an experiment setup based on Power Hardware in the Loop (PHIL) methodology has been developed to verify the outcomes of the research. The simulation results are discussed to emphasise MAS as a distributed and scalable approach to deal with complexities in future power systems and specifically in relation to protection systems which is crucial for reliability and efficiency of the interconnected distribution networks.

碩士
中原大學
電機工程學系
87
The overhead power transmission system is distributed over everywhere, its ground-wires connect all the related grounding system of poles, towers, substations and plants to form an Interconnected Grounding Network (IGN). When the power system occurs ground fault on the IGN, the ground fault current will flow everywhere along the IGN and thus produce the Ground Potential Rise (GPR) on each related grounding system which may damage personnel, animals and equipments. To this problem, the conventional measures are aimed to restrict the grounding resistances of poles, towers, substations and plants under specified values. In the design of a grounding system, the affection of IGN is represented as a "current-division-factor" to conservative estimate the reducing part of ground fault current to be injected into the designed grounding system. However, this design concept has faced some difficulties such as lack of land for constructing power system and very high soil resistivity at field, these let that the low grounding resistance can not be obtained or need very large cost to attain low grounding resistance. In addition to, the ground current and potential are usually very large and distributed everywhere, if no other protective measures, the grounding system still can not protect personnel, animals and equipments from damages of ground potential even the grounding resistance had have within restricted value. To find the effective protective measures, the ground current and potential distributions of the IGN should be first analyzed, and from which the important parameters of IGN can be found out and thus derive effective protective measures. This thesis analyzes the ground current and potential distributions of the IGN considering all the possible affection parameters which include the grounding resistances of related plants, substations, towers and poles and the mutual grounding resistances between them, the self impedances of ground wires and the mutual impedances between all ground-wires and transmission lines. All the parameter characteristics are also surveyed where the important parameters can be found out. The mutual impedances between ground-wires and transmission lines will significant increase the computation time and error during the analysis of ground current and potential distributions of IGN. Thus, the thesis develops the computation algorithm based on the " decoupled method" which will largely reduce the computation time and error and attain precise analysis. Finally the IGN of a practical 69kV overhead transmission system is presented to analyze its ground current and potential distributions with respect to the variations of its important parameters. The analysis results have demonstrated the usefulness of protect analysis method and derived some available recommendations to improve the design of a grounding system.

碩士
國立臺灣科技大學
電機工程系
97
This thesis is to explore the interconnection problem of a meshed distribution network interconnected with distributed generations and to evaluate the reliability of meshed distribution networks. First of all, reliabilities of meshed and radial distribution networks are evaluated. Reliability is one of the major goals of many utilities to optimize their distribution networks in the near future. Next, full-scale circuit model of a sample system in mesh arrangement is constructed and simulated using a professional power system simulation package, CYME. Simulation results are then organized to present the steady-state operating features of the sample meshed distribution network under the normal operating condition. Next, some DGs are embedded in the sample system and the problems caused by DGs interconnection are identified and explored. Finally, some effective measures to overcome the interconnection problems are presented and the binary search method is proposed to improve the network to enlarge maximum allowable capacity of installation of distributed Generations.

No
The traffic pattern has significant impact on the performance of network-on-chip. Many recent studies have shown that multimedia applications can be supported in on-chip interconnects. Driven by the motivation of evaluating on-chip interconnects in multimedia embedded systems, a new analytical model is proposed to investigate the performance of the fat-tree based on-chip interconnection network under bursty multimedia traffic and nonuniform message destinations. Extensive simulation experiments are conducted to validate the accuracy of the model, which is then adopted as a cost-efficient tool to investigate the effects of bursty multimedia traffic with nonuniform destinations on the network performance.