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Lu, Bing. "Calibration, Optimality and Financial Mathematics." Doctoral thesis, Uppsala universitet, Matematiska institutionen, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-209235.
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This thesis consists of a summary and five papers, dealing with financial applications of optimal stopping, optimal control and volatility. In Paper I, we present a method to recover a time-independent piecewise constant volatility from a finite set of perpetual American put option prices. In Paper II, we study the optimal liquidation problem under the assumption that the asset price follows a geometric Brownian motion with unknown drift, which takes one of two given values. The optimal strategy is to liquidate the first time the asset price falls below a monotonically increasing, continuous time-dependent boundary. In Paper III, we investigate the optimal liquidation problem under the assumption that the asset price follows a jump-diffusion with unknown intensity, which takes one of two given values. The best liquidation strategy is to sell the asset the first time the jump process falls below or goes above a monotone time-dependent boundary. Paper IV treats the optimal dividend problem in a model allowing for positive jumps of the underlying firm value. The optimal dividend strategy is of barrier type, i.e. to pay out all surplus above a certain level as dividends, and then pay nothing as long as the firm value is below this level. Finally, in Paper V it is shown that a necessary and sufficient condition for the explosion of implied volatility near expiry in exponential Lévy models is the existence of jumps towards the strike price in the underlying process.
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Ajaja, Adile. "Distribution network optimal reconfiguration." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110641.
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This thesis reports on research conducted on the Optimal Reconfiguration (OR) of distribution networks using Mixed Integer Linear Programming (MILP). At the operational hourly level, for a set of predicted bus loads, OR seeks the optimum on/off position of line section switches, shunt capacitors and distributed generators so that the distribution network is radial and operates at minimum loss. At the planning level, OR seeks the optimum placement of line switches and shunt capacitors so that, over the long-term, losses will be minimized. The main steps and outcomes of this research are (i) the development of a simplified single-phase distribution network model for Optimal Reconfiguration; (ii) the development of a linear DC load flow model with line and device switching variables accounting for both active and reactive power flows; (iii) the development of an algorithm HYPER which finds the minimum loss on/off status of existing line switches, shunt capacitors and distributed generators; (iv) the extension of HYPER to find the optimum (minimum loss) placement of switches, capacitors and distributed generators; (v) the representation of losses via supporting hyperplanes enabling the full linearization of the OR problem, which can then be solved using efficient and commercially available MILP solvers like CPLEX. Keywords: Distribution Network, Optimal Reconfiguration, OR, Loss minimization, Mixed-Integer Linear Programming, MILP, Operations research, Linear network model, DC load flow, Supporting hyperplanes, Real time optimization, Switch, Capacitor and Distributed Generator placement, Power Systems Operations and Planning.Ce mémoire de thèse rend compte des produits d'activités de recherche menée relativement à la Reconfiguration Optimale (RO) de réseaux de distribution par Programmation Linéaire en Variables Mixtes (PLVM). Dans un contexte de conduite de réseau, la RO s'applique à déterminer l'état ouvert/fermé optimal des interrupteurs, disjoncteurs, condensateurs et producteurs distribués, avec objectif d'opérer à un niveau de pertes minimum un réseau de distribution radial. La RO s'applique également, dans un contexte de planification, à identifier l'emplacement optimal sur le réseau d'interrupteurs, disjoncteurs et condensateurs visant le maintien, sur le long terme, des pertes à un niveau minimum. Les principaux résultats de cette recherche sont: (i) le développement d'un modèle unifilaire simplifié de réseau de distribution pour la Reconfiguration Optimale; (ii) le développement d'un modèle d'écoulement de puissance linéaire avec variables contrôlant l'état des lignes, adapté autant pour l'écoulement de puissance actif que réactif; (iii) le développement de l'algorithme HYPER capable d'identifier l'état ouvert/fermé optimal (minimum de pertes) des interrupteurs, disjoncteurs, condensateurs et producteurs distribués; (iv) une extension de l'algorithme HYPER permettant de déterminer l'emplacement optimal (minimum de pertes) d'interrupteurs, disjoncteurs, condensateurs et producteurs distribués; (v) la représentation des pertes via hyperplans-porteurs permettant la linéarisation complète du problème RO et sa résolution par l'emploi de solveurs PLVM performants et commercialement disponibles tels que CPLEX.Mots clés: Réseau de distribution, Reconfiguration Optimale, RO, Minimisation des pertes, Programmation Linéaire en Variables Mixtes, PLVM, Recherche opérationnelle, Modèle de réseau linéaire, Écoulement de puissance linéaire, Hyperplans-porteurs, Optimisation temps réel, Interrupteur, Disjoncteur, Condensateur, Producteur privé, Exploitation, Conduite, Planification.
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Fletcher, Robert Henry. "Optimal distribution system horizon planning /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/6018.
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Melovic, Dejan. "Optimal distribution network design policy." Thesis, University of Manchester, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.557289.
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Khelifa, Abdelghafor. "Design of optimal distribution networks." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/46391.
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Scheer, Natalie [Verfasser], Hanspeter [Akademischer Betreuer] Schmidli, and Josef [Akademischer Betreuer] Steinebach. "Optimal stochastic control of dividends and capital injections / Natalie Scheer. Gutachter: Hanspeter Schmidli ; Josef Steinebach." Köln : Universitäts- und Stadtbibliothek Köln, 2011. http://d-nb.info/1038065259/34.
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Bester, P. G. "Shareholder distribution choices for industrial companies listed on the JSE : share buybacks versus dividends." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/8443.
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Thesis (MBA)--Stellenbosch University, 2008.ENGLISH ABSTRACT: Repurchasing of shares by South African companies were legalised on 1 July 1999. This introduced an alternative to dividends for distributing cash to shareholders. Although dividends and share repurchases realise the same value in a perfect efficient market, the inefficiencies of the South African stock market require managers to carefully evaluate factors like taxation and stock price valuation when selecting appropriate distribution methods. This research report aims to update shareholder distribution trends for industrial JSE listed companies over the past 10 years in order to determine the impact of share repurchases on dividend payouts. Furthermore, this research report examines the factors that may have had an impact on shareholder distribution choices in order to provide some guidelines for choosing appropriate distribution methods. An initial analysis of SENS share repurchase announcements revealed that 121 JSE listed companies repurchased about R50 billion worth of shares up to 30 June 2007. The bulk of the shares, 65% by value, were repurchased on the open market, while 35% was repurchased through specific fixed price offers. However, a comparison of accurate share repurchase data obtained from a sample of company annual reports, indicate that repurchase announcements understate actual repurchases by more than 20% on average. Further analysis of distribution trends were therefore based on actual repurchase data published in annual reports rather than SENS announcements. After the legalisation of share repurchases in South Africa, a decline in dividend paying companies was expected similar to that experienced by the United States since the 80's. However, a detailed analysis of 132 industrial listed companies indicated that the proportion of dividend paying companies increased from a level of 50% to almost 75% since the introduction of share repurchases. On the other hand, the proportion of companies repurchasing shares initially rose to over 25%, but then declined to below 20% by 2007. Ordinary dividends are the dominant shareholder distribution choice with 64% of companies opting for this method. Open market share repurchases have been well adopted with 17% of companies using this method, while only 5% and 4% of companies using special dividends or specific repurchases respectively. Dividends paid out of share premium (capital distributions) have also emerged as a favourite over recent years with almost 20% of companies using this shareholder distribution method. Current tax legislation do not provide all the advantages usually enjoyed by share repurchases internationally and have largely prevented dividends from being substituted by share repurchases. The decline in share repurchases up to 2007 also indicates that share repurchases become less effective as share prices increase to overvalued levels. While tax implications and stock price valuation remain the dominant determinants of shareholder distribution choice, this study shows that shareholder diversity, dividend preferences, size of distribution, and BEE requirements also have significant influences on the choice of distribution method in the South African context.
AFRIKAANSE OPSOMMING: Die terugkoop van aandele deur Suid-Afrikaanse maatskappye is wettig sedert 1 Julie 1999. Dit het 'n alternatief tot dividende in werking gestel om kontant aan aandeelhouers uit te keer. Alhoewel dividende en aandele-terugkoop dieselfde waarde in 'n perfekte doeltreffende mark realiseer, vereis die tekortkominge van die Suid-Afrikaanse aandelemark dat bestuurders faktore soos belasting en aandeelpryswaardasie versigtig moet oorweeg tydens die keuse van geskikte uitkeringsmetodes. Die doelwit van hierdie navorsingsverslag is om die tendense van uitkerings aan aandeelhouers te hersien vir industriele JSE-genoteerde maatskappye oor die laaste 10 jaar om sodoende die effek van aandele-terugkope op dividenduitbetalings te bepaal. Verder ondersoek hierdie navorsingsverslag ook die faktore wat moonlik 'n invloed op aandeelhouers-uitkeringskeuses gehad het, om sodoende riglyne vir die keuse van geskikte uitkeringsmetodes saam te stel. 'n Voorlopige analise van SENS-terugkoopaankondigings toon dat 121 JSE-genoteerde maatskappye ongeveer R50 miljard se aandele teruggekoop het tot en met 30 Junie 2007. Die grootste gedeelte van hierdie aandele, 65% se waarde, is op die ope mark teruggekoop terwyl 35% deur spesifieke vasteprys terugkope verkry is. 'n Vergelyking met terugkoopsyfers wat uit 'n steekproef van maatskappyjaarverslae geneem is, dui egter daarop dat aankondigings die ware terugkope met gemiddeld 20% onderskat. Verdere ontleding van aandeelhouers-uitkeringstendense word derhalwe gebaseer op syfers wat in jaarverslae gepubliseer is, eerder as SENS-aankondigings. Na die wettiging van aandele-terugkoop in Suid-Afrika, is verwag dat dividenduitbetalings sou daal soortgelyk aan dit wat in die Verenigde State ondervind is sedert die 80's. Die ondersoek van 132 genoteerde industriele maatskappye toon egter dat die persentasie van maatskappye wat dividende betaal van 50% tot bykans 75% toegeneem het sedert aandele-terugkoop 'n beskikbare opsie is. In teenstelling hiermee, het die persentasie maatskappye wat aandele terugkoop aanvanklik tot 25% gestyg, maar sedertdien afgeneem tot onder 20% teen 2007. Gewone dividende is die gewildste aandeelhouers-uitkeringsmetode met 64% van maatskappye wat van hierdie metode gebruik maak. Aandele-terugkope op die ope mark is goed verteenwoordig met 17% van maatskappye wat van hierdie metode gebruik gemaak het, terwyl slegs 5% en 4% van maatskappye onderskeidelik van spesiale dividende en spesifieke aandele-terugkope gebruik gemaak het. Dividende uit aandelepremie (kapitaaluitkerings) het ook na vore getree as 'n gunsteling keuse in die laaste paar jaar met bykans 20% van maatskappye wat hierdie uitkeringsmetode gebruik het. Huidige belastingswetgewing bied nie al die belastingvoordele aan aandele-terugkope wat normaalweg deur internasionale maatskappye benut word nie en het grotendeels verhoed dat dividende deur aandele-terugkoop vervang is. Die afname in aandeleterugkope tot en met 2007 is ook 'n aanduiding dat dit minder effektief raak soos wat aandeelpryse oor gewaardeerde vlakke styg. Terwyl belasting-oorwegings en aandeelpryswaardasies steeds die dominante drywers van aandeelhouersuitkeringskeuses bly, bevind hierdie studie dat faktore soos aandeelhouers se diversiteit, dividendvoorkeure, grootte van uitkerings, en vereistes van swart ekonomiese bemagtiging ook 'n noemenswaardige invloed op uitkeringskeuses binne die Suid-Afrikaanse konteks het.
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Okraszewski, Tomasz M. "Optimal concepts for the distribution cable networks /." Aachen : Shaker, 2008. http://d-nb.info/990542262/04.
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Huang, Fengqin 1975. "Optimal Grain Production and Distribution in China." Thesis, North Dakota State University, 2006. https://hdl.handle.net/10365/29908.
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The objective of this study is to evaluate the configuration of China's grain production pattern and the implications for agricultural trade. A spatial equilibrium model is developed to optimize grain production and distribution in China and its trade relationship with its trade partners. This study focuses on four grain crops: rice, wheat, com, and soybeans. The model divides China into 31 producing regions and 31 consuming regions. The model also includes seven exporting countries and six Asian importing regions.
Results indicate that China can improve its grain production and social welfare through production specialization under a free-trade environment. China could become a major wheat and soybean importer, and a com and rice exporter to Asian countries. The study also provides perspectives on U.S. exports to China and other Asian countries.
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Cheng, Mingliang. "Corporate valuation and optimal operation under liquidity constraints." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/corporate-valuation-and-optimal-operation-under-liquidity-constraints(9dbf048a-87e0-434d-aac5-b5bd6b6963c8).html.
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We investigate the impact of cash reserves upon the optimal behaviour of a modelled firm that has uncertain future revenues. To achieve this, we build up a corporate financing model of a firm from a Real Options foundation, with the option to close as a core business decision maintained throughout. We model the firm by employing an optimal stochastic control mathematical approach, which is based upon a partial differential equations perspective. In so doing, we are able to assess the incremental impacts upon the optimal operation of the cash constrained firm, by sequentially including: an optimal dividend distribution; optimal equity financing; and optimal debt financing (conducted in a novel equilibrium setting between firm and creditor). We present efficient numerical schemes to solve these models, which are generally built from the Projected Successive Over Relaxation (PSOR) method, and the Semi-Lagrangian approach. Using these numerical tools, and our gained economic insights, we then allow the firm the option to also expand the operation, so they may also take advantage of favourable economic conditions.
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Zhong, Qinghui. "Optimal operations of large scale water distribution systems." Diss., The University of Arizona, 1994. http://hdl.handle.net/10150/187025.
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Improving water distribution system operations can be achieved through the use of optimally generated pump schedules by minimizing the overall pumping cost while satisfying the water pressure and flow requirements and subject to all physical constraints. This study is devoted to developing a general methodology to determine the optimal operations of large scale water distribution systems. Rather than solving the original mixed integer nonlinear programming problem directly, a two-level hierarchical optimization scheme is proposed. The first level is a NLP problem where the decision variables are each pump station's discharge and added head, pump speeds, valve control settings, nodal pressure heads and tank water elevations. At the second level a simple DP or a direct conversion method is applied to find the best pump combinations based on the optimal solutions obtained from the first level NLP optimization. Prior to solving the two level optimization problem, pre-optimization work is performed which produces a lumped energy function for each pump station to approximate the relationship between consumed energy and pump station's added head and discharge. To make the first level NLP problem solvable, a reduction technique is proposed which uses the network simulation model to reduce the number of constraints and decision variables. This reduction, however, results in a NLP problem with implicit decision variables which are not directly controlled by the decision variables. One strategy proposed is to consider the constraints of the implicit decision variables in a penalty term appended to the objective function. The problem is then structured using an augmented Lagrangian algorithm and solved with a NLP code. The second strategy is to use an active set method. The entire NLP problem is solved using successive quadratic programming where only the active constraint set is considered during the solution process of each quadratic programming subproblem. Two case studies were performed to determine the optimal schedules and compare the two NLP approaches. The Lagrangian seemed to perform better when many constraints were initially violated, while the active set method seemed appropriate to solve systems with few initial active constraints.
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ARROMATE, CLAUDIO JOSE COUTINHO. "A MODEL FOR OPTIMAL LOCATION OF DISTRIBUTION CENTERS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1997. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=8656@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORAs necessidadeS de ganhos de escala para diluir custos fixos de produção, aliadas a grande segmentação e criação de novos mercados faz com que cada vez mais seja preciso produzir em quantidades maiores e vender em quantidades menores; Pressões para para redução de estoques, de produtos acabados e insumos em todos os elos da cadeia; Localização do centro produtor cada vez mais distante do centro consumidor, em função de benefícios fiscais, de infra-estrutura e respeito ao meio-ambiente, fazem do conceito centro de distribuição um dos tópicos mais importantes no gerenciamento da cadeia logística de qualquer empresa, e matéria obrigatória na literatura sobre as várias formas de implementação, e a viabilidade econômica de tais alternativas como forma de agregar valor ao negócio. Independente do modelo a ser adotado, é questão relevante a sua localização. E esta contempla variáveis como o custo de distribuição em função das distâncias ao centro consumidor e centro produtor; custos do estoque e manuseio em função do giro previsto, custos fixos de operação fabris e de armazém, além da necessidade de previsão e dispersão da demanda do item a ser distribuído. Outras variáveis que precisam ser contempladas na prática são as questões tributárias, disponibilidade / qualificação de mão de obra, equipamentos de transporte e questões mercadológicas envolvendo o produto e o consumidor a ser atingido. Escolheu-se uma técnica especifica e facilmente executável em softwares comerciais para cada classe de problemas: Modelo de previsão de vendas - foi desenvolvido um modelo de regressão dinâmica e utilizado o software FORECAST MASTER ; Algoritmo de caminho mais curto para cálculo do custo de distribuição - foi implementado o Algoritmo de Djkstra de caminho mais curto; Modelo para localização e tamanho dos centros de distribuição - foi desenvolvido um modelo de programação inteira mista utilizando o algoritmo de Branch and Bound, implementando no software OSL. Com o intuito de avaliar a performance frente a outras técnicas existentes são vistos sucintamente técnicas de alisamento exponencial (Holt-Winters), o método de Box e Jenkins, com relação ao cálculo de distâncias, os algoritmo de caminho mais curto de Fran Out, formulação como problema de fluxo em redes - cálculo dofluxo de custo mínimo; Em relação ao modelo matemático de localização, um modelo de programação inteira alternativo que é a utilização de plano de cortes. Todas as técnicas foram aplicadas aos dados de uma empresa de bens de consumo de abrangência nacional, cuja distribuição dá-se através de distribuidores de distribuidores independentes que compram os produtos e os retiram nas fábricas produtoras, para posterior revenda aos pontos de venda ao consumidor final, como supermercados, lanchonetes, postos de gasolina, bares, etc. Este estudo serviu como ferramenta prática na tomada da decisão da companhia de localizar seus centros de distribuição.
Gain of scale needsin order to decrease production fixed costs, in addition with large segmentation and the appearing of new markerts, makes more and more important to produce in high quantities and on the other hand to sell in small selling quantities. The inventory costs, and inventory levels, of finished goods and raw materials in the whole supply chain; the plants location more and more far from the consumer´s center (due to tax benefits, infra- structure and environment implications); makes the distribuition center concept one of the most important issues in the supply chain management of any company. This is also a very important subject on the literature, about the many ways of implementation, economic viability of each alternative, and a way to add value to the business. No matter the model is going to be used, it is very a impportant question, the location. And this is envolves distribuition costs, inventory costs, warehousing and handling costs, operations fixed and variable costs, and further the demand forecast of each SKU. Another variables that need to be considered in practice are the legal implications, mão de obra, Real State, transportation equipments and merchandising issues, envolving the product and the target consumer. Such a specific and software easy run technique was chosen for each class of problems: Sales Forecast Model - A Dinamic regression model was developed and the software Forecast Master was used. Shortest path algorithm. Distribuition Center location and size model - A mixed integer program was developed using Branch-and-Bound technique, implemented with OSL software. In order to evaluate the algorithms performance in comparison with other avaible techniques, will be mentioned another models: Demand Forecast - The Exponential Smoothing technique (holt-Winters), and the Box and Jenkins method. About the distances between points - Fan out shortest path algorithm, and the formulation of the shortest path problem stated as a minimum cost flow algoritm. About the Distribuition center location and size model, Such a alternative Integer program approach was tried: the cutting planes. All the tecniques were applied using a countywide bens de consumo company database, whose distribuition is made through independents distributors that buy and pick the products directly in the production plant, and after selling to the final consumer or point of sales in general. This study was used as a tool in practice in the company Distribuition center location decision making.
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Simmons, Craig A. (Craig Alexander). "Optimal surface coating distribution on a femoral endoprosthesis." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/37512.
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Singh, Manish K. "Optimal Operation of Water and Power Distribution Networks." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/86860.
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Under the envisioned smart city paradigm, there is an increasing demand for the coordinated operation of our infrastructure networks. In this context, this thesis puts forth a comprehensive toolbox for the optimization of electric power and water distribution networks. On the analytical front, the toolbox consists of novel mixed-integer (non)-linear program (MINLP) formulations; convex relaxations with optimality guarantees; and the powerful technique of McCormick linearization. On the application side, the developed tools support the operation of each of the infrastructure networks independently, but also towards their joint operation. Starting with water distribution networks, the main difficulty in solving any (optimal-) water flow problem stems from a piecewise quadratic pressure drop law. To efficiently handle these constraints, we have first formulated a novel MINLP, and then proposed a relaxation of the pressure drop constraints to yield a mixed-integer second-order cone program. Further, a novel penalty term is appended to the cost that guarantees optimality and exactness under pre-defined network conditions. This contribution can be used to solve the WF problem; the OWF task of minimizing the pumping cost satisfying operational constraints; and the task of scheduling the operation of tanks to maximize the water service time in an area experiencing electric power outage. Regarding electric power systems, a novel MILP formulation for distribution restoration using binary indicator vectors on graph properties alongside exact McCormick linearization is proposed. This can be used to minimize the restoration time of an electric system under critical operational constraints, and to enable a coordinated response with the water utilities during outages.Master of Science
The advent of smart cities has promoted research towards interdependent operation of utilities such as water and power systems. While power system analysis is significantly developed due to decades of focused research, water networks have been relying on relatively less sophisticated tools. In this context, this thesis develops Advanced efficient computational tools for the analysis and optimization for water distribution networks. Given the consumer demands, an optimal water flow (OWF) problem for minimizing the pump operation cost is formulated. Developing a rigorous analytical framework, the proposed formulation provides significant computational improvements without compromising on the accuracy. Explicit network conditions are provided that guarantee the optimality and feasibility of the obtained OWF solution. The developed formulation is next used to solve two practical problems: the water flow problem, that solves the complex physical equations yielding nodal pressures and pipeline flows given the demands/injections; and an OWF problem that finds the best operational strategy for water utilities during power outages. The latter helps the water utility to maximize their service time during power outages, and helps power utilities better plan their restoration strategy. While the increased instrumentation and automation has enabled power utilities to better manage restoration during outages, finding an optimal strategy remains a difficult problem. The operational and coordination requirements for the upcoming distributed resources and microgrids further complicate the problem. This thesis develops a computationally fast and reasonably accurate power distribution restoration scheme enabling optimal coordination of different generators with optimal islanding. Numerical tests are conducted on benchmark water and power networks to corroborate the claims of the developed formulations.
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Daldal, Mustafa. "Optimal Allocation Of Sectionalizing Switches In Rural Distribution Systems." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12613947/index.pdf.
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The distribution system which forms the final connection between customers and power source plays a vital role in an electrical network. Different studies show that substantial proportion of the customer interruptions occurs due to the failures on distribution network.
The ongoing privatization process of the electrical distribution services in Turkey raises the importance of reliable and continuous electricity supply significantly. The new regulations come up with this privatization process and the electrical distribution companies are strictly required to comply with these regulations to ensure the reliability of the distribution network. The legal framework and severe punishments applied to the electrical distribution companies exceeding the continuity of supply indices force them to invest on their network in order to increase the reliability of their system.
As the reliability of electricity supplied increases, investment cost also increases. However, low system reliability causes higher outage frequency and duration which will increase the damage of these outages to customers and also increases the cost of the distribution company as a result of the penalty payments. This tradeoff between Outage Cost and Utility Cost requires consideration of an optimization when determining the optimal reliability level.
In rural areas where electrical distribution network consists of long radial overhead lines in arborescent structure, continuity of supply is a major problem due to the high failure rates. The implementation of protection devices having reclosing capability and automated sectionalizing switches enhances the continuity of supply on rural networks substantially. The balance between the cost associated with installation of switches and the reduction on Outage Cost is an important optimization issue for distribution network operators.
In this thesis study an algorithm is developed in order to determine the optimum number and locations of the sectionalizing switches on a rural electrical distribution network in Turkey which gives an optimum investment level with an optimum Outage Cost.
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Guler, Hazal, and Camilla Tedgren. "Establishing the Optimal Tariff in Rural Electricity Distribution Networksy." Thesis, KTH, Elektriska energisystem, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-119253.
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Access to electricity is a key factor of improving the living standard in a country, as it enhances the quality of services such as education, health care and productivity. The rural population of Uganda is however only supplied with electricity to a degree less than three percent. There are large financial issues in extending the national electricity grid why small stand alone systems are sometimes a more valuable option. Even then, there are large investment costs that need to be covered by the sale of electricity. Due to the limited buying power of rural consumers, the end-user tariff setting becomes of great significance of the financial outlook. If the tariff is set too high, the consumption will most likely be lower than what it could be, resulting in a loss of revenue as well as inhibiting the improvement of living standards for the consumers. On the other hand, if the tariff is set too low, it could lead to excessive consumption, resulting in power failures. In view of the above, the main aim of this study has been to investigate the consequences of different tariffs in an isolated rural power system. This was done by studying the electricity consumption in two already electrified rural networks in order to find information on demand behavior and load profiles. Interviews with electricity consumers were conducted to investigate how their demand would change if tariffs were altered. Demand as a function of price was shown by linear curves indicating the price sensitivity and demand factor, the latter being the theoretical maximum demand when price is zero. These parameters were modelled in Monte Carlo simulations with the aim to predict the demand behavior of a site that is not yet electrified and find the tariff that should be applied to this site. The simulations were based on two potential economic objectives of how to operate the system; by altruistic or profit maximising means. Depending on whether the system is altruistic or profit maximizing, the optimum point of tariff differs. In the altruistic case, this tariff should be set where the costs are covered by the revenues. The profit maximizing system instead requests the tariff where profit is as high as possible. Furthermore, two different structures of tariff setting were tested for the system; a structure with time-of-use levels where the tariff should be higher during the peak demand hours of the day, and a flat rate structure where the tariff is constant throughout the day. The field study showed that, on average, the price sensitivity factor of domestic consumers were slightly higher than of the commercial consumers. The results also showed that the majority of the commercial consumers reside in the same building as their business. Furthermore, rural consumers exhibit low awareness of their consumption patterns and the price of electricity. Extensive information from the distribution companies to the customers is therefore essential to maintain a sustainable electricity consumption, as it enables consumers to make rational decisions about their electricity consumption and opt for more efficient alternatives. A financial analysis for the specific case study was also conducted from simulations. The analysis found for an altruistic system a tariff slighly lower tariff than the tariff applied in the national grid today. However, the system will require an additional financing to cover the payments before the year when revenues exceed expenses, but can be paid back within eight years. The tariffs found by simulating with a profit maximizing system operator are more than twice as high as the current tariff applied in the national grid today. On the other hand, the system requires a very small additional loan or subsidy compared to the altruistic simulations and has a pay-off time within six years.
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Iqbal, Qamar. "Optimal distillers distribution planning in an ethanol supply chain." Thesis, Wichita State University, 2008. http://hdl.handle.net/10057/2102.
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With the increasing growth of the ethanol industry, the number of co-products is also expanding at a rapid rate. These co-products, namely distillers, can be used as cattle feed in feedlots. Currently, the major feed for cattle is corn, but if distillers are marketed successfully and farmers are educated about their usefulness and how to store them, then they could be remarkably successful in the feedstock market. Some issues associated with distillers need to be addressed and will be discussed in the next section. Since producing distillers does not require building new plants or purchasing new machinery, they are simply a welcome co-product (or by-product) of corn fermentation during ethanol production. Ethanol owners could make good revenue by marketing distillers, since they produce 3.2 million metric tons of dried distillers grains plus solubles annually.Wichita State University, College of Engineering, Dept. of Industrial and Manufacturing Engineering
Includes bibliographic references (leaves 93-98)
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Khomsi, Driss. "Optimal design of water distribution networks with reliability considerations." Thesis, City University London, 1994. http://openaccess.city.ac.uk/7414/.
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The overall aim of this research has been to develop new algorithms and computer software that may be used to assess the reliability of water distribution systems. Such a tool can be used by design engineers to create systems which are both economical in total cost commensurate with meeting targets for a specified level of reliability. The introduction describes how water supply and distribution systems are normally designed, what they comprise and problems associated with failure or lack of availability of an adequate supply to the end user. This is followed by a resume of current methods and algorithms for the analysis of networks and a detailed examination of the previous work on network optimisation and reliability. Three main algorithms exist for the analysis of water networks. These are the Hardy-Cross methods, the Newton-Raphson methods and the Linear method. A computer program based on the Linear method, which is known to be the most reliable, is proposed for the hydraulic analysis part of the present work. With respect to reliability, a full discussion of the topic, including all the various factors which influence it such as the stochastic nature of customer demands, the apparently random occurrence of pipe breakages and the concept of repair time, is presented. A reliability analysis model, that incorporates simultaneously the three reliability factors mentioned, for the assessment of nodal and system availabilities, is proposed, from which an efficient computer program has been developed and tested. Two models for the design of optimal water distribution systems, based on reliability criteria, have been developed, programmed and tested. The first model makes use of the entropy principle for producing 'reliable' distributions of flow and the Linear Programming technique is used for computation of the least cost design. In the second model, however, a Genetic Algorithm procedure, that incorporates the new reliability analysis model and which is superior to other models has been formulated. The thesis concludes with a comparison between the two methods formulated as a result of this research and applied to realistic practical systems, plus suggestions for further work to improve the optimisation of water distribution networks.
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Xu, Chengchao. "Optimal operation and reliability evaluation of water distribution systems." Thesis, Heriot-Watt University, 1990. http://hdl.handle.net/10399/896.
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Dolloff, Paul A. "Optimization in electrical distribution systems : Discrete Ascent Optimal Programming /." Diss., This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-06062008-151439/.
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Iqbal, Qamar Yldirim Mehmet Bayram. "Optimal distillers distribution planning in an ethanol supply chain." A link to full text of this thesis in SOAR, 2008. http://hdl.handle.net/10057/2102.
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Wichita State University, College of Engineering, Dept. of Industrial and Manufacturing Engineering.Copyright 2008 by Qamar Iqbal. All Rights Reserved. Includes bibliographical references (leaves 93-98).
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Ahn, Taejin. "Optimal design of municipal and irrigation water distribution systems." Diss., Virginia Tech, 1993. http://hdl.handle.net/10919/38649.
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In two-dimensional flow, the point of flow separation from the surface coincides with the point at which the skin friction vanishes. However, in three-dimensional flow, the situation is much more complex and the flow separation is rarely associated with the vanishing of the wall shear stress except in a few special cases. Though the effects of cross-plane separation are substantial and have been recognized for some time, the phenomenon of flow separation over three-dimensional bodies is still far from being completely understood. The flow is so complex that no completely satisfactory analytical tools are available at the moment. In an attempt to logically identify the various effects and parametric dependence while simultaneously minimizing configuration dependent issue, the flow over a 6 to 1 prolate spheroid, which is a generic three-dimensional body, is investigated.
For the identification of the general flow pattern and better understanding of the flow field, surface-oil-flow visualization tests and force and moment tests were performed. The angle of attack effect and Reynolds number effect on the separation location are studied with natural transition. Forces and moments tests, surface pressure distribution measurements as well as the surface pressure fluctuations, and mini-tuft flow visualization tests were made to document the flow characteristics on the surface of the body with an artificial boundary layer trip.Ph. D.
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SUBRAMANIAM, PRATHIBA. "OPTIMAL LOCATIONS OF BOOSTER STATIONS IN WATER DISTRIBUTION SYSTEMS." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1005757573.
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Buhari, Muhammad. "Reliability assessment of ageing distribution cable for replacement in 'smart' distribution systems." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/reliability-assessment-of-ageing-distribution-cable-for-replacement-in-smart-distribution-systems(e253c774-b5e3-4872-9139-894e7df553f0).html.
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Majority of electricity networks have growing number of ageing elements. Critical network components, such as ageing underground cables, are very expensive to install and disruptive to replace. On the other hand, global climate changes have made connection of new low carbon technologies (LCT) into the grids increasingly necessary. These factors are contributing to the increasing complexity of the planning and management of power systems. Numerous techniques published on this subject tend to ignore the impact of LCT integration and the anchoring ꞌSmartꞌ solutions on ageing network assets, such as underground cables and transformers. This thesis presents the development procedures of an ageing underground cable reliability model (IEC-Arrhenius-Weibull model) and cable ranking models for replacement based on system wide effects and thermal loss-of-life metrics. In addition, a new concept of LCT integration and distribution network management was proposed using two optimization models. The first optimizes connection of new wind sources by minimizing the connection cost and the cost of cable thermal loss-of-lives in the planning period. In the second stage, the network is optimally reconfigured in such a way to minimize thermal-loss-of-life of ageing cable. Both optimization models are formulated as mixed integer non-linear programming (MINLP) problems applicable to radially operated medium voltage networks. To quantify the reliability benefits of the proposed approach, Sequential Monte Carlo Simulation (SMCS) procedure was formulated. Some of the main features of the SMCS procedure are the IEC-Arrhenius-Weibull model for ageing cable, optimal network reconfiguration, wind generation modelling using ARMA models and real time thermal ratings. The final outputs are reliability metrics, cable ranking lists for replacement, savings due to 'non-spend' cable thermal lives, etc. These studies have proven to be important in formulating an effective strategy for extending the lives of network cables, managing overall network reliability and planning cables replacement in power distribution networks.
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De, Schaetzen Werner. "Optimal calibration and sampling design for hydraulic network models." Thesis, University of Exeter, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322278.
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Fehr, Ralph E. "An integrated optimal design method for utility power distribution systems." [Tampa, Fla.] : University of South Florida, 2005. http://purl.fcla.edu/fcla/etd/SFE0001356.
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Hjort, Mattias. "Bestämning av optimal fordonspark -Distribution av bitumen vid Nynäs AB." Thesis, Linköping University, Department of Mathematics, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2903.
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Nynas produces bitumen at two refineries in Sweden. The bitumen is shipped to seven depots along the swedish coast line, and from the depots special trucks handle the transportation to customers. Recently Nynas has transformed its supply chain and closed down a few depots. At the moment the company is considering a further reduction of the number of depots. In connection to these discussions an analyse of the companys distributionsystem and of possible changes is required. In this thesis an optimization model is developed that simulates Nynas distribution of bitumen from the depots to the customers. The model is used to investigate the required vehicle fleet size for a number of different scenarios, that is with different depots closed down. The question to be answered is, thus, what depots could be closed without any dramatic increase in the required vehicle fleet size? Scenarios where customers are allocated an increased storage capacity are also studied.
The distribution model that is developed is an inventory route planning problem. It is solved by column generation. Each column represents a route and is generated by a subproblem with restrictions on permitted working hours for the truck drivers. Integer solutions are generated heuristically.
Simulations that have been performed with the model reveals interesting differences concerning how the distribution is handled in different parts of Sweden. In western Sweden the transportation planning works well, but the distribution in the central parts of the country could be planned in a better way. Results from simulations also show that the depots in Norrköping and Västerås could be closed down without increasing the vehicle fleet. Probably, the existing vehicle fleet size will be sufficient even with the Kalmar-depot closed down. Nevertheless, Nynas transportation suppliers will have to purchase new vehicles if the Sandarne-depot is to be closed.
Another interesting conclusion that can be drawn from this thesis is that there is a potential for reducing the vehicle fleet size if the storage capacity is increased at a few chosen customers. A considerably small increase in the storage capacity at a few big customers that are located far from the depots will have a great effect.
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Ekmarker, Linda. "Frequency Control : Optimal distribution of FCR-N in real-time." Thesis, Uppsala universitet, Elektricitetslära, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-230897.
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Frequency control systems are used to keep the grid frequency at the nominal value of 50.00 Hz. Vattenfall employ hydropower plants for this purpose as they can easily adapt their production to counteract frequency deviations. This master thesis focuses on trying to improve Vattenfall’s mechanism to provide FCR-N (Frequency Containment Reserve in Normal operation) for primary frequency control, i.e. the turbine governor. The efforts are made to operate the plants more efficiently, decreasing distribution losses and thus increasing the profits. The current control system was modelled in MATLAB’s simulation tool Simulink to understand its complexity and to be used as base for comparison. Then a new model was developed based on the idea to introduce a global governor for the frequency control in each plant which controls the input signal to the individual turbine governors of each unit. OPT-data (tabulated data indicating how to operate a plant at the highest possible efficiency) was used to determine how to optimally distribute the FCR-N among the active units in a plant in real-time. The conclusions which can be drawn from this master thesis are that it is possible to make a more optimal distribution of FCR-N in real-time. However, it has not been possible to make a good comparison between the two models and the results regarding the profits which can be made by introducing this new type of governor are therefore inconclusive. It is of crucial importance to make a better match of the regulating strengths of the two models in order to perform the comparison. Improving the parameter values for the proportional and integral gains of the individual controllers and the precision of the OPT-table lookups may further improve the new model and also make it possible to perform a valid comparison between the two models.
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Okraszewski, Tomasz M. [Verfasser]. "Optimal Concepts For The Distribution Cable Networks / Tomasz M Okraszewski." Aachen : Shaker, 2008. http://d-nb.info/1161304991/34.
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Kahler, Jens. "Optimal sizing and operational scheduling of water distribution network components." Thesis, De Montfort University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433258.
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Paridari, Kaveh. "Optimal and Resilient Control with Applications in Smart Distribution Grids." Licentiate thesis, KTH, Reglerteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-191307.
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The electric power industry and society are facing the challenges and opportunities of transforming the present power grid into a smart grid. To meet these challenges, new types of control systems are connected over IT infrastructures. While this is done to meet highly set economical and environmental goals, it also introduces new sources of uncertainty in the control loops. In this thesis, we consider control design taking some of these uncertainties into account. In Part I of the thesis, some economical and environmental concerns in smart grids are taken into account, and a scheduling framework for static loads (e.g., smart appliances in residential areas) and dynamic loads (e.g., energy storage systems) in the distribution level is investigated. A robust formulation is proposed taking the user behavior uncertainty into account, so that the optimal scheduling cost is less sensitive to unpredictable changes in user preferences. In addition, a novel distributed algorithm for the studied scheduling framework is proposed, which aims at minimizing the aggregated electricity cost of a network of apartments sharing an energy storage system. We point out that the proposed scheduling framework is applicable to various uncertainty sources, storage technologies, and programmable electrical loads. In Part II of the thesis, we study smart grid uncertainty resulting from possible security threats. Smart grids are one of the most complex cyber-physical systems considered, and are vulnerable to various cyber and physical attacks. The attack scenarios consider cyber adversaries that may corrupt a few measurements and reference signals, which may degrade the system’s reliability and even destabilize the voltage magnitudes. In addition, a practical attack-resilient framework for networked control systems is proposed. This framework includes security information analytics to detect attacks and a resiliency policy to improve the performance of the system running under the attack. Stability and optimal performance of the networked control system under attack and by applying the proposed framework, is proved here. The framework has been applied to an energy management system and its efficiency is demonstrated on a critical attack scenario.QC 20160830
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Gotzig, Bernhard. "Recherche du schéma optimal d'exploitation d'un réseau de distribution électrique." Grenoble INPG, 1997. http://www.theses.fr/1997INPG0209.
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Le but de cette thèse est l'exploration du domaine de l'optimisation de la topologie radiale d'un réseau de distribution en temps réel pour différents régimes d'exploitation. Nous avons ainsi développé différents outils de calcul performants, en particulier une approche unifiée qui se prête d'une part pour l'optimisation pour le régime normal d'exploitation, d'autre part pour établir un plan de reprise de service pour les zones îlotées suite à la défaillance d'un élément du réseau. Afin de satisfaire la contrainte temps réel, nous nous sommes basés sur des méthodes heuristiques permettant de s'approcher au plus de l'optimum global en un temps de calcul très court. La vérification de la qualité des solutions obtenues par des méthodes heuristiques est effectuée à l'aide d'autres méthodes d'optimisation plus dédiées à la recherche de l'optimum global. En validant la méthodologie proposée sur des réseaux de distribution réels à grande taille, nous avons montré l'efficacité de notre approche tant au niveau de la qualité des résultats qu'au niveau du temps de calculThe aim of this thesis is the exploration of the do main of the optimisation of the radial topology of a distribution system for different operation states on a real time basis. We have therefore developed several powerful computation utilities, especially a unified approach which may be used both for the optimisation in the normal state and for finding a restoration plan for the isolated llnfalllted areas in the case of an OLltage of an element in the network. In arder to satisfy the real time constraint, we have L1sed heuristic methods which permit the global optimum to be approached effeciently within a very short computation time. The verification of the results obtained by the heuristic methods is done using optimisation methods which are more dedicated for the research of the global optimum. In validating the proposed method with reallarge scale distribution networks, we have shown the efficiency of our approach in both computation time and the quality of the results
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Ghaweta, Ahmad. "OPTIMAL DISTRIBUTION FEEDER RECONFIGURATION WITH DISTRIBUTED GENERATION USING INTELLIGENT TECHNIQUES." UKnowledge, 2019. https://uknowledge.uky.edu/ece_etds/134.
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Feeder reconfiguration is performed by changing the open/close status of two types of switches: normally open tie switches and normally closed sectionalizing switches. A whole feeder or part of a feeder may be served from another feeder by closing a tie switch linking the two while an appropriate sectionalizing switch must be opened to maintain the radial structure of the system. Feeder reconfiguration is mainly aiming to reduce the system overall power losses and improve voltage profile. In this dissertation, several approaches have been proposed to reconfigure the radial distribution networks including the potential impact of integrating Distributed Energy Resources (DER) into the grid. These approaches provide a Fast-Genetic Algorithm “FGA” in which the size and convergence speed is improved compared to the conventional genetic algorithm. The size of the population matrix is also smaller because of the simple way of constructing the meshed network.
Additionally, FGA deals with integer variable instead of a binary one, which makes FGA a unique method. The number of the mesh/loop is based on the number of tie switches in a particular network. The validity of the proposed FGA is investigated by comparing the obtained results with the one obtained from the most recent approaches. The second the approach is the implementation of the Differential Evolution (DE) algorithm. DE is a population-based method using three operators including crossover, mutation, and selection. It differs from GA in that genetic algorithms rely on crossover while DE relies on mutation. Mutation is based on the differences between randomly sampled pairs of solutions in the population. DE has three advantages: the ability to find the global optimal result regardless of the initial values, fast convergence, and requirement of a few control parameters. DE is a well-known and straightforward population-based probabilistic approach for comprehensive optimization.
In distribution systems, if a utility company has the right to control the location and size of distributed generations, then the location and size of DGs may be determined based on some optimization methods. This research provides a promising approach to finding the optimal size and location of the planned DER units using the proposed DE algorithm. DGs location is obtained using the sensitivity of power losses with respect to real power injection at each bus. Then the most sensitive bus is selected for installing the DG unit. Because the integration of the DG adds positive real power injections, the optimal location is the one with the most negative sensitivity in order to get the largest power loss reduction. Finally, after the location is specified, the proposed Differential Evolution Algorithm (DEA) is used to obtain the optimal size of the DG unit. Only the feasible solutions that satisfy all the constraints are considered.
The objective of installing DG units to the distribution network is to reduce the system losses and enhance the network voltage profile. Nowadays, these renewable DGs are required to equip with reactive power devices (such as static VAR compensators, capacitor banks, etc.), to provide reactive power as well as to control the voltage at their terminal bus. DGs have various technical benefits such as voltage profile improvement, relief in feeder loading, power loss minimization, stability improvement, and voltage deviation mitigation. The distributed generation may not achieve its full potential of benefits if placed at any random location in the system. It is necessary to investigate and determine the optimum location and size of the DG. Most distribution networks are radial in nature with limited short-circuit capacity. Therefore, there is a limit to which power can be injected into the distribution network without compromising the power quality and the system stability. This research is aiming to investigate this by applying DG technologies to the grid and keeping the system voltage within a defined boundary [0.95 - 1.05 p.u]. The requirements specified in IEEE Standard 1547 are considered.
This research considers four objectives related to minimization of the system power loss, minimization of the deviations of the nodes voltage, minimization of branch current constraint violation, and minimization of feeder’s currents imbalance. The research formulates the problem as a multi-objective problem. The effectiveness of the proposed methods is demonstrated on different revised IEEE test systems including 16 and 33-bus radial distribution system.
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Park, Suwan. "An Optimal Pipe Replacement Scheduling Model for Water Distribution Systems." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/26171.
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While the idea of critical break rate of water distribution pipeline (defined as the break rate after which it is no longer economical to continuously repair) has been accepted in the literature and among the practicing engineers, the formula to obtain the critical break rate has remained elusive. In this dissertation, an equation for identifying the threshold break rate of a pipe is developed. The threshold break rate equation gives a rule of thumb for pipe replacement decision. Input parameters to obtain the threshold break rate of a pipe are repair and replacement costs, interest rate, and the length of the pipe. In addition, a methodology that enables the use of threshold break rate with the failure intensity and hazard functions is developed. The methodology is drawn by considering the relationships of the definitions of the threshold break rate with intensity and hazard functions in the context of a repairable system's failure process modeling. As a result, the newly developed threshold break rate equation can be coupled with any appropriate intensity and hazard function to obtain economically optimal replacement time of a pipe. Also, practical usage of the threshold break rate is demonstrated with a number of numerical examples. Design aids in the form of charts and tables are provided. The threshold break rate can be easily obtained either graphically or with the aid of the tables. The methodology that links the threshold break rate and failure rate (intensity and hazard) functions is extended to accommodate stress multiplying environmental factors in the form of the proportional intensity and hazards model. The two models consist of an age dependent failure rate function and a covariate structure. They are applied to a case study area pipe system to obtain optimal replacement times for individual pipes in the system. As a result, important hazard characteristics of water distribution pipes are drawn, and implications on the optimal replacement analysis are discussed. A pipe break prediction model is also developed in this research. The model spans the space between the linear and exponential break trends. The model is applied to the case study area pipe system with various cost options. The results from this analysis are discussed in terms of practical implementation of the replacement strategies.Ph. D.
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Nassery, Fatehullah. "Optimal Sizing and Placing of Distributed Generation in Distribution Networks." Kansas State University, 2017. http://hdl.handle.net/2097/35325.
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Master of ScienceDepartment of Electrical and Computer Engineering
Anil Pahwa
Due to the ongoing changes in the structure of the electricity markets, distribution networks have developed an appealing potential for housing distributed generation (DG). In order to make the most out of the present distribution network, this project report verifies the results and method developed in a paper (Optimal Allocation of Embedded Generation on Distribution Networks) by A. Kean and M. O’Malley, which discusses an efficient way of incorporating DG in the current power system. The methodology under consideration elaborates on how certain constraints should be adopted that will lead toward optimally sizing and placing DG in the network under examination. Along with that, the effect of voltage rise and short circuit current are observed which shows that a certain allocation to some buses will cause a sudden rise in voltage and short circuit levels throughout the network. Furthermore, the adopted methodology with its relative constraints is solved using linear programming. Linear programming provides a more accurate allocation than its heuristic counterparts when it comes to embedding DG in smaller networks. The adopted methodology is then applied to a section of the Irish rural distribution network and the results pinpoint that appropriate placement of the DG will pave the way toward higher levels of penetration. The results obtained showed the same pattern as those recorded in the aforementioned source paper, there were only minor differences that are the result of using different software’s than those that were used by the authors of the paper.
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Weerasinghe, Handuwala Dewage Dulan Jayanatha. "Planning optimal load distribution and maximum renewable energy from wind power on a radial distribution system." Diss., Kansas State University, 2015. http://hdl.handle.net/2097/28714.
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Doctor of PhilosophyElectrical and Computer Engineering
Ruth D. Miller
Optimizing renewable distributed generation in distribution systems has gained popularity with changes in federal energy policies. Various studies have been reported in this regard and most of the studies are based on optimum wind and/or solar generation planning in distribution system using various optimization techniques such as analytical, numerical, and heuristic. However, characteristics such as high energy density, relatively lower footprint of land, availability, and local reactive power compensation ability, have gained increased popularity for optimizing distributed wind generation (DWG) in distribution systems. This research investigated optimum distributed generation planning (ODGP) using two primary optimization techniques: analytical and heuristic. In first part of the research, an analytical optimization method called “Combined Electrical Topology (CET)” was proposed in order to minimize the impact of intentional structural changes in distribution system topology, in distributed generation/ DWG placement. Even though it is still rare, DWG could be maximized to supply base power demand of three-phase unbalanced radial distribution system, combined with distributed battery energy storage systems (BESS). In second part of this research the usage of DWG/BESS as base power generation, and to extend the ability to sustain the system in a power grid failure for a maximum of 1.5 hours was studied. IEEE 37-node, three-phase unbalanced radial distribution system was used as the test system to optimize wind turbines and sodium sulfide (NaS) battery units with respect to network real power losses, system voltage profile, DWG/BESS availability and present value of cost savings. In addition, DWG’s ability to supply local reactive power in distribution system was also investigated. Model results suggested that DWG/NaS could supply base power demand of a threephase unbalanced radial distribution system. In addition, DWG/NaS were able to sustain power demand of a three-phase unbalanced distribution system for 1.5 hours in the event of a power grid failure.
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AbdelMeguid, Hossam Saadeldin. "Pressure, leakage and energy management in water distribution systems." Thesis, De Montfort University, 2011. http://hdl.handle.net/2086/4905.
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A fast and efficient method to calculate time schedules for internal and boundary PRVs and flow modulation curves has been developed and implemented. Both time and flow modulation can be applied to a single inlet DMA. The time modulation methodology is based on solving a nonlinear programming problem (NLP). In addition, Genetic Algorithms (GA) has been proposed and investigated to calculate the optimal coefficients of a second order relationship between the flow and the outlet pressure for a PRV to minimize the background leakage. The obtained curve can be subsequently implemented using a flow modulation controller in a feedback control scheme. The Aquai-Mod® is a hydraulic device to control and modulate the outlet pressure of a PRV according to the valve flow. The controller was experimentally tested to assess its performance and functionality in different conditions and operating ranges. The mathematical model of the controller has been developed and solved, in both steady state and dynamic conditions. The results of the model have been compared with the experimental data and showed a good agreement in the magnitude and trends. A new method for combined energy and pressure management via integration and coordination of pump scheduling with pressure control aspects has been created. The method is based on formulating and solving an optimisation NLP problem and involves pressure dependent leakage. The cost function of the optimisation problem represents the total cost of water treatment and pumping energy. Developed network scheduling algorithm consists of two stages. The first stage involves solving a continuous problem, where operation of each pump is described by continuous variable. Subsequently, the second stage continuous pump schedules are discretised using heuristic algorithm. Another area of research has been developing optimal feedback rules using GA to control the operation of pump stations. Each pump station has a rule described by two water levels in a downstream reservoir and a value of pump speed for each tariff period. The lower and upper water switching levels of the downstream reservoir correspond to the pump being “ON” or “OFF”. The achieved similar energy cost per 1 Ml of pumped water. In the considered case study, the optimal feedback rules had advantage of small number of ON/OFF switches, which increase the pump stations lifetime and reduce the maintenance cost as well.
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Rodríguez, Martínez Eugenio Vicente. "On dividends and other quantities of interest in the dual risk model." Doctoral thesis, Instituto Superior de Economia e Gestão, 2016. http://hdl.handle.net/10400.5/15844.
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Doutoramento em Matemática Aplicada à Economia e à GestãoNesta dissertação trabalhamos em teoria do risco. Damos principal ênfase principal nos modelos de risco e teoria de ruína, dedicando a nossa atenção a algumas das mais interessantes e relevantes quantidades da área: a probabilidade da ruína, a transformada de Laplace e os dividendos descontados esperados. Os modelos de risco têm o objetivo de resolver, ou pelo menos, fornecer uma solução aproximada, a problemas que aparecem na prática do negócio dos seguros. Os desenvolvimentos que produzimos nesta dissertação têm a mesma finalidade. A nossa intenção é apresentar novas ferramentas para o cálculo das quantidades mencionadas acima, e uma melhor compreensão delas na prática. Consideramos o modelo dual de risco quando os tempos entre ganhos seguem uma distribuição exponencial matricial e, quando for possível, dar exemplos dos nossos resultados para casos particulares, como as distribuições Phase–Type e Erlang. Mostramos, na maioria dos casos, fórmulas e fazemos uso de técnicas matemáticas de várias áreas, como a teoria da probabilidade, a teoria das equações integro–diferenciais, a ágebra linear, análise complexa, entre outras.
In this manuscript we work on risk theory. The main emphasis is on risk models and ruin theory, devoting our attention to some of the most interesting and relevant quantities in this area: ruin probabilities, Laplace transforms and expected discounted dividends. Risk models are meant to solve or, at least, provide an approximate solution, to problems that appear in the practice of the insurance business. The developments we produce in this dissertation have the same goal. Our aim is to present new tools for computation of the quantities mentioned above, and a better understanding of them in the practice. We consider the dual risk model when the interclaim times follow a matrix exponential distribution and, whenever possible, we give examples of our findings for particular cases, like the Phase–Type, the Generalized Erlang and the Erlang distributions. We show, in most cases, explicit formulas and we make use of mathematical techniques from several areas, like probability theory, the theory of integro–differential equations, linear algebra, complex analysis, among others.
info:eu-repo/semantics/publishedVersion
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Frank, Stephen M. "Optimal design of mixed AC-DC distribution systems for commercial buildings." Thesis, Colorado School of Mines, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3558161.
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With the advent of inexpensive computing and efficient power electronics, the load mix in commercial buildings has experienced a fundamental shift away from almost exclusively traditional alternating current (AC) loads toward primarily direct current (DC) loads—devices which use DC electricity either for end-use or as a power conditioning stage. Simultaneously, installations of DC distributed generation sources for commercial buildings, such as rooftop photovoltaic arrays, are accelerating. Despite this proliferation of DC devices, the basic design of building electrical distribution systems has changed very little in the past century: AC distribution remains the industry standard. The AC-DC electricity conversions required to connect DC sources and loads to the AC electric grid result in wasted energy. Partial replacement of AC distribution with DC distribution can improve overall building electrical energy efficiency; the result is a mixed AC-DC electrical distribution system. This dissertation develops a modeling framework, mathematical program, and global optimization algorithm which determine maximally energy efficient designs for mixed AC-DC building electrical distribution systems. The research approach precisely quantifies building electrical energy efficiency at a systems level, not simply the level of individual devices. The results of two case studies validate the power of the optimization algorithm and demonstrate that well designed mixed AC-DC building electrical distribution systems can achieve higher efficiency than either AC or DC distribution used alone.
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Chen, Yue-Chun. "Analysis, modelling and optimal control of water supply and distribution systems." Thesis, De Montfort University, 1989. http://hdl.handle.net/2086/10730.
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This thesis is concerned with the developments of analysis, modelling and optimization techniques and computer program algorithms, with the ultimate aim of control of water supply and distribution systems to lead to overall optimal operation. Typical system features and operational conditions are analyzed, and the requirements for the overall objective are examined, to determine an overall control strategy which is subsequently developed and tested on real systems throughout this thesis. As a prerequisite, short-term water demand forecasting is extensively studied by employing time series analysis. Special consideration is given to improving the forecasting accuracy of the method and its on-line implementation. In order to speed up the solution time of optimal system operation, simplified system models -- namely, piecewise macroscopic model and equivalent network model -- are developed respectively. Then by employing the piecewise macroscopic model, a nonlinear programming method is developed to cater for the optimal operation of a class of multi-source systems without significant storage. The optimal operation policy obtained by this method is realized at two levels: the first level calculates the optimized apportioning of water to be delivered by different sources; the second level decides the least cost pump schedules to supply the optimized apportioning of water. Based on the equivalent network model, a linear programming method is developed for optimization of a class of multi-source, multi-reservoir systems with a mixture of fixed speed pumps and variable speed and/or variable throttle pumps. This method yields directly optimized pump schedules and reservoir trajectories in terms of least cost system operation. The integration of the developments results in a scheme which can be applied to give overall dynamic control of a wide range of water supply and distribution systems. The application results presented in this thesis justify the theoretical developments and show that benefits can be obtained from these developments.
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Kuntz, Paul A. "Optimal reliability centered vegetation maintenance scheduling in electric power distribution systems /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/5969.
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Behnood, Aref. "Optimal Operation of Battery Energy Storage Systems in Radial Distribution Networks." Thesis, Uppsala universitet, Elektricitetslära, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-397113.
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In recent years, power systems are facing with various challenges arising from the increased share of renewable energy systems. Among all sections of power systems, distribution grids are affected the most since the majority of renewable energy sources are connected to distribution grids. As the penetration of Variable Energy Sources increases in electric grids, energy storage systems have become more influential. In this context, this thesis presents a new algorithm for the optimal operation of Battery Energy Storage Systems in distribution grids. The proposed algorithm aims to define the optimal operation of Battery Energy Storage Systems considering the network topology, the output power of Variable Energy Sources and the electricity prices from the one-day ahead electric market as well as real time control of the batteries through smart appliances. In order to do this, firstly a comprehensive study on the existing Optimal Power Flow methods is carried out. Then, AR-OPF which is a novel Optimal Power Flow method for radial distribution systems is presented and the required mathematical constraints, equations and parameters of Battery Energy Storage Systems for modelling in distribution systems are described. Then, the problem formulation and the proposed algorithm are discussed in detail. Further to energy storage as the main function of Battery Energy Storage Systems, the impact of the proposed method on other functions of Battery Energy Storage Systems such as voltage control, grid support and loss reduction will be investigated. In order to do so, the proposed algorithm is applied to the IEEE 34 node test system as a case study. This will be carried out through defining several different scenarios. Finally, a sensitivity analysis is performed on the size of the existing batteries and the electricity price. The thesis will be concluded by the findings and possible future works.
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Shah, Mahesh. "A heuristic method for the optimal design of water distribution systems." Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/88600.
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The water distribution system design problem consists of finding a minimum cost combination of network layout and sizes of system components so as to satisfy flow demands, minimum and maximum head requirements and a reliability criterion. A two step procedure is proposed to find a near optimal design. The first step considers obtaining a near optimal tree layout using a heuristic tree search algorithm. Two different methods are followed for the tree search - one for single source networks and the other for multiple source networks. The second step adds loop forming redundant links to the tree layout in such a way that every demand node has two paths from source node(s). The methodology is applied to a single source network and a multiple source network. In both the cases better results arc achieved than those obtained previously by other researchers.Master of Science
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Wallace-Finney, Sheena R. "Determining the Optimal Aisle-Width for Order Picking in Distribution Centers." Wright State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=wright1312569054.
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Cheng, Fan-Tien. "Efficient algorithms for optimal force distribution in multiple-chain robotic systems /." The Ohio State University, 1989. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487598303840124.
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Bianco, Nicola. "Optimal control of particle size distribution in semi-batch emulsion polymerisation." Thesis, Imperial College London, 2009. http://hdl.handle.net/10044/1/7474.
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Mvondo, Bernardin Gael. "Numerical techniques for optimal investment consumption models." University of the Western Cape, 2014. http://hdl.handle.net/11394/4352.
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>Magister Scientiae - MScThe problem of optimal investment has been extensively studied by numerous researchers in order to generalize the original framework. Those generalizations have been made in different directions and using different techniques. For example, Perera [Optimal consumption, investment and insurance with insurable risk for an investor in a Levy market, Insurance: Mathematics and Economics, 46 (3) (2010) 479-484] applied the martingale approach to obtain a closed form solution for the optimal investment, consumption and insurance strategies of an individual in the presence of an insurable risk when the insurable risk and risky asset returns are described by Levy processes and the utility is a constant absolute risk aversion. In another work, Sattinger [The Markov consumption problem, Journal of Mathematical Economics, 47 (4-5) (2011) 409-416] gave a model of consumption behavior under uncertainty as the solution to a continuous-time dynamic control problem in which an individual moves between employment and unemployment according to a Markov process. In this thesis, we will review the consumption models in the above framework and will simulate some of them using an infinite series expansion method − a key focus of this research. Several numerical results obtained by using MATLAB are presented with detailed explanations.
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Wu, Shin-Yun, and 吳心云. "The Optimal Cash Dividends: Theory and Evidence." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/8963st.
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碩士國立暨南國際大學
經濟學系
91
Abstract: In this thesis, we propose a theoretical model of dividend smoothing based on intertemporal current account model to investigate the optimal cash dividend for a representative firm. " Save for a rainy day ", a well known theory first proposed by Campbell (1987) , indicated that a rational individual will adjust his consumption and saving behavior based on his prospects of future earnings in order to maintain a paramanent consumption level. Analogous to a consumer''s motive of consumption smoothing, we may infer a firm''s manager will behave to smooth its dividend over time. Therefore, a manager''s prospects of firm''s future net earnings will affect his attitude about current dividend policy. That is, if he expects the firm''s future net earning will decline, he will lower cash dividends and retain more earnings in the firm to invest on new investment opportunities in the future, or to maintain a smoothing cash dividend level in the future once the net earnings really turn down. On the other hand, if the manager expects the firm''s net earnings will increase, it is not necessary to retain too much dividend in the firm, he then will increase cash dividend to signal the public in the market about the firm''s good prospects, and result in its stock price to rise. Because the increase of cash dividends and the rise of stock price, the shareholder''s utility (wealth) will increase. According to this logic, we successfully extend the application of intertemporal current account model to analyze the optimal cash dividend problem of a firm. In this thesis, we not only propose a dividend-smoothing model, but also apply thirty-six firms'' (16 in Taiwan, 20 in the US) actual financial data to the empirical studies. Our results show the theory of dividend-smoothing can well explain the dividend policies over time for most of Taiwanese and American firms'' being investigated. Also, there are more American firms behave as the optimal cash dividend policy suggests than Taiwanese firms.
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Li, Chiu-chan, and 李秋貞. "Leptokurtic Distribution and Optimal Hedge Ratio." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/84503226020231308652.
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碩士國立高雄第一科技大學
金融營運所
92
When we use futures to hedge a portfolio of risky assets, the most important objective is to estimate the optimal hedge ratio (OHR). When the futures price follows a martingale and investors have mean-variance utility, the OHR is equal to the minimum variance hedge ratio. Owing to time-varying volatility in financial asset returns, moving average, GARCH, or EWMA models are commonly employed to estimate OHR. All of the approaches to estimating the OHR described above are based on the sample variance and covariance estimators of returns. These are consistent estimators of the population variance and covariance, irrespective of the underlying distribution of data, but they are not in general efficient. In particular, when the distribution of the data is leptokurtic, these estimators will attach too much weight to extreme observations. This paper uses the Power EWMA estimator of Guermat and Harris (2002) to estimate OHR. The Power EWMA estimator (that is, the robust estimator) can capture the leptokurtic distribution of the data. We also compare the results of the robust estimator to those based on the standard estimators. Our empirical analysis is restricted to the SGX-DT and the TAIFEX Taiwan stock index futures. The empirical results show that use of the robust estimator generates reductions in the variance of the hedged portfolio and the volatility of the OHR for the SGX-DT futures market, and for subperiod 1 of high kurtosis. It also reduce the transaction costs of rebalancing that are associated with changes in the OHR.
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WANG, ZHE-XIU, and 王哲修. "Optimal grounding planning for distribution system." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/57005400922458095636.
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