Dissertations / Theses on the topic 'Expected energy not supplied'

Актуальність теми. Проблема надійного забезпечення споживачів електричною енергією є однією з найважливіших при вирішенні задач проектування та експлуатації систем електропостачання (СЕП) міст, промислових підприємств та окремих об’єктів. Вимоги з питань надійного електропостачання визначаються відповідними нормативними документами і мають бути беззаперечно враховані і виконані. І споживачам, і підприємствам електричних мереж завдається істотна шкода внаслідок вимушених перерв живлення. На будь-якому рівні інфраструктури електроенергетики забезпечення надійності електропостачання споживачів завжди було важливою науково-технічною проблемою, дослідженню і вирішенню якої присвячено численні роботи вчених та науководослідних і проектних організацій (КПІ, ТГУ, МЕІ та ін.). Основні напрямки досліджень: отримання, систематизація та опрацювання статистичної інформації, оцінювання її достовірності; розроблення адекватних розрахункових моделей з оцінювання та оптимізації надійності елементів, схем та системи електропостачання вцілому; визначення ефективних системних показників надійності та методів їх розрахунку і прийняття оптимальних рішень; економічні показники втрат споживачів та електропостачальних організацій від недоотримання та недовідпуску електричної енергії. Загальний аналіз роботи електричних мереж на даний момент показує, що технічний їх стан є незадовільним, спостерігається старіння обладнання, що прогресує, та, відповідно, зниження показників надійності елементів та систем електропостачання. Більш того, постійне ускладнення структури та поява нових елементів мереж потребує розвитку теорії вирішення задач оцінювання і підвищення надійності енергозабезпечення. Відповідно, з’являється необхідність розробки методології прийняття рішень на стадіях будівництва, реконструкції та експлуатації розподільних електричних мереж (РЕМ). При оцінюванні надійності систем електрозабезпечення споживачів зазвичай розглядають такі показники, як ймовірність випадкової події перерви в електропостачанні, випадкова величина недовідпуску електричної енергії споживачам (що мала місце за результатами подій, що відбулися, або прогнозована, розрахункова), реальні або прогнозовані збитки споживачів або електропостачальної організації. Проведений аналіз свідчить про те, що показники пошкоджуваності елементів розподільних мереж та значення збитків, що несуть споживачі, практично завжди залежать від конкретних умов. Більш того, навіть для одних і тих же умов експлуатації мають місце коливання інтегрованих за рік показників пошкоджуваності елементів мереж в рази, тобто більш ніж на 100 відсотків. Це свідчить про те, що в умовах кожної системи необхідно проводити аналіз даних аварійної статистики з визначенням реальних факторів впливу на вихідні розрахункові показники (довжин ліній, схемних рішень, кількості вузлів та інші) Так само має розглядатись і враховуватись при визначені збитків (що мали місце або прогнозованих) їх суттєва залежність від сезону, часу доби, а також в значній мірі – від того, скільки часу тривала перерва в живленні споживача. Аналіз статистичної інформації свідчить про суттєву нестабільність, нестаціонарність показників, що використовуються при формуванні розрахункових моделей, оцінюванні надійності схем. Системний підхід до питання розроблення більш ефективних моделей та методів оцінки надійності розподільних мереж є як ніколи актуальним. Мета та завдання дослідження. Метою роботи є формування методології оцінювання достовірності вихідних параметрів надійності РЕМ, що визначаються по обмеженим обсягам даних аварійної статистики, та впливу прийнятих розрахункових моделей на результати обчислення показників надійності мережі. Відповідно до мети, в роботі вирішувались наступні завдання:  аналіз інформації щодо функціонування розподільних електричних мереж;  оцінка достовірності вихідних показників надійності, визначення і урахування впливових факторів, законів розподілу випадкових величин;  вибір та порівняння розрахункових моделей оцінювання надійності розподільних електричних мереж напругою 6-10 кВ на підставі опрацювання отриманих даних аварійної статистики;  послідовність реалізації системного підходу до аналізу статистичної інформації та здійсненню оцінювання надійності електропостачання. Об’єкт дослідження – розподільні мережі систем електропостачання міст. Предмет дослідження - математичні моделі та методи оцінки надійності систем електропостачання, з урахуванням особливості умов експлуатації та обсягів отримуваної вихідної інформації. Методи дослідження. Основу виконаних досліджень склали такі методи: – нелінійне програмування – метод дискретного покоординатного спуску для прийняття рішень з оптимізації точок розмикання мережі; – теорія ймовірності – використовується для оцінки впливу похибок вихідної інформації на точність визначення втрат потужності і значення ймовірного недовідпуску електричної енергії споживачам при розрахунках показників надійності; – математична статистика – для побудови гістограм розподілу згідно даних аварійної статистики, а також визначення законів розподілу та їх параметрів; для опису кривих, що показують залежність можливої похибки розрахунку значень від об’єму статистичних даних що стосуються показників надійності; – метод статистичних випробувань (Монте-Карло) – для визначення впливу похибок вихідної інформації на прийняття рішень за умови мінімізації недовідпуску електричної енергії споживачам. Елементи наукової новизни одержаних результатів. 1. Реалізовано комплексний підхід при вирішенні питань оцінки похибок вихідної інформації та їх впливу на розрахункові моделі, а саме на достовірність. 2. Запропонована методологія оцінювання впливу достовірності вихідної інформації на значення розрахункових показників надійності розподільних мереж при використанні заходів та методів уточнення показників, які визначаються. 3. Проведено згладжування статистичних розподілів даних аварійної статистики та порівняльний аналіз розрахункових моделей, що враховують індивідуальні фактори. 4. Оцінено вплив прийнятих розрахункових моделей на результати оптимізації режимів розподільних мереж виходячи з мінімізації втрат потужності і врахування надійності забезпечення споживачів електричною енергією. Практичне значення одержаних результатів. У магістерській дисертації отримано наукові результати, що мають цінність для підприємств електричних мереж у питаннях збору, систематизації інформації для її подальшої обробки для отримання параметрів розрахункових моделей. Завдяки цьому значно підвищується достовірність вихідної інформації, розрахункових моделей, а також безпосередньо розрахунків показників надійності розподільних мереж.
Actuality of theme. The problem of reliable supply of electricity to consumers is one of the most important in solving the problems of designing and operating power systems (EPS) of cities, industrial enterprises and individual objects. Requirements for reliable electricity supply are defined by the relevant regulatory documents and must be clearly considered and implemented. Both consumers and businesses are seriously harmed by forced power outages. At any level of electricity infrastructure, ensuring the reliability of electricity supply to consumers has always been an important scientific and technical problem, the research and solution of which is devoted to the numerous works of scientists and research and design organizations (KPI, TSU, MEI, etc.). Main directions of research: obtaining, systematization and processing of statistical information, evaluation of its reliability; development of adequate calculation models for evaluation and optimization of reliability of elements, circuits and power supply system as a whole; determination of effective systemic reliability indicators and methods of their calculation and making optimal decisions; economic indicators of losses of consumers and power supply organizations from under-receipt and under-release of electricity. General analysis of the operation of electrical networks at the moment shows that their technical condition is unsatisfactory, there is an aging equipment, progressing, and, consequently, a decrease in the reliability of the elements and power systems. Moreover, the constant complexity of the structure and the emergence of new network elements requires the development of a theory of solving the problems of estimating and improving the reliability of energy supply. Accordingly, there is a need to develop a decision-making methodology at the stages of construction, reconstruction and operation of distribution grids (DG). In assessing the reliability of consumer electricity systems, such indicators as the probability of an accidental event of a power outage, the accidental magnitude of unavailability of electricity to consumers (which occurred as a result of events that have occurred or are predicted, calculated) are usually considered, real or projected losses of consumers or electricity supply organization. The analysis shows that the damage rates of the elements of distribution networks and the value of losses borne by consumers almost always depend on the specific conditions. Moreover, even for the same operating conditions, fluctuations in the integrity indicators of network elements are occasionally fluctuated, by more than 100 percent. This indicates that in the conditions of each system it is necessary to analyze the data of the accident statistics with the determination of the real factors of influence on the original design indicators (lengths of lines, circuit decisions, number of nodes, etc.) It should also be considered and taken into account when determining the losses (which occurred or projected) their essential dependence on the season, time of day, and also - to a large extent - on how long the break in the power supply of the consumer. The analysis of statistical information indicates a significant instability, non-stationarity of indicators used in the formation of calculation models, evaluation of the reliability of schemes. The systematic approach to developing more efficient models and methods of assessing the reliability of distribution networks is more relevant than ever. The purpose and tasks of the study. The purpose of the work is to develop a methodology for evaluating the reliability of the original parameters of the reliability of the SEM, which are determined by the limited amount of data of the accident statistics, and the influence of the adopted calculation models on the results of calculating the network reliability indicators. Research objectives:  analysis of information on the functioning of distribution electric networks;  assessment of reliability of baseline reliability indicators, determination and consideration of influential factors, laws of distribution of random variables;  selection and comparison of calculation models of reliability estimation of distribution electric networks with voltage of 6-10 kV on the basis of processing of received data of emergency statistics;  sequence of implementation of the systematic approach to statistical analysis information and assessing the reliability of electricity supply. Object of research - Distribution networks of power supply systems of cities. Subject of research - Mathematical models, methods for assessing the reliability of power supply systems, taking into account the peculiarities of operating conditions and the amount of received information. Research methods. The basis of the performed research was the following methods:  nonlinear programming - a method of discrete coordinate descent for making decisions on the optimization of network breakpoints;  probability theory - is used to estimate the effect of initial information errors on the accuracy of determining power losses and the value of the probable non-release of electricity to consumers when calculating reliability indicators;  mathematical statistics - for plotting distribution histograms according to emergency statistics, as well as determining distribution laws and their parameters; to describe the curves showing the dependence of a possible error in the calculation of values on the volume of statistics relating to reliability indicators;  statistical test method (Monte Carlo) - to determine the impact of errors of initial information on decision making, while minimizing the lack of electricity to consumers. Elements of scientific novelty of the obtained results. 1. A comprehensive approach was implemented in addressing the issues of estimation of source information errors and their impact on the calculation models, namely reliability. 2. A methodology for estimating the impact of the reliability of the source information on the value of the calculated reliability indicators of the distribution networks when using measures and methods of refining the indicators that are determined is proposed. 3. Smoothing of statistical distributions of data of emergency statistics and comparative analysis of calculation models taking into account individual factors is carried out. 4. The influence of the adopted calculation models on the results of the optimization of the modes of distribution networks is estimated, based on the minimization of power losses and taking into account the reliability of providing consumers with electricity. The practical value of the results. In the master's thesis the scientific results are obtained that are of value for the enterprises of electric networks in the issues of collection, systematization of information for its further processing in order to obtain the parameters of the calculation models. This significantly increases the reliability of the source information, the calculation models, as well as directly calculating the reliability of distribution networks.

Universal access to electricity stands high on the global agenda and is regarded as essential for positive development in sectors such as health care, education, poverty reduction, food production and climate change. Decentralized, off-grid electrification is deemed an important complement to centralized grid extension. By utilizing a renewable energy source, solar technology for the generation of electricity, photovoltaics (PV) is being considered as a way forward to minimize the environmental problems related to energy use. This thesis aims to contribute to improving the technical and social feasibility of PV and PV-diesel hybrid micro-grids for the purpose of providing access to electricity to people in rural areas of countries with low level access to electricity. In line with these general aims, the focus has been to address three questions related to challenges in three phases of rural electrification. The work has a multi-disciplinary approach, addressing mainly technical and social aspects of long-term sustainability of micro-grids, in a local context, and the changes these are intended to generate. One specific micro-grid in Tanzania has been used as a major case study. The thesis is developed through three papers, all presenting methodologies or aspects for investigation in rural electrification projects and studies in general, and for PV-diesel hybrid micro-grids in particular. Paper I puts forward a methodology to facilitate non-social scientific researchers to take social aspects increasingly into consideration. Paper II is a guideline to support system users to increasingly apply an evaluation based system operation. Paper III specifically highlights the importance to consider blackouts when investigating how an existing off-grid PV-diesel hybrid system shall be utilized when a national grid becomes available.

The ignition process is a critical consideration for combustion devices. External energy transfer to the combustor is required for ignition in common combustion systems. There are many ways to deposit energy into the flow but a standard method is a spark discharge because it is simple, compact, and reliable. Sparks can be categorized as either inductive or capacitive sparks that use a coil or an electrical resonance circuit with capacitor, respectively, to amplify the voltage. The creation of a successful ignition event depends on the spark energy deposited into the flow, the initial composition, pressure, temperature, turbulence level of flow etc. The deposited energy by the spark into the flow is critical for estimation of initial energy available for ignition of the mixture. Therefore, the electrical characteristics of the sparks were investigated under various flow conditions. Then measurements of deposited energy into the flow were conducted using a very accurate experimental procedure that was developed in this research. The results showed considerable electric energy losses to the electrodes for the relatively long, inductive sparks. However, the short, capacitive spark deposits electric energy into the flow with minimal loss (above 90% deposition efficiency). In addition, the characteristics of inductive spark are affected by flow velocity and by the existence of a flame. However, variations in the flow conditions do not affect the characteristics of the capacitive spark such as voltage-current time trace and energy deposition efficiency. Two ignition systems using above mentioned two spark types were developed. First, the capacitive spark energy was directly deposited into the premixed flow. Most researchers have not concentrated on the early initiation process but on the flame growth. Therefore, the generated kernel formed by the energy deposition was observed and characterized using optical methods, immediately following the spark. In addition, the mixing effect for this ignition kernel with surrounding gas was simulated using a numerical method. Based on the time trace of the OH* chemiluminescence, the reaction starts with the discharge and it is continuous until combustion begins. This means that in the presence of a high density spark in premixed flow, there exists no traditional delay as defined by other researchers for auto ignition. A simple Radical Jet Generator (RJG) was developed that is able to ignite and stabilize a flame in a high-speed flow. The inductive spark initiates the combustion in the RJG chamber. The RJG then injects the partially-burned products carrying large amounts of heat and radicals into a rapidly moving flammable main stream. Then it ignites and stabilizes a flame. The RJG requires low levels of electrical power as long as the flow velocity is relatively low since most of the radicals are produced by the incomplete combustion in its chamber. The importance of radicals was analyzed by RJG experiments and numerical methods. The reaction zone for RJG using a rich mixture was located both inside and outside of the RJG chamber. Therefore, the RJG using a rich mixture performed better in the ignition and stabilization of combustion in the main flow. According to an analysis using the CHEMKIM simulation software combined with the San Diego chemical mechanism, the RJG jet resulting from a rich mixture contains more radicals and intermediates than that produced by a lean mixture for the same sensible enthalpy. In addition, the burned gas contains less radicals and intermediates than the partially burned gas. If the RJG is operating with a high speed main flow, the flow rate through the RJG chamber must be increased to allow the radical jet to penetrate well into the rapid flow due to their higher injection velocity. Unfortunately, this leads to unsteady combustion in the RJG, which results in the pulsation of the radical jet. This reduces the number of radicals injected into the main flow. To investigate this operating condition, special attention was focused on four possible factors: unburned reactant pockets caused by motion of the spark channel, spark frequency, flame propagation speed and ignition delay. It was shown that the unsteadiness is affected by the flame speed and ignition delay because the frequency of pulsation in the chamber is highly dependent on the equivalence ratio. In addition, the interaction between the RJG operation and the combustion dynamics in the main combustor was documented. The acoustic pressure oscillations in the main combustor were suppressed when the RJG jet was turned on because the reaction region is relocated by the operation of the RJG.

In this thesis project, a building in Vegagatan 12, Gävle has been analysed. The main objective has been to find why it consumes more energy than it was expected and to solve theoretically the problems.This building is a low energy building certified by Miljöbyggnad which should use less than 55kWh/m2 year and nowadays it is using 62.23 kWh/m2. In order to find why the building is using more energy than the expected several different things has been measured and analyzed.First of all, the heat exchanger of the ventilation unit has been theoretically examined to see if it works as it should and it does. This has been done using the definition of the heat exchangers.Secondly, the heating system has been analysed by measuring the internal temperature of the building and high temperatures have been found (around 22°C) in the apartments and in the corridors. This leads to 5-10% more use of energy per degree.Thirdly, the position and the necessity of all the heaters have been checked. One of the heaters may not make sense, at least in the way the building has been constructed. This leads to bigger heating needs than the expected.Fourthly, the taps and shower heads have been checked to see if they were efficient. Efficient taps and shower heads, reduce the hot water use up to 40%. The result of this analysis has been that all taps and shower heads are efficient.Fifthly, the hot water system has been studied and some heat losses have been found because the lack of insulation of several pipes. Because of this fact 8.37kWh/m2 are lost per year. This analysis has been carried out with the help of an infra red camera and a TA SCOPE.Sixthly, the theoretical and real U values of the different walls have been obtained and compared (concrete and brick walls). As a conclusion, the concrete wall has been well constructed but, the brick wall has not been well constructed. Because of this fact 1 kWh/m2 of heat are lost every year. Apart from that, windows and thermal bridges have also been checked.

Electricity generation through solar photovoltaic (PV) technology has been one of the leading renewable energy generation options in the global arena and in many countries that are working to address increasing energy demand and high fuel import dependencies. Due to the feed in tariff (FIT) amendment in 2011 and decreasing costs in global PV sector, the interest in this emerging market is quickly increasing in Turkey. The aim of this thesis is to explore the prospects for development of the solar PV market in Turkey, considering residential, commercial and utility scale PV systems with rooftop or ground mounted installations. The economic situation, the energy profile, regulatory framework for solar energy and the market conditions in the country were researched. The ultimate purpose was to assess the overall conditions to attract investors, and estimate the development of the solar PV market growth in Turkey particularly in the next few years. High irradiation levels, limited domestic energy resources and high interest in license applications suggest a big potential for solar PV electricity in Turkey. However, the regulatory framework is not yet suitable for a fast growth of this emerging solar PV market in the country due to lack of political support and experience in related government functions. Despite the high interest and demand for commercial systems, the solar PV market in Turkey is expected to grow linearly as a start. This contrast with precedents in leading European markets, which experienced exponential growth at the beginning. This study shows that there is a need for performance improvement within the regulative authorities, time for stakeholders to experience the market and more comprehensive and stable legislation. However, in the long term, solar PV technology is expected to gain high competitive advantage due to improving financial conditions in the country, increase in electricity prices (e.g. grid parity has already been reached for residential systems), and cost reductions for PV components around the world.

Reduction of carbon emissions is understood to be vital to help mitigate catastrophic climate change. In Europe, 40% of energy use is attributed to the built environment (European Commission, 2010), with a large proportion of this from dwellings. In line other legislation for decarbonisation under the Climate Change Act of 2008, the UK Government has agreed that all new housing will be ‘zero carbon’ from 2016 onwards. From a technical aspect this task is feasible using improved insulation performance, more airtight building techniques, efficient servicing, and renewable energy technologies. In practice however, post-occupancy evaluation studies highlight a discrepancy between design energy use and measured energy performance, with a tendency for real buildings to use more energy than designed and for projects regarded as ‘low energy’ in design to use an equivalent amount of energy as a pre-existing counterpart (Bordass, 2001; Branco, Lachal, Gallinelli, & Weber, 2004; Gill, Tierney, Pegg, & Allan, 2011). This difference between design and use - ‘the design gap’ - is attributed to both the physical ‘hard’ features of the building (form, area, systems) and occupant-driven or ‘soft’ features (ventilation & heating preferences) by a number of studies (Guerra Santin, Itard, & Visscher, 2009; Socolow, 1978). This body of work begins with a review of the field and state of the art - occupant influence on energy use in a domestic environment. The first contribution to knowledge is in the adapted utilisation of a piece of software by Richardson et al. which stochastically generated electricity use profiles for homes which are shown to be similar to measured energy usage, both in net energy use and in load profiles (Richardson, Thomson, & Infield, 2008). This adapted software was implemented to generate appliance use profiles for a number of dwelling models. These results are then interrogated and a regression model proposed based on a number of dependent variables identified in the input profiles. The theory of planned behaviour is used to underpin a survey in which a number of households are asked to comment on their attitude and behaviour with regards to energy use in the home – the homes in this case being new-build Passivhaus council-housing in Devon. The results of this project form the second aspect of this work’s contribution to knowledge.

Value at risk (VaR) and Expected Shortfall (ES) are commonly used risk measures in the financial literature. They have however not been applied to a great extent on energy derivatives. This paper compares the performance of several VaR and ES models for energy commodity futures on some of the world’s largest commodity exchanges. In total 14 different VaR models and nine ES models are evaluated; GARCH and GJR-GARCH with normal, student t, GED and skewed student t distributions and EWQR are used to obtain both VaR and ES forecasts. In addition, five CAViaR models are used in the VaR analysis.EWQR is by far the best ES model. It has very good test results for all markets and quantiles considered. The VaR results vary greatly, and there does not appear to be any clear pattern in which some models are better suited for certain markets or commodities. The VaR models with best performance overall are however EWQR, the adaptive CAViaR and GARCH and GJR-GARCH models with student t and skewed student t distributions.

The 2050 national energy scenarios as planned by the DECC, academia and industry specify a range of different decarbonised supply side technologies combined with the electrification of transportation and heating. Little attention is paid to the household demand side; indeed within many scenarios a high degree of domestic Demand Side Management (DSM) is implicit if the National Grid is to maintain supply-demand balance. A top-down, bottom-up hybrid model named Shed-able Household Energy Demand (SHED) has been developed and the results of which presented within this thesis. SHED models six published national energy scenarios, including three from the Department for Energy and Climate Change, in order to provide a broad coverage of the possible energy scenario landscape. The objective of which is to quantify the required changes in current household energy demand patterns via DSM, as are implicit under these highly electricity dominated scenarios, in order to maintain electrical supply-demand balance at the national level. The frequency and magnitude of these required household DSM responses is quantified. SHED performs this by modelling eleven years of supply-demand dynamics on the hourly time step, based on the assumptions of the published energy scenarios as well as weather data from around 150 weather stations around the UK and National Grid historic electricity demand data. The bottom-up component of SHED is populated by 1,000 households hourly gas and electricity demand data from a recently released dataset from a smart metering trial in Ireland. This aggregate pool of households enables national domestic DSM dynamics to be disaggregated to the aggregate household level. Using household classifications developed by the Office for National Statistics three typical ' households are identified within the aggregate pool and algorithms developed to investigate the possible required responses from these three households. SHED is the first model of its kind to connect national energy scenarios to the implications these scenarios may have on households consumption of energy at a high temporal resolution. The analysis of the top-down scenario modelling shows significant periods where electrical demand exceeds supply within all scenarios, within many scenarios instances exist where the deficit is unserviceable due to lack of sufficient spare capacity either side of the deficit period. Considering the level of participation required within the modelled scenarios in order to balance the electricity system and the current lack in understanding of smart metering and Time-Of-Use (TOU) tariffs within households, it would seem there is a disconnect between the electricity system being planned, the role this system expects of households and the role households are willing to play.

Cette étude s’intéresse à la conception systémique intégrant simultanément les questions de dimensionnement et de gestion optimale de l'énergie. Le système étudié concerne un procédé de pompage intégrant un processus de dessalement d’eaux saumâtres alimenté par des sources de puissance hybrides renouvelable incluant un minimum de stockage électrochimique. Ce cas d’étude appartient à une classe typique de systèmes autonomes alimentés par des sources intermittentes dont profil de puissance a une forme "donnée" : « selon les conditions climatiques (ensoleillement, vent), avec un minimum de stockage d’électricité, la puissance offerte doit être convertie ou stockée hydrauliquement sous peine d’être gaspillée ». L'influence des conditions d'environnement et la robustesse du processus d’optimisation est enfin aussi discutée dans cette thèse. Deux types de modèles mathématiques, dynamiques et quasi-statiques, sont mis en œuvre pour décrire l'ensemble du dispositif. Le système est tout d’abord modélisé dynamiquement par Bond Graphs. Pour une simulation plus rapide, plus adaptée à l’optimisation globale du système, un modèle quasi-statique est créé pour être simulé dans l'environnement Matlab. Pour de tels dispositifs, étant donné une certaine puissance offerte au fil du vent et du soleil, trouver le point optimal de fonctionnement à chaque période consiste en un partage de puissance entre les sous systèmes de pompage et de traitement de l’eau : ce processus est plutôt complexe compte tenu des non linéarités (courbes rendement – puissance) et de la présence de nombreuses contraintes relatives aux limitations de puissance des pompes, aux conditions de niveau des réservoirs, ainsi qu’aux limitations de pression et de débit dans les processus hydrauliques (pompes osmoseur). Nous montrerons qu’il n’est pas si trivial de choisir une fonction objectif qui assure simultanément la performance et la robuste du système vis-à-vis des conditions d’environnement : une fonction objectif robuste quel que soit le profil de puissance des sources est ainsi proposée pour mettre en œuvre une gestion optimale de l’énergie. Le problème d’optimisation étant posé sous forme standard, consistant en la maximisation d’une fonction objectif sous contraintes, des approches d’optimisation efficaces par programmation non linéaire sont employées. La question du dimensionnement et son couplage à la gestion énergétique est finalement étudiée. En particulier, l’intérêt de la modularité des systèmes, considérant plusieurs pompes connectées en parallèle pour la même fonction, est investigué
This study focuses on systemic design, integrating simultaneously issues of sizing and optimal energy management. The system under study consists of a pumping process including a brackish water desalination system fed by hybrid renewable power sources with minimum electrochemical storage. Such a device belongs to the class of “autonomous systems” supplied by intermittent sources whose power profile has a “given” waveform: “with minimum electrical storage, power has to be converted, stored in water tanks, or wasted following climatic (sun, wind) conditions”. Influence of environment conditions and robustness of the optimization process is then also discussed in this thesis. Both dynamic and quasi static models are implemented for representing the whole system. The device is firstly modeled dynamically by Bond Graph methodology. For faster simulations, which are more suitable for system optimization, a quasi static model is created to be simulated in the Matlab environment. For such systems, given a certain source power, finding optimal operation point at each period consists of a power sharing between all pumping devices: it is a complex process with huge nonlinearities (efficiency vs power curves) and with many constraints as for the limitation of pump powers, tank level conditions, or pressure and flow limitations in hydraulic network and pumping devices. It is not so trivial to define an objective function which ensures system performance and robustness versus environment conditions: a convenient objective function, whatever the input power profile, is then proposed to implement the optimal management. The optimization problem being mathematically expressed, consisting of objective function maximization under constraints, efficient optimization methods by non linear programming are implemented. The issue of sizing and its coupling with system management efficiency is finally studied. In particular, the interest of modular operation with several pumps connected in parallel is also concerned in this research

A number of natural resources can be exploited for providing energy, such as the sun, wind, water flow, tides, waves and deep heat generated within the earth. Recently, renewable resources especially that extracted from solar have been significantly encouraged mainly for environmental worries, such as climate change mitigation and global warming, coupled with high oil cost and security and economic matters. The crucial need of energy in human development has also been another important drive pushing the rapid progresses in renewable technologies, which results in both large-scale strategic projects for covering wide urban and rural areas and simple systems suitable for individual buildings. Solar energy has become a widely desired option, especially in high solar radiation areas. The Middle East, especially Gulf region is an ideal geographical area for solar power where it has one of the highest solar irradiation rates across the world. The population in Gulf Cooperation Council (GCC) countries is significantly small compared to the geographical areas and populations are distributed mostly throughout huge areas forming small villages and rural communities on substantial distances from the main power networks. In Saudi Arabia, there is a crisis in supplying enough electricity to the large cities and domestic remote area in various parts in the country and a wide range of remote areas still suffer from a severe shortage of power supply. In this project, the opportunity of using small-scale solar energy technologies, such as Stand-Alone Building-Integrated PV (SABIPV) systems has been investigated as an optimal solution for providing solar energy to a great deal of off-grid areas in Kingdom of Saudi Arabia and the expected short and long-term impacts of such solution have been studied. The study showed that the main reasons behind the crisis in supplying electricity to domestic remote and rural off-grid areas in Saudi Arabia are the weakness of the financial returns compared to the cost of providing the service, the difficulty of the natural topography of areas, high cost of maintenance works, and the regulations of providing electric services in Saudi Arabia. This is in addition to the expected environmental impacts, such as raising the pollution rates in the area and the safety influences of extending the high voltage lines over huge areas. On the other hand, the lack of the necessary infrastructure services, particularly electricity and the looking forward for better level of prosperity lead people who live in countryside and remote areas usually to immigrate to in-grid areas which has several short and long-term negative impacts on economic, social and security sides. This study shows that SABIPV system is a cost-Impactive, powerful, and fundamental solution for all off-grid areas in Saudi Arabia including remote villages and rural communities and providing the same level of electricity services that can be achieved in urban on-grid areas. The system is expected to have positive impacts including reducing pollution and greenhouse gas emissions, the expansion of agricultural land and reduce desertification, reducing the influence of high-voltage electrical lines on living organisms, providing adequate electricity service at lower cost, offering more job opportunities for people in remote areas, increasing agricultural and handicraft products, developing the tourism sector in rural areas, reducing the rate of migration from rural areas to the cities, and reducing the slum areas in cities which helps to reduce the rate of crimes, ignorance, the low level of morality, and health and environmental problem.

The municipality of Uppsala together with eight constructors are currently planning a sustainable residential area in Östra Sala backe. The aim of this report is to identify the main factors that are important when calculating the specific energy use in an apartment building. Two previous similar projects, Västra Hamnen in the city of Malmö and Hammarby Sjöstad in the city of Stockholm, are studied and simulations in VIP-energy are performed. Sensitivity analyses concerning the indoor temperature, the efficiency of FTX-systems and the U-values of windows are also executed. The simulations are based on information from the constructors of Östra Sala backe, standard values and mean values from Västra Hamnen and Hammarby Sjöstad. The results show that differences between the estimated and measured values in specific energy use can reach about 50 %, or 25.2 kWh per m2 ATEMP and year, and that the efficiency of the FTX-system is the most important parameter.

Network lifetime is an important performance metric in Wireless Sensor Networks (WSNs). Transmission Power Control (TPC) is a well-established method to minimise energy consumption in transmission in order to extend node lifetime and, consequently, lead to solutions that help extend network lifetime. The accurate lifetime estimation of sensor nodes is useful for routing to make more energy-efficient decisions and prolong lifetime. This research proposes an Energy-Efficient TPC (EETPC) mechanism using the measured Received Signal Strength (RSS) to calculate the ideal transmission power. This includes the investigation of the impact factors on RSS, such as distance, height above ground, multipath environment, the capability of node, noise and interference, and temperature. Furthermore, a Dynamic Node Lifetime Estimation (DNLE) technique for WSNs is also presented, including the impact factors on node lifetime, such as battery type, model, brand, self-discharge, discharge rate, age, charge cycles, and temperature. In addition, an Energy-Efficient and Lifetime Aware Routing (EELAR) algorithm is designed and developed for prolonging network lifetime in multihop WSNs. The proposed routing algorithm includes transmission power and lifetime metrics for path selection in addition to the Expected Transmission Count (ETX) metric. Both simulation and real hardware testbed experiments are used to verify the effectiveness of the proposed schemes. The simulation experiments run on the AVRORA simulator for two hardware platforms: Mica2 and MicaZ. The testbed experiments run on two real hardware platforms: the N740 NanoSensor and Mica2. The corresponding implementations are on two operating systems: Contiki and TinyOS. The proposed TPC mechanism covers those investigated factors and gives an overall performance better than the existing techniques, i.e. it gives lower packet loss and power consumption rates, while delays do not significantly increase. It can be applied for single-hop with multihoming and multihop networks. Using the DNLE technique, node lifetime can be predicted more accurately, which can be applied for both static and dynamic loads. EELAR gives the best performance on packet loss rate, average node lifetime and network lifetime compared to the other algorithms and no significant difference is found between each algorithm with the packet delay.

The rapid integration of intermittent renewable energy sources (IRES) has caused a growing demand for power system flexibility on energy markets all over Europe. Being the only commercially proven large scale energy storage technology, pumped storage hydro power (PSHP) has by several studies been suggested as an efficient solution to miti­gate the impact of IRES. However, despite the perceived technical demand profit­ability remains as a major obstacle for PSHP development. In this study, a market requirement for PSHP profitability, defined in terms of price volatility, is pre­sented. Considering capital and operational expenditures as well as modelled potential price arbitrage revenues for a greenfield PSHP plant, it may be used as a tool for initial assessments of PSHP profitability in relation to market outlooks or modelled future prices. The results have further been used in a case study, where the price volatility required to motivate a restora­tion of the now decommissioned Swedish PSHP plant Juktan has been determined. The results show that the high capital expenditures characterising PSHP development do comprise in a high risk for developers; while feasibility depends on the sustainment of a highly volatile price climate during several decades, energy markets are often extremely uncertain.

A continuidade no fornecimento de energia elétrica a clientes é um objetivo constante das distribuidoras de energia, as quais estão constantemente buscando desenvolver soluções tecnológicas a fim de melhorar o desempenho das redes de distribuição. Com o crescimento das cargas eletrônicas e o expressivo aumento dos dispositivos automáticos nas redes, surge uma nova forma de analisar a rede de distribuição sob o aspecto da filosofia da proteção, considerando interrupções sustentadas e momentâneas, sob dois aspectos distintos, o primeiro considera o custo da energia não fornecida sob o período de contingência, enquanto que o segundo refere-se ao impacto do custo social para diferentes classes de clientes, durante o período das interrupções. Desta forma este trabalho propõe o desenvolvimento de uma estratégia de minimização de custos dessas interrupções considerando as características das cargas, bem como o tempo necessário para reinicialização da carga. Para este fim, é aplicado um modelo de programação não-linear, que emprega variáveis binárias para definir a habilitação ou não de curvas rápidas nos religadores e uma abordagem de otimização clássica. Os algoritmos foram desenvolvidos no software Matlab e posteriormente convertido para linguagem GAMS (Generic Algebraic Modeling System). A metodologia foi testada e validada em um alimentador de distribuição real urbano, localizado na região metropolitana de Porto Alegre (RS, Brasil).
Uninterrupted power delivery is a permanent goal of power utilities. One way of attaining this objective is constantly investing in technological solutions to improve the performance of distribution networks. With increasing loads, mainly electronic ones, as well as growing insertion of automatic reclosers, the protection philosophy of distribution systems has to be rethought taking into account temporary and permanent interruptions. In this work, we propose a strategy to minimize the cost of interruptions taking into account the load characteristics and the time required to restart the load. This is achieved by deriving a mixed integer nonlinear programming model. The proposed model uses binary variables to define if the instantaneous characteristic of the recloser should be enabled and a classical explicit mathematical optimization approach. The algorithms were developed with Matlab software and the conversion was made to a General Algebraic Modeling System (GAMS). The applicability of the proposed methodology is tested in an actual feeder from Porto Alegre.

Yes
Wind Energy published by John Wiley & Sons Ltd. Maintenance is essential in keeping wind energy assets operating efficiently. With the development of advanced condition monitoring, diagnostics and prognostics, condition-based maintenance has attracted much attention in the offshore wind industry in recent years. This paper models various maintenance activities and their impacts on the degradation and performance of offshore wind turbine components. An integrated maintenance strategy of corrective maintenance, imperfect time-based preventive maintenance and condition-based maintenance is proposed and compared with other traditional maintenance strategies. A maintenance simulation programme is developed to simulate the degradation and maintenance of offshore wind turbines and estimate their performance. A case study on a 10-MW offshore wind turbine (OWT) is presented to analyse the performance of different maintenance strategies. The simulation results reveal that the proposed strategy not only reduces the total maintenance cost but also improves the energy generation by reducing the total downtime and expected energy not supplied. Furthermore, the proposed maintenance strategy is optimised to find the best degradation threshold and balance the trade-off between the use of condition-based maintenance and other maintenance activities.
UK Engineering and Physical Sciences Research Council (EPSRC). Grant Number: EP/P009743/1

The demand to integrate more features has significantly increased the complexity and power consumption of smart portable devices. Therefore extending the battery life-time has become a major challenge and new approaches are required to decrease the power consumed from the source. Traditionally the focus has been on reducing the dynamic power consumption of the digital circuits used in these devices. However as process technologies scale, reducing the dynamic power has become less effective due to the increased impact of the leakage power. Alternatively, a more effective approach to minimize the power consumption is to continuously optimize the ratio of the dynamic and leakage power while delivering the required performance. This works presents a novel power-aware system for dynamic minimum power point tracking of digital loads in portable applications. The system integrates a dc-dc converter power-stage and the supplied digital circuit. The integrated dc-dc converter IC utilizes a mixed-signal current program mode (CPM) controller to regulate the supply voltage of the digital load IC. This embedded converter inherently measures the power consumption of the load in real-time, eliminating the need for additional power sensing circuitry. Based on the information available in the CPM controller, a minimum power point tracking (MiPPT) controller sets the supply and threshold voltages for the digital load to minimize its power consumption while maintaining a target frequency. The 10MHz mixed-signal CPM controlled dc-dc converter and the digital load are fabricated in 0.13µm IBM technology. Experimental results verify that the introduced system results in up to 30% lower power consumption from the battery source.

碩士
淡江大學
財務金融學系碩士班
101
This paper employs the KMV (Kealhofer-McQuown-Vasicek) model to consider with the eight PV (Photovoltaic) related companies from first season of 2010 to fourth season of 2011. The raw data includes a total number of 64 observations,and with the sixteen LED (Light Emitting Diode) related companies from first season of 2007 to fourth season of 2011. The raw data includes a total number of 320 observations. It’s use to calculate the EDF (Expected Default Frequency) with each company, and relatedness of financial variable target EDF by the panel data either, and discusses influence factor the anticipated violation probability size. The empirical results confirm that is take the decision reference for the investor that the PV and LED can affected under attack by the international finance event and a part norms of financial statement can effect the EDF.

碩士
中原大學
電機工程研究所
102
In this thesis, we applied PSS/E software to simulate the expected energy not supplied in the peak time of Summer months (power curtailment and forced outage included), and we calculated the expected energy not supplied of users under the circumstances of Lungmen Nuclear Power Plant stop functioning. Firstly, we analyzed the East system in the Northern Taiwan, and finding the 345kV Bulk Supply Substation of East system and the 345kV power lines which connect between the East and West system; according to the result, we analyze the influences toward the East and West system in the Northern Taiwan under the circumstances of Lungmen Nuclear Power Plant stop functioning. In addition, this study applied PSS/E to simulate the Power Flow in Taiwan and analized the higher capability of the energy not supplied of the area of the East system in the North Taiwan, recommending the creation of the line. This study submits a method which estimates the expected energy not supplied and the capacity and total energy of ADR that should be purchased in every over-loading Substation of Taipower for the future years under the circumstances of Lungmen Nuclear Power Plant stop functioning. All the parameters in this study are set in 2016, we demonstrates the adaptability of the method we submitted.

碩士
國立臺北科技大學
電機工程系研究所
99
In wireless sensor networks (WSN), most nodes have limited energy for working, so WSN’s routing algorithm has to consider energy problem. For this, low energy adaptive clustering hierarchy (LEACH) solves energy problem by rotation as cluster head (CH), and be able to raise network energy efficiency. However LEACH uses random mechanism to select CH, the energy of selected node may not be enough to be the CH. To solve this problem, we have provided a novel CH selection algorithm. This algorithm uses expected energy consumption (EEC) and residual energy to be fuzzy logic system (FLS) inputs to compute the CH chance. According to the CH chance, we select CH with two-layer filter CH selection algorithm. Using this mechanism, we discover that network life time (such as the first node dead, half nodes dead and last node dead) is longer than that of LEACH. Furthermore, CH may be failed by some problems, such as energy being not enough in the steady state. The agent concept is used to solve this problem. According to EEC, which will make CH know its energy sufficient or not, we insert a time slot at time-division multiple access (TDMA) schedule for synchronizing and CH’s status noticing. Thus, we may avoid CH failure problem occur, and let CH has enough energy to work in steady state. In this paper, the proposed CH selection mechanism may effectively prolong network life time, and the agent mechanism may provide the fault-tolerant ability in steady state.

Yes
The concept of smart city is emerging as a key strategy to tackle the problems generated by the urban population growth and rapid development. It is widely recognised that Information and Communications Technology (ICT) play a key role in addressing some of the urban societal challenges such as improving energy efficiency and reducing carbon emissions. Although there are various ICT tools providing intelligence and services relating to energy consumption and monitoring processes, they mostly tend to work in isolation. Therefore, this paper presents the outcomes and impacts of the concept of DAREED which aims to deliver an integrated ICT service platform to drive energy efficiency and low carbon activities at neighbourhood, city and district levels. Furthermore, the research highlights the need for ICT-driven policy making using platforms such as DAREED in the context of e-Government. This paper contributes to the current understandings of e-Government literature in terms of how ICT can help public authorities and stakeholders such as policy makers to achieve and drive energy efficiency. From a practical stance, the paper offers valuable insights to public administrations on how ICT can be used to address pressing societal challenges such as efficient energy use and facilitate better policy making.

Currently, major power systems almost invariably operate under interconnected conditions to transfer power in a stable and reliable manner. Multi-area reliability evaluation has thus become an invaluable tool in the planning and operation of such systems. Multi - area reliability evaluation is typically done by considering equivalent tie lines between different areas in an integrated power system. It gives approximate results for the reliability indices of a power system as it models each of the areas as a single node to which are connected the entire area generation and loads. The intratransmission lines are only indirectly modeled during the calculation of equivalent tie lines' capacities. This method is very widely used in the power industry, but the influence of the various approximations and assumptions, which are incorporated in this method, on reliability calculations has not been explored. The objective of the research work presented in this thesis is the development of a new method called Composite system based multi - area reliability model, which does multi - area reliability evaluation considering the whole composite system. It models the transmission system in detail and also takes into account the loss sharing policy within an area and no - load loss sharing policy among the areas. The proposed method is applied to standard IEEE 24 bus Reliability Test System (RTS) and the traditional equivalent tie-line method is applied to the multi-area configuration of the same test system. The results obtained by both the methods are analyzed and compared. It is found that the traditional model, although having some advantages, may not give accurate results.