Енергетика та системи керування (EPECS-2013). – 2013 р.
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Матеріали IV Міжнародної конференції молодих вчених EPECS-2013
У збірнику опубліковано матеріали конференції, присвяченої проблемам у галузі енергетики. Видання призначено для науковців, аспірантів, студентів.
Енергетика та системи керування : матеріали IV Міжнародної конференції молодих вчених EPECS-2013, 21–23 листопада 2013 року, Україна, Львів / Міністерство освіти і науки, молоді та спорту України, Національний університет "Львівська політехніка". – Львів : Видавництво Львівської політехніки, 2013. – 104 с. : іл. – (4-й Міжнародний молодіжний фестиваль науки "Litteris et Artibus"). – Паралельний титульний аркуш англійською.
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Item Математичне моделювання температурного режиму потоку газу в системах його обліку при імпульсних режимах роботи(Видавництво Львівської політехніки, 2013) Федоришин, Роман; Комарецький, Олександр; Чура, Мар’янThe mathematical model of the temperature regime of gas flow in a metering system is built based on the law of conservation of energy. Using the developed model the transient processes are simulated and compared to the results of experimental studies. On the basis of verification of the developed model it was defined that the maximum absolute deviation of the simulated values from the experimental results was 0.73 ºC. The developed model provides the possibility to define the systematic error of natural gas flow temperature measurement caused by inertia of the thermometer in pulse regimes of flow. The pulse regime of flow is present in natural gas metering systems installed in boiler houses where the switching on and off of the boiler leads to the pulse regime of gas consumption. Ways to define and eliminate the systematic error of flow temperature measurement caused by inertia of the thermometer in pulse regimes of flow are proposed in this paper in order to improve the accuracy of natural gas metering.Item Планування виробничих експериментів для багатофакторного дослідження технології сушіння торфу в парових трубчатих сушарках(Видавництво Львівської політехніки, 2013) Кулаковський, Леонід; Алтухов, ЄвгенійThe paper highlights the necessity for planning the experiment in steam pipe dryers of peat for multivariate investigation of the drying process and for further searching power saving regimes of drying. Analysis of plans of experiments allowed to identify the main criteria for the construction plan of the experiment in steam pipe dryer. The basis for the planning of the experiment should take regime maps of tube steam dryers, which provide required quality of a dried peat and changing of control actions carry out in the range of operating conditions. In order to decrease the number of experiments, and also not to rid planning matrix its best features is necessary to develop fractional factorial experiment (FFE) and to identify fractional replica. The optimal experiment’s plan for creating a mathematical model of the drying process is FFE 25-1 with shoulder g=1 and experiments in the center of the plan.Item Умови реалізації цифрових регуляторів на цифрових системах з обмеженою розрядністю(Видавництво Львівської політехніки, 2013) Сольський, Мар’янThe problem of impact of finite-precision data on digital control systems synthesis and practical realization is described. Dependences between the accuracy of elementary first and second order dynamic links coefficients and minimal admissible sampling step were determined and analyzed.Item Зміст до "Енергетика та системи керування - EPECS-2013"(Видавництво Львівської політехніки, 2013)Item Розрахунок теплового пункту з підмішувальними помпами формалізованими методами(Видавництво Львівської політехніки, 2013) Музичак, Андрій; Павликівська, ХристинаTraditionally, the heat points are calculated from pressure at the input without influence of neighboring consumers. This cause errors in the analysis of modes of consumers and does not instrument for improvement modes of heating system as a whole. To eliminate these defects can use formalized methods for the analysis of the theory of hydraulic circuits. The object of research was the development of mathematical model of heating points with mixing pumps and methods of setting up by formalized methods. In these heat points also install the heat flow regulator for automatic control mode. This regulator is an active element. Its hydraulic resistance varies depending on the heat take-off from the network. Calculation of flux-distribution for these heating points must perform two nested iterative procedure. In the inner loop calculate flux-distribution with fixed hydraulic resistance brunches. External process for the algorithm given in this paper corrects resistance regulators to minimize the difference between the current and desired heat-carrying agent. Developed a mathematical model and algorithm are instruments for identifying and providing energy saving modes of heat points and heat supply system as whole.Item Increasing efficiency of radiant heating systems’ work(Видавництво Львівської політехніки, 2013) Shepitchak, Volodymyr; Zhelyh, VasylThe possibility of the application of energy efficient heating systems based on infrared light for heating industrial premises has been analyzed in the article. The experimental studies of temperature condition exposure zone of the rotary infrared heaters. The rotary radiation heater represents the distribution of the exposure intensity depending on the height disposition. The results are presented in graphical interpretation.Item Титульний аркуш до "Енергетика та системи керування - EPECS-2013"(Видавництво Львівської політехніки, 2013)Item Вплив гідродинамічних збурень на точність вимірювання швидкості потоку ультразвуковими витратомірами газу(Видавництво Львівської політехніки, 2013) Роман, Віталій; Матіко, ФедірThe modeling of perturbed velocity profile of turbulent gas flow using computational fluid dynamics method (CFD) is carried out. The algorithm for determining the average velocity along the acoustic path is developed using the results of CFD-modeling. The effect of influence of flow profile distortions produced by the fitting "90° elbow" on the average velocity measurement error is investigated for single channel ultrasonic flowmeter with diametrical acoustic channels. Modeling of such flowmeter is carried out for various angles of the plane of diametrical acoustic channel (0°, 45°, 90° and 135°). The dependence of the relative deviation (error) of average velocity on the angle of acoustic channel and on the distance between the flowmeter and the fitting "90° elbow" is investigated. The angle of acoustic channel of ultrasonic flowmeter that provides the minimum error of flow velocity measurement downstream of fitting "90° elbow" is defined. The distance between the ultrasonic flowmeter and the fitting "90° elbow" is defined to provide the velocity measurement error smaller than 0.5%.Item Знаходження сталої часу теплової вимірювальної комірки з метою підвищення швидкодії газоаналітичних приладів(Видавництво Львівської політехніки, 2013) Макар, Олег; Кріль, Олександр; Кріль, БогданIn gas analysing equipment heat detectors are widely used for converting thermal physical and mechanical parameters of the gaseous mixture into an electrical signal. Heated by electric current these detectors sense thermal conductivity, heat capacity and project gasous mixture expenditure. Sensitivity and performance velocity are among the main parameters of these detectors determining the irmetrological characteristics. The given paper provides the equation of time constant of the heat measuring cell, common in gas analysing equipment, for the purpose of studying the influence of detectors’ mode changes on the performence velocity of gas analysing equipment.Item Моделювання процесів в теплоенергетиці за допомогою використання дробових похідних(Видавництво Львівської політехніки, 2013) Кравець, Тарас; Кузнецова, МартаSymbolic models of technological processes in the heat power engineering, based on classic differential equations, fail to provide certainty in some cases and may contain considerable skewing. The object of this research is dynamic and static processes of heat power systems, that are described by means of differential equations of fraction order, specifically, the processes of temperature alternation in heat-exchange units. The aim of the article is to use the method of reduction of order to provide analytical solution of heat and mass transfer problems in different environments, with different boundary conditions, for flat, cylindrical and spherical surfaces on the edge of heat carriers in motion. The paper reveals, that the use of the theory of fractional estimation to describe the processes of coordinate alternation in heat-exchange units allows finding solution in the cases of other mathematical methods inefficiency.Item Оцінка ефективності застосування загущеної присадками індустріальної оливи у вузлах тертя енергетичного устаткування(Видавництво Львівської політехніки, 2013) Коваленко, Тетяна; Івасик, ЯрославPolyfunctional lubricant performance properties indicates its significant impact on the longevity and efficiency of work of contact pairs. About 30% of the total energy produced is consumed to friction. The improvement of lubricant and efficiency of lubricating can reduce energy costs by 45%. Therefore, the correct choice of lubricant depends on energy consumption to overcome friction, wear of rubbing surfaces. The most economical way for the improvement of work of the friction units in different environmental conditions is the development of new lubricant compositions with the addition of an effective multifunctional additives as so base oils don't meet all of requirements put forward to them. The polymethacrylate additives with enhanced functionality were obtained in this work. The influence of the concentration of the additives on the viscosity-temperature, depressor and anti-wear properties of industrial oil I-20A were studied. Found that received additives improve the performance properties of oil-20A, respectively, contribute the reliable lubrication of the friction units in power plants at different natural conditions.Item Дослідження перенапруг під час дугових замикань на землю в електромережах 35 кВ(Видавництво Львівської політехніки, 2013) Яцейко, Андрій; Горошко, ОлегIn this article it is researched the influence of grounding conditions of neutral of electrical network 35 kV on the level of arc overvoltage due to the theory by: Petersen, Peters - Slep'yan and Belyakov – Dzhuvarly. There were given schematic dependencies of arc overvoltage multiplicities which depend on neutral grounding, given main schematic dependencies of combustion of grounding arc. It is shown that values of arc overvoltages significantly increased with increasing of the value of the capacitive current in the electrical network. Combined condition of neutral grounding reduces the level of arc overvoltages the best. Multiplicity does not exceed 2.4 for all theories for various values of capacitive current.Item Design of marketing system of control by energy consumption modes at the retail power market(Видавництво Львівської політехніки, 2013) Petrova, Kate; Serebrennikov, BogdanThe methods of managing the modes of electric load for structural levels of the power system were examined. The effectiveness of marketing approach of forming the energy efficient modes of power consumption in transformed model of power market were proved. The levels of segmentation of the retail power market were grounded, the relevant criteria for consumers' segmentation considering their specifics of power consumption mode regulation were determined. The significance of criteria was proposed to consider in calculation of differentiated prices.Item Визначення відносного діаметра діафрагми оптимальної за точністю вимірювання витрати природного газу(Видавництво Львівської політехніки, 2013) Кузик, Володимир; Чабан, Богдан; Лесовой, ЛеонідThe national literature review showed that the mathematical model for the relative standard diameter of narrowing device calculating because of the introduction of new national standards should be clarified. The components of flowrate measurement error, directly dependent on the design parameters of the standard narrowing devices are found. The optimality criterion for calculating of the structural parameters of the standard narrowing devices for optimal precision flow measurement of natural gas is proved in this paper. An algorithm of calculating of the structural parameters of the standard narrowing devices of differential pressure flowmeter for natural gas measurement, that enhances the accuracy of flowrate measurement by reducing of systematic errors that depend on the design parameters of the standard narrowing devices, was made as well.Item Алгоритм роботи комбінованої автономно-мережевої системи електроживлення окремого об’єкта(Видавництво Львівської політехніки, 2013) Климко, ВолодимирIn this article an algorithm of work of a combined autonomous and network power supply system of a individual object is considered, and also work of the scheme used in this system is described. For providing the consumer with necessary capacity, it is offered to combine of using of energy of renewable sources, such as wind and solar, and the energy arriving from the centralized network. Use of the electrochemical storage battery as a part of installation for an uninterrupted power supply of object is offered. To management the process of generating of electric power, its distribution between consumers of a certain object, and also optimization of work of elements of installation, the using a controller as a part of a power supply system is offered. The main criterion for the application of the given combined system for ensuring needs of the consumer is direct consumption of the electric energy generated by the wind turbine and the photovoltaic unit. The main goal of this work is improvement an algorithm of work of the combined autonomous and network power system. Relevance of it work consists in using of a new type of the combined power supply system for providing the consumer with qualitative electric energy at any moment.Item Investigation of light intensity and temperature dependency of solar cells electric parameters(Видавництво Львівської політехніки, 2013) Tobnaghi, Davoud Mostafa; Madatov, Rahim; Farhadi, PayamIn this paper, the performance and overview use of solar cells is expressed. The role of temperature, sunlight intensity on the solar cells electric parameters has been studied. Experimental results the amount of solar cell output parameters variations such as maximum output power, open circuit voltage, short circuit current, and fill factor in terms of temperature and light intensity shows. the most significant is the temperature dependence of the voltage which decreases with increasing temperature. Also output current of solar cells is directly proportional to the light intensity. The best performance of solar panels in sunny and cold day has been suggested. Obtained results could lead to optimal use of solar cells.Item Алгоритм та програмна реалізація декартового множення як елемент побудови моделі гідрогазодинамічних дросельних схем(Видавництво Львівської політехніки, 2013) Грудецький, РоманIn the design of modern technological parameters of transducers having trouble choosing scheme of the converters, which would provide the necessary technical and metrological characteristics of them. One such problem is the lack to date methodologies describe outline of transducers that describe the relevant circuit solutions , with which to perform synthesis and optimization of transducers. Proposed to be used for this set-theoretic concept, extending the number of concepts and operations of set theory. This will formalize the description and modeling scheme of the transducers, and on this basis to develop a theory of synthesis circuit solutions that automate the process of decision-making circuit. For a given or re-synthesized circuit building measuring transducer to explore its functionality and specifications. It is necessary to develop a methodology for modeling of converters and make it algorithmization that will implement the following processes on the computer. The result of research is to develop computer-aided design elements mentioned above transducers.Item Визначення бажаного характеристичного поліному для узагальненої електромеханічної системи оптимального керування(Видавництво Львівської політехніки, 2013) Волянський, Роман; Послайко, Ілля; Садовой, ОлександрThe paper deals with the comparison and generalization results of synthesis of electric drives control systems by using modal control and solving problem of controllers analytical design. It shown the definition of the desired characteristic polynomial for a given closed-loop system and the functional quality that defines the purpose of control. Conditions of corresponding modal control to problem of controllers analytical design are found. These conditions cause the creation of simplified procedures for the synthesis of high-precision control systems. This procedure can be used to create control systems of electric drives that are experiencing the sliding modes of different orders by using nonlinear activation function.Item Аналіз аварійних режимів роботи вимірювальних трансформаторів струму(Видавництво Львівської політехніки, 2013) Яцейко, Андрій; Ференсович, РоманDisconnecting the secondary circuits from current transformers are accompanied by the occurrence on the terminals of their secondary windings surges which are dangerous for isolation of current transformers, attached to them equipment and life staff. The paper analyzes emergency modes of working two-stage current transformer type TFZM-500 after disconnecting secondary windings its stages. Researches were conducted on created in computer program design scheme of this cascade transformer which allows to model various modes of its working. Results of investigation have theoretical and practical significance for further analysis modes of disconnecting secondary circuits of current transformers in order to create effective and reliable methods of protecting from surges. It is shown a block diagram of current transformer protection system from action of dangerous surges after disconnecting its secondary circuits which based on using microprocessor technology.Item Аналіз та оцінка впливу шкідливих викидів ТЕС України на навколишнє середовище(Видавництво Львівської політехніки, 2013) Коваленко, Тетяна; Коваленко, ПавлоThe development of science and technology continually affects the growth of human impact on the environment. Especially in our time, the problem of pollution of the atmosphere, lithosphere and hydrosphere and their negative impact on the biosphere, human life and health becomes more and more relevance in the world. Therefore, the analysis of current research and publications concerning the effects of emission of thermal power plants in Ukraine on the environment have been done in this work. The reasons that lead to the pollution of the biosphere were generalized and the ways to overcome this environmental problem were given. The main conclusions of the work were made according to the scientific research.