Academic literature on the topic '621.315.1'

Based on the continuity equation and the motion equation of fluid dynamics, a mathematical model of high pressure transients in water hydraulic pipeline is presented. In the model, the friction item is consist of steady friction item and dynamic friction item, using the Darcy-Weisbach equation to solve steady viscous friction item and using four exponential terms instead of weighting function to solve dynamic friction item. By finite difference method accompanied with Matlab/Simulink, an example of high pressure turbulent flow in water hydraulic pipeline is configured so as to simulate the dynamic characteristics of pressure transients. The comparison between the observed result and the simulation result shows the mathematical model of high pressure transients in water hydraulic pipeline with turbulent flow is reasonable.

UDC 338:336.02:621.311 Svitlana Sivitska, Ph.D., Associate Professor at Finance and Banking Department, Vice-Rector for Scientific, Educational, Social Work and International Cooperation. Poltava National Technical Yuri Kondratyuk University. Identification of strategic priorities of investment into development of alternative energetics. There are the stages of the methodology for choosing the strategic priorities of investing in alternative energy explored in the article. The potential of alternative energy analyzed. The strategic priorities of alternative energy have been explored. An integrated analysis of the potential of alternative energy is carried out on the territorial basis done. The matrix of choice of strategic priorities of investing in alternative energy determined. Keywords: energetic security, alternative energetics, renewable sources of energy, investment, strategic priorities, matrix.

Магістерська дисертація складається з пояснювальної записки на 106 сторінках та графічної частини на 8 листах. В роботі наведено 46 рисунків та 13 таблиць. Робота містить такі розділи: 1. Загальні відомості щодо ожеледно-вітрових навантажень та коливань проводів ПЛ. 2. Моделювання коливань проводів ПЛ з урахуванням ожеледно-вітрових навантажень. 3. Методи та засоби захисту ПЛ від вібрації та галопування. 4. Методи та засоби захисту ПЛ від ожеледно-вітрових навантажень. Актуальність роботи: Одним з найголовніших принципів сучасної енергетики є забезпечення надійної та безперебійної роботи обладнання електроенергетичних систем і електричних мереж. Для повітряних ліній електропередавання одним з актуальних є питання їх захисту від зовнішніх впливів природного походження, таких як вітрові та ожеледно-вітрові навантаження. У зарубіжних країнах немає єдиної методики нормування розрахункових кліматичних умов для проведення їх районування за інтенсивністю ожеледоутворення, тому питання організації боротьби з різними видами відкладень на проводах ліній електропередавання на сьогоднішній день поставлене першочергово і є дуже актуальним. Для швидкого та точного вирішення цього питання необхідним є уточнення всіх існуючих знань та матеріалів щодо вітрових та ожел едно-вітрових навантажень, створення комп'ютерних моделей аналізу та прогнозування даних відкладень на проводах ліній електропередавання і створення нових методів та типів захисту ліній електропередавання від впливів природного походження Мета дисертаційної роботи: Аналіз і вивчення повного циклу виникнення ожеледних відкладень на лініях електропередавання з врахуванням впливу дії вітру, аналіз впливу та створення комп'ютерної моделі ожеледно-вітрових навантажень на проводи ліній електропередавання, запропонування методик та типів захисту ліній електропередавання від ожеледно-вітрових навантажень. Об’єкт дослідження: проводи повітряних ліній електропередавання усіх класів номінальних напруг. Предмет дослідження: процес виникнення ожеледних відкладень під дією вітру та їх вплив на проводи ліній електропередавання усіх класів номінальних напруг. Ключові слова: проводи ліній електропередавання, ожеледні відкладення, ожеледоутворення, ожеледно-вітрові навантаження, захист від ожеледно-вітрових навантажень.
The master's dissertation consists of an explanatory note on 106 pages and graphic part on 8 paper. There are 46 pictures and 13 tables. The work contains the following sections: 1. General information on ice-wind loads and fluctuations of wires. 2. Modeling of fluctuations of wires of the power lines, taking into account the ice-wind loads. 3. Methods and means of protection of the submarine from vibration and galloping. 4. Methods and means of protection of submarines from ice-wind loads. Actuality of work: One of the most important principles of modern energy is to ensure reliable and uninterrupted operation of equipment of electric power systems and electric networks. One of the most urgent issues is to protect them from external influences of natural origin, such as wind and ice-wind loads. In foreign countries there is no uniform method of normalization of the calculated climatic conditions for their zoning based on the intensity of ice-forming, so the issue of organizing the fight against various types of deposits on the lines of transmission lines has been put to the fore today and is very topical. In order to quickly and accurately resolve this issue, it is necessary to clarify all existing knowledge and materials concerning wind and ice-wind loads, to create computer models of analysis and forecasting of these deposits on wires of power transmission lines and to create new methods and types of protection of transmission lines from natural influences. The purpose of the dissertation work: Analysis and study of the full cycle of occurrence of iced deposits on transmission lines, taking into account the influence of the wind, impact analysis and the creation of a computer model of ice-wind loads on the transmission lines, offering methods and types of protection of transmission lines from ice-wind loads. Object of research: conducting of overhead transmission lines of all classes of nominal voltages. Subject of research: the process of occurrence of iced ice deposits under the influence of wind and their influence on conduction lines of electric power transmission of all classes of nominal voltages.

The development of power generation technologies and the deregulation of the power market has led to an increasing interest in distributed power generation, mainly the simultaneous exploitation of electricity and heat from the same energy source, known as combined heat and power (CHP) systems. As a consequence of the high competitiveness of power markets and increasing environmental concerns, distributed power generators have to make reasonable choices at multiple levels of complexity. A key issue to successfully approaching these problems is the development of decision making support tools that rely on service life prediction, intelligent economic dispatch optimisation techniques and condition monitoring. This research introduces the concept and development of a decision making support tool for a mini-pool nerve centre based on distributed gas turbine generation units operating in a competitive market. The nerve centre framework leads naturally to a multi-criteria optimisation problem which is solved in this research with a hybrid genetic algorithm adapted priority list and creep life assessment. The proposed hybrid approach can result in a significant saving to generators as it efficiently optimises mini- pool profits and service hours between failures in an acceptable computation time and accurately. Life cycle assessment combined with generation schedule optimisation can enhance the maintenance strategy activities and the competitiveness of gas turbine distributed generation plants, particularly for generators trading energy in a highly competitive market. Gas turbine combined heat and power distributed generators are unlikely to succeed in competing individually with centralised generation technologies within the present market framework, but they can be more competitive in an information technology based mini-pool. Additionally, results show that the development of a low carbon emission power industry can result in an outstanding opportunity for combined heat and power mainly in power markets currently highly dependent on coal and oil powered stations.

Synchronous generators are the most widely used machines in power generation. Identifying their parameters in a non invasive way is very challenging due to the inherent nonlinearity of power plant performance. This thesis proposes a parameter identification method using particle swarm optimisation (PSO) for the identification of synchronous machine, excitation system and turbine parameters. The PSO allows a generator model output to be used as the objective function to give a new, more efficient method of parameter identification. This thesis highlights the effectiveness of the proposed method for the identification of power plant parameters, using both simulation and real recorded transient data. The thesis also considers the effectiveness of the method as the number of parameters to be identified is increased, and the effect of using differing forms of disturbances on parameter identification.

This thesis focuses on using power electronic techniques to addresses grid integration for wind energy conversion systems. Different approaches to mitigate the low frequency generator torque ripple caused by diode bridge rectifiers are proposed. The advantages and disadvantages of the methods are discussed. A relationship for maximum power point tracking is theoretically analysed. Based on this relationship, two new maximum power point tracking techniques are proposed, which show benefits over conventional tracking methods. Then a pulsewidth modulated current source converter based parallel connected wind energy conversion system is investigated. A new inverter controller for this system is proposed, which is able to maintain a constant average DC network voltage to give satisfactory system performance whilst controlling output reactive power. Practical results support the presented simulations. Furthermore, a fault ride through scheme is proposed for the current source converter based system. The protection scheme uses a shunt resistive chopper to dissipate the active power during faults, and allows the inverter to supply reactive power to support the grid. The space vector modulation for the current source inverter is modified for this application and the design of the dumping resistor is discussed. The system shows riding through capability to both AC and DC network disturbances. This aspect is substantiated by simulation.

The technique of damping torque analysis (DTA) is proposed on the basis of linearized Philips-Heffron model of a single-machine infinite-bus power system. Analysis is to examine the electric torque contribution from a particular source to the electromechanical oscillation loop of generator in the power system. An effective engineering method - phase compensation method - for the design of PSS was developed on the basis of DTA. In study of real large power systems, modeling of the whole power system is very complicated. The generators in the large power system and other equipments result in a very high order of system model. Therefore a proper simplification method has to be applied to reduce the high order of real large power system. The aim of system simplification is to reduce the order of the linearized model of the large power systems, maintaining the characteristics of the under studied low frequency. Power system stabilizers (PSSs) have been adopted to mitigate low-frequency oscillations in the grid. However, in concerning of efficiency of damping controller in the power systems, decomposed analysis of PSS is studied to be further evidence for selecting installing location of PSS in the power systems. With greater integration of wind turbine generators in the introduced realistic large-scale power systems, impact of doubly fed induction generators (DFIGs) has been investigate for further study of renewable energy connected power systems. In terms of coordinated design of PMU and PSS in real large-scale power systems, developments in communication systems have made it feasible to also use remote signals as PSS inputs provided by PMU units. So as to the selection of signals from multiple locations can be further improved..

This thesis proposes a method to establish the accurate parameters of stabilisers in the context of power systems with increasing penetration of Doubly Fed Induction Generators (DFIGs), Solid Oxide Fuel Cells (SOFCs) and Photovoltaic (PVs) using a hierarchical coordinated strategy and localised design. The performance of the tuned stabilisers is verified using modal analysis results and non-linear simulation. This thesis proposes that by using regulated stabilisers, the dynamic stability of a power system with large-scale Distributed Generation (DG) integration can be maintained. SmartParks have been proposed in published literature to support emergent electric vehicle charging. In practice, a SmartPark can be configured as an adjustable load, in charging mode, or a regulated generator, in a discharging mode using a voltage control strategy. In this thesis, damping torque analysis (DTA) has been used to investigate the impact on dynamic stability of the joint operation of SmartParks in power systems with conventional synchronous machines. The analysis reveals that in terms of the local damping ratio, optimal charging and local capacity is best considered during SmartPark design. According to a Phillips-Heffron model developed for a multi-machine system with SmartPark, active and reactive power stabiliser can be incorporated into the SmartPark control loops to improve the damping of the system. Finally, this thesis considers the economic operation of micro-grids by proposing a combined EV charging/discharging model which incorporates stochastic uncertainties in vehicle travel patterns and initial battery state of charge (SOC). The model includes provision of energy storage and renewable generation infeed is used to establish an economic basis for micro-grid operation based on market revenues.