ВИЗНАЧЕННЯ ПАРАМЕТРІВ ФОТОЕЛЕКТРИЧНОЇ СИСТЕМИ З АКУМУЛЯТОРОМ ДЛЯ ПОТРЕБ ЛОКАЛЬНОГО ОБ’ЄКТУ

Purpose. Improving the methodology for determining the parameters of a photoelectric system with a battery for the needs of a local object using archival data of the generation of a photoelectric battery with planning the cost of energy consumption from the network for all seasons of the year.Methodology. Using an archive of data on the power generation of a photoelectric battery and analysis of energy processes in a photoelectric system with a battery using computer simulation.Findings. Calculated according to the archive data for five years, the average monthly values of photoelectric battery generation power for time intervals during the day determined according to tariff zones. Dependencies to determine the recommended average value load power of a local object at time intervals.Originality. It is proposed to determine the base schedule of the local facility and the parameters of the photoelectric system based on the average monthly values of photoelectric battery generation in the transition seasons – October, March and the expected cost of energy consumed from the grid during the year. The recalculation of the base value of power during the year is substantiated taking into account the duration of daylight. A method for determining the recommended load schedule of a local object with the formation of the battery charge according to the average monthly value of the photoelectric battery generation power at time intervals during the day, which are determined by archival data for the object location.Practical value. The obtained solutions are the basis for designing photoelectric systems with a battery to meet the needs of local objects.

Statistical approach and multiplicative models for electric vehicles charging behaviour patterns

Since the charging processes of electric vehicles are stochastic and time-dependent, the paper views an approach based on a statistical analysis of real data on electricity consumption at charging station connection points. Other types of data (geographical, public sites, distance between individual charging stations, etc.) are also taken into account when making the analysis. Multiplicative models are the most suitable for studying and forecasting time series with pronounced cyclicity and seasonality. Their application allows us to consider the correlation of the load in the consuming nodes with regional features, climatic factors and seasonality. The method and approach discussed in this paper make possible the processing of a large amount of data and the detection of load cyclicity in the load schedule of electricity facilities. The results of the model will identify the requested charging power in a developing charging infrastructure.

Selection of the optimal flow path and control program for the turbo drive of remotely operated underwater vehicle

Обеспечение высокой экономичности не только на режимах номинальной мощности, но и на частичных режимах при изменении внешних параметров приводит к необходимости оптимизации проточной части турбины с объективным учетом ее характеристик на переменных режимах. Приводятся результаты многорежимной оптимизации МРТ в составе ЭУ АНПА на базе подхода разработанного авторами. Представлены основные результаты сравнительного анализа многорежимной оптимизации МРТ с оптимизацией на i-тый режим и работающей на остальных режимах как переменных для различных программ регулирования мощности. Выявлено сильное влияние на результаты многорежимной оптимизации основного ограничения в виде равенства мощности турбины мощности задаваемой графиком нагрузки, а также программ регулирования. Возможность применения соплового регулирования приводит к ослаблению степени воздействия основного ограничения. Установлено, что оптимальные геометрические характеристики стремятся к режиму с большей работой. Представлены результаты многорежимной оптимизации МРТ для различных программ регулирования и графиков нагрузок по отношению к результатам многорежимной оптимизации с программой реализующей сопловое регулирование в сочетании с изменением начальных параметров перед турбиной. Многорежимная оптимизация для программы, реализующей сопловое регулирование в сочетании с изменением только начальной температуры перед турбиной, выявила узкую регулировочную способность начальной температуры, и невозможность в некоторых случаях удовлетворения основным ограничениям по равенству мощностей для всех исследуемых графиков нагрузки в пределах заданных ограничений на режимные параметры. Результаты численного эксперимента свидетельствуют, что разработанный автором подход к многорежимной оптимизации МРТ позволяет снизить расход топлива при условии обеспечения заданного графика нагрузок по сравнению с традиционными методами проектирования на номинальный режим. Ensuring high efficiency not only at nominal power modes, but also at partial modes when changing external parameters leads to the need to optimize the flow path of the turbine with objective consideration of its characteristics at variable modes. The results of multi-mode optimization of a low-consumption turbine as part of a power unit of remotely operated underwater vehicle based on the approach developed by the authors are presented. The main results of a comparative analysis of multi-mode optimization of a low-consumption turbine with optimization for the i-mode and operating in other modes as variables for various power control programs are presented. A strong influence on the results of multi-mode optimization of the main limitation in the form of equality of the turbine power to the power set by the load schedule, as well as control programs is revealed. The possibility of using nozzle regulation leads to a weakening of the degree of influence of the main restriction. It was found that the optimal geometric characteristics tend to the regime with more work. The results of multi-mode optimization of a low-consumption turbine for various control programs and load schedules are presented in relation to the results of multi-mode optimization with a program that implements nozzle control in combination with a change in the initial parameters in front of the turbine. Multimode optimization for a program that implements nozzle regulation in combination with changing only the initial temperature in front of the turbine revealed a narrow adjusting ability of the initial temperature and the impossibility, in some cases, of satisfying the basic constraints on the equality of powers for all the studied load curves within the specified constraints on operating parameters. The results of the numerical experiment indicate that the approach developed by the author to the multi-mode optimization of a low-consumption turbine makes it possible to reduce fuel consumption, provided that a given load schedule is provided in comparison with traditional design methods for the nominal mode.

Basic bases of calculations and optimization of NPP power unit equipment parameters methods of mathematical modelling

The materials of the article consider the optimization of certain parameters and characteristics of the equipment of NPP power units, which are closely related to the processes of their design and construction. Modern NPP power units are complex technical systems. They include a set of interconnected equipment for different technological purposes, which ensures the performance of power units of a complex function of electricity production and heat of the specified quality and according to a given load schedule. Complete mathematical models of the functional state of steam turbine power units are characterized by a large number of nonlinear connections and contain implicit functions. This complicates their widespread use to solve problems of systematic analysis of the quality of operation of power units. The aim of the work is to analyze the basic theoretical foundations, methods and approaches to the calculation and optimization of the parameters of the equipment of NPP power units by methods of mathematical modeling. The solution of the problem of optimization of NPP power unit parameters includes the following stages: selection of optimality criteria (objective functions); development of a system of interconnected mathematical models in accordance with the required hierarchical level of optimization research; selection of computational methods and optimization algorithms. Taking into account the above methodological provisions and approaches increases the efficiency of mathematical modeling to solve problems of calculations and optimization of NPP power unit parameters.

MODEL OF EVALUATION THE FEASIBILITY OF INDUSTRIAL CUSTOMERS TO HOURLY ACCOUNTING OF RETAIL ELECTRICITY MARKET

The main differences in pricing and tariffing for industrial consumers of electricity with different forms of electricity metering are considered. Based on the analysis of tariff formation for the final consumer of electricity, components are identified that have a significant impact on the results of solving the problem of assessing the feasibility of the consumer's transition to hourly electricity metering. Such components include the cost of purchasing electricity in the market segment "day ahead" and the cost of accrued imbalances. The relative daily profile of electricity consumption is considered in order to study the influence of the features of the daily load schedule on the weighted average daily market price of electricity. The importance of estimating the cost of daily load profiles when comparing the cost of electricity for the consumer in the group with integrated electricity metering and in terms of individual hourly metering is substantiated. The effect of underestimation of volumes and value of imbalances in the group with integrated electricity metering in comparison with hourly accruals of volumes and value of imbalances is theoretically substantiated. The main components for comparative assessment of the expediency of the consumer's exit from the group with integrated metering of electricity and the transition to its hourly metering according to the individual daily load schedule are identified. Mathematical models for comparative calculations are developed. The use of these models allows to make an economically justified decision on the expediency of the consumer leaving the group without hourly metering of electricity to the model of purchasing electricity with hourly metering. The main approaches to such an assessment are demonstrated on the example of calculations for an industrial enterprise in some regions of Ukraine. Bibl. 15, fig. 3.

Automatic Asynchronous Drive Efficiency Control with Soft-Starter Function

Digital models of pulse-width voltage control system with step switching of power supply frequency and automatic control of induction motor are developed and built, the recommendations on the algorithm of their control and circuit solution for the implementation of smooth start modes, nominal and frequency-step control from low-power -variable load schedule are provided. The novelty of the work lies in the substantiated sequence and conditions of control and originality of the structure of the automatic system of smooth start-up and activation of the effective mode of the asynchronous drive. The introduction of the conversion system will create an automatic system of asynchronous drive, due to which it is possible to achieve energy conservation at all levels of the electromechanical system, with minimum capital investment.

Four Point Bend Test of 5LPP – Concrete Coated Pipe

The objective of this paper is to present a 4-point bend test of 5LPP (Five Layer Polypropylene) concrete coated pipe. This is the first of its kind of bend test for a complex coating combination of 5LPP and concrete layers. The bend tests have been carried out to simulate S-Lay installation loading conditions to assess the coating integrity of the pipeline during installation. This paper reports the test arrangements including instrumentation, load schedule, test procedure and the challenges involved. Finally, the preliminary results and conclusions of the tests are documented. Two separate full scale four-point bend tests are carried out to study the behavior of the 5LPP concrete coated pipe. The purpose of the first test is to understand the complex behavior of the 5LPP/CWC coated test pipe and validate previously made industry standard assumptions regarding the calculated coated joint stiffness. The purpose of the second test is to observe the coating integrity of the test joint and slippage behavior due to the simulated installation conditions (overbend and sagbend bending moments and/or corresponding curvatures). The nonlinear moment-curvature for the concrete coated pipe is estimated based on an analytical approach taking into consideration plane bending theory and slippage behavior of the coating layers. The moment-curvature is used to prepare the load schedule for the tests. The test string consists of a test joint (40ft) welded to half joints at the ends. The bend test is performed using industry established full scale 4-point bend test arrangements. A global finite element model is used to simulate the tests using the analytical moment-curvature of the concrete coated pipe. The stiffness of the test pipe is calculated using the first bend test and compared against the analytical stiffness. The second test is carried out by applying loads corresponding to an estimated maximum overbend bending moment and then the test string is unloaded and rebent in opposite direction by applying loads corresponding to an estimated maximum sagbend bending moment. The results of the second test are documented at each load step and the integrity of the coating is measured against specified concrete coating damage criteria for tension as well as compression. Finally, field observations from the actual installation operation are compared against the bend test results. Conclusions are presented to address various aspects of concrete coated pipe for S-Lay installations.

Management of power consumption in a photovoltaic system with a storage battery connected to the network with multi-zone electricity pricing to supply the local facility own needs

Purpose. Improving the principles of management of photovoltaic system with storage battery and with autonomous functioning during daylight hours for a local object, connected to the grid with multi-zone payment when excluding the generation of energy into the grid. Methodology. Modeling and analysis of energy processes in the photovoltaic system was performed using the Matlab software package. The simulation model of energy processes is based on calculated expressions taking into account the characteristics of the battery. Operability of the proposed solutions are confirmed on an experimental setup based on a standard hybrid inverter. Results. It’s shown, that due to the battery energy during the most loaded peak hours and part of the daytime the system operates autonomously and does not depend on possible violations of the quality of electricity in the grid. Scenarios of the recommended load schedule are proposed in accordance with the ratio of the predicted value of the daily energy generation of the photovoltaic battery to its possible maximum value. A simulation model of energy processes in the system with the correction of the recommended load value was developed. Originality. A method of the recommended load calculation with current correction for the actual generation and degree of battery charge is proposed, which allows taking into account differences the actual generation of the photovoltaic battery from its predicted value and the actual load from the recommended one. Practical value. The obtained solutions are the basis for the design of new and modernization of existing photovoltaic systems of local objects using software and hardware complexes for power consumption management.

Use of large irrigation pumping stations for highly manual daily regulation of capacities in the energy system of the Republic of Uzbekistan

Information about the problems arising from the uneven production and consumption of energy in power systems, including in the power system of the Republic of Uzbekistan, is given on the example of a daily electrical load schedule. It is noted that to successfully solve these problems, energy is accumulated in the hours of minimum consumption so that it can be used in peak hours with high consumption, and for this purpose, pumped storage power plants are used. A diagram of hydraulic energy storage is given at large pumping stations used to accumulate water in the upper reservoir in hours of minimum loads, and the accumulated volume of water is directed to generate energy, which can be used by pumping stations to supply additional water to its consumers, replenishing its losses in hours of hydraulic energy storage. The method of selection and optimization of the main parameters of this complex, based on minimizing fuel consumption in power plants while limiting the amount of accumulated energy based on the capabilities of water and energy resources of pumping stations, is presented. The calculations using the example of the Syrdarya thermal power plant show that with the integration of five nearby pumping stations into the process of energy storage and generation, significant cost savings are achieved, and the daily load schedule is significantly leveled.