POWER ENGINEERING: economics, technique, ecology

SIMULATION OF TRANSIENT PROCESS ON WWER-1000 USING COUPLED APPROACH

2024-05-01T14:17:34+03:00

Research and modeling of thermohydraulic processes in NPP equipment is necessary for a deep and improved justification of reliable and safe operation of nuclear installations. Taking into account the accumulated experience and the latest technologies, the study of thermohydraulic processes is developing in the direction of applying innovative approaches to conducting both experimental studies and expanding the calculation capabilities of thermohydraulic codes.

The article presents an approach to the decomposition of the thermohydraulic model of the WWER-1000 reactor plant on submodels, which are calculated in coupling with separate instances of the system thermohydraulic code RELAP5/Mod 3.2. Coupling is implemented using a specially developed module. This approach allows you to "bypass" the internal limitations of RELAP5 in the number of components (hydrodynamic volumes, thermal structures, "trips" and control variables) that can be used for computational analysis. As a result, it becomes possible to achieve a higher degree of detail for the entire reactor installation. In addition, the article confirms the possibility of applying the previously developed coupling module to such a non-equilibrium model as a nuclear reactor model. At the same time, the use of the RELAP5 model as a reactor model makes it possible to avoid inaccuracies that arise when applying assumptions about the transverse profiles of the input variables of the CFX model, as well as to perform the validation of the RELAP5 model of the RU loops.

Coupled calculation of stationary and transient mode of reactor installation WWER-1000 is performed. The reliability of calculation results obtained in conjugation is evaluated by comparing them with the results of autonomous calculations in RELAP5. The analysis of the results of computational modeling confirms the possibility of applying the developed coupling module to such a non-equilibrium model as a model of a nuclear reactor, and also confirms the correctness of the RELAP5 model of the loops of the reactor plant obtained on the basis of the modification of the full-fledged RELAP5 model.

PHYSICAL FACTORS OF THE INFLUENCE THE EXPLOSION ON ENCLOSURE GLASS STRUCTURES. OVERVIEW OF TESTING METHODS

2024-05-01T14:50:30+03:00

The article examines the main physical parameters of an explosive wave, the properties of explosive loads, as well as the peculiarities of the propagation of waves in space and their dynamic influence on enclosing structures, including translucent The considered temporal and spatial conditions under which the formation of the quasi-flat front of the blast wave takes place and the blast loads can be considered as uniformly distributed along the vertical plane. If the distance to the explosive charge exceeds half of the value of the width and height of the structure or its element (provided that the charge is located in the center of the structure or element), then the load on them can be considered approximately averaged by area. The thermophysical factors of influence, which the building structure must withstand, are analyzed. The main differences of explosive and shock effects from static loads, which are taken into account during construction design, are described.

The main real-time methods of determining the parameters of the blast wave in real time and the factors of its destructive effect on the elements of the enclosing structures of buildings are considered.

The determination of the critical pressure for a specific structure is tied to the determination of the critical distance at which the structure will not withstand the destructive impact of the shock wave.

The main real-time methods of determining the blast wave parameters in real time are considered. It was determined that the use of the shock tube method is rational for conducting research in laboratory conditions.

The work was carried out with the assistance of the National Research Fund of Ukraine. The materials of the article contain scientific results obtained as part of the implementation of the project No. 208/0172 "Aerodynamics, heat exchange and innovations to increase the energy efficiency of window structures and their use for the reconstruction of war-damaged buildings of Ukraine" of the competition "Science for the reconstruction of Ukraine in the war and post-war periods".

ANALYSIS OF THE SMART GRID CONCEPT IN THE RAILWAY TRACTION POWER SUPPLY SYSTEM

2024-05-01T09:36:13+03:00

The Smart Grid network system is a concept of a fully integrated, self-regulating and renewable electric power system, which has a network topology and includes all generating sources, trunk and distribution networks and all types of electric energy consumers, managed by a single network of information and control devices and systems in real time mode. The article proposes the introduction of the Smart Grid concept into the traction power supply system of railways. The functional properties and technical solutions that will allow implementing the principles of Smart Grid intelligent power supply systems are considered. A comparative description of the functional properties of the existing energy system and the energy system based on the Smart Grid concept is presented. Possibilities of introducing Smart Grid into the traction power supply system of direct current due to increasing the carrying capacity of trunk networks, consumption management, location of distributed energy sources in distribution networks and closer to consumers have been determined. The limits of the energy-saving effect from the introduction of the Smart Grid concept into the traction power supply system have been determined.

NON-INSTRUTIVE LOAD MONITORING – A PROSPECTIVE DIRECTION OF BUILDING ELECTRICITY CONSUMPTION MONITORING

2024-05-01T15:15:42+03:00

It is shown that in order to adapt to changing models of energy supply and increase reliability, utilities need intelligent monitoring of power grids in order to track dynamic operating conditions in distribution networks. Smart monitoring can provide utilities with a detailed description of consumer habits and maximize user awareness of consumption, leading to behavioural change and smoothing global energy demand. The driving factors of the smart home monitoring and security market are given. An increasing number of internet users, the rapid proliferation of smartphones and smart gadgets, and growing concern about remote monitoring of homes have been identified as key factors contributing to the growth of the smart home security market. It is shown that the Smart monitoring methodology on the example of a building reflects the goals of both actual monitoring and control: to reduce the energy consumption of buildings and/or to reduce electricity bills for residents; to offer grid managers more tools to better manage the growing demand and possible interruptions in energy production due to the growing integration of RES into the grid.

Non-intrusive load monitoring (NILM) is analysed – a method of analysing data on the total electrical load, obtained by measuring the current and voltage at one point, followed by the division of the total load into a load of individual devices, which can play a key role in the digital transition in the electric power industry. This technology is able not only to improve the current operational activities of electricity companies but also to form the basis of the formation of new relations between subjects of energy markets. NILM technology has seen significant success thanks to advances in machine learning, signal processing, and pattern recognition. It was determined that the fundamental stages of a typical NILM structure are data collection, feature extraction, signal decomposition, and device identification.

CALCULATION OF COMPLEX RELIABILITY INDICATORS OF THE AUTOMATED EQUIPMENT MONITORING SYSTEM

2024-05-01T15:27:49+03:00

In the modern industrial environment, automated equipment monitoring systems play an important role in ensuring the efficiency and safety of technological processes. However, ensuring the reliability of these systems requires careful calculation of complex indicators. Research is focused on the development of methodologies and algorithms for calculating the reliability of automated monitoring systems.

The article provides an overview of the comprehensive reliability indicators of the automated equipment monitoring system. First of all, the work defines the critical components of the system, evaluates their reliability and interaction. Reliability analysis methods include elements of probability theory and mathematical statistics. Among them is the calculation of the average time of failure-free operation, the probability of failure and other criteria that allow evaluating the functioning of the system in real conditions. In accordance with regulatory documents, a list of reliability indicators for equipment and the monitoring system as a whole has been created. The methodology for calculating complex indicators of the reliability of the automated monitoring system is given. An example of failure intensity calculation and complex reliability indicators for an analog measuring channel of an automated equipment monitoring system is given. The calculation example shows the estimated failure intensities of the components of the calculated analog channel and the total working time per failure.

Therefore, the research is focused on the development and optimization of methods for calculating complex indicators of the reliability of automated equipment monitoring systems, which helps to improve their functionality and ensures effective control of technical processes in industrial conditions.

SOFTWARE ARCHITECTURE OF INTELLIGENT SYSTEMS FOR MANAGING ENERGY EFFICIENCY OF ELECTROMECHANICAL SYSTEMS

2024-05-15T15:04:27+03:00

In the modern world, it is not the possession of energy resources that occupy a dominant place, but innovative technologies for the efficient use of energy resources, renewable energy sources, means of intellectualization of energy supply systems and energy consumption. The philosophy of the competitive world has changed: from a society of unlimited consumption of resources to sustainable development, "green transition", "smart" energy consumption and, in the future, the active use of artificial intelligence. Under these conditions, the role of increasing energy efficiency is growing as the main factor that "entails" the modernization of the entire enterprise or the energy-efficient design of a new one, increasing production productivity and product quality, and improving the environmental situation. The principle of "Energy efficiency above all" should become the main slogan in the recovery of Ukraine’s economy and the transition from the raw material model of development to industries with a high degree of processing (mechanical engineering), which will allow, among other things, the development of the domestic military-industrial complex.

The greatest impact on the efficient use of electricity by the enterprise is caused by the energy efficiency of the electromechanical system (EMS) as the main consumer of electricity (more than 80% in industry). Intellectualization of electrical energy consumption involves the creation of a digital EMS energy efficiency management system in real time. Unfortunately, today the practice of assessing the energy efficiency of EMS has been established at best periodically, for example, during an energy audit. Therefore, the urgent task is to create intelligent systems for managing the efficiency of EMS electricity consumption and monitoring the factors that affect them: the quality of electrical energy, equipment loading and the technical condition of EMS. Modern developments in measuring and computing technology make it possible to create such systems, which consist of technical (current, voltage sensors, technological parameters of the production process) and software parts.

A promising tool for energy management is the introduction of intelligent EMS energy efficiency management systems based on client-server architecture with software separation of layers of business logic, data and presentation of results - determination of energy efficiency, other parameters for prompt response to an increase in power consumption, deterioration of technical condition or violation of the technological regime. Optimization of EMC power consumption, making informed decisions on their further operation by identifying uneconomical, inefficient, emergency operating modes, hidden defects by means of intelligent energy efficiency management systems also provides for the availability of information on instantaneous values of EMS current and voltage, calculation of parameters according to diagnostic and reference models in real time; detection of deviations of parameters from the established ones.

Intelligent EMC energy efficiency management systems using the MVC software architectural pattern allows you to introduce modern smart information technologies into the energy management system of the enterprise and automate the implementation of such components of the ISO 50001:2020 standard as the installation of an energy baseline, control of energy efficiency indicators, monitoring and necessary measurements to determine the level of energy efficiency, energy analysis, energy planning and formation of technical reports, etc.

POLLUTION OF GROUNDWATER RESOURCES BY PROCESSES IRON ORE SURFACE USE

2024-05-01T13:58:30+03:00

In Ukraine, as in most countries of the world, preservation of the natural qualities of surface and underground water resources is one of the difficult to solve problems. Groundwater pollution is carried out spontaneously and as a result of organized emissions on the surface of territories and into underground cavities. Contaminated areas of territories around mineral deposits, industrial facilities, as well as masses of pollutants, are growing. In terms of scale, it is necessary to single out groundwater pollution as a result of ore extraction and placement of rocks in dumps, as the most harmful for agricultural lands and surface water bodies. Calculating the amount of compensation for damages caused by contamination of groundwater with harmful substances requires further official adjustments, taking into account the factor of public ownership of natural resources in general.

Therefore, it is necessary that the following situations are officially taken into account in the normative legal acts of local authorities: underground waters and their environment belong to objects of public property, therefore, in the methods of determining and calculating the ecological consequences of pollution of underground waters and their underground environment, it is necessary to provide that damages must be studied and assessed from the point of view of damage to public property; polluted underground waters and their underground environment are located locally on the territories of territorial Starostov districts, which represent the people of Ukraine; in accordance with clause 1, when calculating the amount of compensation for pollution, it is generally necessary to determine the losses for the population of these districts and the amounts of charges and payments to them; local authorities need to organize compensation processes, monitor their implementation and effectiveness.

The definition of an environmental tax does not correspond to the definition of the concept of a tax as an unconditional payment to the budget, since in its essence it is a punishment for the discharge of polluted substances into water bodies and ecological pollution of water resources.

ANALYSIS OF THE LEVELS OF NON-OPTIMALITY MODES OF LOW-VOLTAGE ELECTRICAL NETWORKS WITH UNEVENNESS OF ELECTRICITY GENERATION AND CONSUMPTION

2024-05-01T09:45:56+03:00

An analysis of the levels of non-optimality of electricity generation and consumption processes in low-voltage electrical networks with the unevenness of electricity generation and consumption was carried out. Measures to reduce electricity losses in such networks have been systematized. The assessment of the influence of uneven electricity generation and consumption on the level of costs in the electric network is given. To reduce electricity losses by analyzing the potential of managing power supply modes, it is proposed to use the method of assessing non-optimal levels of the local electric power system using the reactive power of Frize Q_F.

The non-optimality of selection from the generator and consumption of electricity loads is evaluated from the point of view of the operation of the electricity system as a whole. The degree of deviation from uniform energy consumption with the average level of active power transfer for a given time interval was chosen as an evaluation criterion. The power of Frize Q_F is used to compare the real mode of operation of the electric power system with the optimal mode. This calculation can cover any time. The use of Q_F made it possible to unify the analysis of energy supply processes of electric power system loads, providing the possibility of retrospective, current, and prospective analysis. The use of Frize Q_F power provides an opportunity to assess technical, economic, and technological factors, such as the influence of various factors on the appearance of additional electricity losses, and the stability and stability of the system when changing the operating modes of generators and loads.

The conducted analysis made it possible to propose an algorithm for assessing the level of optimality of mode management in electrical networks, which can be implemented both with the involvement of a dispatcher and in automatic mode. The evaluation of the addressable impact based on the Frize power is of particular relevance for local electric power systems, where various types of generators of limited power based on renewable energy and various types of energy consumption technologies are widely used.

COMPARATIVE ANALYSIS OF ALGORITHMIC AND SOFTWARE SOFTWARE FOR MODELING PROCESSES IN SYSTEMS WITH ACTIVE CONSUMERS WITH PHOTOVOLTAIC GENERATION

2024-05-01T09:51:11+03:00

The article considers the use of algorithmic and software in the context of smart grid development. It has been determined that energy storage systems are key elements of energy management systems for smart communities, as they allow storing energy generated by renewable energy sources (RES) and compensating for the uneven demand for electricity. A comparative analysis of different EMS strategies that combine solar panels and batteries is carried out.

The main energy management strategies are analyzed and the advantages and disadvantages that should be taken into account when choosing them are identified. The concept of smart inverters and their integration into energy storage systems is considered. The structure of hybrid energy storage systems and the main roles of energy storage are presented. The economic benefits of implementing Microgrid and Smart Grid in the energy sector are shown. The development of integrated strategies for managing energy storage systems that take into account all aspects of electricity generation, storage and distribution in smart grids, promoting sustainable and efficient use of resources, is proposed.

The main models and frameworks used for modeling energy systems are considered and the advantages and disadvantages of the models that should be taken into account when researching clear issues in the context of energy management systems development are identified.

ANALYSIS OF RESEARCH ON THE INFLUENCE OF TEMPERATURE ON THE DEGRADATION AND EFFICIENCY OF SOLAR PANELS

2024-05-01T09:56:55+03:00

The article substantiates the relevance of the issue of researching and analyzing the impact of degradation on the efficiency of solar panels. A brief analysis of the main features of the use of solar panels of various types is carried out, their main characteristics that affect their service life are presented. The main types and causes of degradation of photovoltaic modules, which are associated with both mechanical and environmental influences, as well as with the influence of electrical quantities during the operation of solar panels, are considered in detail. The main conclusions about the most influential degradation factors are obtained, among which it is advisable to highlight the influence of temperature - both the external air temperature and the heating temperature of the solar panel itself - for further study. An analysis of current research on the study of the peculiarities of degradation of photovoltaic modules under the influence of various factors associated with both environmental influences and the influence of electrochemical processes directly in the panel system is carried out. Particular attention is paid to studies of the effect of temperature on their performance. Preliminary experimental measurements of solar panel performance parameters at different light intensities and when the panel is heated in the range from 19 to 78 °C were carried out on the basis of a laboratory setup. Based on the data obtained, a graph of the dependence of the efficiency of a solar PV module on its surface temperature was constructed and it was found that the efficiency of the panel begins to decline actively after the temperature of its surface rises above 50-55°C. To confirm and detail the data obtained, the next task is to conduct similar studies with different types of solar panels and under different operating conditions. Also, the next step will be to further investigate the impact of ambient temperature on the efficiency of photovoltaic modules, as well as to find a specific link between the impact of this temperature on the heating of solar cells and, accordingly, to assess the impact of these parameters on the degradation of solar panels in general.

METHODS AND TOOLS FOR IN-DEPTH ANALYSIS OF ENERGY CHARACTERISTICS AND MANAGEMENT OF ENERGY CONSUMPTION IN EDUCATIONAL INSTITUTIONS

2024-05-01T10:06:08+03:00

A factor of the state's national security is reducing energy dependence and taking measures to increase energy efficiency, especially in the budgetary sphere, because about 90% of such buildings do not meet modern energy efficiency requirements. Creating a reliable energy consumption management system, choosing measures to reduce consumption and diversifying energy sources is a difficult task that requires consideration of building energy consumption processes as a complex problem with the use of modern tools of the energy management system, modeling, and the use of modern approaches to automation and measurements.

The object of research is energy consumption processes in educational institutions. The subject of the research is energy characteristics and methods of energy consumption management in educational institutions. Research methods. analytical methods, system analysis, synthesis, modeling, systematization, method of comparative and structural analysis. One of the tasks of this study is to review the capabilities of software products that can be used by energy managers of educational institutions to monitor, analyze and forecast energy consumption, as well as to create reports. Also in the work, an analysis of the state of affairs regarding energy consumption management was carried out on the example of KPI named after Igor Sikorskyi; proposals for the development of the automated energy monitoring system were provided, in particular, the architecture of the web application was developed taking into account the support of existing databases to improve the energy monitoring process.

STATISTICAL ESTIMATES OF VARIABLES DETERMINING THE INTERVAL OF ELECTRIC POWER MONITORING

2024-05-01T10:14:51+03:00

It is demonstrated that digital processing of information on electricity consumption is possible when transforming the studied process into a discrete form. The correct choice of the monitoring interval allows for the accurate reconstruction of the values of the studied function in the intervals between measurements. It is shown that when organizing the monitoring of average power, it is necessary to select a discretization interval that provides adequate representation of the current process. The proposed procedure for choosing the interval of electric power monitoring is based on determining the duration of the deviation of the random function of electric power change, subject to certain constraints. The justified number of monitoring studies is established to determine the optimal interval of electric power monitoring. It is shown that the most rational method of processing experimental data will be the method of joint estimation for correlation and standard deviation.

ANALYSIS AND OPTIMIZATION OF ELECTRIC VEHICLE CHARGING PROCESSES IN TRANSACTIVE ENERGY SYSTEMS

2024-05-01T10:26:07+03:00

Впровадження розумної зарядки електромобілів дозволяє операторам локальних електромереж і постачальникам електроенергії впроваджувати нові бізнес-моделі взаємодії електромобілів з мережею. Крім оптимального відбору потужностей Мicrogrid при заряді електромобілів, важливо і використання різних методів заряду. Для задоволення інтересів всіх учасників локальних систем з економічної та технічної точки зору обрано концепцію транзактивної енергії. Проведено дослідження впливу різних методів керування зарядом на ККД батареї EV, таких як двоетапне заряджання (СС-СV), прискорену заряду (ВС) та альтернативну багаторівневу зарядку MSCC. Оптимізація процесів заряду має на меті не тільки збільшення прибутку від продажу електроенергії, а також мінімізація витрат на зарядку за допомогою оптимального потоку електроенергії від мережі до автомобіля. Запропонована цільова функція залежить від потужності генерації усіх джерел які входять до системи, стану заряду систем зберігання, часу добу, часу заряджання електромобілів, швидкості заряджання, ціни на електроенергію. Система керування, вирішуючи цільову функцію, сама обирає та пропонує споживачу та агрегатору метод заряджання, який для даних параметрів системи буде оптимальним для усіх учасників транзактивної системи. Цифровим моделюванням досліджено три методи заряд, для чотирьох різних типів електромобілів, всі розглянуті методи заряду високі показники енергоефективності які можливо використовувати, як методи керування при заряді електромобілів від локальних систем.

CONCERNING THE ARRANGEMENT OF THE ELECTRICAL SUPPLY SYSTEM OF BUILDINGS WITH RENEWABLE ENERGY SOURCES

2024-05-13T14:41:26+03:00

Buildings are currently one of the largest consumers of energy resources in Ukraine, including electricity[1], accounting for about 40% of energy consumption. In Ukraine, the requirements for energy consumption in buildings are regulated by the Law "On Energy Efficiency of Buildings" through the relevant energy efficiency classes[2]. The issue of improving the energy efficiency of these facilities is a global challenge at the global level. In particular, the 2019 UN Climate Summit set a goal to achieve zero energy consumption in new buildings by 2030 and the same level in existing buildings by 2050. The use of renewable energy sources is an absolute and necessary component of achieving these goals. In addition, it should be understood that the share of renewable energy will grow steadily, in particular in household facilities. Over time, every building will be powered by renewable energy in one way or another. A review of the literature on the design of energy-efficient buildings in terms of engineering systems design revealed a low level of coverage of issues related to the design and design of power supply schemes for buildings with RES[3-7]. The article presents existing circuit solutions for the integration of RES (solar photovoltaic generation) into the building power supply system, in particular, a building power supply system with a grid-tie inverter and power optimizers, a building power supply system with microinverters, a building power supply system with twin microinverters and a prefabricated combined switchboard, a building power supply system with a backup power source, a power supply scheme with redundancy and a smart controller. A variety of schematic solutions for the power supply system allows you to choose the one that will meet a single or a set of criteria: the location of the panels by the cardinal points (one side or several); redundancy; cost; "intelligence" of the system.

STUDY OF THE EFFICIENCY OF HEAT PUMPS FOR ENERGY SUPPLY OF APARTMENT BUILDINGS

2024-05-01T15:07:54+03:00

The relevance of using energy obtained from the external environment with the help of heat pumps for energy supply of buildings is due to the increase in costs for centralized energy supply; improving technologies and reducing the cost of implementing similar technical solutions; active development of this direction in the European Union and changes in the legislative framework in Ukraine to stimulate the wider implementation of the use of renewable energy sources.

Research object: energy consumption processes and technical and economic indicators of combined energy supply of multi-apartment buildings using heat pumps.

The subject of the study is methods and tools for evaluating the effectiveness of heat pumps for the needs of hot water supply and heating of multi-apartment buildings using a heat pump and centralized heat supply. Research methods: analytical methods, system analysis, mathematical modeling, the method of comparative and structural analysis. This study was carried out as part of a master's thesis. The practical significance of the results lies in the application of the developed mathematical model for simulating the operation of the heat pump taking into account the dynamic change of COP and water distribution on the example of multi-apartment buildings.