POWER ENGINEERING: economics, technique, ecology

IMPLEMENTATION OF BASIC INTERNATIONAL SMART GRID STANDARDS IN UKRAINE: CURRENT STATE

2023-02-02T13:17:18+02:00

In this paper, the main components of the basic model of the Smart Grid architecture according to the standard IEC TR 63097:2017 "Smart Grid Roadmap" are considered. The list of basic and particularly important international standards, which have a significant impact on the application of Smart Grid, has been identified and analyzed. A group of standards describing the basic principles of Smart Grid systems application is selected. These groups are unifying and allow to eliminate contradictions between other existing standards, to ensure their consistency. The development of a strategy and the creation of a road map for the adoption of modern European and international standards in Ukraine in the field of Smart Grid substantiated. A list of relevant directions and functional systems necessary for the implementation of the components of the Smart Grid concept is given. These directions require a detailed analysis to establish priority levels during the implementation of relevant modern European and international standards in Ukraine, taking into account the specifics of the Ukrainian electricity market.

THE CONCEPT OF ENHANCING ENERGY AND ENVIRONMENTAL SECURITY THROUGH THE DISPOSAL OF PLASTIC WASTE AND WASTE TIRES

2023-02-02T11:42:03+02:00

Accumulations of unused plastic waste and wast tires pose a great threat to humanity. Despite the convenience and benefits that products from these materials bring, their waste pollutes soils and water bodies, the atmosphere, and poses a threat to human health. The problem is that plastic and waste tires have a long decomposition time, and their recycling requires significant economic resources and well-established logistics. For example, more than 8 million tons of plastic enter the oceans every year, and used tire landfills are enriched by 7 million tons. In addition, as a result of military actions, the energy and environmental security of Ukraine are under threat. Mass fires, a large amount of generated waste on our lands, missile attacks on infrastructure facilities – all this requires finding ways to increase energy and environmental security. One of the ways to increase the latters is the disposal of dangerous plastic and waste tires by chemical means, as a result of which it is possible to obtain fuel. Therefore, in the article examines the energy potential of obtaining fuel from waste plastic and waste tires in Ukraine. According to the results of the research, the already existing potential for obtaining fuel from plastic and waste tires formed at specially equipped landfills by the end of 2020 amounts to an average of 11,31 and 2,56 thousand tons of fuel, respectively. The annual potential of obtaining fuel from the remains of plastic waste is on average 19,56 thousand tons of fuel, and from waste tires – 6,77 thousand tons of fuel. By 2030, in case of better logistics, it is possible to obtain an average of 275,07 thousand tons of fuel from the collection of accumulated unutilized plastic waste, and an average of 143,59 thousand tons of fuel from waste tires. The obtained values indicate that the improvement of the logistics of plastic and waste tires contributes to ensuring energy saving of their use, improving the health of people and animals, as well as increasing the energy and environmental security of Ukraine and the economy of enterprises.

DECOMMISSIONING OF UKRAINE'S NPP. PREDICTIVE DETERMINATION OF THE TYPES AND QUANTITY OF RADIOACTIVE WASTE AT DIFFERENT STAGES OF DECOMMISSIONING

2023-02-02T13:09:48+02:00

Today, an important issue is the preservation of the environment and the improvement of the living conditions of humankind. Taking this into account, nuclear generation is considered one of the cleanest branches of electricity production and at the same time stands out with a high level of safety and reliability. Along with the process of electricity production, a sufficient amount of operational radioactive waste (RAW) and spent nuclear fuel is generated, which accumulate every year at the NPP site and require processing and disposal in the near future. The infrastructure for handling NPP RAW is not sufficiently developed and organized, which prevents the transfer of NPP RAW to long-term disposal. The problem will become significant at the time of decommissioning of the first reactor units in Ukraine. Based on the IAEA's 10th fundamental safety principle "Protective measures to reduce existing or unregulated radiation risks" and a number of regulatory documents and IAEA guidelines, the above study of the publication is aimed at early predictive determination of the channels of RAW formation of individual systems and elements of the reactor installation. Early planning will make it possible to determine the area and number of specialized storage facilities in a timely manner, as well as to put into use the latest technologies for handling RAW. The analysis of the issue of RAW management highlighted the need to plan the last stage of the life cycle management of a nuclear installation, since this process is the most dangerous due to the possibility of excessive exposure of personnel and the release of radioactive products of nuclear fuel decay outside the NPP. The work contains recommendations on the predictive determination of the types and quantity of radioactive waste on the example of a separate safety system - the low-pressure emergency core cooling system of the Rivne NPP WWER-440. As a result of the study, the stages of decommissioning of the most radioactive equipment and elements of the second channel of the specified safety system were identified. The obtained amount and types of RAW of the system at the end of decommissioning create the basis for the RAW management, which is a positive side of early planning of NPP decommissioning.

OVERVIEW OF FACTORS AFFECTING THE ESTIMATION OF LIGHTNING SHIELDING PERFORMANCE OF OVERHEAD TRANSMISSION LINES

2023-02-02T15:16:49+02:00

This paper examines the risk of lightning stroke to overhead transmission line. The estimation procedure for the lightning performance of overhead power lines is based on the selected lightning attachment model, available lightning parameter statistics, the transmission tower design and voltage levels, type of overvoltage and other characteristics. In this paper the overview of factors affecting the estimation of lightning shielding performance of overhead transmission lines was performed. Among the factors that can affect the estimation accuracy, one can list insufficiently accurate data on the ground flash density in the area of interest and lack of complete data on statistical distribution of lightning current magnitudes. The paper shows that the influence of wind on the increase in the horizontal exposed distance of the phase conductor is not also taken into account. In this research traditional electro-geometric model was used for estimation of lightning performance of 220 kV overhead power line. Results obtained suggest that swing of suspension insulator strings caused by strong winds may lead to increased risk of lightning shielding failure during thunderstorm. Calculation performed for 3 kA lightning current magnitude shows that at swing angle equal to –1 degree, the horizontal unprotected distance of phase conductor increases by 3.1%, that corresponds to 5.240 m uncovered width. When the swing angle is increased to –5 degree, the uncovered width is increased by 15.8% that corresponds to 5.885 m uncovered width. It is proposed that an increase in the risk of lightning shielding failure as a result of wind load can be accounted by applying an appropriate correction factor in expressions for calculation of shielding failure rate, shielding failure flashover rate, etc. Proposed correction factor should account frequency and strength of wind in the area of transmission line route and depend on transmission line voltage level and tower design. Further efforts should be focused on obtaining and justifying the numerical values of this correction factor.

FUZZY MODELING OF SWITCHING EQUIPMENT FOR TASKS OF ASSESSING THE RISK OF EMERGENCY SITUATIONS IN THE EPS IN CASE OF ELECTRICAL EQUIPMENT FAILURES

2023-02-02T15:46:02+02:00

Today in the electric power industry of Ukraine the issue of assessing the risk of EPS operation due to failures of electrical equipment is particularly important. Failures are associated with significant level of aging and low replacement rates of electrical equipment, also with the possible simultaneous emergency decommissioning of several elements as a result of terrorist attacks.

Based on the analysis of the operating conditions of high-voltage switching equipment, standards and operational documentation method of diagnosing the technical condition of SF₆ circuit breakers is proposed. This method is based on the use of fuzzy set theory.

To assess the risk of power outages in the EPS in case of electrical equipment failures, a linguistic model is proposed for determining the total residual life and the probability of failure of SF₆ high-voltage circuit breakers of various types. Which is based on the aggregation of information on the technical condition of individual functional units.

An approach is proposed to take into account the importance of individual units of the circuit breaker in terms of the impact on the total residual life by weight coefficients determined due to failure statistics. The result of determining the total residual life is the ability to estimate the probability of failure on the observation time interval.

Tuning and adaptation of the developed linguistic model of the SF₆ circuit breaker to real operating conditions is provided by adjusting the parameters of the membership functions of the terms of the input linguistic variables using weighting coefficients and fuzzy inference with weighted average truth.

The developed linguistic mathematical model for assessing the technical condition and probability of failure of SF₆ circuit breakers can be used as a component of the complex of risk analysis programs in the EPS. And the formation of preventive actions to ensure the operational reliability of electrical equipment and regime reliability of the EPS in case of emergency equipment failures.

IMPLEMENTATION OF 20 kV VOLTAGE NETWORK IN UKRAINE

2023-02-02T16:10:44+02:00

Background Due to the war, the medium voltage networks are in an extremely difficult condition, they have a high degree of depreciation of electrical equipment and a low level of automation. The energy system of Ukraine has a problem of modernizing medium voltage networks and transfer them to a new class of rated voltage of 20 kV.

Objective Overall overview of 20 kV networks and organization of their topology with renewable energy sources and " energy storages ".

Methods A network model in the MatLab software package was used to study "energy accumulators". The study of the efficiency of the "energy storages" was carried out in the variability of the power to the total load, as well as the time of connection to the network.

Results The need to transfer voltages of 6 (10) kV to a higher level of 20 kV has been proven. Various methods of grounding the neutral of medium voltage networks are considered and the most effective modes of neutral grounding for 20 kV networks are determined: through an arc suppression coil or through a resistor. A comparative analysis of networks with and without energy storage was carried out. In 20 kV networks, without the use of energy storage, energy consumption from the network and power losses will increase. When using storage devices, they are permanently connected to the network and have their own power losses. Batteries connected to a 20 kV network lead to an oscillating process that has a damping character (within 2 seconds).

Conclusions The transition from the voltage level of 6 (10) kV to 20 kV will significantly increase the efficiency of distribution networks and reduce electricity losses. The installation of energy storage in 20 kV distribution networks will allow the introduction of new intelligent systems to ensure the interests of safety, economy and energy efficiency and will create the prerequisites for the implementation of the Smart Grid concept.

ТЕХНІЧНЕ Й ЕКОЛОГІЧНЕ ОБҐРУНТУВАННЯ ВИБОРУ ТИПОРОЗМІРІВ ГІДРОТУРБІН ДЛЯ НИЗЬКОНАПІРНИХ МАЛИХ ГЕС

2023-02-02T16:24:10+02:00

The purpose of the work is to minimize the harmful impact on the environment of low-pressure micro-hydropower plants, which are equipped with axial propeller hydro turbines and give all generated electricity to the grid at a preferential "green" tariff. Methodology. Analytical methods have been used in the theoretical studies described in this article. Findings. At small low-pressure hydropower plants up to 100 kW, 2 or 3 hydraulic units with different geometrically similar propeller turbines should be installed. We have proven this from economic, technical and environmental points of view. The proportionality factor of the impeller diameters of these turbines shall be √2. Originality. We have analytically determined a denominator of geometric progression equal to √2 to create a model row of propeller geometrically similar hydro turbines for small hydroelectric power plants (i.e., the proportionality factor of the impeller diameters of any two adjacent turbine sizes must be equal to √2). Practical value. The results of the studies can be used in practice when designing propeller hydro turbines for small hydroelectric power plants up to 100 kW, which operate at pressures up to 5 meters of water column. Conclusions. It is established that the best option for ecological and economic reasons is the equipping a small hydroelectric power plant up to 100 kW and a head of up to 5 m with three different propeller turbines – large, medium and small – with a 4:2:1 ratio of water consumption. This option allows for uniform discrete seven-stage regulation of water flow by the station with the following characteristics: depth of control – 86%, discretion of regulation – 14%. In this case, the relative water consumptions by the station may take the following values: 100%, 86%, 71%, 57%, 43%, 29%, 14%. Slightly worse in terms of ecology, but economically preferable option with two different propeller turbines – large and small – with a 2:1 ratio of water consumption. It allows providing a uniform discrete three-stage regulation of water flow by the station with the following characteristics: depth of regulation – 67%, discretion of regulation – 33%. In this case, the relative water consumptions by the station can take the following values: 100%, 67%, 33%.

ЩОДО ПРИНЦИПІВ ВІДНОВЛЕННЯ ЕЛЕКТРОЕНЕРГЕТИЧНОЇ СИСТЕМИ УКРАЇНИ

2023-02-02T16:29:43+02:00

Targeted attacks on the unified energy system of Ukraine have led to its significant destruction. Currently, about 50% of the country's energy infrastructure has been destroyed. Despite this, the system, thanks to the professional, heroic, desperate efforts of industry specialists, continues to work and feed end consumers. Also, one cannot but take into account the high level of reliability of the system, which is manifested in a significant number of generation sources dispersed throughout the territory of Ukraine and a high level of redundancy of connections between the system elements. Nevertheless, the military actions have shown the weaknesses ("bottlenecks") of the united energy system of Ukraine, including the high level of dependence of heat supply services on the availability of electricity. Thus, the concept of a new, "victorious" energy system of Ukraine is needed, in the composition and form of which all the advantages and disadvantages of the existing system, best practices of industry experts, and state-of-the-art technologies will be taken into account. This article is devoted to some issues of restoring the energy sector of Ukraine on the principles of redundancy and controllability. The article proposes a control system for end-user electrical appliances.

ENERGY STORAGE DEVICES. MAIN TYPES AND PROSPECTS OF APPLICATION

2023-02-02T20:17:59+02:00

The article considers energy storage equipment as a key element of the power supply chain. The need to accumulate energy arose at the beginning of the creation of energy networks and, with the development of technologies for the production, transmission and consumption of energy, the relevance of the creation and rational use of storage devices is growing. Quite a few types of storage devices have already been created, some of them are quite widely used, many are still at the testing stage, but have good chances for development and integration into power systems of various types. The article attempts to analyze the main types of energy storage devices, which differ from each other in the way of accumulation, energy, type of energy, storage time, accumulated power, etc. and summarizes their main characteristics in order to compare them with each other.

The results obtained in this article will allow us to pre-select a certain type of energy storage device depending on the power system that is being designed, which will make it possible to most rationally manage energy flows in the process of transmission, energy storage and its supply to the grid.

PREDICTION OF THE INTENSITY OF HEAT RELEASE IN SUBSTRATES OF BIOGAS TECHNOLOGY

2023-02-02T13:40:41+02:00

For our country, the development of energy saving and environmental protection technologies is at the development stage, therefore there is a need for an economically profitable determination of the intensity of heat exchange in a multi-phase multi-component environment, as there is a question in the production of energy-saving thermal power equipment.

The paper considers the heat exchange of the substrate from the operating biogas plant. In general, substrates consist of three phases, namely liquid (water and solution), solid (vegetable impurities, leaves, animal manure) and gas (biogas bubbles). The presence of various impurities in the mixture can change its rheological properties depending on the nature of the substrate and its context. In biogas technologies, different substrates have different thermophysical properties. The greatest difficulty is the measurement of thermal conductivity, other thermophysical properties can be estimated using existing methods.

To use the given method for predicting the intensity of heat transfer in substrates of biogas technology, the authors have accumulated observations and experimental results on an experimental stand on liquids with known thermophysical properties.

In biogas technologies, there is a problem of determining the intensity of heat exchange in multi-phase and multi-component environments, when solving it, it is advisable to use the theory of a regular thermal regime.

On the presented experimental stand, an array of information on "model fluids" with known information on thermophysical properties was obtained, on the basis of which the dependence on heat exchange is derived in a criterion form.

In the case under consideration, only a sample of a multiphase liquid medium, the thermophysical properties of which are limited, appears as initial data, only fragments of information can be found in the literature.

In the paper, only general recommendations are given regarding the determination of the intensity of heat exchange.

DETERMINATION OF OPTIMAL PACKAGES OF ENERGY EFFICIENT MEASURES FOR PUBLIC BUILDINGS

2023-02-02T13:53:40+02:00

The paper is devoted to the problem of improving the energy efficiency of public buildings maintained with funds from the state and/or local budgets. Optimization modeling is proposed as an instument to determine the optimal packages of energy efficiency measures according to the criterion of maximum achieved savings of fuel and energy resources. Approbation of the mathematical model on actual data has shown its practical value - depending on a given budget, the optimal packages of energy efficiency measures for public buildings (on the example of Zaporizhzhia city) are determined. Based on the results of computational experiments, energy efficiency measures with the best and worst ratios of implementation costs and achieved savings of fuel and energy resources were identified. The impact of additional constraints on the composition of an optimal package of energy efficiency measures was shown to make informed and rational decisions on investing in energy efficiency improvement projects for public buildings.

GLOBAL TRENDS IN IMPLEMENTATION OF RENEWABLE ENERGY SOURCES AND FEATURES OF THEIR IMPLEMENTATION DURING THE RECOVERY OF UKRAINE'S ECONOMY

2023-02-01T21:12:28+02:00

The world trends in the introduction of renewable energy sources (RES) and the peculiarities of their implementation during the recovery of the economy of Ukraine are considered.

It is shown that the world energy sector is undergoing a fundamental transformation, therefore it is necessary to develop a new energy security paradigm that will ensure reliability and availability while simultaneously reducing emissions, and green energy is an unconditional global trend of the coming decades. It has been determined that diversifying our energy supply by investing in RES is one of the promising ways to protect ourselves from the risks of energy dependence. The state and effectiveness of RES use at the beginning of the third decade of the 21st century is analysed (according to the Renewable Energy Policy Network for the 21st Century and The International Renewable Energy Agency).

Consolidated energy and climate statistics for 2021 according to the document World Energy & Climate Statistics - Yearbook 2022 (World energy and climate statistics - yearbook 2022) are provided, comparing statistical data of individual countries and Ukraine. The analysis of the effectiveness of the implementation of various types of RES at the level of world markets and Ukraine for the period 2010–2021 and 2020–2021 was evaluated using the average estimated cost of electricity production throughout the life cycle of these power plants (LCOE).

When considering the European policy in the field of RES and energy efficiency, the schedule of the development of renewable energy in the EU and the characteristics of the REPowerEU plan, developed by the European Commission, are presented, which outlines the course for reducing the consumption of oil and gas in general, as well as the introduction and use of "green" energy sources. A detailed description of the development of renewable energy in Ukraine in 2020-2021, as well as world trends in RES, which will affect the reconstruction of the Ukrainian economy, is provided. The impact of the full-scale war unleashed by Russia against Ukraine on the operation of renewable energy in Ukraine is shown, the main directions of the recovery of our country in the post-war period with the use of RES are highlighted.

DIODE EXCITERS OF A BRUSHLESS MEDIUM POWER SYNCHRONOUS GENERATOR

2023-02-02T21:11:21+02:00

The aim of the work is a comparative analysis of the parameters of the diode exciter of a brushless synchronous generator of medium power on the number of pole pairs of an auxiliary electric machine, the development of recommendations for choosing the number of pole pairs of an auxiliary electric machine and the design of the exciter.

An improvement of the automated method of electromagnetic calculation of the exciter of a brushless synchronous machine has been carried out. The diode exciters of a brushless synchronous generator with a power of 250 kW with the number of pole pairs p = 2 based on a three-phase bridge rectifier and an auxiliary electric machine of a synchronous type with different numbers of pole pairs are compared. At the first stage, a preliminary electromagnetic calculation of the auxiliary electric machine is performed, taking into account the initial value of the relative magnitude of the resulting electromotive force, the allowable values of inductions in all sections of the magnetic circuit in in forced mode, the length of the magnetic circuit and the rotor winding support are determined. According to the results of the calculation of the rectifier model in the quasi-steel mode of operation, the relative value of the resulting electromotive force of the auxiliary electric machine is specified.

At the first stage, a preliminary electromagnetic calculation of the auxiliary electric machine is performed, taking into account the initial value of the relative magnitude of the resulting electromotive force, the allowable values of inductions in all sections of the magnetic circuit in in forced mode, the length of the magnetic circuit and the rotor winding support are determined. According to the results of the calculation of the rectifier model in the quasi-steel mode of operation, the relative value of the resulting electromotive force of the auxiliary electric machine is specified p_B = 4.

SIMULATION OF VARIABLE INDIVIDUAL GRAPHS OF THE ELECTRICAL LOAD OF THE INDUSTRIAL ELECTRIC DRIVE

2023-04-17T16:49:38+03:00

In the process of developing and creating means of controlling the energy efficiency of technological processes based on electric drives, a task arises related to the modeling of individual electric load schedules of the electric drive. In the analytical study of electricity consumption, the substantiation of the mathematical model of the random process is important. This model, on the one hand, should most adequately reflect the properties of the real process of electricity consumption, and on the other hand, it should allow research of this process using known theoretical methods. A way out should be sought on the basis of compromise solutions regarding the choice of the simplest, but sufficiently accurate models, which will solve the tasks in the most rational way.

The probabilistic approach to load estimation allows the most probable description of the process of changing the electrical load over time, given the random nature of this change. The application of this approach should be based on reliable statistical data, which allows to ensure high accuracy of the obtained models. The task consists in simulating random processes of electricity consumption by the main consumer of electrical energy - the electric drive.