GENERAL ISSUES RELATED TO RELIABILITY AND SAFETY OF THE POWER INDUSTRY
One of the promising directions for further development of the methodology for investigating and ensuring the reliability of energy systems is the consideration of integrated energy systems. This is caused by the need for the adequate reflection of their joint operation. Previously, the authors proposed several methodological approaches based on "node," "system," and "evaluation" to assess the adequacy of an electric power system when this is operating jointly with a gas supply system. In that case, the focus was made only on high-pressure gas supply systems (simplified calculation). This work aims to consider not only the high-pressure gas systems, but also to take into account the influence of lowpressure gas systems (refined calculation) on the adequacy of electric power system. This approach appears to be more technologically advanced and corresponds to the real conditions of the functioning of integrated power systems. The studies were carried out using the “node” approach, its reference calculation being the most accurate one. The methods applied in the research are probability theory and mathematical statistics: a particular theorem on the repetition of experiments (Bernoulli's trial), calculation of probability distribution series, theorems of addition and multiplication of probabilities. A comparative analysis of reference calculations of the electric power system adequacy was carried out for simplified and refined connection schemes in the gas system (two cases were considered: a highly reliable low-pressure gas system and a low-reliability one). The calculations were performed on an illustrative example of a power system. Assessment of the load supply reliability in integrated systems must factor in the process features of the systems at issue, the block diagram of their connections, as well as the accuracy of the results obtained and the complexity of searching and preparing initial data for the corresponding research model.
DESIGN, RESEARCH, CALCULATIONS
The article describes the results of work on the creation of neural networks calculating the technical and economic parameters of all possible modes of operation of a thermal turbine unit with a steam turbine of type PT-60-130/13. In accordance with the objectives set, recommendations for the preparation of training data samples are formulated. The input and output parameters of the condensing and heating modes of operation of the steam turbine are determined. The results of research on determining the most optimal architecture of neural networks for calculating the energy characteristics of steam turbine plants of the heating type are presented. The results of calculations of the mean squared errors of neural network predictions from the results of calculations performed using a verified object-oriented model of a PT-60-130/13 turbine unit are tabulated.
Graphs of the dependence of the specific heat consumption for the generation of electrical energy on the power of a PT-60-130/13 turbine unit for condensation and heating modes of operation using neural networks are plotted. The conclusion is formulated about the possibility of using neural networks for the development of energy characteristics and regulatory documentation on fuel use of equipment of thermal power plants.
The issues of numerical modeling of hydrodynamics of a spouted fuel bed in the furnace of a solid-fuel boiler are considered. At present, solid-fuel boilers are widely used in the power industry of the Russian Federation, with the share of coal-fired generation to remain significant in the projected terms. Therefore, the study of the efficiency of thermal and hydrodynamic processes that ensure the implementation of clean coal technologies is a relevant task both today and in the long term. The article presents the following main stages of numerical modelling of the hydrodynamics of the spouted bed: problem formulation with selection of boundary and initial conditions, methods of solving the Navier-Stokes and continuity equations for the air flow, Newton's equations and diffusion equations for particles. The k-omega turbulence model was used in the calculations that is described by means of two partial differential equations for the variables k (kinetic energy of turbulence) and omega (specific dissipation rate). A comparative analysis of environmental advantages and disadvantages of existing methods of combustion of low-grade coal in schemes with in-cycle gasification (ICG) is carried out. Advantages and difficulties of switching to structures with CFB in the spouted bed mode are shown. Numerical modeling of the cold spouted bed created by means of particle injection is performed, a set of initial settings and boundary conditions is presented, the adequacy of the obtained results is verified by hydrodynamic characteristics of the isothermal process. The obtained results allow us to proceed to the next stages with non-isothermal models, with heat exchange and combustion reactions in the spouted bed of coal taken into account. The following refinement of the physical model will allow to achieve more accurate and reliable results and to ensure their correct scaling.
The scheme of internal heat supply of residential buildings with independent connection of the heating system to the external heating networks and connection of the heater of the DHW system in a parallel single-stage arrangement, providing reliability of heat supply and the necessary comfort in the premises due to the unrelated regulation of heat supply for heating, ventilation and DHW even in case of fluctuations in water intake, is considered. A mathematical model describing the non-stationary modes of operation of DHW system heaters under the conditions of implementation of this scheme is constructed and investigated. Calculations were carried out using this model, including numerical simulation on a computer using the Monte Carlo method. It is established that in this case, a decrease in the average heat transfer coefficient of the heater of the DHW system due to fluctuations in the flow of mains water following the daily change in water consumption at the DHW can be neglected, since this decrease lies within the usual error of engineering calculation, despite the fact that this coefficient depends on the flow in a nonlinear way, and its growth during the period of increased water intake for DHW does not fully compensate for the decrease during the reduction of water consumption. At the same time, it is proved that with a characteristic number of heat transfer units in a DHW system heater referred to the heated stream, the total amount of heat transferred can decrease quite noticeably, by an amount of 10 to 12 percent; however, with a rational choice of the heater size, such a decrease is within the limits allowed by the applied factors of margin when setting determination of the heat exchange surface.
An important area in the field of solar energy is considered, focusing on the use of a hydraulic drive in high-power solar trackers. In the context of the relevance of environmental problems and the commitment to energy efficiency, the role of solar trackers in increasing the productivity of solar power plants is investigated. An analysis of current trends in the field of hydraulic drive is presented, highlighting the prospects for its application. The analysis of the directions of improvement of the drives of the solar tracker is carried out. The hydraulic drive of the tracker is considered as an object of regulation. Disturbing loads of various types acting in the process of changing the position of the tracker are determined. The main load acting on the tracker drive is positional, caused by the gas–dynamic effect of the wind flow impinging on the tracker plane or the ambiguity of the behavior of the snow and ice cover. It is determined that the inertial load, when turning a high-power tracker, has a significant effect on the friction forces in the attachment points of the hinge support mechanisms. Options for the implementation of new circuit solutions for the tracker hydraulic drive are considered. Using information from sensors of movement of the rods of hydraulic motors of the tracker position drive, the sun position sensor, the control electronic module positions the solar tracker platform by supplying control signals to the electric hydraulic distributors of the drive. The hydromechanical regulators of the pump adjust the characteristics of the system to a random change in external loads on the tracker. A mathematical model of the hydraulic drive of the basic circuit tracker has been developed. The digital model of the tracker drive is designed to optimize the operation of the hydraulic drive, taking into account various factors such as inertia, viscous damping, hydraulic losses, system nonlinearities, thermal losses, elasticity of elements and the impact of external factors. The results obtained emphasize the efficiency and accuracy of the control system, making the hydraulic drive an important element in the development of clean and efficient energy.
Condensation processes are widely spread in various branches of industrial production and, in particular, in electric power industry, where, according to experts' data, heat removal in thermodynamic cycles of steam turbine plants (STP) operating as part of combined cycle plants (CCP) and autonomously, in the 21st century will be exercised mainly in air-cooled condensers (ACC). At the same time, the use of ACC as a part of steam turbine units operating in climatic conditions typical for the Russian Federation (RF) determines the relevance of problems to be solved to ensure their safe operation at subzero outside temperatures. One of these challenges is to ensure long-term safe operation of the ACC, with the formation of ice on the inner surface of the heat exchange pipes minimized. To conduct the research, Steam Turbine Air-Cooled Condenser research and training stand was used. The paper presents the combined circuit and measurement diagram of the research and training stand, and gives a brief description of the design of the ACC. Experimental modes have been determined, and methods for processing experimental data and analyzing the results obtained have been developed. As part of the study, experiments were carried out on 18 steady-state operation modes of the stand. At the same time, the values of the main operational parameters of the ACС varied within the following limits: the temperature of the cooling air at the ACС inlet — from minus 11,5°C to minus 1,8°C; the cooling ratio — from 176 to 790. The relative weight content of air in the vapor varied from 0,051% to 0,12%. An analysis of the obtained results was carried out, on the basis of which a relationship was established that allows, for various negative temperatures of the cooling air at the inlet to the ACС, to determine the highest value of the cooling ratio at which its long-term safe operation is possible. An algorithm for using the obtained relationship is given.
On a specialized testing installation — a high-voltage Marx generator, which allows the formation of a spark discharge up to 20 meters long, the process of the impact of lightning radio emission in the microwave range on an aircraft (AC) is simulated. A metal AC model made on a scale of 1:50 was placed in a 9 m long rod-plane spark gap. A positive voltage pulse was applied to the high-voltage electrode from the generator (front 100 μsec, duration 7500 μsec). The generated spark discharge passed through the AC model. It was found that when the spark channel passes through the body of the model, electromagnetic pulses of the microwave range with a duration of less than 500 psec and a rise time of less than 100 psec arise. The measurement of the resulting microwave pulses was carried out using special radio equipment in the subnanosecond range. High-speed photography of the discharge development, carried out synchronously with electromagnetic measurements, showed that microwave pulses (up to 10 GHz) arise at the stage of development of the spark discharge leader in the part of the “high-voltage electrode – insulated model” gap. Such pulses can be considered as a factor dangerous for various AC microwave radio systems, when the AC is struck by lightning, as well as for other objects, including power facilities, which contain equipment with microelectronics. Such microwave pulses can also occur during nearby lightning discharges (for example, in a lightning rod of a power substation), when a powerful streamer corona occurs on devices and wires of ultra-high voltage lines), and when a high-voltage spark discharge occurs when switching equipment (disconnectors, arresters) is triggered. In this case, disruptions are possible in the operation of control equipment (for example, relay protection devices) that contains microelectronics, as well as various communication means available at electric power facilities operating in the microwave range (above 1 GHz).
In modern conditions, when parity international financial and monetary relations are turning from traditional instruments of economic interaction into instruments of neocolonial political pressure and blackmail of economically strong countries against weaker ones, the need for a new global financial order and monetary standard, that would be independent of the will of any central bank, but with a value as reliable as that of modern fiat currencies, is increasingly realized. Today, the global economy feels the urgent need for fundamentally new opportunities for market interaction and monetary exchange. Cryptocurrencies have become such tools — electronic decentralized money issued by specific individuals in specialized open computer networks through the transformation of electricity into fixed computer codes. The process of such transformation is called mining, which uses ASIC miners as computer equipment to obtain cryptocurrency. The concept of cryptocurrencies and the specifics of investing in them are considered. The characteristic is presented of the current state and dynamics of the development of the crypto market. The possibilities and methods of forecasting the development of the cryptocurrency market are shown both using classical methods of economic forecasting and a fundamentally new methodology based on the current assessment of the psychological state of participants in the crypto market and their readiness to commit certain economic actions. An assessment is given of the possibilities of investing in mining as a technology for mining cryptocurrencies. Requirements to special mining equipment — ASIC miners — are described. An assessment is given of the prospects for the development of the crypto economy.
OPERATING EXPERIENCE
The analysis of the electric energy transmission through the distribution electric networks of the branch of PJSC Rosseti Volga — Samara Distribution Networks over the period of 2018 – 2022 was carried out. The structure of the company is considered, the characteristics of the main elements of the power grids under study are given, the balance of the electric energy transmission in and out of the company's networks is estimated. Based on the information published in public media on the accident rate in the company's power grids, assessment was made of the number of emergency situations that occurred over the period under study, assessment of the duration of interruptions in power supply to consumers, as well as the amount of undersupplied electric energy caused by these interruptions. The influence of the seasonal component on the number of emergencies during the period under study is considered. Based on the 2022 data, the analysis of the main causes of damage to components of power grids and the classification of failures are presented, their main characteristics over the period in question are considered. The percentage ratio of the number of failures for the most characteristic reasons to the total number of shutdowns over the period under study was established, and the classification of the number of emergency shutdowns according to the degree of undersupply of electrical energy was made. General scientific methods, numerical methods of analysis, methods of the electrical circuit theory were used in the study. To visualize the results of the analysis, the technologies of the MATLAB graphics editor were used. The results obtained may be of interest to the heads of power grid companies, as well as researchers and engineers engaged in research in the field of power supply reliability.
VOICE OF YOUTH
The importance of international cooperation is considered in the context of ensuring Japan's energy security. The concept of energy security and its importance for the sovereignty of the state is analyzed. The role of international energy relations in the modern world is analyzed, and the strategic partnerships that Japan is developing to ensure sustainable access to resources are highlighted. Special attention is paid to Japan's diplomatic efforts aimed at diversifying energy sources, ensuring technological exchange and promoting the development of energy-efficient solutions. Japan has historically considered international cooperation as one of the ways to solve its energy problems. The country is a member of many international organizations and actively participates in international conferences and initiatives. Japan is not only a stable importer of resources, but also an exporter of various energy technologies. Japanese electric power companies operate all over the world. Each of Japan's electric power companies has individual agreements with foreign companies to share a wide range of information including that on power generation, distribution and quality control. Due to the fact that Japan does not have a significant raw material base for the development of industry and meeting energy needs, the main tool for solving the country's resource problems is to build active long-term relationships with resource-rich countries. The conducted research shows that ensuring stable supplies of energy resources has been the cornerstone of Japan's economic diplomacy for many decades. The article emphasizes the importance of global cooperation in the field of energy for ensuring sustainable development and ensuring national energy security in the face of modern challenges and changes in the global energy paradigm.
DISCUSSIONS
INFORMATION
ISSN 2542-2057 (Online)