Major trends in the development of the gas industry point to a large-scale expansion of the liquefied natural gas (LNG) market, which continues to be a fast-growing segment compared to other energy sources. The national policy of the Russian Federation is aimed at developing the infrastructure of LNG complexes. This article analyses the world experience in the use of LNG complexes in gas consumption peak damping installations, which meet the conditions of LNG use as a backup fuel by PJSC Mosenergo branches (low-tonnage production combined with a large volume of LNG storage). It is shown that, in terms of the conditions of production and use of LNG at power plants, the most suitable are installations with 90–100% liquefaction of the incoming gas flow with an external refrigerating circuit using a mixed refrigerant or nitrogen, which provide the composition of regasified LNG almost identical to the composition of the source gas. The authors have formulated requirements for the development of energy-efficient LNG complexes at PJSC Mosenergo branches, including ensuring cycle energy consumption by expanding the network gas in the expander with utilization of refrigerating capacity in the liquefaction cycle, as well as cooling the compressed coolant of the refrigerating circuit by gas flows supplied further for combustion. The technological features of implementation of the LNG complex for production, storage and regasification of LNG as a reserve fuel for TPPs are reviewed. The study has shown that the most suitable power plant for the introduction of an LPG complex is TPP-22, for which a new fuel oil facility is being designed. Despite the current practice of using fuel oil and diesel fuel as backup fuels, LNG can have a competitive advantage through the use of secondary energy resources of TPPs. 

The purpose of the article is to analyze the damage rate of overhead power transmission lines (OPL) in medium-voltage electrical distribution networks of the Irkutsk region. The established International Indices that determine the level of reliability of the functioning of electric networks are considered, and information on the compliance of the condition of electric networks in Russia with these indices is analyzed. Analytical information on the damage rate of elements of these networks and their causes in Europe, America, and Russia is presented. The emphasis is placed on the fact that the most common damage is characteristic of overhead power lines, especially 6–10 kV lines. As an object of research, two branches of the Irkutsk electric grid company (IEC) were taken, one of which provides electricity to rural consumers, the other — mainly to consumers residing in the territory of the city Irkutsk. The characteristics of these electric networks, their territorial location and basic technical data are presented. To conduct analytical monitoring of the level of reliability of overhead power transmission lines, logs of disconnection of the Eastern and Southern electric networks of the IEC over a long-term period were used. On the basis of this information, tables of failures and their consequences in the studied electrical networks were compiled for monthly average data over the period under examination for various causes of damage. To plot time diagrams of the parameters under examination, computer programs were compiled in the Matlab system, the use of which made it possible to obtain visualization of changes in failures for various reasons for the electrical networks under consideration. The information on the time of power supply interruptions in these networks, as well as the amount of electricity underutilized by consumers during these interruptions and its cost are analyzed. It is shown that in the electric networks under consideration, most of the power failures are related to the territorial dispersion of these networks, and the low level of equipment controls and insufficient qualification of operating personnel, as evidenced by the significant number of failures for unknown reasons. Besides, a significant part of the failures is due to damage to the overhead line wires, switching equipment and the effect of wind load. Recommendations for improving the condition of power transmission lines and a number of measures aimed at improving the level of reliability of power supply are presented.

The organization of operation, maintenance and repair of the basic technological facilities of electric power systems (EPS), which are beyond their designed service life (hereinafter referred to as ageing facilities, or AFs) is one of the problems that determine the energy security of many countries, including economically developed nations. The principal cause of insufficient overall performance of AFs is the traditional focus of the EPS management on economic efficiency and the insufficient attention to reliability and safety of AFs. The tendency to nonlinear growth in the frequency of occurrence of unacceptable consequences in the EPS requires ensuring the operational reliability and safety of AFs. The averaged estimates of reliability and safety used at designing power facilities are not suitable for characterization of overall operational performance. Among the basic and the least investigated (in terms of operational reliability and safety) EPS facilities are overhead power transmission lines (OPL) with a voltage of 110 кV and above. This is for a reason. OPL are electric power facilities with elements distributed along a multi-kilometer line (supports, insulators, wires, accessories, etc.). That is what makes the organization of continuous monitoring of the technical condition of each of these elements, and, consequently, the assessment of operational reliability and safety, so problematic. A method is suggested for assessment of “weak links” among the operated OPL on operative intervals of time along with a method for assessment of the technical condition of OPL at examination of a representative sample.

A method of thermomechanical improvement of pulsating air flows in the intake system of a turbocharged piston engine is described. The main objective of this study is to develop a method for suppressing the rate of heat transfer to improve the reliability of a piston turbocharged engine. A brief review of the literature on improving the reliability of piston engines is given. Scientific and technical results were obtained on the basis of experimental studies on a full-scale model of a piston engine. The hot-wire anemometer method was used to obtain gas-dynamic and heatexchange characteristics of gas flows. Laboratory stands and instrumentation facilities are described in the article. The data on gas dynamics and heat exchange of stationary and pulsating air flows in gas-dynamic systems of various configurations as applied to the air supply system of a turbocharged piston engine are presented. A method of thermomechanical improvement of flows in the intake system of an engine based on a honeycomb is proposed in order to stabilize the pulsating flow and suppress the intensity of heat transfer. Data were obtained on the air flow rate and the local heat transfer coefficient both in the exhaust duct of the turbocharger compressor (i.e., without a piston engine) and in the intake system of a supercharged engine. A comparative analysis of the data has been carried out. It was found that the installation of a leveling grid in the exhaust channel of a turbocharger leads to an intensification of heat transfer by an average of 9%. It was found that the presence of a leveling grid in the intake system of a piston engine causes the suppression of heat transfer within 15% in comparison with the baseline values. It is shown that the use of a modernized intake system in a diesel engine increases its probability of failure-free operation by 0.8%. The data obtained can be extended to other types and designs of air supply systems for heat engines.

In the course of developing designs for mixing heat exchangers that operate on the principle of throttling the working medium on perforated grids, special attention is paid to ensuring the reliability of structures subject to erosive wear when subjected to dripping moisture and temperature stresses.
JSC “NPO CKTI” has years of experience in the development of contact-type heat exchangers and was directly involved in the design of separate power plant equipment for LK-60, including a throttle and dampening device (TDD).
It provides a description of the functional purpose of the TDD as part of the LK-60 nuclear power plant, the principle of operation and significant differences of the new design from those previously used. It is noted that while in previous designs the TDD included four columns connected in pairs, on LK-60 there are two columns located on top of the condenser. The TDD for LK-60 is designed to receive 132.5 t / h of steam of higher parameters than the previous generation designs intended to receive about 50 t / h of steam.
The main technical solutions in the development of the design of the TDD are presented. The design provides access to the throttling lattices for diagnostics and their replacement if necessary which ensures a high degree of maintainability and reliability of the device. Perforation of the lattices arranged in series in the direction of the steam flow is made in such a way that the openings of the previous lattice, if possible, are not located opposite the openings of the subsequent lattice. The distance between the throttling lattices was taken from the conditions for ensuring the design course of the steam throttling process.
Results are given of thermal and hydraulic calculations of the TDD. The calculation consists of two main parts. The first part includes thermal and hydraulic calculations with the determination of the degree of perforation of the lattices, the distribution of temperature and vapor pressure over the cross-sections of the TDD, etc. The second part contains the calculation of the cooling condensate injection nozzles.
In the course of design studies, strength calculations were performed for all versions of TDD and individual parts. In addition, the nozzles underwent a full test cycle (determination of flow characteristics, water spray quality) in accordance with the test program.

Combined air and water heating schemes have been actively used recently for heating public and residential premises. They have certain advantages in countries with a warm climate, whereas in a temperate climate, their use may be unfeasible. The most effective regulation of the heating system in the building can be expected, if all the technology specifics are taken into account, in terms of both the purpose of the room and the methods of regulation. A system focused only on weather-based regulation falls short of meeting to energy-efficient control classes: a heat carrier with the same temperature is distributed among rooms with different requirements for temperature and humidity characteristics. The issues of ensuring the energy efficiency of the combined air and water heating system in public buildings for the temperate continental climate of Russia — the academic building (AB) and laboratory building (LB) of the Kazan State Energy University (KSEU) have been considered. Heating devices of the KSEU heating system have manual control valves installed in the premises, or radiator valves with thermostatic heads, but without room controllers, which does not meet the energy-efficient control classes. An experimental survey of the functioning of the heating system of the KSEU buildings during the 2019 – 2020 and 2020 – 2021 heating seasons was conducted. The optical pyrometry method was used to measure the temperature of the surfaces of windows, walls and elements of the heating system, as well as the temperature and humidity of the air in lecture rooms and corridors of the AB and LB of the KSEU. The parameters of heating devices and indoor air in rooms of various purposes were found compliant with the current sanitary and hygienic requirements. At the same time, the need to switch to a higher class of regulation has been revealed, since, under the current situation, the parameters of the indoor air depend on the outdoor temperature: in the abnormally warm winter of 2020, the indoor air temperature was at the edge of the maximum permissible value, while in the normal climate of winter of 2021, it was at the edge of the minimum permissible value.

Power transformers are key equipment in power generation, transmission, and distribution systems. The reliability of power transformers is based on the performance of the insulation system, which includes solid cellulose insulation and a liquid dielectric. Modern power engineering requires liquid insulation to have excellent insulating properties, high fire resistance, and biodegradability. Mineral oil that has been in use for over 100 years does not meet certain requirements. Therefore, various methods of enhancing the insulating properties of the oil are currently being considered, including mixing it with other liquid dielectrics, which have excellent properties. Synthetic and natural esters are considered as alternative fluids.
This article discusses the possibility of enhancing the insulating characteristics of mineral oil with a high content of aromatic hydrocarbons (for example, T-750 oil) by mixing it with synthetic ester Midel 7131. Assessment is given of insulating parameters of the resulting mixtures with an ester fraction in mineral oil from 0% to fifty%. The main characteristics of the mixtures are described, such as density, kinematic viscosity, flash point, dielectric loss tangent, relative dielectric permittivity, breakdown voltage, and moisture content. It is shown that with an increase in the proportion of ester, some parameters of the obtained insulating liquid improve (flash point, dielectric constant, breakdown voltage), while values of other parameters (density, kinematic viscosity, dielectric loss tangent) with an ester content of more than 10% in the mixture do not meet the requirements for mineral oils.

When a pipeline is subjected to an external influence that can affect the frequency of its natural vibrations, the parameters of its natural vibrations change, which increases the measurement error, and often simply distorts the results of vibration control. For pipelines, such an impact may be the influence of the soil when pipelines are laid without a channel. Different types of soil affect the change in the natural vibration frequency of the pipeline in different ways.
The purpose of the article is to analyze the influence of various types of soils on the parameters of natural vibrations of the pipeline. The aim of the study was to theoretically confirm the dependence of the change in the frequency of vibration of the pipeline under the influence of soil.
A modal analysis of natural oscillations of 5 polyethylene pipelines was performed. As initial data, it is assumed that the design pipeline is laid in a trench with inclined walls, with the slope laid on a flat base at a depth of 2.5 m. The calculations were performed in the ANSYS finite element analysis software package. In order to build a mathematical model, the degree of soil impact on pipelines is determined by studying the vertical and lateral pressure of the soil on the above pipelines, and the natural vibrations of pipelines are analyzed.
The results of the modal analysis for polyethylene pipes with a laying scheme with inclined walls and different soils (gravel sands, coarse and medium-sized; heavy clays) are presented. The soils were chosen that are the most common on the territory of Russia.
Thus, the obtained dependence of the degree of influence of different soil on the natural frequencies of pipelines significantly increases the reliability of vibration diagnostics of buried communications, can facilitate the work on its organization and allow determining long-term forecasts of pipeline operation.

The article is devoted to the so-called "war of currents", which unfolded in the United States in the late 19th-early 20th century. The winner of this "war" was a talented Serbian inventor Nikola Tesla. He professed the ideas of alternating current. He was opposed by the famous American businessman and scientist T. Edison. Enterprises of the latter produced machines running on direct current. It made a big profit. After a number of conflicts, Tesla, who worked for Edison, left his company and organized a business of his own jointly with an industrialist D. Westinghouse. Tesla's ideas and projects won a landslide victory. The development of direct current systems ended in the late 1920s, despite the efforts of T. Edison. N. Tesla was at the origins of alternating current systems, the appearance of electric motors, robotics, wireless charging devices and much more. Today, the ideas of the great Serbian inventor, even the most fantastic ones, are experiencing a rebirth.

The question of the relevance of reducing energy consumption is considered. An assumption is made that in cases where indoor illuminated switches are used that control a group of lamps, currents of the order of microamperes flow in the lighting network in the switched-off mode.
The regulatory documentation related to the normative indicators of illumination as well as the typical area of premises is analyzed, and on the basis of the listed data, the calculation of the minimum required luminous flux emitted by lamps is made. The normalized calculated luminous flux was divided by the luminous flux from one lamp, with the resulting ratio rounded up. This ratio is the approximate number of lamps. This number of lamps will enable to calculate the total current of the entire lighting network.
The standard rates for the operating time of the lighting network are taken into account. The operating time of the lighting network in the "standby" mode is the difference between the total number of hours per day and the standard operating time of the lighting network.
Knowing the power consumption and the network operation time in the "standby" mode, we can calculate the power consumption of the lighting network in the "standby" mode.