A study has been conducted on the peculiarities of electric energy transport in the power supply systems of Mordovenergo for the period 2018–2023. The structure of the company is described, the characteristics of the main elements of the studied electric networks are provided, and an assessment of the balance of transmission of electric energy in and out of the company's networks is presented. Based on information published in the open press, an analytical assessment of the failure rate in the company's electrical networks was carried out on a monthly basis for each year of the study period. An assessment has been made of the consequences of emergency shutdowns in terms of the amount of electrical energy undersupplied to consumers. Based on the proposed classification, an analysis of the failure intensity was performed, and the percentage of failures of various intensities was determined. Notably, slightly more than 1% of the total number of high-intensity failures accounts for up to 28% of the total amount of electrical energy undersupplied to consumers. A detailed analysis of the main causes of damage to electrical network elements has been performed. The percentage ratio of the number of failures attributed to the most common causes relative to the total number of outages during the study period was established. It was found that more than 72% of failures occurred due to non-compliance with maintenance regulations and delays in detecting and addressing defects. The obtained indicators were compared with similar indicators in the electrical networks of other branches of PJSC ROSSETI Volga. The research employed general scientific methods, as well as numerical analysis techniques. Visualization of the obtained analysis results is presented using the capabilities of the MATLAB graphics editor. The results of this research may be of interest to the management of electric grid companies, as well as researchers and engineers engaged in studies related to reliability of power supply. 

The study focuses on developing a safety control program concept for nuclear power plants (NPPs) to enhance risk management reliability, personnel protection, public safety, and environmental security. The introduction emphasizes the relevance of radiation safety issues, the necessity of adapting existing monitoring methods, and the need for rapid response to potential threats. Modern control systems require integration with automated platforms to improve emergency management efficiency. Given the potential technological risks, the development and implementation of a new safety control program are crucial for the nuclear energy sector.

The aim of this study is to create a program that systematizes risk data and ensures its effective use. The methodology includes an analysis of NPP safety passports, the development of a centralized database structure, and the implementation of modern technologies such as Django, Docker, and SQLite3. The program features a web interface for real-time access, containerization tools, and system performance monitoring. Key methods used include probabilistic analysis, accident scenario modeling, data visualization, and information systematization for decisionmaking. Data analysis enables risk forecasting, potential impact assessment, and the development of preventive measures.

The results demonstrate the advantages of the proposed concept over traditional monitoring methods. Graphs help assess accident probabilities, damage distribution, and the impact of response time on mitigating consequences. The analysis indicates that an automated system enhances prediction accuracy, accelerates data processing, and reduces human error risks. Additionally, the proposed system shortens decision-making time, improves emergency planning efficiency, and enhances coordination among safety and security services.

The conclusions highlight that the proposed safety control program concept ensures a higher level of protection. It is adapted for practical implementation, integrates with existing systems, and serves as a valuable tool for improving the safety of nuclear power plant operations while minimizing potential risks and increasing resilience. 

Reliability of autonomous power plants based on gas piston and gas turbine power units for auxiliary needs (APU) of gas industry enterprises is one of the key factors for ensuring uninterruptible power supply and efficient functioning of gas industry facilities. In modern economic conditions, stable operation of APU is important, and any failures can lead to significant financial losses and shutdown of production processes. Modern APU are complex technical systems that include various types of equipment. The article analyzes statistical data on failures that occur during operation of autonomous power plants for auxiliary needs of fuel and energy complex enterprises. Based on the data on the number of failures and mean time between failures (MTBF) of APU units from the beginning of operation, their statistical processing was carried out, and empirical dependencies of reliability indicators were established. The values of the probabilities of failure-free operation and the probability of failure, as well as the probability density functions of failures, were obtained. A hypothesis was put forward on the distribution of the average time to failure according to the Weibull distribution law. In accordance with the Pearson goodness-of-fit criterion, it was found that the obtained experimental data correspond to the theoretical model of the Weibull distribution. Based on the obtained statistical model of the mean time between failures, dependencies of the reliability indicators of the electric units of the APU were constructed. The Weibull distribution function proven during the study is the basis for further scientific research. 

The problems related to increasing the energy efficiency of heating of premises in the construction industry are considered, which can have a tangible effect in moving towards low-carbon production. Most of the heating systems of completed construction sites in Russia have a "weather regulation" level. To ensure its correctness, it is first of all necessary to create correct digital information models (DIM) of buildings, which are created mostly on the basis of a software package (SP) — Revit, and recently — on the basis of the domestic product Renga. At the same time, the modeling results of both SPs require verification and validation. The heat engineering calculations integrated into them are performed for stationary modes of heat flow passage, whereas the heat flows of heating systems of most objects operating in automatic weather regulation mode can change several times during the day. Since at present, when the structure of enclosures is designed, their thermal inertia is not taken into account, temperature fluctuations can have a noticeable effect on the results of heat loss calculations. An expression for comparing the Fourier criterion and the thermal inertia of the enclosure of premises has been obtained, which allows for adequate assessment of the similarity of heat flows through enclosures of various designs and selection of the parameters of the characteristics of the simulated enclosures to maintain the similarity. To validate the results of the SP modeling, a full-scale model of a fragment of the building subject to numerical modeling was created and tested. The geometric and thermal characteristics of the models are given; a description of their designs and measurement methods is given. The results of full-scale studies has shown good similarity with the numerical studies. The obtained results will allow adjustments to be made to the calculations of heating systems and thermal protection of buildings, taking into account the nonstationarity of heat losses in premises due to weather regulation or climatic instability. 

The study examines the internal heat supply scheme for residential and public buildings, featuring an independent connection of the heating system to external heating networks through a surface heat exchanger. This configuration ensures the reliability of heat supply, stability of the hydraulic regime, and the necessary comfort within the premises. A mathematical model has been developed to describe the variable operating modes of the heaters of the heating system during the heating period, taking into account changes in the heat transfer coefficient of the device and the average temperature difference of the heat carriers. Calculations using this model revealed that the heat transfer coefficient of the heater decreases monotonically with an increase in outdoor air temperature. This decrease is attributed to changes in the physical properties of water when regulating its temperature according to the heating schedule, reaching approximately 20% at the beginning and end of the heating period. Additionally, it was shown that when using a typical heating schedule, the average logarithmic temperature difference of the heat carriers in the heater decreases significantly more slowly than the thermal load on the heating system and the heat transfer coefficient. As a result, the actual heat transfer in the heat exchanger at the boundaries of the heating season is also about 20% higher than required. This finding suggests that such devices should be calculated for the conditions at the breaking point of the temperature graph, similar to heaters in hot water supply systems, or that the introduction of a 20% margin to the calculated heating surface should be reconsidered 

One of the priority tasks of improving combined-cycle gas recovery plants is to determine the optimal parameters of the gas turbine unit (GTU) cycle and the rational degree of complexity of the technological scheme of the combined plant. The most promising options in terms of thermal efficiency are binary combined-cycle gas turbines (CCGTs) of the recycling type, which include one or two GTUs with heat recovery boilers and a steam turbine. At the same time, it is important to enhance the reliability and efficiency of the steam turbine unit operating in the CCGT cycle, as the turbine efficiency does not exceed 33–36% due to low initial steam parameters, the absence of a regeneration system and the intermediate superheating of steam that has partially passed through the turbine. Equally significant is the task of increasing the efficiency of the heat recovery boiler. To improve the reliability and efficiency of a combined-cycle gas recovery unit, it is proposed to replace the low-pressure circuit in a two-circuit recovery boiler with a two-stage intermediate superheater for the secondary superheating of steam that has been spent in the turbine's high-pressure cylinder (HPC) and low-pressure cylinder (LPC). In this configuration, the steam turbine is designed with three cylinders, and additional heat exchange surface for preheating the source (or mains) water is placed in the tail section of the recovery boiler. An analysis of the operation of the PGU-200 combined-cycle gas unit at the Syzran thermal power plant was conducted, comparing performance with and without the use of two-stage intermediate superheating of steam. Additionally, the study analyzed the impact of changes in the temperature of the outside air and the pressure of the steam spent in the turbine’s HPC and LPC and discharged to intermediate overheating on the main performance indicators of a combined-cycle gas installation. Calculations indicate that double intermediate superheating of steam can increase the power and reliability of the steam turbine by improving the efficiency and dryness of the steam exiting the turbine, while also reducing the specific consumption of conventional fuel for electricity generation by 1.16% (from 231.99 to 229.29 g/(kW·h). 

Studies of the maximum heating loads for cooling systems coatings made from natural materials have been conducted. To investigate cooling coatings based on natural materials, an experimental setup including a coating spraying tool has been developed. The conditions for spraying the material onto the heating surface, as well as the design principles for nozzles and combustion chambers, have been established. In the area of the steam-generating surface’s limiting state, shielded from burnout by cooling, these investigations are practically significant. Cooling systems with porous coatings have been developed, which make it possible to prevent the development of fractures in the coatings of chambers and nozzles through the use of thermodynamic and acoustic screens from three heating sources, as well as devices for spraying coatings with detonation high-temperature flares emanating from nozzles and combustion chambers that are cooled by capillary-porous coatings. High-speed filming and holography were used during the investigation. Heat fluxes, temperatures, flow rates, and pressures of liquid and gas flows were measured. The degree of unaccounted flow at different pressures was determined. A model of the interaction of an axisymmetric supersonic detonation jet of gases from the thermal tool normal to the coating has been constructed. Thermodynamic characteristics of oxygen-kerosene burners for the generation of supersonic high-temperature detonation flares by spraying of coatings from powders of natural materials have been established, and the granulometric composition of materials has been determined. Hydrodynamic operating modes of the burners were selected for specific heat fluxes in the range of (2·10⁶ ÷ 2·10⁷) W/m² from the jet torch into the coating. The oxidizer-to-fuel ratio varied between 0.3÷0.8; the jet torch temperature was (850÷3000)°C; the jet length was (0÷0.16) m; the jet radius was (3÷10) ·10^-3 m, and the burner axis angle to the coating was (90÷0) degrees. Capillary-porous and flow-through cooling systems showed high reliability, with the former reducing coolant consumption by up to 80 times.

The paper presents brief statistics on damage to asynchronous electric motors, which serve as drives for the main equipment of metallurgical industry enterprises and for the auxiliary systems of electric power plants. It is noted that the most frequent faults include damage to the bearing unit, stator windings and rotor bars. Among the general statistics of failures of the electrical part of asynchronous electric motors, the majority are damages associated with the development of cracks or destruction of the bars of the squirrel-cage rotor winding. Operation of asynchronous electric motors with broken bars can lead to damage to the windings and the stator magnetic circuit, resulting in complete motor failure. The mathematical model of an asynchronous electric motor presented in this work enables the simulation of asynchronous electric motors with any number of damaged bars in a squirrel-cage rotor, facilitating the analysis of transient processes in the event of broken rotor bars.

The mathematical model proposed in the work can be used to determine the efficiency of existing methods for diagnosing the state of an asynchronous electric motor by means of their mathematical modeling or to determine criteria and develop new methods for diagnosing the electrical part of an asynchronous motor based on the analysis of transient processes in the stator windings in the event of damage to one or more rotor bars and damage to the stator windings. 

An azimuth thruster (AT) is a key component of a ship’s electric propulsion system, providing both thrust and maneuverability. The AT integrates a propeller-driving motor with a steering mechanism. Grounding systems and condition monitoring are employed to protect the propeller shafts and propellers from electrochemical corrosion. Current collectors equalize the electrical potential between the shaft and the hull, preventing corrosion, but they are susceptible to vibrations generated during ship operation. These vibrations can disrupt the operation or cause failure of the current collectors.

This paper analyzes the vibration reliability of current collectors developed by JUVTEK LLC for Ats installed on high ice-class vessels. Tests conducted on a vibration test stand at NPO СKTI JSC evaluated the strength of the brush holders and the brush-shaft contact stability under various vibration levels. The research demonstrated that vibrational loads are critical to the reliable operation of the current collectors.

The tests included monitoring contact resistance under vibration at amplitudes of ±2.3 mm and ±3.3 mm in the frequency range of 2–100 Hz. The contact remained stable, but at frequencies above 130 Hz, disruptions occurred due to resonance. Critical frequencies affecting device reliability were identified. Recommendations for design improvements are proposed, including adjusting brush spring pressure and modernizing the brush holder bracket.