A study was conducted of electrical energy transmission through distribution electric networks of various rated voltage classes, which are on the balance of the Kostromaenergo branch of PJSC ROSSETI Center. A brief structural description of the company, its composition, as well as the characteristic features of electricity consumption is provided. Based on the publicly available initial information, an analytical assessment of emergency situations occurring in the company's electrical networks, as well as the consequences of these failures for the period 2016 2025, was performed. A quantitative analysis of emergency outages is given, as well as the volume of undersupplied electrical energy to consumers as a result of these failures. It was found that 15,555 failures occurred during the study period, resulting in more than 2,365 MWh being undersupplied. The largest number of emergency outages occurred in 2022 (almost 17% of all failures during the study period). An analysis of the main causes of the failures was performed. Five main cause groups were identified for these failures. The analysis found that more than 53% of all outages occur due to natural phenomena, which, along with significant wear of electrical grid equipment, leads to emergency damage to electrical network components. The second main cause of failures (more than 22%) is insufficient maintenance and untimely repairs of electrical equipment. General scientific methods, numerical analysis methods, and the libraries of the MATLAB graphics editor were used to visualize changes in the studied indicators. Based on the findings, recommendations were formulated for the company's management to improve power transmission reliability. The obtained research results may be of interest to the management of Kostromaenergo, other electric grid companies, as well as engineering and scientific personnel investigating power transmission reliability.

Plain bearings and their dynamic properties primarily determine the reliable operation of shaft lines in high-power turbine units, since not only disturbing hydrodynamic forces, but also damping forces are concentrated in the oil layer of the bearings. What is decisive is not the forces themselves, but the work performed by these forces over the displacements and velocities of these displacements. First of all, it is necessary to ensure the design loads on the bearings during operation, which is achieved by optimal alignment of the rotors at the half-couplings. Firstly, in the power industry, the culture of correctly determining rotor alignment at half-couplings is disappearing, and repair errors are superimposed on manufacturing imperfections. Secondly, bearings with maximum stiffness anisotropy and optimal degree of ellipticity should be used. Unfortunately, manufacturing plants often follow old books on mechanics, which propose setting a side clearance of the order of one thousandth of the diameter, and this has found its way into old repair documentation. At the same time, theory and field adjustments show that the clearance in the elliptical plain bearing of a large rotor should not be less than 0.002 of the diameter, or the relative clearance with respect to the trunnion radius should be about 0.004. The alignment of the rotors at the half-couplings must take into account the different lift of the rotor journals in adjacent bearings. The need to choose the degree of ellipticity of small-diameter bearings for high-pressure rotors of high-power turbines is especially noted.

An analysis of regulatory and technical documentation reveals that a unified industry classifier of structural element damage that could be used in the development of steam turbine diagnostic systems is currently lacking. This, in turn, may lead to a situation where diagnostic systems being developed and implemented at power plants lack uniform approaches to describing damage manifestations. The scope and methods of equipment diagnostics may also vary significantly. Therefore, the authors believe it is advisable to develop a classifier of damage to structural elements of steam turbines. An important task in creating the classifier is the selection of classification subsets that should contain information on damage, its manifestations during equipment operation, manifestations detected during equipment repair, detection (inspection) methods, causes of damage, the rate of damage development (sudden or gradual failure), the influence on the occurrence and development of other damage, and an assessment of the hazard (criticality) of the damage. Classification of damage by the types of causative impacts should cover possible types of impacts on turbine elements during operation (centrifugal forces, friction forces, vibratory impact, thermal impact, erosive impact, corrosive impact, impact loads, etc.). Classification of damage by diagnostic capabilities and methods should allow for the detection of defects during operation on running equipment (based on monitored parameters), on stopped equipment (e.g., using endoscopy methods), or during repair disassembly. Classification of damage by degree of danger should include an assessment of the damage's effect on the possibility of reliable operation of the equipment and serve as the basis for recommendations to operating personnel. The fundamental classification subset should be the classification by object, i.e., a list of damages correlated with the structural elements of the equipment.

Amid the ongoing transformation of power systems driven by increasing renewable energy integration, combined heat and power plants have become a critical flexible reserve ensuring grid stability and supply reliability. This study aims to comprehensively assess the impact of equipment technical condition on the capability of CHP plants to effectively function in the balancing electricity market. The research methodology encompassed analysis multi-year operational data analysis, expert inspections of main and auxiliary equipment, thermovision and acoustic diagnostics, and the development of a mathematical model for the equipment availability coefficient using exponential approximation methods to forecast degradation processes. Findings reveal that a substantial portion of equipment has been in operation for an extended period, resulting in reduced boiler efficiency, increased air in-leakage in the flue gas ducts, increased specific fuel consumption, and deterioration of the availability coefficient to below regulatory levels. The developed forecasting model demonstrates a consistent declining trend in the availability coefficient over the forecast horizon, creating significant risks for effective participation in the balancing market. A direct correlation between the availability coefficient and economic performance indicators has been established. The results confirm the necessity of transitioning from reactive to proactive reliability management through comprehensive equipment modernization and the implementation of digital technologies for forecasting technical condition, thereby ensuring CHP plant competitiveness and operational sustainability in market-driven power systems.

The development of additive technologies and polymer materials opens up new applications in mechanical engineering, particularly in turbine engineering. For instance, studies have already demonstrated the potential of using polyamide parts manufactured by SLS printing for low-flow turbine stages, with experimental investigations confirming their effectiveness. This manufacturing method allows the consideration of new shapes for elements of the flow part of gas turbines that cannot be produced by mechanical machining of workpieces. This article discusses a radial centripetal impeller of Leningrad Polytechnic University design, intended for use in an autonomous turbogenerator in a gas distribution line. This impeller features an adapted bandage seal designed to accommodate the specific requirements of SLS printing manufacture. The aim of this work is to demonstrate the effectiveness of the proposed seal design through a gas dynamic analysis of three stage variants: without a seal, with a bandage seal, and with a counter labyrinth on the stator. The calculation was performed at the design parameters, accounting for the circumferential periodicity of the stage in the Ansys CFX software package during the combined operation of the nozzle assembly and the impeller. The final comparison is made by calculating the adiabatic efficiency, determined from the power generated on the impeller (via torque) and the available power. Analysis of the results showed the positive effect of using this seal, especially for the variant with reciprocal labyrinth channels, indicating the feasibility of introducing this design into such machines and the need for further work to optimize the seal in terms of both gas-dynamic and strength properties.

Mathematical modeling of thermal and hydraulic conditions in individual heating substations (IHS) is a priority task for the design, adjustment, and dispatching of heat supply systems as a whole. IHSs serve as the link between heating networks and building engineering systems, so their reliability and safety largely depend on correct design decisions, which are impossible without the development of adequate mathematical models. Solutions are needed that will significantly improve the quality of heat supply regulation at IHSs. The use of a mathematical model of IHSs will also enable planning of measures for the rational use of energy resources. The reliability of IHS pipeline networks requires closer attention to design decisions. Thus, refined mathematical models of heating substations allow for both capital savings and reliable transportation of heat energy.

Objective: To develop a mathematical model of flow distribution in an individual heating substation to ensure the reliability and safety of district heating systems in real time. Methods: Computer modeling of flow distribution at individual heating substations (IHSs) with various characteristics and connection schemes to district heating networks. Results: A mathematical model of an IHS is proposed, enabling the assessment of its operational reliability through the use of computer and software technologies. Software was developed for taking measurements in real time. It is shown that regulation of heat flows does not always correspond to the actual needs of buildings, which can lead to an incorrect assessment of specific heat losses. Conclusions: The constructed mathematical model of a heating substation allows a sufficiently complete picture of the flow distribution state in an IHS to be obtained and an assessment of the reliability of heat supply to buildings and structures.

The paper describes an approach to the thermohydraulic calculation of the cooling system of a single-shaft gas turbine engine (GTE). The calculation is based on the development of a detailed one-dimensional model of the channel geometry of the cooling air supply system to the main cooled elements of a gas turbine engine. The calculation in the mathematical model is based on Kirchhoff's laws 1 and 2, with the identification of a minimum spanning tree in the form of a graph in which branches and nodes form a hydraulic network. The arrangements of cooling air supply from the axial compressor to the journal bearing, thrust bearings, and stator and rotor of the turbine are considered. A detailed one-dimensional model of the channels of the cooling air supply system has been developed, including one-dimensional models of the cooling air channels in the nozzle and rotor blades of the turbine. As a result, the distribution of pressures and flow rates in the channels of the cooling system was obtained. One-dimensional computational models of the cooling channels of the nozzle and rotor blades of the turbine are verified based on cold flow tests on a flow capacity test bench. One-dimensional (at the mean diameter) and three-dimensional (CFD) gas-dynamic calculations of the turbine were performed to determine the distribution of gas flow parameters across the turbine blade rows. The results of these calculations were used as boundary conditions for the mathematical model of the cooling system channels. A thermohydraulic calculation of the regenerative cooling system of the combustor liner in a one-dimensional formulation was also performed. As a result of the calculation, the total pressure losses and wall temperature distribution of the liner were determined along the cooling air flow.

Based on the developed one-dimensional model of the gas turbine engine cooling system, the hydrodynamic characteristics were determined; the velocities, flow rates, pressures and temperatures of the coolant in all channels of the cooling passage were determined.

The use of hybrid renewable energy systems (HRES) based on diesel power plants with integration of renewable energy sources (RES) improves the efficiency of electricity supply to decentralized consumers in conditions of expensive fuel delivery. The study aims to develop methods for accounting for the reliability of backup diesel generator sets (DGS) during multi-criteria optimization of HRES equipment composition, since their failure during periods of low RES generation and discharged batteries becomes the primary cause of electricity undersupply. A two-level approach is used for multi-criteria optimization of HRES equipment composition. At the upper level, a set of Pareto-optimal HRES configurations is formed; at the lower level, hourly simulation of HRES operation is performed for a detailed assessment of each option according to the criteria of economic and environmental efficiency, and reliability of power supply. Two approaches to accounting for the reliability criterion are proposed: a simulation-dynamic approach, which models DGS failures as events in time using the Weibull distribution, with consequences of these failures assessed using short-term simulation and the Monte Carlo method, and a combinatorial-probabilistic approach based on the binomial distribution law for analyzing all possible static states of a group of DGS. The impact of the decision-maker's preference structure on the equipment composition is demonstrated through a case study of selecting an HRES for the village of Kovran in Kamchatka Krai. The simulation-dynamic approach provides a more accurate assessment of the risk of long power supply interruptions by accounting for the temporal correlation between DGS failures and restorations. The developed approaches make it possible to substantiate the appropriate composition and capacity of HRES equipment, including the number and unit capacity of DGS, taking into account the stochastic nature of electricity consumption and RES generation, and equipment failure.

A comprehensive approach to solving the problem of accidents and leaks in pipeline and boiler systems is considered, combining risk forecasting methods with modern computer vision algorithms for video stream analysis. The relevance of the study is due to the high accident rate of engineering networks, significant economic losses, and environmental risks associated with delayed leak detection. The aim of the work is to develop and experimentally evaluate a hybrid method for accident and leak prevention based on risk forecasting and real-time neural network analysis of video data. Within the framework of the study, convolutional neural network architectures used for video stream processing are analyzed, and the limitations of traditional monitoring methods based on point pressure and flow sensors are shown. Based on historical, operational, and telemetry data, a predictive risk table is formed determining the priority of monitoring potentially hazardous sections of engineering systems. For sections with elevated risk levels, a hybrid neural network model is applied, including a spatiotemporal anomaly detection module and a semantic segmentation module for identifying visual indicators of leaks. The results of the experimental study, conducted on a dataset of 120 hours of video recordings from 20 industrial facilities, demonstrate detection accuracy of up to 94.7%, an F1-score of 92.9%, and an average response time of approximately 22 seconds. In conclusion it is noted that the proposed solution allows a transition from a reactive to a proactive model of engineering systems, enhances industrial and environmental safety, and can be integrated with existing monitoring means to expand the monitoring zone.