The issues of improving the methods for assessing and predicting the metrological serviceability of electric energy meters, characterized by the value of the inter-verification interval with a given probability, are considered. The paper presents an analysis of the generally accepted methodology for assessing inter-verification intervals of measuring instruments according to РМГ [RMG] 74–2004 from the standpoint of correctness, efficiency, and transparency. It has been established that the model of drift of metrological characteristics of a controlled batch of measuring instruments (MI) proposed in РМГ [RMG] 74–2004, as a regression model, is an interpolation model, i.e. it determines the inter-verification interval that should be in the period between the initial and current verifications, and therefore is not predictive in fact. The necessity of developing an extrapolation model of the drift of metrological characteristics and a corresponding methodology for predicting inter-verification intervals based on methods of statistical analysis of time series is substantiated. Two possible methods for determining inter-verification intervals of electricity meters have been identified: by quantitative and alternative criteria. For each method, models for extrapolating the drift of metrological characteristics of a controlled sample of measuring instruments are proposed. To predict inter-verification intervals based on a quantitative feature, a combined drift model is justified, in which the drift of the mathematical expectation of errors of metering devices in a sample is described by a linear model, and the drift of the mean square deviation of errors is described by an exponential model. To predict inter-verification intervals based on an alternative criterion, the simultaneous consideration of two drift models is justified. The drift of the mathematical expectation of errors of metering devices in the sample is described by the model of a “linear” random process, while the standard deviation of errors is constant. The drift of the standard deviation of the errors of the measuring instruments in the sample is described by the model of a “fan” random process, while the mathematical expectation of the errors is constant. The predicted value of the inbter-verification interval is defined as the smaller value of the results of the two models. The proposed approach ensures sufficient reliability of the forecast of the inter-verification interval of electricity meters based on at least two verifycations of the controlled batch of measuring instruments (primary and first periodic).

In recent years, the understanding of the efficiency of technical diagnostics of electrical equipment has increased significantly. The main reasons for this are that more than half of the equipment in operation has exhausted its estimated service life; the rate of equipment aging exceeds the rate of its renewal due to limited funds for technical maintenance, as well as due to the transition to repairs based on technical condition. High quality and timely diagnostics improve the objectivity of assessing the technical condition of high-voltage electrical equipment. All this allows planning and timely execution of necessary maintenance and repair operations, which makes the operation of electrical equipment more reliable, extends its service life, saves money, and reduces the risk of damage. One of the factors influencing the efficiency of diagnostics of the condition of electrical equipment is the noticeable shortage of qualified specialists in the field of technical diagnostics. A method for assessing the moment of occurrence of a change in the growth of concentration of gases dissolved in oil has been developed, which allows to establish the presence of a developing transformer defect, the main gases, the probable type of defect and the nature of its manifestation. A method and algorithm for predicting the time of occurrence of a faulty state of power transformers based on data of chromatographic analysis of gases (CADG) dissolved in transformer oil are proposed. The recommended algorithm for calculating the time of occurrence of a defect, the intensity and duration of the impact of operational factors on the change in the concentration of dissolved gases according to the CADG data will improve the objectivity of comparing similar indicators of gases dissolved in oil at the initial stage of wear changes. The proposed methodology for assessing the statistical significance of the considered features and their varieties allows us to ensure the objectivity of calculating these indicators. It has been established that the main indicator should be considered the calculated time interval before the defect occurs.

The choice of a grounding scheme for the screens of power cable lines is a complex engineering and economic task that affects the efficiency, safety and cost-effectiveness of the operation of electrical networks. Existing approaches are often based on individual technical or economic criteria without taking them into account comprehensively. The purpose of this work is to develop a method for selecting the optimal grounding scheme for screens based on the criterion of minimum reduced costs, taking into account technical limitations on induced voltage and line capacity. The paper examines three basic grounding schemes (one-sided, two-sided, transposition), for which capital costs, annual operating costs, induced currents and voltage on the shields, and long-term permissible cable load currents were calculated. The maximum length of a cable line with one-sided grounding is determined based on the induced voltage condition. The areas of applicability of various schemes are indicated: one-sided grounding is applicable for short lines (up to 0.5–1.5 km depending on the cross-sectional area of the conductors); two-sided grounding is optimal for lines with a small current load; transposition of screens is recommended for long lines with a relatively high current load. It has been established that the transition from double-sided grounding to single-sided grounding or transposition for 110 kV cables increases the capacity of the cable line by 1–26 % depending on the cross-sectional area of the core and screen. The development of software to automate the process of selecting the optimal grounding scheme for screens seems relevant. The practical application of the developed methodology allows optimizing technical solutions in the design of cable lines, reducing capital and operating costs of electrical networks.

The article is devoted to current issues of energy security and risk management in the nuclear energy industry of the Republic of Belarus. The authors examine the strategic importance of developing nuclear energy to ensure the country’s energy independence, and also analyze the consequences of major accidents at nuclear power plants (Three Mile Island, Chernobyl, Fukushima), emphasizing the need to improve methods for assessing and minimizing risks. Particular attention is paid to the methodology of probabilistic safety analysis (PSA), which is used to analyze the reliability of systems, including modeling emergency scenarios using fault trees. The practical application of the method is demonstrated using the example of the AAR water filtration system of a nuclear power plant: fault trees are constructed, the probability of system failure is calculated, and key vulnerabilities (pump power supply failures) are identified. A comparative analysis of risk assessment methods (adjustment of the discount rate, expert assessments, the Monte Carlo method, etc.) was conducted, and their advantages and limitations were highlighted. It is emphasized that simulation modeling and PSA provide the most comprehensive approach to risk management, combining the analysis of technological processes and the human factor. Based on the results of the study, recommendations are proposed to improve the reliability of nuclear power plant operation, including regular monitoring of equipment and improvement of safety systems.

The energy policy of the Republic of Belarus is aimed in reducing the consumption of hydrocarbon raw materials and strengthening the national energy security. The strategic aim is to maximally involve in the fuel and energy balance, in addition to nuclear energy, our own fuel and energy resources, including renewable energy sources (RES). The development of RES contributes to the decarbonization of economic activity. The resource potential for biogas production in the Republic of Belarus, taking into account the dynamics of organic raw material formation, is about 3.265 million tons of equivalent fuel per year, which is much higher than similar indicators for other local types of fuel. In the country, biogas is produced by wet and dry fermentation. Wet fermentation is used to produce biogas from organic livestock waste (secondary biomass), which contains a high moisture fraction – up to 90 %. The equipment used is bioreactors and cogeneration units. Dry fermentation is used to produce landfill gas from solid organic waste of housing and communal services, using gas piston units (organic waste degassing units). Currently, the production of biogas by wet and dry (semi-wet) fermentation is approximately 50% each. Modern co-fermentation technologies allow to model the composition of the organic waste used for preparing co-substrates. Moreover, the composition of the substrates used can be extremely diverse, without fundamental limitations. This innovative technique regulates the stability of the microbiological process, ensures uniform loading of biogas equipment during the calendar year, increases the economic efficiency of biogas plants, without high investment costs. This approach to the application of biogas technologies gives a new qualitative impetus to their development, while simultaneously reducing the volume of organic waste storage and reducing the national carbon footprint. The use of co-substrates provides technological, economic and environmental advantages, since the methane output under these conditions is quite stable and guaranteed. Currently, specific conditions have developed for the functioning of “green” energy. Taking into account the new economic conditions, it is advisable to partially reorient the economic activities of large biogas plants to the production of heat energy, the production of organic fertili-zers and other valuable products with added value.

The regularities of drying thin and thick ceramic samples and clay plates are considered, the values of the Biot heat exchange number in the process of drying ceramics and clay plates of different thicknesses are established, as well as the nature of the change in the drying temperature coefficient for its various values. An analysis of the experiment on drying of thin and thick materials showed that such division based on one Biot number is insufficient, since the Biot value depends on many factors – the drying mode, the heat transfer coefficient, the type of wet body and its coefficient of thermal conductivity of a dry body. The most significant influence on the Biot value is exerted by the complex form of the dependence of the coefficient of thermal conductivity of a wet body on moisture content and temperature. Based on the study and analysis of many sources, formulas have been established for determining the coefficients of thermal conductivity of wet bodies. For a comprehensive assessment of the possible division of materials into thin and thick, the influence of a group of heat and mass transfer similarity criteria on the temperature coefficient of drying was studied. A possible method for dividing materials into four groups based on the value of heat and mass exchange Biot numbers and the Lykov criterion is proposed. The limits of change in the Lykov criterion are established depending on the value of the Biot numbers. Calculations of the average temperature during drying of thin and thick ceramic samples and clay plates are presented using formulas and a comparison of the values with experimental data is given.