The paper proposes new knowledge in cable engineering by studying the operation of up-to-date high-voltage cable line under the non-nominal and emergency conditions to ensure its reliability and service life. The temperature conditions for operation of an underground 110 kV three-phase cable line with cross-linked polyethylene insulated cables in the nominal and emergency modes of short circuit and short-term overload of cables are studied by computer finite-element method. A number of practically important problems for designing such cable lines are solved. In particular, the computation of the three-phase short-circuit mode in the line is carried out taking into account its reconnection after short circuit with certain delay time (5, 10 or 15 s) and at different loads (50% and 100% of the nominal current). The results obtained allow determining the permissible operating time for the line operation with the temperature of the cable conductor not higher than the permissible limiting value. The nature of the increase in the temperature of the cables within the time of different current overloads varying from 120% to 200% is investigated. The results give a possibility to determine the permissible operating time of the line when the temperature of the cable conductor does not exceed 130°С. In the case of the double-circuit cable line, the computational results for non-stationary thermal process under emergency condition of one circuit failure and the transmission of double power through the other circuit are presented. It is shown that the limiting conductor temperature of 130°C is reached after 1.3 hours of line operation. The problems solved in the paper answer the questions regarding the thermal stability of the high-voltage cable line in emergency modes and are of interest to designers of such lines as well as organizations responsible for their safe operation and power companies for more efficient use of cable lines. References 36, figures 5, tables 2.
A scheme of a reverberatory furnace for melting aluminum waste with a cylindrical electrovortex chamber, in which a vortex (rotating) flow of liquid metal is created using a curve inductor, is presented. This chamber is connected to the melting bath of the furnace by two channels and performs two functions: it stirs the molten metal in the furnace bath and immerses crushed metal scrap into the melt to protect the metal from oxidation with its subsequent transportation to the melting bath. For such a system, a mathematical model has been formulated to study electromagnetic and hydrodynamic processes in it, taking into account the deformation of the free surface (meniscus) of the liquid metal. The model consists of two parts - systems of differential equations that describe the specified processes. The deformation of the free surface was determined by the moving grid method. The study was conducted for different values of the height of the metal in the furnace bath, which varied from the initial value of 0.2 m to the full height of the bath of 0.5 m, which simulated the process of metal deposition in the furnace during operation. Two options for the location of the inductor along the height of the vortex chamber were considered: one – in its lower part, and the second – in the middle relative to the height of the metal of the fully deposited furnace bath. As a result of the simulation, the velocity distributions of the liquid metal in the furnace bath and the vortex chamber were obtained, the deformation of the upper free surface of the metal in the chamber and the average level of metal in it relative to the level of metal in the melting bath were determined. For different fillings of the furnace bath, the trajectories of the movement of the liquid metal in the electrovortex chamber were determined. References 10, figures 8.
This article presents an approach for the fast online identification of weak interfaces in large transmission power systems (PS). Ensuring the stability of a PS is a critical challenge, especially due to the increasing complexity of interconnections and the growing demand for efficient energy transmission. One of the key factors affecting system stability is the reliable opera-tion of critical interfaces, which can be compromised due to excessive or unforeseen power flows. An in-depth analysis of weak interface identification are provided. The specific methodology that enables real-time monitoring and detection of weak interfaces, ensuring that power system operators can take timely corrective actions has been devel-oped. The proposed ap-proach is based on analysing electrical distances, load distributions, and system stress points, allowing for improved control over power flow stability. Additionally, the study highlights the impact of weak interfaces on system reliability, emphasizing their role in preventing cascading failures. The findings contribute to the field of power system management, offering practi-cal solutions for improving the reliability and operational efficiency of large-scale transmission grids. Future research direc-tions may include further refinements of weak interface detection algorithms and the integration of artificial intelligence-based predictive models for enhanced grid stability assessment. References 6, tables 2, figures 5.
A three-dimensional mathematical model of interconnected electromagnetic, hydrodynamic and thermal processes has been developed for an electromagnetic doser with induction current supply to the channel. By comparing with experimental data obtained for a prototype of a MHD installation for the production of lead pellets, a mathematical model of electromagnetic processes in the dosing unit was validated. Using mathematical modeling, physical processes in the system " dosing unit inductor - short-circuited channel with liquid metal - dosing unit magnet" were investigated. The electromagnetic and energy parameters of the dosing unit were determined, and the features of the thermal state of the liquid metal in its channel were established. Recommendations were formulated to reduce metal overheating in the channel during feeder operation. References 9, figures 10.
In this paper for the control system of a doubly fed machine (DFM) previously proposed by the authors, a discrete extended Kalman observer is synthesized in order to develop a sensorless relay – vector control system for the DFM with two extremum regulation loops. The Kalman observer is of relatively high order because in addition to identifying the reference stator flux linkage vector and rotor angular speed – which is sufficient for induction machines (IM) with a squirrel-cage rotor controlled through the stator – this observer also estimates the rotor position angle and the external disturbance, represented by the static load torque applied to the DFM shaft. A second feature of the proposed Kalman observer lies in the inclusion of the stator voltage vector projections onto the orthogonal rotor-related axes within the observer’s state matrix. Thus, these projec-tions are computed as state variables rather than external inputs, with the only external control actions being the voltages applied to the rotor circuit of the DFM. In the rotor and stator reactive power channels optimization of the DFM’s energy performance is achieved under steady-state operating conditions. The standard Kalman filtering algorithm is applied here to a deterministic system to enable the identification of all necessary process variables within a single observer. The Kalman observer operates stably because the measured rotor currents of the DFM, from whose estimation errors the corrective feed-backs are formed, contain high-frequency pulsations under direct relay control; these pulsations are perceived by the ob-server as random measurement noise. Through mathematical modeling of a DFM with a fan-type mechanical load on the shaft, the high quality of speed regulation and the achievement of extremal energy performance values in steady state have been theoretically confirmed for the sensorless control system based on the proposed Kalman observer. References 21, figure 1.
The work is devoted to the study of processes of conversion of low-potential thermal energy into electrical energy using a solid-state heat engine based on shape memory alloys (SMA). The relevance of the topic is due to significant losses of low-temperature heat in industrial and energy systems and the need to improve the energy efficiency of autonomous power sources. NiTi alloy springs are used as drive elements, which implement reversible austenite-martensite phase transformations and ensure the direct conversion of thermal energy into mechanical work. The aim of the work is to develop a physically based mathematical and numerical model of a heat engine, taking into account cyclic heating and cooling, thermomechanical hysteresis, the inertia of the mechanical system and electromechanical interaction with the generator, as well as to evaluate the energy characteristics of the power generation plant. A three-level approach to modelling is proposed, including an analytical quasi-static model for engineering estimates, a quasi-stationary moment balance model for determining steady states, and a complete dynamic system of differential equations that takes into account non-stationary heat transfer, phase kinetics, and inertial effects. Numerical integration was performed in Py-thon using fourth- and fifth-order Runge–Kutta methods. The simulation results confirmed the adequacy of the pro-posed model and showed the formation of self-stabilised rotation modes and power saturation. It was found that simpli-fied approaches provide a conservative estimate of energy performance, while the full dynamic model more accurately reproduces transient processes and real operating characteristics; the discrepancy between the models does not exceed 15–20%. The influence of the bilateral shape memory effect, which in the temperature range of 70–80 °C can increase electrical power by 20–30 %, was investigated. The expediency of partial immersion of SMA elements in the coolant to ensure stable cyclic heat exchange was demonstrated. The results obtained confirm the prospects of using SMA engines for the utilisation of low-potential heat and the creation of compact autonomous systems for small-scale electricity generation. References 20, figures 7.
Using the example of modeling the longitudinal feed of the working body (WB) of a precision metal-cutting machine tool model 24K70AF4 during the cutting process (PC), the possibility of a significant comparative increase in the effi-ciency of electromechanical energy conversion in the electric drive (ED) of the machine tool feed is proven by using the proposed iterative two-channel ED with a conditional PC compensator (PCCC) instead of the traditional single-channel ED. This allows you to significantly improve the quality of WB feed control and, as a result, significantly in-crease the potential competitiveness of the output of heavy metal-cutting machine. Detailed simulation computer models of the compared two-channel and single-channel EDs have been constructed, which contain the corresponding dynamic models of the PC and the PCCC compensators and take into account the influence of nonlinear friction forces in the load on the dynamics of the drives. Indicative comparative electrodynamic characteristics of the systems were obtained. Significant (multiple times) potential advantages in the speed and accuracy of feed control of a dual-channel ED have been established. The modeling results showed for the first time that the accuracy of the feed of the WB in the metal-working mode can be significantly increased not only due to the iterative structure of the two-channel control system of the ED, but also additionally by building an electronic model of the PC itself and including this model together with the PCCC in the control loop of the feed ED. References 13, Tables 2, Figures 7.
It is proposed to use a digital notch filter to form a reference compensation signal for a parallel single-phase active current harmonic filter, which is simple and flexible compared to known methods in its technical implementation. Mathematical modelling of the digital filter was performed in Matlab, and the results of the practical implementation of the filter-compensating device are presented, confirming the main theoretical results of the study. References 8, fig. 6.
Residual tensile stresses in welded joints negatively affect the fatigue strength, corrosion resistance, and dimensional accuracy of metal structures. Treatment with a pulsed electromagnetic field allows for optimization of the stress state and metal microstructure of the welded joints, thereby contributing to enhanced reliability and longevity of structures, and consequently extending their operational lifespan. The aim of this work is to determine, through mathematical modeling, the distribution of the electromagnetic field and magnetic forces within the volume of a weld seam in an aluminum alloy plate with isotropic parameters during its treatment by the magnetic field of an inductor with pulsed current. A three-dimensional mathematical model of the induction system was developed to calculate the electromagnetic field equations. The calculation of pulsed current in the inductor winding conductors along with the electromagnetic field of the entire induction system was performed using electrical circuit equations based on Kirchhoff's second law and electromagnetic field equations based on Maxwell's equation system. A comparison of magnetic forces, field strength, and eddy current density in the weld seam area was conducted for plates with thicknesses of 6 mm and 3 mm. The 6 mm plate can be interpreted as two 3 mm plates, one with a weld seam and the other acting as a screen, which allowed investigation of such screening effect on force and current distribution. A study was conducted of the vector quantities of field strength, current density, and magnetic forces in the volume of the weld seam area being treated, as a function of time. Based on the developed methodology, experimental studies were performed to assess the impact of magneto-pulse treatment on residual welding stresses and the metal microstructure of welded joints made of AMg6 aluminum alloy. It was demonstrated that treating the weld metal during or after welding contributes to reducing residual tensile stresses and dispersing the microstructure of the weld metal. References 16, figures 11, tables 2.
The study addresses the problem of forecasting the electrical load of an energy facility under conditions of high consumption variability. A comparative analysis of forecasting model performance is carried out for horizons of 1 and 24 hours. For the first case, the SSA, Holt–Winters methods, as well as LSTM and Transformer neural network architectures, were examined. For the second case, models with prior decomposition based on the Hilbert–Huang transform (model M1) and polynomial regression (model M2) were additionally considered. The quality of the models was evaluated using four metrics: mean error (ME), mean absolute error (MAE), root mean square error (RMSE), and mean absolute percentage error (MAPE). The results show that, for the 1-hour horizon, the Transformer model achieved the lowest MAE and MAPE values (2.54 kW and 4.95%, respectively), indicating high accuracy. LSTM demonstrated similar accuracy, with the smallest forecast bias. The SSA and Holt–Winters models were significantly less accurate, though they showed better stability in avoiding large errors. For the 24-hour horizon, the Transformer model achieved the best results in both accuracy and stability (MAE = 3.61 kW). The M1 model, based on the Hilbert–Huang transform, showed balanced performance across all metrics, while LSTM achieved high absolute accuracy. Additional analysis of mean error distribution frequencies showed that Transformer and LSTM provide high densities of accurate forecasts within narrow error intervals, unlike SSA and Holt–Winters, which are characterized by systematic biases. The conclusions have practical significance for energy management tasks in microgrid conditions, particularly for operational load planning, loss reduction, and optimization of backup power sources. References 16, figures 2, tables 3.
Vector-controlled induction electrical drives are one of the main types of modern AC electrical drives due to the well-known advantages of induction motors. Recent years have been marked by a renewed interest in the further development of IM control methods due to the existing limitations on the use of rare-earth materials in the manufacturing of permanent magnets synchronous motors. A full-scale study of the dynamic and static characteristics of induction motors field-oriented control systems, as well as their comparative analysis with existing analogues, is an important and mandatory stage in the modern AC electrical drives design. Since IM field-oriented control systems are essentially nonlinear multi-dimensional systems with a partially measured state-space vector, there are no general standard methods for design and analysis, including the dynamic and static characteristics investigation under parametric disturbances. Control algorithms are designed based on various conceptual approaches, and the same applies to the research methods of the closed-loop systems robustness properties. The literature offers a large number of both theoretically proven and practical solutions, which use different sets of tests and different criteria for evaluating effectiveness, making their comparative analysis virtually impossible. A systematic approach to comparative testing and analysis of control quality and robustness indicators of field-oriented control systems under disturbance conditions in the form of active rotor resistance variations is proposed. It can be considered as a component of a general testing platform for vector-controlled electrical drives. A comparative study of a class of systems with indirect and direct field orientation, based on the concept of improved (robustified) vector control of IM drives, demonstrates a significant increase in the robustness properties of the flux vector regulation, both in terms of amplitude and angular position. In turn, it compensates for the negative impact of active rotor resistance variations on dynamic control processes and the efficiency of electromechanical energy conversion processes. References 21, figures 6.
A method for reducing power losses in the diodes of the output push-pull high-frequency rectifier of a switching DC power converter during their parallel operation is proposed. The use of the proposed method in a switching DC power converter based on high-frequency magnetic amplifiers is reasoned theoretically and investigated experimentally. The results of experimental research and the examples of the proposed method implementation for the output high-frequency rectifier in semiconductor power converters for a wide variety of applications are presented. In particular, the uniform distribution of current between the diodes switched on for parallel operation is proven, and it is shown that when using the proposed method at the 30 A output current and 50 kHz operating frequency, the diode overlap time in the push-pull circuit at the beginning of each half-cycle has decreased by several times (from 4μs to 1μs). References 21, figures 6.
The paper examines the theoretical and practical aspects of rod-structured matrix filters with double-periodic ar-rangement of elements, commonly employed in high-gradient magnetic separation technologies, with particular atten-tion to comparative analysis and matrix optimization. An increasing number of studies on the development of highly efficient and lightweight high-gradient systems with reduced energy consumption is noted. The aim of the article is to substantiate and develop a method for optimizing matrix parameters according to the criterion of minimizing the spe-cific energy of the magnetic field in the extraction zone, based on the calculation of local and effective force and energy characteristics of the magnetic field. The efficiency and universality of the proposed method are confirmed by a series of computational experiments with comprehensive consideration of factors influencing the quality of the final product. Specific examples demonstrate that the formation of an array of constant-magnetic-force lines (isodynes) serves as the principal means of investigating the extraction capacity of a matrix. A simple and effective approach to visualizing potential extraction zones is proposed in order to simplify the calculation of their areas. The application of the integral equation method with respect to the magnetization vector of matrix elements is substantiated, as it ensures maximum universality, simplicity, and accuracy in the analysis of complex double-periodic structures. The necessity of determin-ing not only local but also effective magnetic field parameters in energy optimization is demonstrated. The dependence of matrix efficiency on the magnetic field intensity, rod shape and concentration, and their mutual arrangement is illus-trated. The developed method is emphasized as being of a theoretical nature and is proposed as an effective comple-ment to experimental analysis methods. It is shown that practical implementation of the method requires consideration of technological characteristics and constraints. Its value lies in the completeness and reliability of the additional in-formation obtained on the basis of operational experience and high-quality experimental studies. References 20, figures 3, table 1.
The paper considers the energy strategy for implementing reliable uninterrupted power supply of critically important technological equipment of an industrial enterprise of Ukraine in modern military conditions by creating its industrial microgrid and solving scientific and technical problems regarding the optimal use of its elements and reducing overall costs, which take into account the cost of electricity received from each source of the microgrid. To solve this problem, a computer modeling method was used. It is shown that for modeling long-term (24-hour) electromagnetic processes in a microgrid, it is advisable to use a generalized method for calculating complex currents, which is usually used to calculate sinusoidal current electrical circuits. However, in this task, it is also necessary to take into account that in a microgrid, not only the amplitudes of currents change slowly over time, but also their phases, so it is advisable to use the dynamic phasor method, according to which the calculation is performed simultaneously in the complex and time planes. To implement this method in the Matlab/Simulink package, it is necessary to develop appropriate system models for all power sources and time-varying loads. The paper presents the results of calculating long-term (over a day) active and reactive power flows in the microgrid of a typical industrial enterprise, which contains such power sources as a solar power plant and a cogeneration unit, which can operate both in parallel with the external power grid and without it. The daily costs of electricity obtained from each power source are determined. In order to identify ways to reduce the total cost of electricity, the paper considers various scenarios for connecting power sources and determines their impact on the total daily costs of the enterprise. References 32, figures 8, table 1.
The article presents the results of the optimization-based parametric synthesis of an induction motor with a solid core for a submersible borehole pump operating at doubled supply frequency. The proposed synthesis methodology is based on a weakly coupled circuit-field mathematical model with iterative parameterization of field analysis results. This approach makes it possible to account for nonlinear magnetic properties, rotor-induced currents, additional losses in the solid ferromagnetic rotor, and the interaction of all elements of the electromechanical system. According to the criterion of maximum efficiency, the optimal values of the variable design parameters of the induction motor with a solid core for the submersible borehole pump were determined, taking into account the load magnitude at supply frequencies of 50 and 100 Hz. The results demonstrate a significant improvement in system performance: a 2.2-fold increase in water lifting capacity, a 4% increase in motor efficiency, a 1.9-fold reduction in the payback period of the borehole, and a threefold reduction in the number of impellers in the pump. Design solutions are substantiated for the induction motor with a solid rotor-shaft and a dismountable stator made of powder material with closed slots, which contribute to reducing copper, steel, and fluid losses. The proposed technical solutions lay the groundwork for designing optimized electromechanical systems for submersible borehole pumps with improved capital and operational cost indicators. References 20, figures 3, tables 2.
The publication is devoted to the description of the mathematical model for solving the problem of planning schedules of purchase and sale of electric energy by a prosumer. The main goal of optimization is to maximize the benefit as the difference between revenues from the sale of electric energy and costs for the purchase of electric energy. The objective function and the system of equations of electric energy balances are given. Models for controlling the directions of energy flows in individual nodes of the local electric energy system of a prosumer are formalized. The mathematical model for controlling the level of filling of the energy storage unit as the main means of balancing energy flows in the microgrid is detailed. The features of the formation of optimal schedules of purchase/sale of electric energy, as well as schedules for regulating the modes of the energy storage unit under conditions of different volumes of electric energy release from the source of unregulated generation are investigated. References 19, figures 3.
Залишкові напруження розтягу, що є у зварних з’єднаннях, негативно впливають на втомну міцність, корозійну стійкість та точність геометричних параметрів металевих конструкцій. Обробка імпульсним електромагнітним полем дає змогу оптимізувати напружений стан та структуру металу зварного з’єднання. Це сприяє підвищенню надійності та довговічності конструкцій і, як наслідок, подовженню їх експлуатаційного ресурсу. Метою роботи є встановлення за допомогою математичного моделювання розподілу електромагнітного поля і магнітних сил в об’ємі зварного шва у пластині зі сплаву алюмінію з ізотропними параметрами під час його оброблення магнітним полем індуктора з імпульсним струмом. Розроблено тривимірну математичну модель індукційної системи для розрахунку рівняння електромагнітного поля. Виконано розрахунок імпульсного струму в провідниках обмотки індуктора разом з електромагнітним полем всієї індукційної системи, використовуючи рівняння електричного кола за другим законом Кірхгофа та рівняння електромагнітного поля на основі системи рівнянь Максвелла. Проведено порівняння магнітних сил, напруженості поля та густини вихрових струмів у області зварного шва для пластин товщиною 6 мм і 3 мм. Пластина товщиною 6 мм може бути інтерпретована як дві пластини по 3 мм, одна з яких має зварний шов, а інша виконує роль екрану, що дало можливість дослідити вплив такого екранування на розподіл сил і струмів. Виконано дослідження векторних величин напруженості поля, густини струму та магнітних сил в об'ємі ділянки зварного шва, яка піддається обробці, залежно від часу. На базі розробленої методики проведено експериментальні дослідження впливу магніто-імпульсного оброблення на залишкові зварювальні напруження і структуру металу зварних з’єднань із алюмінієвого сплаву АМг6. Доведено, що обробка металу шва в процесі або після зварювання сприяє зниженню залишкових напружень розтягу та диспергуванню структури металу зварного шва. Бібіл. 16, рис. 11, табл. 2.
Сформульовано, обгрунтовано та досліджено метод зменшення втрат потужності в діодах вихідного двотактного високочастотного випрямляча імпульсного стабілізатора постійної напруги за їхньої паралельній роботі. Теоретично обґрунтовано та експериментально досліджено використання цього методу в імпульсному стабілізаторі постійної напруги на основі високочастотних магнітних підсилювачів. Наведено результати експериментальних досліджень та приклади впровадження методу виконання вихідного високочастотного випрямляча в напівпровідникових перетворювачах електроенергії для найрізноманітніших замовників. Зокрема доведено рівномірний розподіл струму між діодами ввімкненими на паралельну роботу і показано, що у разі використання даного методу за вихідного струму перетворювача на рівні 30 А на робочій частоті 50 кГц час перекриття діодів в двотактній схемі на початку кожного півперіоду зменшився в кілька разів (з 4 мкс до 1 мкс). Бібл. 21, рис. 6.
Представлено результати оптимізаційного параметричного синтезу асинхронного двигуна з суцільним осердям зануреного свердловинного насосу за подвоєної частоти живлення. Запропонована методологія синтезу, що базується на слабкозв’язаній коло‑польовій математичній моделі з ітераційною параметризацією результатів польового аналізу, яка дає змогу врахувати нелінійні магнітні властивості, наведені струми в роторі, додаткові втрати в масивному ферромагнітному роторі, взаємодію усіх елементів електромеханічної системи. За критерієм максимуму ККД асинхронного двигуна з суцільним осердям зануреного свердловинного насосу визначено оптимальні значення варіюємих конструктивних параметрів з урахуванням величини навантаження за частоти живлення 50 і 100 Гц. Результати дослідження свідчать про суттєве покращення ефективності системи: збільшення продуктивності водопідйому у 2,2 раза, підвищення ККД двигуна на 4 %, скорочення терміну окупності свердловини у 1,9 раза та зменшення кількості робочих коліс насоса у 3 рази. Обґрунтовано конструктивні рішення для АД із суцільним масивним ротором‑валом та розбірним статором з порошкового матеріалу і закритими пазами, що сприяють зниженню втрат у міді, сталі та рідині. Запропоновані технічні рішення створюють передумови для проєктування оптимізованих ЕМС занурених свердловинних насосів із покращеними показниками капітальних та експлуатаційних витрат. Бібл. 20, рис. 3, табл. 2.
У роботі розглянуто теоретичні та практичні аспекти поширених у технологіях високоградієнтної магнітної сепарації магнітних (матричних) фільтрів (МФ) стрижневої структури з двоякоперіодичним розташуванням елементів. Особливу увагу приділено порівняльному аналізу та оптимізації МФ. Відзначається зростання кількості досліджень з розробки високоефективних і легких високоградієнтних систем зі зменшеним енергоспоживанням. Мета роботи – обґрунтувати та розробити метод оптимізації параметрів МФ за критерієм мінімуму питомої енергії магнітного поля в зоні вилучення на основі розрахунку локальних і ефективних силових та енергетичних характеристик магнітного поля. Ефективність розробленого методу підтверджено серією обчислювальних експериментів з комплексним урахуванням ряду базових факторів впливу на якість кінцевого продукту. На конкретних прикладах доведено, що формування масиву ліній постійного значення магнітних сил (ізодин) є основним засобом дослідження вилучальної здатності МФ. Запропоновано простий та ефективний спосіб візуалізації потенційних зон вилучення задля спрощення розрахунку їхніх площ. Обґрунтовано використання методу інтегральних рівнянь відносно вектора намагніченості елементів МФ, що забезпечує найбільшу універсальність, простоту і точність під час аналізу складних двоякоперіодичних структур. Доведено необхідність визначення не лише локальних, а й ефективних параметрів магнітного поля під час реалізації енергетичної оптимізації. Проілюстровано залежність ефективності МФ від інтенсивності магнітного поля, форми і концентрації стрижнів, їхнього взаємного розташування. Відзначено теоретичний характер розробленого методу, який пропонується розглядати як ефективне доповнення до експериментальних методів аналізу. Доведено, що задля практичної реалізації методу необхідно враховувати технологічні характеристики та обмеження. Його цінність забезпечується повнотою і достовірністю додаткової інформації, отриманої на основі досвіду експлуатації та якісних експериментальних досліджень. Бібл. 20, рис. 3, табл. 1.
