THE PURPOSE. Adapt the method of measuring the propagation of Lamb waves in thin two-layer plates to the study of the dependence of the phase velocity on the technical condition of pipelines with a protective outer coating. To perform a modification of the numerical-analytical algorithm for measuring the thickness of the coating and areas of non-adhesion of materials in thin two-layer plates for vibroacoustic diagnostics of technical pipelines. To investigate the propagation of a symmetric Lamb wave in a steel pipeline with a protective outer coating. METHODS. To solve the problem of localizing damage to technical pipelines, traditional methods of non-destructive testing based on vibroacoustic diagnostics are considered. RESULTS. Work on the construction of a mathematical model of the dependence of the propagation of the phase velocity of the Lamb wave on the thickness of the object under study has been carried out. The numerical analysis of the measurements was carried out using the example of thin two-layer segments of pipelines. The presence of changes in the thickness of the pipeline is taken as the effect of material defects on the propagation parameters of the Lamb wave mode. CONCLUSION. A numerical-analytical method for calculating the propagation of a symmetric Lamb wave mode in a thin segment is presented. The dependence of the propagation velocity of Lamb waves on the segment thickness is demonstrated. Based on the described technique, it seems possible to estimate not only the thickness of the segment and the area of non-adhesion of the layers, but also the total area of the defective area. This will allow in the future to record the relative changes in the thickness of the walls of pipelines to determine changes in the physical properties of the material or the presence of a defect.

THE PURPOSE. The presented work aims to analyze the realities and prospects for the use of working media in the production of biodiesel fuel, including the supercritical fluid state. METHODS. Methods for obtaining biodiesel fuel are considered, including the method of transesterification, as the most common, as well as methods of pyrolysis and the combined process of hydrolysis and esterification. RESULTS. Traditional (industrially used methods for producing biodiesel fuel), as well as methods involving supercritical fluid media at their core, are considered. Along with a description of the state of affairs on the issues under discussion in the world, the results of our own research carried out by the team of authors of this article are also presented. Attention is drawn to the prospects of ultrasonic emulsification of the reaction mixture and the use of heterogeneous catalysts in order to mitigate supercritical fluid conditions for the process of obtaining biodiesel fuel and save energy. The conditions for obtaining biodiesel fuel without free glycerol and converting it into a fuel component are also discussed. CONCLUSION. Transesterification carried out under supercritical fluid conditions provides significant advantages over the traditional process and, especially in terms of the possibility of using a variety of raw materials, including low-quality ones, facilitates the procedure for isolating the final product and, finally, makes it possible to switch from relatively small-scale implementations with batch reactors to high-performance plants with flow reactors.

TARGET. The purpose of this work is to develop a method for diagnosing the equipment of sucker-rod pumping units (SRPU) during operation by spectral analysis of the wattmetergram array signal. A wattmetering module is used as a measuring element, the developed software in the MatLab software package serves as a signal processing tool. The amplitude spectra of the object under study, constructed from an array of wattmetrograms by fast Fourier transform, in the MatLab software environment, are used to analyze the technical condition of the SRPU.
METHODS. The method of wattmetering and spectral analysis of the signal of wattmetergram arrays makes it possible to control the SRPU during its operation under voltage. This control method is characterized by high accuracy, sensitivity to damage formation and allows the use of computer technologies for signal processing and analysis in order to diagnose devices. RESULTS. The method of spectral analysis is fully disclosed. The concept of spectrum and its construction is considered. The method of wattmetry is disclosed, as well as the principle of operation and the main characteristics of the wattmetry sensor. The removal and evaluation of experimental data from the operating SRPU during its operation was carried out. A wattmetrogram is constructed and a spectrum is constructed from the signal data array. The wattmetrogram of the SRPU with complicated working conditions, in which foaming was observed, showed a jump in the electrical load at the upper point of the balancer position. Spectral analysis showed an increase in amplitudes at certain frequencies, which may indicate the presence of oil foaming in the pump cylinder.
CONCLUSION. This method of spectral analysis of the wattmetrogram signal with the help of the MatLab program makes it possible to identify mechanical and chemical defects of the SRPU according to the amplitude-frequency characteristics of the wattmetrogram parameters.

PURPOSE. To develop a differential parametric inductive transducer of vibration values into an electrical signal, which is a vibration displacement sensor (DV) with a new principle of operation. Theoretically substantiate the performance of the proposed DV. To develop a new system for vibroacoustic monitoring of the technical condition of overhead power transmission line (TL) supports using the proposed DV. METHODS. When solving this goal, the theory of parametric transducers and the main provisions of the theory of vibration diagnostics were used. RESULTS. The design feature of the developed DV is the absence of an excitation coil, and its functional elements form a full-fledged measuring bridge, the arms of which include interturn capacitances of the windings of the first and second measuring coils, as well as capacitances formed by a metal cylindrical electrode with a coaxially located inside it ferromagnetic rod and the first lower rows of wire windings of the measuring coils. The bridge circuit operates in a resonant mode, which ensures the high sensitivity of the proposed sensor, and the quadrature conversion of the information signal provides the necessary level of noise immunity. The received signal is a functional dependence of the output voltage of the measuring bridge on the magnitude of external vibrations, the characteristics of the temporary realizations of which reflect the degradation processes occurring in the power transmission line supports. CONCLUSION. The proposed system for monitoring the integrity of power transmission line supports is actually a distributed real-time sensor network that implements PLC technology. The DV of each sensor module registers microvibrations of the structural elements of the corresponding power transmission line support, caused by natural disturbing factors during their operation, and converts them into an electrical information signal, which forms the basis of monitoring information about the current state of the power transmission line support structural elements.

THE PURPOSE. Harmonic resonance has become a serious problem of shunt capacitor banks for reactive power and voltage support. Effective solution to damp out the capacitor-caused resonance is the series connection of capacitor bank with harmonic damping network. This paper presents a general design method for shunt capacitive compensating units with damping networks. The damping unit is designed in such a way that it provides harmonic filtering and adequate damping of the transient oscillations. METHODS. The method was developed for designing damping network in the form of ladder LC-two-port. The design is based on minimization of voltage total harmonic distortion (VTHD) in the point of common coupling. Normalized element parameters of the different order damping networks have been determined. RESULTS. Comparative study of transient behavior of shunt capacitive compensating units with damping networks illustrate the effectiveness of the propose structure. It has been observed that there is a significant reduction of transient overvoltage in switching of capacitor bank with damping network. CONCLUSION. This paper presents a new design method for capacitive compensating units with damping networks for industrial power systems with powerful nonlinear loads. The paper illustrates superior performance characteristics of proposed shunt capacitive compensating units by computer simulations.

THE PURPOSE. To analyze scientific and technical information and practical experience of the functioning of autonomous electrical complexes with asynchronous electric motors in the composition. To develop a mathematical model of an autonomous electrical complex of a drilling rig with the presence of an active rectifier, an inverter with pulse-width control signals, as well as combined backup power sources – a battery and a diesel generator set. To establish the influence and expediency of using a combined composition of backup power sources on reliable operation and the possibility of overcoming the voltage failure caused by a sharp increase in load in the steady-state operation of an autonomous electrical complex. METHODS. For the successful fulfillment of the tasks set, this study applied the methods of mathematical modeling of power supply systems, methods of simulation modeling, the theories of automatic control, automated electric drive, and electrical circuits. Also, in research used the MATLAB software package with the built-in Simulink graphic modeling environment to create a mathematical computer model and to process the data obtained analytically. RESULTS. The article describes the relevance of the research topic. The study provides criteria for choosing the composition of backup power sources. Mathematical and simulation models of an autonomous ETC have been developed according to the “power source-frequency converter-industrial load” scheme, taking into account the influence of a non-linear load on the specified power quality indicators. The study has developed the structure of an autonomous electrical complex with a combined composition of backup power sources, which allows to overcome the voltage drop in the network caused by a sharp load surge, while ensuring the required indicators of electricity quality. CONCLUSIONS. The use of a rechargeable battery makes it possible to increase the overload threshold of the main diesel generator set regulated by GOST R 53987-2010 from 30% to 60%, as well as to ensure reliable connection of a backup diesel generator set without interrupting technological processes.

THE PURPOSE. Consider the use of automatic systems for controlling reduced sources of electricity in local electrical networks. Explore the possibilities of expanding the functions of such automatic control systems to improve the quality of electricity in terms of eliminating power exchange and common-mode oscillations. METHODS. Studies of diesel generator units operating in parallel in local electrical networks were carried out using mathematical modeling methods. The mathematical model takes into account the presence of the "backlash" phenomenon in the speed control loops. RESULTS. The expediency of using batteries, rectifier and inverter converters in local electrical networks is noted. Experimental studies in the local electrical network revealed the existence of power exchange and common-mode oscillations. Mathematical modeling also confirmed the occurrence of power exchange oscillations in the local electrical network due to the “backlash” in the frequency controller circuit, as well as power common-mode oscillations due to the difference in the frequency controller transmission coefficients for diesel generator units operating in parallel. A map of the dependence of the amplitude of power exchange oscillations on backlash gaps and a map of the dependence of the amplitude of power common-mode oscillations on the values of the gain of the frequency controller are obtained. CONCLUSION. The possibility of eliminating power exchange and common-mode oscillations by reducing and ensuring equality of the transmission coefficients of frequency controllers has been established. Adding the function of eliminating power exchange and common-mode oscillations to automatic control systems for reduced sources of electricity in local electrical networks ensures that the required quality of electricity is maintained in quasi-steady operating modes.

THE PURPOSE. The use of rare earth permanent magnets in electric motors has become commonplace. The use of rare earth magnets in electric motors, such as neodymium (NdFeB), gives a significant increase in the characteristics of the electric motor. The prices of permanent magnet motors made of rare earth elements are highly dependent on the prices of magnets. So in 2012, prices for rare earth magnets increased sharply, which in turn led to a sharp increase in the cost of electric motors. The difficult situation in the world, as well as a possible new price hike for rare earth magnets, is worrying. Therefore, alternatives to rare earth permanent magnets should be considered. The aim of the study is to study and compare various alternatives to rare earth permanent magnets. Compare different types of electric motors. METHODS. When solving the tasks set, a comparative analysis of magnets made of various materials was carried out, which could replace neodymium magnets, which are most often used in electric motors. A comparison of different types of electric motors was also made. RESULTS. The article describes the relevance of the topic under consideration. The problems associated with the use of rare earth magnets are considered. Alternative options for rare-earth magnets, which are used in electric motors, are considered. Various types of electric motors are considered, the pros and cons of various types of electric motors are given. CONCLUSION. The article describes the reasons why it is necessary to abandon the use of rare earth magnets in electric motors (the most common neodymium magnets). The negative aspects of the use of rare earth magnets in electric motors are described. Alternative applications of rare-earth magnets in electric motors are described. This describes the possibility of restoring rare earth magnets, as well as the possibility of using various materials to create permanent magnets. After studying the problems with the use of rare earth magnets in electric motors, they came to the conclusion that it is necessary to consider various options for electric motors that would use magnets without the use of rare earth elements. Or consider different types of electric motors that do not use permanent magnets. So to replace the widely used neodymium magnets, ferrite magnets can come.

THE PURPOSE. The relevance of research is that the comprehensive substantiation of issues aimed at ensuring the effective functioning of the electrical complex with the presence of an electric motor load in conditions of low-quality supply voltage. The aim of the work is to study the effect of the asymmetry of the supply voltage on the service life of an asynchronous motor with a short-circuited rotor. The main attention is paid to the dynamics of changes in the service life of low-voltage asynchronous electric motors of various series, depending on the level of voltage asymmetry. Asynchronous electric motors of the classic series (4A, AI) and the upgraded (5A, AI’) are identified as the object of research. As is known, the efficient and reliable operation of electric motors is characterized by the service life of the insulation of the windings. A qualitative assessment of the operational reliability of AM is determined by the accuracy of forecasting the real life of their service. That is why, it becomes obvious, the task of an adequate assessment of the operational reliability of low-voltage asynchronous electric motors operating under conditions of low-quality supply voltage directly depends on the complex of studies of such an external influencing factor as the asymmetry of the supply voltage. METHODS. The realization of the research objectives was carried out using the software package "SimPowerSystems" of the interactive programming environment Matlab/Simulink. RESULTS. The research was carried out on asynchronous motors with a short-circuited rotor: classic series (4A132S4, AIR160S8), upgraded series (5A132M6, AIR132S4) with P_H = 7,5 kW, rated speed n = 1500 rpm. Modeling of the physical processes of the studied electric motors was carried out by changing the voltage asymmetry coefficient in the reverse sequence (K_2U) from 0 to 5% in increments of 1%. Based on the obtained simulation results, diagrams of the change in the service life of AM from the magnitude of the influencing factor are constructed. The studies performed using computer modeling based on the "SimPowerSystems" software package of the Matlab/Simulink system made it possible to predict changes in the service life of AM, estimate the limits of permissible values of the voltage asymmetry coefficient in the reverse sequence, compare the studied electric motors by the level of resistance to an external influencing factor. CONCLUSION. A comprehensive solution to issues related to improving the operational reliability of low-voltage asynchronous electric motors is one of the priority areas, mainly aimed at ensuring the effective functioning of the electrical complex with an electric motor load. In the course of the study, a detailed assessment and analysis of the degree of influence of the asymmetry of the supply voltage on the operational reliability of low-voltage asynchronous electric motors was carried out. The results of the study were discussed, recommendations for the use of asynchronous electric motors in the presence of asymmetry of the supply voltage were formulated.

THE PURPOSE. Reducing the cost of external electrical networks in the housing construction of multi-apartment residential buildings (MKD) in Moscow and the Moscow Region by substantiating the value of the correction factor to the standard values of specific electrical loads and developing appropriate amendments to SP 256.1325800.2016 “Electrical installations of residential and public buildings. Rules for design and installation. METHODS. The half-hour graphs of electrical loads installed directly at the objects under study were experimentally obtained from intelligent electricity metering devices. To process the measurement results, statistical methods for processing a large amount of data were applied. RESULTS. The article substantiates the relevance of the topic, analyzes the electrical loads of residential buildings in Moscow and the Moscow region, which confirmed the need to develop a correction factor, the value of which characterizes the difference between real and calculated values. Accepted for statistical processing are the results of measurements of electricity consumption in apartments per day with the maximum total electricity consumption of MKD. Based on the calculations performed, amendments were prepared to section 7 of SP 256.1325800.2016 “Electrical installations of residential and public buildings. Design and installation rules”, including clause 7.1.10. is set out in a new edition, and table 7.5a is formed. CONCLUSION. Based on the analysis of the calculated specific electrical loads of apartment buildings in Moscow and the Moscow region, the value of the correction factor for the city of Moscow and the Moscow region in relation to the MKD of standard projects, which amounted to 0.81, was justified, taking into account the margin. The use of a correction factor to determine the design load of a residential building will reduce costs in the construction of external electrical networks of residential buildings with a simultaneous increase in the efficiency of power transformers in Moscow and the Moscow Region.

The article PURPOSE with the problem of monitoring the state of high-voltage overhead power lines in order to ensure uninterrupted and reliable supply of consumers with electricity. METHODS. As parameters of the state, the sag, the tensile force and the mass per unit length of the wire hanging in the span are defined. IT IS STRESSED that a complete picture of the state of an overhead line can be established by determining the spectral composition of the wire vibrations using mounted automated multi-parameter sensors with accelerometers as sensors. It is shown that the currently used dynamic models for describing the motion of a wire as a pendulum and as a tightly stretched string are not complete enough to represent the vibrations of the wire in all three spatial coordinates, do not cover vibrations with odd harmonics and symmetrical vibrations. A system of equations has been OBTAINED that makes it possible to describe the spatial oscillations of the wire along all three axes, taking into account the difference in heights of the wire suspension points. IT IS SHOWN that the analysis of the higher harmonics of the spectrum of vibrations of the wire makes it possible to determine all the main mechanical parameters of the wires of overhead power lines.

THE PURPOSE. Development of diagnostic methods for high-voltage insulators in operation based on continuous recording of electromagnetic radiation. Hardware and software implementation of the device based on this technique. Carrying out experimental researches. METHODS. Received signal strength indicator measuring method of electromagnetic signals and method of determining the attenuation of electromagnetic radiation in space were used. RESULTS. The article describes relevance of the topic, considers various physical methods for registering partial discharges (PD) and their localization. Studies of the average signal level of defective and non-defective high-voltage insulators on load operation (10-15 kV) were carried out using the laboratory stand. An experiment was carried out to determine the space attenuation of a local signal from the PD. CONCLUSION. A technique for diagnosing high-voltage insulators during operation has been developed. This technique is based on continuous monitoring of electromagnetic radiation from partial discharges. Method for diagnosing high-voltage insulators makes it possible to monitor the insulation condition remotely and continuously.

THE PURPOSE. Development and implementation of a set of theoretical and practical recommendations for creating scientifically founded heat flow diagrams for pulp and paper processes, intensifying heat exchanging processes under the economical use of energy resources. METHODS. The method of thermodynamic analysis on the basis of exergy increments in the process of interaction of heat flows is proposed, it allows evaluating the energy efficiency of both individual PPI units and the entire process flow; mathematical relationship between exergy efficiency of process elements and that of a complex heat flow diagram; schematic diagram of a heat recuperator of PBM drying section with a closed loop for the air delivered to drying. RESULTS. Thermodynamic analysis was made to evaluate energy efficiency of PPI equipment; the relationship between conversion factor of thermal pumping plant and thermodynamic properties of actuating media was obtained. Sulfate pulp production was considered in detail. The low energy efficiency of the existing process flow diagram is shown, with its exergy efficiency being equal to 48%. A main share of the consumed exergy (71% of the incoming one) relates to the recovery boiler processes. The process flow diagram consisting of hydrochemical pulpchips processing is suggested. The recovery boiler and rotary-type lime kiln are removed from that flow diagram. Risks of air and water basins pollution fall. The main ways for increasing energy efficiency of lignosulfonates production at sulfite pulp plants are mentioned. DISCUSSION. Further development of energy efficient pulp technologies can be forecasted on the basis of application of fluid technologies such as supercritical water oxidation (SCWO). The positive results of research in water chemistry under supercritical parameters give promise to predict success in developing the energy efficient pulp technology by exposing pulpchips to water at the subcritical and supercritical parameters. Paper and board production relates to the complex physical–chemical and heat-wet processes. The thermodynamic studies allowed determining low exergy efficiency of a drying section of paper and board machine that is because of inefficient operation of the heat recuperation unit. This circumstance is responsible for the bulk supply of low pressure steam from a heat and power plant. The main ways for improving the heat flow diagram of PBM drying section are shown. Cogeneration issues in the pulp and paper industry are considered. The essential attention is given to environmental safety of energy efficient technologies. CONCLUSION. The paper presents main ways for increasing energy efficiency of basic production processes at pulp and paper enterprises. Based on the analysis of exergy efficiency of individual equipment elements and the entire process flow diagrams bottlenecks were revealed and measures for their removal were suggested.