PECULIARITIES OF MODELING OF STRESS-STRAIN STATE OF PIPELINES THROUGH WHICH GAS-LIQUID MIXTURES WITH AGGRESSIVE COMPONENTS ARE TRANSPORTED

The task of estimating the stress-strain state of pipelines through which gas-liquid mixtures with aggressive components are transported is considered, the purpose, object and object of research are established. The analysis of the current state of scientific and technical researches on the given subject is carried out, the circle of unresolved problems is revealed. The combined effect on the pipelines through which gas-liquid mixtures with aggressive components are transported stress – strained state change is estimated by two models - the model for determining the change of the stress-strain state of the pipeline by data on the surface points certain set displacement taking into account the quasi-stationarity of the process. The device uses interpolation smoothing splines and methods of differential geometry, 6 components of strain and stress tensors are determined. In order to substantiate the method of estimation of annular stresses at the wear of the pipeline walls due to the action of the aggressive components of the transported mixtures, systems of equilibrium equations for pipeline sections and for quasi-rectilinear sections with altered cross-section configuration have been derived. Boundaryt conditions for equilibrium equations are established. Calculation formulas for estimation of annular stresses arising under the action of internal pressure for sections with shape defects caused by the action of aggressive components are established. The results of calculations that allow to quantify the change of the most significant ring stresses arising in the pipeline material under the action of internal pressure in the pipeline cross sections, which were exposed to the aggressive components, are presented. It is assumed that the deformed sections are little different from the shape of the circle.

ANALYSIS OF METHODS AND MEASURES OF MEASUREMENT OF HEAT OF COMBUSTION OF NATURAL GAS IN UKRAINE AND ABROAD

In connection with the increase in prices for natural gas, the urgent issue is to calculate not only the amount of gas consumed, but also its quality precisely with the consumer. The quality of gas is the compliance of its physicochemical parameters with established regulatory documents. With the current gas accounting and payment system in Ukraine, consumers using the same number of cubic meters receive different heat of combustion. The paper analyzes the regulatory framework for assessing the energy performance of natural gas. The necessity of the transition to accounting for natural gas in energy units is substantiated. Existing methods and means for determining the calorific value of natural gas that are used in Ukraine and abroad are considered. Currently, direct and indirect methods are used to determine the calorific value of natural value of natural gas. The most common is the calculation method based on chromatographic analysis, the implementation of which requires expensive equipment. Other methods for determining the calorific value of natural gas is correlation. The essence of which is to establish the relationship between a certain physicochemical property of natural gas and calorific value, which can be established by experimental observations and based on theoretical analysis, which makes it possible to draw a conclusion about the calorific value of natural gas. Based on the analysis, it was found that currently there are no simple in design and not expensive means of controlling the qualitative characteristics of natural gas commercially available. Therefore, it is relevant to solve the problem of operational control of the quality of natural gas, through scientific justification, development and improvement of tools that enable the indirect accounting of the energy value of natural gas in accordance with global trends in energy accounting. A correlation analysis was carried out to establish the relationship between the thermal conductivity and the calorific value of natural gas. The use of the thermocatalytic method for determining the calorific value of gas is proposed, which will allow designing a relatively cheap and easy-to-use device for monitoring the quality of natural gas specifically for the consumer.

AUTOMATION OF THE HEAT STATE ANALYSIS PROCESS HIGH-VOLTAGE CURRENT TRANSFORMERS

Thermographic control of electrical equipment allows you to draw preliminary conclusions about the technical condition of insulation, contact joints, windings, structural elements and cooling systems of electrical equipment of voltage classes 0.4 ÷ 750 kV. However, it should be borne in mind that the results of temperature measurement and assessment of the thermal state of electrical equipment are influenced by such factors as: environmental conditions, qualifications of personnel performing thermographic control and data interpretation, the need to improve regulatory documents for assessing the thermal state of electrical equipment and develop unified algorithms analysis of the results of thermographic examinations and gradation of the development of defects in electrical equipment. Modern research in the field of thermographic control of electrical equipment is developing in several directions, namely: the use of automated (stationary or mobile) systems for collecting thermographic data; development of algorithms for processing thermal images that reduce the influence of extraneous noise on the values of the measured temperatures, select the image of the object being examined, select the optimal level of contrast of the thermal image to detect thermal anomalies; using statistical processing of thermal fields of thermal monitoring objects and making decisions about the thermal state of equipment using neural networks, machine learning and expert knowledge. Automation of the analysis of thermographic control data is an urgent scientific and practical task, the solution of which will improve the quality of maintenance, repairs, extension of the operating life and operational management of electrical equipment in conditions of a significant level of aging of the main production assets of electric companies and change of generations of staff. Measuring current transformers of voltage classes 330 ÷ 750 kV are critical elements in the distribution schemes of electric power and in electric networks, and their technical condition directly affects the reliability of electric networks and power supply to consumers. The paper considers the reasons for the development of defects in current transformers of voltage classes 330 ÷ 750 kV, and also proposes relationships to take into account the influence of the air flow rate and the actual value of the emissivity of the structural element of the current transformers, as well as elements of the algorithms for analyzing data from thermal imaging surveys to reduce the influence of environmental factors and qualification level of the personnel performing the analysis, diagnostic results.

PROBLEMS ISSUES OF REGULATORY PROVISION OF PRODUCTION ACTIVITY OF NATURAL GAS MARKETS

The formation of the modern Ukrainian natural gas market is accompanied by profound transformations of the national gas infrastructure: the creation and operation of new market operators, the redistribution of infrastructure facilities, the development and implementation of new requirements for the effective functioning of the entire system. At the same time, this requires from all parties a verified and balances strategy for the optimal implementation of all the obligations that Ukraine has undertaken to fully implement the requirements of the EU Third Energy Package, which aims to create an effective natural gas market based on the principles of free competition, proper consumer protection and security of supply. Despite the fact that the capacity of the Ukrainian gas transmission system and gas storages is one of the largest in Europe, the unbanding process has caused a number of threats in the area of regulatory support for production activities, requiring the consolidation of specialists' efforts to form optimal solutions to the problems that have arisen. In addition, the lengthy process of reforming and reorganizing the Ukrainian gas distribution system has led to a situation where the work of a natural gas distribution operator is facing a risk of imbalance in terms of inefficient standardization of the main areas of operation to meet the EU legislation requirements implemented in Ukraine. Therefore, to develop basic directions for the future work of gas infrastructure operators, it is necessary to take into account the acting capabilities of existing system for transportation, underground storage and gas distribution (taking into account the significant number of standardized indicators defined by the existing normative documents of the former USSR) and in accordance with the trends in the development of the European gas infrastructure introduce economically and technically feasible measures to standardize performance activities. Such works have to be incorporated into integrated research programs, during which regional and international trends are to be taken into account and adapted, the results of which will be the basis for future roadmaps and programs for the development of natural gas supply and distribution systems.

THE MOBILE SYSTEM REDUCTION FOR THE VIBRATION CONTROL IMPLEMENTATION

Since the mining and oil and gas industries play a decisive role in the Ukrainian economy, the adequacy and proper assessment of the accuracy of the monitoring is of great national importance. A mathematical model for the measurement of MSCs is constructed, which determines the sequence of mathematical operations that must be performed to obtain the quantitative characteristics of the objects of control. If there is a function that is a solution and that describes the object of the MSC, then it is a reduction to the ideal MSC. The solution of the problem of reduction (synthesis) MSC is realized by the choice of design and is provided with such a connection between the signals at its input and output MSC, which leads to the best results. This formulation of the problem of reducing the MSC has several disadvantages. The MSC measurement result is always influenced by a number of minor factors. Their effect leads to the fact that the measured value of a certain value is different from the value predicted by the model of measurement of the ISC on the noise (experiment error), which is random. The noise level of MSCs has a significant effect on the result of mathematical processing, and the less the noise, the better the result of the reduction of MSCs. Previously, the task of instrumentation was to create an MSC that provides the least distortion of the measurement results, while using mathematical methods to reduce instrumentation the task of reducing instrumentation noise is MSC. The given solution is realized by the choice of design and is provided with such a connection between the input and output signals, which leads to a decrease in the level of random noise MSC. The description of MSC enhancement has the instability of the solution of the equation with respect to the initial data errors, which is a property of almost all integral equations and does not depend on the method of their solution. The proposed mathematical method of reduction of the mobile control system (MSC) as one of the variants of regularization of the incorrectly set problem arose and was further developed under the influence of the ideas of academician AN Tikhonov and Professor Yu.P. Pytiev . The author suggests taking a different look at the control tasks and the accuracy of assessing the accuracy of MCSs by reducing the level of random noise. The author proposed the implementation of the MCS by choosing a design and providing such a connection between the signal at its input and output, which leads to the best results in solving reduction problems. The author proposed an adaptable model of MCSs using modern ideas and mathematical methods.

DETERMINATION OF THE ACTUAL AREA OF DRY ACOUSTIC CONTACT IN THE SYSTEM “TRANSDUCER–PRODUCT” IN LOW-FREQUENCY DEFECTOSCOPY

The conditions for the emission of acoustic energy into the pipeline environment and the reception of reflected signals from inconsistencies in dry acoustic contact cause certain dimensions of the actual contact area between the transducers and the pipe surface. The basic approaches to the determination of the actual area of ​​dry acoustic contact between the surfaces of the piezoelectric transducer and the pipe are formulated under the influence of constant static force of pressing the surfaces in low-frequency flaw detection using ultrasonic directional waves. Expressions have been proposed to determine the area of ​​actual acoustic contact for single and numerical micro projections of the pipe surface. The principle of quality control of balancing of acoustic antenna piezoelectric transducers in modern systems of low-frequency diagnostics of the technical state of longitudinal pipelines by ultrasonic directed waves is described. It is revealed that after correct balancing of all the acoustic antenna piezoelectric transducers, the column image does not appear on the display screen and the mathematical support of the system will automatically collect the technical status of the diagnosed section of the pipeline, the results of which are displayed on the display screen. It is established that the actual area of ​​dry acoustic contact in the "piezoelectric product" system in low-frequency defectoscopy depends on the magnitude of the static force of pressing the surface of the piezoelectric transducer to the surface of the product. It is revealed that the deformation of the micro protrusions of the surface of the product under the action of static clamping force is uneven, which does not allow to fully calculate the actual area of ​​dry contact by mathematical methods. It is shown that in modern systems of low-frequency ultrasonic diagnostics of extended pipelines, directional waves control the quality of dry contact of the surface of the piezoelectric transducer with the surface of the pipe by balancing acoustic antennas with the use of special test programs.

CONTROL OF WETTING PROPERTIES OF THE ARTIFICIAL VESSELS SURFACES

The influence of the surface properties of different solid materials on the process of blood flowing through them is analyzed. Based on the dependence of the blood coagulation rate on the wetting properties of the solid surfaces on which it spreads, the urgency of developing an express method of controlling the process of blood wetting of the artificial vessels surfaces to prevent thrombosis is substantiated. The adhesion work which is consumed of blood drainage is determined. The impedance method was developed, which is based on the relationship between the flow rate and the change in impedance The impedance method was developed, which is based on the relationship between the flow rate and the change in impedance of the flat capacitor, between the plates of which is the investigated system blood – implant. The interelectrode space of the cell (the investigated system) can be considered as a heterogeneous dielectric, which is a collection of blood, air, and implant samples. Each of these layers can be represented by a set of capacitors and resistors in parallel and connected in series. In the course of blood drainage on the inclined surface of the test sample of implant material, which is located on the bottom plate of the condenser, the redistribution of blood layers, air and sample of the implant occurs, that is, the dielectric constant of the electrode medium changes. The design of the device implementing the impedance method and the results of laboratory tests are presented. Graphic dependencies for establishing the wetting degree of blood the most used materials in the creation of artificial vessels, which confirmed the need for special coatings to increase the blood coagulation time.

GENERATOR OF POWERFUL HIGH-FREQUENCY PACKAGE CURRENT PULSES FOR POWER SUPPLY OF ULTRASONIC ELECTROMAGNETIC-ACOUSTIC TRANSDUCERS

It is possible to increase the sensitivity of electromagnetic-acoustic transducers by three main methods: increasing the induction of a polarizing magnetic field; increase in strength of high-frequency current in the inductor of the converter; using modern methods of processing information packet pulses excited and received from the product. The increase in magnetic field induction of the converter is limited by the capabilities of modern powerful permanent magnets. In addition, there are significant difficulties in monitoring ferromagnetic control samples, due to the large pressing force between the sample and the transducer and sticking of scale to the transducer. Usage of modern processing methods significantly complicates and increases the cost of electromagnetic-acoustic testing devices. Of the selected sensitivityincreasingmethods, the most acceptable way is to increase the power of high-frequency current generators under the condition of excitation of packet pulses. Power supply process of the converter is carried out in two stages. Meander type powerful high-frequency current pulses are excited, which ensures operation of the output transistors in key mode. Isolation of a powerful sinusoidal high-frequency packet current pulse is carried out directly on the electromagnetic - acoustic transducer, the elements of which are included in the resonant circuit with low quality factor. Based on the transistors switched in the push-pull circuit in the key mode, a small-sized generator design has been created that excites a peak current of up to 800 A in the electromagnetic-acoustic transducer and a voltage of up to 3 kV in the transducer in the frequency range 0.3 ... 8 MHz. It was experimentally determined that the new design of the probe pulse generator made it possible to increase the amplitude of pulses reflected from a flat-bottom reflector with a diameter of 2 mm with respect to the interference amplitude by more than 2 times.

MATHEMATICAL MODEL OF SPEED DATA TRANSMISSION FROM SEGMENT LENGTH OF SPECIALIZED G3-PLC DIGITAL NETWORK

Power Line Communication (PLC) systems are actively evolving and becoming more and more widespread worldwide. They are used in the automation of technological processes, the organization of video surveillance systems and to control the "smart" home. The G3-PLC provides high-speed and high-reliability long-distance communication over the existing power grid. Due to the fact that G3-PLC provides the ability to transmit data including through transformers, infrastructure costs are reduced. In addition, the G3-PLC network can support IPv6, which will allow the G3-PLC to easily integrate into common IPv6-based communication lines in the future. G3-PLC-based bilateral communications networks can provide grid operators with intelligent monitoring and control capabilities. Operators will be able to monitor electricity consumption across the network in real time, apply variable tariff schedules and set limits on electricity consumption. In turn, consumers will be able to control electricity consumption in real time. By using variable tariffs, users can reduce their electricity consumption during peak use. The G3-PLC dedicated digital network can be used in process automation systems where traditional or traditional data transmission is difficult or impossible. As a result of the research, a polynomial mathematical model was found that best reflects the change in data rate depending on the length of the G3-PLC network segment. It is also found that for the simplified calculation, a linear model determined during the studies can be used. The established mathematical models of data transmission rate dependence on the segment length of the G3-PLC dedicated digital network will contribute to better design of G3-PLC-based networks.

VIBRATION FREQUENCY DENSITY CONTROL METHOD IN VIBRATION CONDITIONS

The use of existing vibration frequency measuring instruments for monitoring technological parameters inside apparatus and equipment is limited due to the presence of vibrations and industrial noise. The lack of data on the use of part of the technological apparatus as flow resonators through the unexplored basic analytical equations for determining the amplitude-frequency characteristics of such resonators determined the direction of these studies. The article is devoted to studies aimed at establishing the relationship between the vibrational field of the resonator, which is used as part of the technological apparatus with a controlled environment, and its reaction in the form of a change in the frequency or amplitude of the resonator’s own vibrations, which carries information about the properties of the substance in the apparatus. The experimental setup diagram, experimental methodology, and data on determining the oscillation frequency of the resonator under vibration conditions for metallic (corrosion-resistant steel) and non-metallic (organic glass) resonators are presented. The curves obtained from the experimental values were approximated using linear and hyperbolic approximations. It was found that the use of hyperbolic approximation reduces the average approximation error by more than six times. It was found that the error of the hyperbolic approximation error does not exceed 0.022% for a metal resonator and 0.05% for an organic glass resonator. The conducted experimental studies confirm the presence of a determinate coupling of the measured frequency characteristics of the resonator with the density, which was measured inside the equipment. The obtained data was used to develop the scientific and methodological foundations of the vibrational frequency control method in conditions of vibration using a part of the device as a resonator of the vibrational frequency sensor.