bluuebunny/crossref_metadata_2025 huggingface dataset:
Problems of diagnostics of asynchronous motor powered by an autonomous voltage inverter
Authors: Korolev N A , Solovev S V , Zhukovskiy Y L
Published: November 2019

The article considers the most modern and most informative methods for diagnosing faults in squirrel-cage induction motors with a short-circuited rotor. The methods are based on the evaluation of vibrations and electrical parameters, as well as coordinates during operation and are normalized when powered from a sinusoidal voltage with frequency of 50 Hz. The main advantages and disadvantages of these methods, as well as the main indicators characterizing the general technical condition of the electric motor, are described. The application of these methods when powered from a non-sinusoidal voltage is impossible due to the complex harmonic composition of current and voltage. The consequence of this composition are the ripple moment and additional power loss. The interaction of the harmonics of the inverter and subharmonics, caused by faults, leads to the occurrence of a resonance phenomenon, and therefore to a decrease in the stability of the electric drive.
Diagnostics of inter-turn short-circuit in the stator winding of the induction motor
Authors: Smirnov A I , Voytyuk I N
Published: November 2019

A stator malfunction occurs due to insulation damage, which means that the stator is directly connected to the power supply, and a direct connection is the direct cause of a major accident. For this reason, a lot of research is being done to identify faults. In recent years, studies on Motor Electrical Signature Analysis are being performed, sensorless methods for fault diagnosis of the stator of an induction motor. However, it has problems with it, it has the difficulty in interpreting multi-faults and in detecting an inter-turn short circuit of a stator. This paper suggested a tool that can diagnose 2-turn short circuit, through the relationship between self-inductance and mutual inductance in the synchronous reference frame of a D-Q transformation.
Bearing diagnostics of slow speed industrial rotating equipment by shock pulses
Authors: Barkova N A , Barkov A V , Fedorishchev V V , Grishchenko D V
Published: November 2019

Fifty years have passed since the world’s first patent for a widely used method of the rolling element bearings condition monitoring by ultrasonic pulse vibration (SPM-method) was registered. The method is widely used in the power industry and in other industries. During these years, several technical realizations of this method were implemented. These methods are based both on the form of the recorded single pulses analysis and on the spectral analysis of the envelope of periodic pulses. But in all implementations, there remains a problem of establishing the relationship of controlled vibration parameters with the defect severity. The paper analyses the possibility of detecting and assessing the risk of rolling element bearing defects in low-speed rotating units by vibration excited by shock pulses, the sources of which can be both the bearings and the tooth wheels. In the production of electricity such units include rotary heat exchange equipment, among the major consumers - rotary steel furnaces for different purposes The proposed solution - a synchronous analysis of the pulse vibration of all bearings of low-speed units at medium, high and ultrasonic frequencies.
Analysis of research and area of application of self-resetting liquid metal fuse
Authors: Kuznetsov A V , Yurenkov Y P
Published: November 2019

The article shows that the level of research to date, both in Russia and abroad, does not yet allow the development of industrial samples of liquid metal self-resetting fuses. However, the high speed and current-limiting properties of the self-resetting liquid metal fuse are of interest in continuing research. The use of the self-resetting liquid metal fuse as a current limiter competitive with current-limiting reactors received a more complete scientific substantiation and development. It has been found that a common disadvantage of all structures of self-resetting liquid metal fuses is that during the switching process the channel of the dielectric bushing of the self-resetting liquid metal fuse is subjected to arc erosion with each triggering, which reduces its switching resource. There are proposals to increase the switching resource through the use of materials more resistant to the effects of an electric arc, constructive and circuit solutions. From the point of view of speed and current-limiting properties, it is preferable to use fusible alkali metal inserts in the self-resetting liquid metal fuse. It is noted that the amount of research that has been conducted makes it possible to create a current-limiting device based on a competitive self-resetting liquid metal fuse with current-limiting reactors. To do this, it is necessary to combine the efforts of all interested industrial and scientific organizations, to create and explore a mock-up sample.
Stability analysis of piecewise defined nonlinear ambiguous system by direct Lyapunov method
Authors: Bruslinovskiy B V , Dobroskok N A , Lavrinovskiy V S , Galiullin R I , Mokhova O V
Published: November 2019

In this paper the piecewise defined nonlinear ambiguous system is considered. The stability of such objects is investigated using separately excited DC generator with two excitation windings with relay control system taking into account magnetic hysteresis phenomenon. The Lyapunov function for this system is designed by direct Lyapunov method and its generalization through Dini derivatives that allows approving the stability of generator with nonlinearities.
Simulation modeling of DC electric drive for mine hoist
Authors: Pogorelov A V
Published: November 2019

The article describes the adjustable electric drive of skip hoisting installations of the mining enterprise. A simulation model of this object has been developed in the MatLab software package using the Simulink environment. The lift cycle was simulated using a five-period motion tachogram and graphs of dependencies of the following variables on time were obtained: the movement speed of the skip, the armature current and the motor torque. The simulation results showed that this simulation model corresponds to the actual technological process and allows further research on the operation of skip hoists.
Differential equations of synchronous generator with active-inductive load
Authors: Tokarev L N
Published: November 2019

This article presents differential equations of the synchronous machine transformed by Park in line with the theory of two reactions, i.e. in axes d-q. These equations were transformed, in turn, by the author. Using the equations transformed by the author it is possible to create programs of transients analysis in ships’ electric power plants. Generator voltage values are output ones–like in physical systems–in computer programs developed with the help of the given equations.
Autonomic energy supply of distributed/isolated villages in Russia by using combination of LNG/CNG/LPG/diesel and renewable energy
Authors: Karasevich V , Li V , Kashlaev R , Fedyukhin A
Published: November 2019

This article is dedicated to search of right balance for heat and power supply of distributed villages in different conditions in Russia. Russia has a huge territory that is not connected to power grids, many villages aren’t connected to natural gas network and don’t have district heating systems. Approach consists of several steps. On the first step we choose isolated areas and villages that have no chances to get connection to natural gas grid. Even if they are connected to power grids, they still have a room for autonomic solutions in producing heat/hot water. In many cases quality of power is not very good. Then on the second step we compare different combinations of traditional (LNG/CNG/LPG/diesel) and renewable (PV panels, solar collectors, wind turbines + heat/power storage units) power sources in order to find the best way of power/heat supply for the village. In the article the approach is shown on two different examples – Dagestan (south of Russia) and Yakutia (north of Russia). Article also covers some ways and proposals of renewable energy supporting considering current situation in this industry.
Passive harmonic filters for high voltage transmission systems
Authors: Dovgun V , Egorov D , Boyarskaya N , Novikov V , Prozorov N
Published: November 2019

This paper presents a new passive filter configurations that can reduce the harmonic penetration into high-voltage transmission system. Proposed configurations utilize the secondary winding of a step-down transformer as a part of the filter. A general method for harmonic filters design, based on the theory of passive circuit synthesis, is considered. The simulation results show that the proposed filter is an efficient tool for attenuating harmonics penetrating high voltage transmission systems.
Network composite insulators for overhead lines: disconnecting due to unidentified reasons
Authors: Yarmarkin M K , Ivanov S A
Published: November 2019

The characteristics of disconnecting overhead transmission lines 110-400 kV due to unidentified reasons (DUR) are under consideration. An explanation of DUR associated with settling the web on line insulation during mass migration of spiders.
The use of GA in the problems of circuit-mode optimization of electrical networks
Authors: Stsepuro K I , Bodrenkov E A
Published: November 2019

A method for determining the optimal state of the electrical network according to the criterion of minimum active losses using a genetic algorithm is presented. The algorithm is implemented in the programming language Visual Basic. The advantages of the proposed approach in comparison with the brute force are the reduced brute force required to determine the optimal scheme, the flexibility of setting the user controlled values. The practical significance lies in the possibility of implementing the approach of a distribution grid company and solving optimization problems in a timely manner. The algorithm was tested on 10-35 kV electrical network diagrams.
The question of specific features of overvoltages when switching parallel-connected vacuum breakers
Authors: Belsky R , Skornyakov V , Savelieva I
Published: November 2019

The paper presents the results of analyzing switching overvoltages occurring with simultaneous shedding of active inductive load by vacuum breakers jointly connected to one bus. It is established that with the available spread in current choppings of vacuum breakers, the maximum overvoltage occurs on the contacts of a vacuum breaker out of the number of parallel connected ones, in which the gap is de-ionized last. It is recommended to damp any occurring overvoltages by arresters located in parallel to separate groups of breakers connected to one bus.
The application of mathematical simulation for solution of linear algebraic and ordinary differential equations in electrical engineering
Authors: Bebikhov Yu V , Semenov A S , Yakushev I A , Kugusheva N N , Pavlova S N , Glazun M A
Published: November 2019

The application of mathematical simulation for the solution of linear algebraic and ordinary differential equations regarding to complex electrical circuits, systems of automatic control and regulation is discussed in the paper. MatLab software package of mathematical simulation and one of its built-in environments - Simulink were chosen to be used in the experiment. MatLab is the most commonly used application in engineering practice in comparison with the other similar programs and it has proved to be reliable for technical calculations. The calculation methods of complex electrical circuits by the solution of linear algebraic and differential equation systems were developed and tested. The equations of electric equilibrium were written for each element of an electric circuit on the basis of Ohm’s and Kirchhoff’s laws. The example of the calculation of branches currents and nodal potentials of electric circuit by the matrix method in MatLab was presented. The approximated polynomial function was calculated and its graph was plotted applying the developed technique. Thus, the coincidence with the original data was proved. The calculation of differential equations of successively connected inductive and resistive elements of electric circuit was made in Simulink environment. Finally, the dependences of voltage and current on time were found using the direct Laplace transformation. The graphs were plotted due to the application of the oscilloscope built into the program. It has been concluded that the application of mathematical simulation for engineering calculations in order to solve the problems of automatic control and power engineering is the most suitable and universal technique.
Liquid-phase synthesis, surface morphology and properties of the electrode materials based on MnO2 for electrochemical devices
Authors: Ivanova A G , Masalovich M S , Zagrebelnyy O A , Shilova O A , Yu Kruchinina I
Published: November 2019

The article focuses on the problems of development of electrochemical devices. The effect of a synthesis method and fabrication technology on the electrochemical performance of a MnO2-based electrode is discussed.
Determining of the characteristics of nonlinear resistive-capacitive and resistive-inductive elements
Authors: Selitrenikov D A , Bodrenkov E A
Published: November 2019

We present a method for finding the dependency of resistance and inductance on the current for the series connection of resistive and inductive nonlinear elements and finding the dependency of resistance and capacitance on the applied voltage for the parallel connection of resistive and capacitive nonlinear elements at a constant frequency. The initial data are current and voltage oscillograms measured for different moments of time. Examples of determination of the specified dependencies are given, estimates of the absolute and relative error of the approach are given.
Numerical simulation of high power RF–RF hybrid plasma torch
Authors: Frolov V , Ivanov D , Sosnin V
Published: November 2019

In this paper the possibility of operation of a high-power RF-RF hybrid plasma torch for materials processing is shown with help of numerical simulation. That kind of plasma torch consists of two coaxial ICP/RF torches connected in series. A mathematical model is presented which includes assumptions, basic equations, a computational domain with main sizes. The results of the calculation i.e. the temperature distributions inside the plasma torch for two modes of operation are shown. In the first mode the power is fed only to the first plasma torch (P
1=40 kW, P
2=0), in the second mode the both parts of the RF-RF hybrid plasma torch (P1 = 40 kW, P2 = 600 kW) operate. The obtained results can serve as a basis for further analysis of the operation of a high-power RF-RF hybrid plasma torch.
Assessment of the influence of interference on the sliding mode observer
Authors: Zhiligotov R , Davydov V
Published: November 2019

The article presents the results of studying the effect of interference on the sliding mode observer. The effect of interference in the lines feeding the engine is evaluated. The measured interference is present in the current signal. The operation of a sliding observer of the position and speed of the rotor of a permanent magnet synchronous motor is described. This observer is used as part of a sensorless vector drive control system. The presented version of the motor state observer is implemented by creating a model in the Matlab Simulink software package and tested on the bench using a 200W motor. The aim of the work is to develop an observer who is resistant to drive parameter changes.
Numerical simulation of the outdoor insulator breakdown
Authors: Murashov Iu , Safonov E , Markelov V
Published: November 2019

The article is devoted to the development of a mathematical model of an insulator breakdown and the methodology for assessing the development of a breakdown. The main calculation expressions are presented in the article. The design of a real insulator (the outdoor voltage insulator of 35 kV type IOSK 3/35 UHL1) is presented as an example of the technique applicability. The datasheet of this outdoor isolator was used to verify the mathematical model and the results of numerical simulation. The results of numerical simulation and the outdoor insulator breakdown voltage are presented in the article. Numerical simulation was carried out in Comsol Multiphysics software. The obtained results can be applied in the engineering design of outdoor insulators and elements of electrical constructions.
Development of digital twin of high frequency generator with self-excitation in Simulink
Authors: Murashov Iu , Zverev S , Smorodinov V , Grachev S
Published: November 2019

The article presents the numerical simulation results of the high frequency generator (electron tube type) with self-excitation in the Simulink. The main structural element of this generator is an electron tube GU-66A. Digitization characteristics of the electron tube is made. A mathematical model of the HF generator, taking into account the anode and grid characteristics of GU-66A according to the passport data of the product, has been developed. The parameters of the HF generator circuit are determined. A plasma-chemical reactor and its equivalent electrical parameters (set in a wide range of accepted values) are used as a load oscillation circuit. The developed model allows to determine the optimal parameters of the HF generator, as well as to predict operating modes, providing continuous supply of HF power for a long time (more than 20 hours). The equivalent electrical parameters of the plasma-chemical reactor are designed to ignite plasma discharges in argon and gas mixtures based on argon at atmospheric pressure.
Mathematical model of solid-liquid phase transitions applied to thermal energy accumulators
Authors: Yu Zakharova V , Kuznetsov P A , Baranenko A V
Published: November 2019

The paper presents a mathematical model for the numerical calculation of the heat flow and the volumetric fraction of the liquid phase of phase change materials (PCM) in containers of thermal energy accumulators of spherical and cylindrical shape, used in air conditioning and ventilation systems. The comparison of the calculated and experimental values for n-octadecane showed good convergence of the results. When using in geometry optimization algorithms of containers and when choosing PCM, the model has an advantage due to the high speed of calculations on it.
Assessment of energy efficiency of channel with nozzles
Authors: Dudarovskaya O
Published: November 2019

An algorithm for calculating the energy coefficient has been obtained, which makes it possible to estimate the efficiency of channel with various heat exchange intensifiers in the form of chaotic nozzle elements. The numerical study results are presented in the form of relationship between the energy coefficient Ed and the Reynolds number Ree. This made it possible to assess these heat exchange intensifiers from the point of view of energy efficiency and to determine the most optimal ones.
A new approach to overcome the imbalance in three-phase systems using the new proposed fractional-polynomial functions
Authors: Sy V Q
Published: November 2019

Non-linear or unbalanced loads, etc., are the typical causes of asymmetry in the three-phase systems. The typical difficulty that exists in many methods of symmetrisation is the calculation of the adjusted values (regulable parameter). In this paper, we propose a new method to overcome all of the above problems, which includes: introduction of the new dependence of the basic electrical quantities (voltages and currents) on the controllable values of the static compensation devices; the proposed new method of overcoming the asymmetric operation regime in the three-phase systems, in which we aim to reduce the number of compensating devices.
Current collector optimizer topology to improve maximum power from PV array under partial shading conditions
Authors: Refaat A , Osman M H
Published: November 2019

The power generated from photovoltaic (PV) series-parallel (SP) array topology is greatly harmed by partial shading phenomenon. Power losses due to shadow may reach up to 30% of total power expected, depending on PV array topology and climate conditions. This paper presents a current collector optimizer (CCO) topology to enhance the power harvest from the PV array under partial shading conditions. A comparative study is carried out using MATLAB/Simulink in order to illustrate the effectiveness of the proposed topology. According to results, the global maximum power generated by CCO topology is substantially increased compared to traditional SP array topology, while the mismatch power losses are significantly reduced during different shading patterns.
Innovative local heat supply stations for industrial buildings
Authors: Volkov V D , Sergeev V A , Shelyakin V P , Sitnikov N V , Goremykin S A , Mamontov D A
Published: November 2019

Energy saving effect in heating systems of industrial buildings without 24-hour supervision is reached using the automatic heat management systems. Our paper offers a specific scheme for the automation of a local heat supply station (LHS) with an autonomous heat accumulator and a dual-circuit coolant circuit. The proposed technical solutions can only be effective if the compliance of the thermal resistance of the external enclosing structures of the building to the established requirements is observed.
Process equipment pump-controlled hydraulic drive: improving energy efficiency
Authors: Kozhukhova A V , Sakharova O N , Dmitrieva I A
Published: November 2019

The paper addresses the issues of stepless speed control of the hydraulic drive output link by means of frequency control, throttle control and pump-throttle control; they are compared, and their applicability in various types of hydraulic drives is analyzed [1, p.619]; a mathematical model of losses arising in a volumetric rotary hydraulic machine with volumetric (pumping) control and frequency management is given; a mathematical model is formed on the basis of which the dynamic characteristics of removable hydraulic drive with frequency control with varying parameters of external load and operating factors will be studied. The paper is based on theoretical research of the frequency-controlled hydraulic drive that was carried out [2, p.41]. As a result of the research, a schematic solution and a mathematical model of the developed hydraulic drive have been proposed. The main structural and technical and economic indicators are: a change in the angular velocity of the rotor of the machine in a given range, and an increase in the energy efficiency of the drive.
Improving the efficiency of combined-cycle plant by cooling incoming air using absorption refrigerating machine
Authors: Mendeleev D I , Maryin G E , Akhmetshin A R
Published: November 2019

The purpose of the paper is to study and analyze the possibility of increasing the power of combined cycle gas turbine (CCGT) unit during the period of positive ambient temperatures. The other aim is to study usage of an absorption refrigerating machine in a CCGT cycle to increase its energy efficiency. The third aim is to analyze the operation of 110 MW combined-cycle power unit at various ambient temperatures, and to obtain alterations in the main CCGT characteristics when the ambient temperature changes. Calculations of the thermal scheme of a gas turbine were carried out using mathematical modeling, the steam turbine was calculated basing on the guidelines. The possibility of increasing the capacity of a CCP-110 MW was studied and analyzed. The conducted studies allowed us to conclude that the use of absorption refrigerating machine in the cycle of a combined-cycle plant can improve the efficiency of the unit, increase profits from power generation, and reduce penalties for non-compliance with the load schedule.
Empirical performance modelling of a lithium-ion battery of a solar car
Authors: Kasatkin I , Egorov M , Zakhlebaev E , Kotov E , Selin I , Kukolev M
Published: November 2019

The aim of the work is to ascertain a solar car battery performance. The student engineering team of Peter the Great Petersburg Polytechnic University designs the car. Parameters as terminal voltage, operating current, power losses and efficiency are determined depending on battery state of charge (SOC) and operating power. For electrochemical transient modelling, an equivalent RC-circuit is included based on Thevenin battery model. It is assumed in the model that internal resistance, open circuit voltage and the RC-circuit voltage drop depends only on the SOC. Experimental data was obtained from the LG INR18650 MJ1 battery discharge curves. Modelling was performed for SOC values in the range of 0.17 to 0.95 since the terminal voltage dependence on SOC is nearly linear there. The proposed model is sufficient for state of charge estimating and battery performance determination.
Utilization of electrochemical energy storage devices in autonomous power supply systems
Authors: Fedotov A , Misbakhov R , Chernova N , Bakhteev K
Published: November 2019

Diesel and gas piston power units are used as a source of electrical power in autonomous power supply systems. For diesel power plants located in remote areas, the main component of the costs are the cost of imported fuel. For gas piston power plants operating on associated gas, the main problem is to ensure the stabilization of the frequency of alternating current with sudden load changes. The use of electrochemical electricity storage devices as part of power plants largely solves these problems. The article considers the choice of storage capacity for fuel economy, reduction the installed capacity of a power plant and frequency stabilization in the power supply system. It is shown that for diesel power plants, the use of electrochemical accumulators leads to both fuel savings and a decrease in its nominal capacity. For gas piston units, where the specific increase in fuel decreases with increasing load, the use of electrochemical accumulators reduces the installed power, but increases fuel consumption. The accumulator parameters for gas piston units are determined by the allowable overload/discharge of the load, and according to the energy intensity, they are determined by the duration of the maximum load, which is smoothed by the drive operation. We present numerical examples for estimating fuel consumption taking into account the efficiency in the charge-discharge processes of storage batteries. The simulation models show the impact of the electrochemical storage device on the stabilization of the frequency of an autonomous electric power supply system.
Roadmap for intelligent energy systems
Authors: Vasilev Valeriy V
Published: November 2019

The article is devoted to the prospects for the development of the energy complex of the Russian Federation within the framework of the concept “Industry 4.0”, the problems of integration of electricity, heat, cold and gas supply systems and energy security issues. A comparative analysis of the state and prospects of development of the fuel and energy complex of various regions of the world is given, and a forecast of the demand for integrated intelligent energy system is given.
Application prospects for vector time maps of cognitive images links
Authors: Pustovoy E A , Pustovaya O A
Published: November 2019

Neural networks have a great advantage in the analysis of implicit dependencies, big data analysis, image recognition and other recognition systems. However, they do not perform the function of memorizing information in an explicit form, they cannot logically think like a person. Neural networks are not managed repositories of information about cognitive images. They are quite difficult to edit or create new structures based on existing trained models. They do not have the necessary flexibility and scalability in the process of learning and in use. We propose to create vector-time communication maps of cognitive images links, containing functions for memorizing individual cognitive images and their links, with the possibility of forming explicit centers and with the possibility of scaling.
Digital diagnostic complex for power turbine units equipment
Authors: Murmanskii Ilia B , Aronson Konstantin E , Blinov Vitaly L , Zhelonkin Nikolay V , Murmansky Boris E
Published: November 2019

The study is devoted to the problem formulation for creation a concept of digital complex for power turbine equipment diagnostics using a reference turbine model formed by a set of computational models of thermal and gas-dynamic processes, by diagnostic expert systems (probabilistic type and decision tree type), by functional standard characteristics and statistical models. As part of the study it is proposed to develop diagnostic methods and algorithms for characteristic malfunctions causes for various subsystems of power equipment, which will allow them to be detected at an early stage and to prevent unplanned (emergency) equipment shutdown.
Fiber-optic sensors for monitoring the stress-strain state of construction objects
Authors: Badeeva E , Serebryakov D , Shachneva E , Badeev A , Murashkina T
Published: November 2019

For the timely detection of significant changes in the stress-strain state in the bearing elements of various building structures, which may lead to a deterioration of the technical condition of the object or transfer it to the emergency state, the use of fiber-optic sensors is proposed. The main advantageous characteristics of fiber-optic sensors, describing the promise of their application for practical applications, are disclosed. As a parameter recorded by the measuring transducer, the fiber-optic sensors use the intensity of the light wave. The mechanism of changing the optical intensity can be due to reflection, absorption, refraction of light rays passing through the measurement zone. The authors have developed a fiber optic attenuator type deformation sensor capable of controlling mechanical deformations of structural elements caused by disturbed internal geometric characteristics, destruction of structural integrity and negative influence of external weather conditions, seismic factors, temperature drops during operation. When developing the design of a fiber-optic sensor, the fundamentals of circuit design of measuring devices, methods of geometrical and fiber optics are used. As a basic measuring transducer, a fiber-optic microdisplacement transducer with a limiting attenuator is used, in which the intensity of the optical signal is modulated by changing the position of the attenuator placed in its path or increasing the optical power. A design-structural diagram of a fiber-optic micro-displacement measuring transducer and a block diagram and the design of a new sensor are presented. The principle of operation of an attenuator-type fiber-optic strain gauge is described.
Electromechanical drive fault detection
Authors: Iureva R , Margun A , Maltseva N , Vedernikov K
Published: November 2019

The paper presents the simulation model for the process of electromechanical drive disorder detection which is used to evaluate the drive reliability. The low efficiency and inoperability of the drive could be partial or complete. A proper functional drive provides under certain conditions the maximum efficiency of its use. The ability of the partially operating object application in the same conditions is less than the maximum possible one, but its indicators could be still within limits established for the proper functioning, which is considered normal. A partially inoperable object could function, and at the same time, its level of efficiency is lower than the allowed one. An inoperable object couldn’t be used as it was intended, and the research presented in this paper shows how to enable providing the drive reliability evaluation and analyze its proper functioning.
Numerical simulation of heat transfer processes of the circuit breaker contact system
Authors: Murashov Iu , Frolov V , Kvashnin A
Published: November 2019

The article is devoted to the study of heat transfer processes of the high-current AC circuit breaker contact system. The creation of a mathematical model is based on the application of well-known physical laws such as the Joule-Lenz and Fourier laws, which describe physical processes in the form of partial differential equations. Cooper-Mikic-Yovanovich correlation is used for evaluation of thermal and electrical contact conductance. The developed mathematical model is verified by the results of experimental studies. The calculation of the composite material properties for numerical simulation of heat transfer processes is presented. The calculation is presented for the actual design and materials of the circuit breaker.
Criteria for ensuring acoustic safety in the assembly shops of machine-building enterprises
Authors: Kaverzneva T , Tarkhov D , Uljanov A , Senchenko V , Pshenichnaya C , Alibekova I
Published: November 2019

We consider the problem of providing acoustic safety at the machine-building enterprises, where manual pneumatic tools and electrical tools are widely used in assembly shops. As an example we considered the noise during operation of pneumatic tools, which are the most preferable from the point of view of ensuring electrical safety. The necessity of monitoring audiograms of operators performing assembly operations, repair and adjustment at the machine assembly lines is justified. We analyzed the types of the used pneumatic tools and their service life, measured the level of generated noise and compared the obtained data with the passport acoustic characteristics from manufacturer. As a result, we showed the need to take into account the operating characteristics of instrument while ensuring acoustic safety. The main criteria for acoustic safety are defined.
Human safety ensuring in power supply systems with dead-earthed and insulated neutral wire
Authors: Markelov V , Vostrov K
Published: November 2019

In the current paper, the human safety issues in different power supply systems are considered. The conditions for residual-current device utilization and protective characteristics in grounded-neutral and insulated-neutral power supply systems are reviewed. Also, the endangerment factors and accident statistics are analyzed. Based on the given data, the judgment on the safety of different power supply system is given and a novel approach in the residual-current device setting up is proposed. Finally, the topology for IT system performing from TNC system is shown.
Shaping of structural and mechanical properties of heavy duty mandrels used for seamless pipe rolling
Authors: Gevogian G A , Vorobyev R A , Pachurin G V , Filippov A A , Mukhina M V , Kutepova L I
Published: November 2019

The main spheres of high-strength seamless pipes application are oil and gas production sectors, as well as the defense industry. Therefore, increasing the piercing rolling efficiency, increasing the strength and durability of the tool are the main factors that ensure the smooth production of seamless pipes. The article justifies the choice of the steel grade and displays the developed manufacturing technological cycle of heavy duty mandrels used for piercing and helical rolling of seamless pipes.
Ventilation modes of operation and their representation at the power characteristics of turbine stages and compartments
Authors: Tatarinova Natalia , Suvorov Dmitry
Published: November 2019

The article proposes an analysis of the main approaches in the theory of ventilation processes applied to the correct determination of ventilation losses occurring in the stages and compartments of TPP steam turbines in operating modes with low volumetric flow rates in a low-pressure cylinder. The features of the flow of ventilation processes in the low-pressure flow parts of CHP steam turbines and methods of their study are presented. New physical and mathematical models for calculating the ventilation power losses in the flow part of the turbine are considered. The universal generalized mathematical dependence for a high-precision estimation of the ventilation power losses of the turbine compartments is substantiated, taking into account the whole variety of parameters determining the level of these losses. On its basis, the authors have created mathematical models for calculating several types of CHP steam turbines for rapid assessment and accounting of technical and economic indicators of turbine operation all the possible range of operating modes. The basis of the new calculation models is adequate power and flow rate characteristics of the turbine stages and compartments, so the computational results correlate well with the experimental data, allowing to analyze a wide range of operating modes.
The possibility of increasing the efficiency of condensers at the CHP
Authors: Stepanov Oleg , Antonova Elena , Rydalina Natalya , Zakharov Vladislav , Antipin Stepan
Published: November 2019

In traditional condensers of combined heat and power (CHP) plants, water is used, which is discharged into the environment and creates environmental stress. It is proposed to cool the steam by air or freon. The basic schemes of CHP condensers operating on compressed air and freon are given. A comparative calculation of the condenser operating on water, air and freon was carried out. Analysis of the results shows the effectiveness of air, and freon compared to water. The advantage of freon is that it circulates in the heat exchanger, forming a closed system. At decreasing the temperature difference at the inlet and outlet to the condenser, the heat transfer coefficient of freon is higher than that of air.
Multi-criteria optimisation of subsonic axial compressor blading
Authors: Blinov Vitalii , Sedunin Viacheslav , Komarov Oleg
Published: November 2019

The novel approach to parametric topology of the 2D compressor airfoil was tested at multi-criteria optimisation problem for high speed subsonic application. Some results regarding the shape of the blade are presented.
The influence of design parameters on the blade flutter boundaries
Authors: Abdukhakimov Farrukh , Vedeneev Vasily , Kolotnikov Mikhail , Makarov Pavel
Published: November 2019

Blade flutter is one of the major problems that designers of modern gas-turbine engines face. In this paper, a study of the influence of the design parameters on prediction of blade flutter in compressors of gas-turbine engines is presented. As a rule, the flutter of compressor blades is predicted using simplified criteria based on the experience of designing and refining engines. These empirical and probabilistic criteria are not applicable to evaluation of the flutter since the parameters in question are not among the decisive parameters for simplified criteria. In this work, the energy method is used. It is shown that the inter-blade tension value has a significant influence on the blade flutter prediction, while the effect of other design parameters under investigation on the blade flutter prediction is insignificant.
To investigation of performance of the gas turbine plant, which operates with the working medium humidification in the inlet and overexpansion in the outlet
Authors: Osipov B M , Kh Perelshtein B , Zunino P , Derevianko O
Published: November 2019

The possibilities of increasing the specific power and efficiency of the gas turbine plant are considered by the working medium overexpansion behind the power turbine and the water injection into the engine inlet. The paper demonstrates that such a means can be used not only for a newly designed GTP, but also implemented in already operating power plants.
Mathematical modeling of operation processes of refrigerant compressor self-acting valves of domestic refrigerators
Authors: Petrosov S P , Kozhemyachenko A V , Alekhin S N
Published: November 2019

The article presents a mathematical model of refrigerant compressor self-acting valves for domestic refrigerators providing a set of data characterizing compressor operating cycle: change in the cylinder pressure, change in cylinder volume, and change in gas flow entering or leaving the cylinder, change in moving trajectory of the valve plate. The technique and algorithm for calculating valves parameters in the compressor operating cycle is proposed. The presented mathematical model provides valves calculation and ensures calculation analysis of the valves depending on their parameters for a particular model of a refrigerant compressor.
Experimental validation of a compact mixed-flow compressor for an active high-lift system
Authors: Kauth Felix , Maroldt Niklas , Seume Joerg R
Published: November 2019

Compact, electrically-driven compressors are a core component of a novel active high-lift system for future commercial aircraft. A newly-developed aeromechanical optimization process was used to design the compressor stage. The optimization resulted in an unusual mixed-flow compressor design with very low aspect ratio blades and a high rotational speed of up to 60,000 rpm. Due to the unusual design, experimental validation of the performance predictions by means of CFD is necessary. This paper presents the first experimental results obtained using a preliminary prototype at part-speed, i.e. rotational speeds from 20,000 to 30,000 rpm. The experimentally-determined pressure ratios deviate up to 1.5 %, the polytropic efficiencies up to 4 percentage points from the CFD predictions. Besides the deficiencies of available turbulence models, the underestimation of overall losses is presumably due to the omission of the volute in the CFD model. An experimental validation of the CFD predictions at full-speed is under way.
Prospects of binary energy generation systems based on the joint use of traditional sources of energy and wave motion energy
Authors: Yu Shabalov M , Filatova I I , Kuskova Y V
Published: November 2019

Electricity consumption of offshore oil and gas drilling platforms is usually provided by gas generator installations. However, such installations are expensive in operation and emit significant amounts of carbon dioxide and nitrogen oxides. Electricity consumption from the main grid is the best option, but expensive for platforms located far from the coast and with limited environmental benefits, if not supported by environmentally friendly production. Offshore wave energy technology, which is currently being developed for deep-water areas, can be connected directly to the platforms and work in parallel with gas turbines. Wave power station will save fuel and reduce carbon dioxide emissions, while there is no need for a long and expensive connection to the coastal grids. Operational strategies and fuel savings and emissions, depending on the size of the wind farm, are quantified by the example of the offshore oil and gas platform in the Far East shelf. In this paper, an assessment is made of the prospects of using the approach of dual power generation systems, which in turn will provide a significant reduction in fuel consumption and emissions, especially if we consider starting and stopping gas turbines. The main task is to find the optimal work strategy that balances the number of starts and stops of gas turbines with dissipative energy and fuel economy.
Theoretical study of gas parameters influence on reciprocating compressor performance intended for NGV-refueling compressor station
Authors: Kotlov A A , Kuznetsov L G
Published: November 2019

Ensuring the reliable and efficient operation of the reciprocating compressors in the wide range of the operating parameters is one of the important issues at designing, manufacturing and operating the compressor equipment. The quality of any equipment is determined by the improvement of calculating methods used at its designing. While designing the reciprocating compressors with a high compression degree the issue arises of determining the actual properties of the medium being compressed. The theoretical investigation of the gas initial parameters influence on the reciprocating compressor operation process is represented in this study. The results of the comparison of the reciprocating compressor operation for compression of ideal and actual gas are given in this study.
Comparative evaluation of renewable energy scenario in Ghana
Authors: Agyekum E B , Velkin V I , Hossain I
Published: November 2019

Availability of cheap, reliable and safe energy is very essential to the growth and development of every nation. This paper assesses solar radiation and wind speed at one site each in the southern, middle-belt and northern part of Ghana to estimate the potential of integrating solar and wind energy into the country’s energy mix. The analysis included the financial viability of a possible 2.5 MW installed solar power plant in Gomoa, Kintampo and Navrongo. The RETScreen software was used for the feasibility and financial viability evaluation. The study found out that the southern part of the country experiences the least solar irradiation as it recorded 4.73 kWh/m2/day, the middle belt recorded 5.28 kWh/m2/day, the northern belt however recorded the highest level of solar irradiation of 6.07 kWh/m2/day. It was also found out from the research that the southern belt has the highest annual average wind speed of 2.8 m/s followed by the northern sector with 2.3 m/s and the least was recorded in the middle-belt with an average wind speed of 2.2 m/s. The financial indicators like the internal rate return, equity payback years, cumulative cash flows and simple profitability index all indicated that the northern sector is the best site for the development of solar energy although the other parts of the country are also positive. The impact of the development of these plants will also have a considerable impact on the environment since the research shows some 93% reduction in the emission of greenhouse gases (GHG).
Development of the schematic thermal circuit of the heat power complex for highly effective use of secondary and renewable energy resources
Authors: Dyakonov Evgeniy , Papin Vladimir , Bezuglov Roman , Denisova Irina , Yanuchok Alexander , Dobrydnev Denis
Published: November 2019

Development process of a schematic thermal circuit of a heat power complex for highly effective use of secondary and renewable energy resources is considered in this article. Earlier authors developed basic elements of the developed scheme they are warmth transformation block (cascade thermal pump) and warmth accumulation block (accumulators of warmth and cold). The schematic thermal circuit of a heat power complex also contains additional units. It is the module of additional low-potential sources of warmth and cold connection, solar collector, the soil probe (heat exchanger), consumers of heat energy for a heat power complex. Authors defined receivers they are heating, hot water supply, conditioning, freezing and sources of energy are low-potential energy soil/air, solar energy, recuperation of ventilating air, utilization of warmth when conditioning rooms, using a sewer source.