bluuebunny/crossref_metadata_2025 huggingface dataset:
Wireless local data transmission network through LED lighting compatible with IEEE 802.11 protocol communication systems
Authors: Kozyreva O A , Polukhin I S , Shiryaev D S , Shcheglov S A , Borodkin A I , Gareev E Z , Kondakov D V , Matveev Y A , Odnoblyudov M A , Bougrov V E
Published: July 2019

We developed a wireless duplex communication system using visible light communication concept. In this work we investigated a downlink data transmission channel. We modelled the optical configuration of the system, calculated optical losses, fabricated the system and measured downlink channel parameters under test of analog and digital signals. The analysis showed that with a heterodyne scheme used for transmitting signals through visible light, the model of additive Gaussian noise is applicable to the channel and there are no phase distortions in the system. The system has shown the capability to operate with modulation types according 802.11 IEEE protocol.
Research on Switching Overvoltage of MMC-MTDC System with Hybrid DC Circuit Breaker
Authors: Chen R Q , Ning L H , Ma Z X , Yin Y J , Zhao Q X
Published: July 2019

The modular multilevel converter based multi-terminal HVDC (MMC-MTDC) system with hybrid DC breakers should consider the influence of the action of the DC breaker on the switching overvoltage, which puts higher requirements on the overvoltage protection of the system. Flexible DC demonstration project in Zhangbei will realize the first engineering application of hybrid DC circuit breaker. Based on this project, an overvoltage protection scheme for MMC-MTDC system is proposed. Firstly, this paper investigates the effect of the operation mode of the DC grid on the switching overvoltage level. Secondly, typical faults and the protection action sequence of various faults are analyzed in detail. The characteristics and laws of various switching overvoltage are deeply studied. Finally, the switching overvoltage of converter station is calculated on the basis of the control and protection system, and the recommended values of the insulation level of converter station equipment for the ±500kV MMC-MTDC system with hybrid DC circuit breaker are given.
Theoretical and Simulation Study on On-line Monitoring Technology of Transformer Short-Circuit Impedance
Authors: Liu Hao , Gan Zhaohui , Liu Xi , Yang Fanglin , Wang Chan , Wang Chengwu
Published: July 2019

Based on the equivalent circuit of transformer, this paper deduces the calculation method of short-circuit impedance of three-phase transformer based on multiple measurement data. Taking a single-phase transformer as the research object, the ‘magnetic field-circuit’ simulation model is established. The normal operation and winding deformation caused by different axial displacements are simulated and analyzed. The results show that short-circuit impedance changes when transformer winding is axially deformed, and the degree of change is related to the degree of deformation. Compared with the normal situation, the short-circuit impedance increases by 52.1% when the four transformer coils are moved 15 mm each. Therefore, on-line monitoring of the transformer short-circuit impedance can reflect the abnormal deformation of the transformer winding to a certain extent.
Research on Optimal Operation Mode for Large-scale Urban Distribution Network Considering Safety Constraints
Authors: Fan Yang , Lei Yang , Jun Liu , Ling Shi , Haifeng Tang
Published: July 2019

As an important measure for structure optimization, the network reconfiguration has been drawing attention of scholars at home and abroad. At present, the general goal for network reconfiguration is to reduce network line loss achieving load balance. In this paper, the reconstruction methods for distribution network considering closed loop constraints is proposed from the perspective of load transfer between different loops to improve closed system reliability. After Dongjing Town distribution network verification, this method has shown important theoretical significance and high practical value.
Conic Programming Based Day-ahead Optimization Dispatch in Distribution Network Containing Large-scaled Distributed Generation and Electric Vehicle
Authors: Gao Fei , Song Xiaohui , Shi Haifeng , Li Jianfang , Zhang Yu , Li Yajie , Zhao Shanshan
Published: July 2019

Regarding day-ahead optimization dispatch in distribution network containing large-scaled distributed generations (DGs) and electric vehicles (EVs), this paper proposes an optimization dispatch method based on conic programming. A model for dispatch that can optimize the EV aggregator charging power and the output of DGs is established. The proposed model takes the constrains of EV charging energy and charging power into consideration. In addition, DG can curtail the active power in the model to guarantee the operation safety. Then nonlinear optimization dispatch model are transformed and relaxed into second-order cone programming model to be solved. The optimization dispatch method proposed in this paper is verified by the IEEE33 node test system.
Site Selection and Capacity Determination of Multi-Types of DG in Distribution Network Planning
Authors: Wang Y N , Zheng T
Published: July 2019

Site Selection and Capacity Determination of Multi-Types of Distributed Generation (DG) have a significant impact on the distribution network planning. Therefore, it is necessary to scientifically analyze the impact of the distributed generators on the distribution network, Considering the minimum sum of investment cost, network loss cost and power outage loss cost, the grid planning model is established by considering network constraints such as voltage constraint, line capacity constraint, power flow constraint and reverse power flow constraint.. The genetic algorithm is used to solve the optimal grid planning scheme for the distribution network with microgrid. Finally, the IEEE 14-bus Distribution Network is analyzed for the DG location and volume planning in Distribution Network to verify the validity and feasibility of the planning model.
Research on Distributed Energy Storage Operation Mode and Technical Economy under the Background of Energy Internet
Authors: Shi Zhiyong , Li Qionghui , Huang Bibin , Hong Bowen
Published: July 2019

Energy storage subverts the traditional concept of source-network-load, breaks the inherent property of power supply and consumption at the same time. Distributed energy storage plays an important role in the energy internet. The paper introduces the technical characteristics of distributed energy storage, builds typical application scenes under the energy internet environment. Given this background, two typical operation modes of customer-side distributed energy storage are proposed based on different operational objectives and constraints. After studying the basic strategy of the operating model and evaluating the distributed energy storage economy from the perspective of users and electricity retailers, it can be concluded that distributed energy storage is able to effectively improve system flexibility and energy utilization. Its economy is determined by various factors such as technical route, configuration capacity, and electricity price. A reasonable operation mode can promote the sustainable development of distributed energy storage.
Research on the Static Test of Active Power Compensation Coefficient for Compressed Air Energy Storage
Authors: Wen Xian-kui , Zhong Jing-liang , Li Pan , Chen Wen
Published: July 2019

Peak load regulation and frequency regulation of electric power system are the main roles of Compressed Air Energy Storage(CAES). The static test method to active power compensation coefficient (APCC) has never been founded yet. Based on the operation character of CAES, the range of APCC has been given in this paper. This paper also introduced the static test system for APCC and the process of static test. In the end, the method of calculating for APCC has been established. With the static test, the APCC can be evaluated, which can make the grid more stable.
Valuation of Energy Storage at User Side Considering Total Life Cycle
Authors: Hu Jing , Hong Bowen , Ma Kai
Published: July 2019

With the continuous progress of energy storage technology and the substantial reduction of cost, as well as the development of China’s energy Internet, customer-side distributed energy storage has been applied more and more widely. Considering the customer-side distributed energy storage which takes the grid-connected “distributed solar + energy storage” as the main application mode, a distributed energy storage evaluation model based on double-granularity optimal operation strategy is proposed, which is built on life-cycle cost-benefit analysis model for customer-side distributed energy storage considering its operation optimization in advance. Taking large industrial and business consumers in one province in China as an example, the sensitivity analysis of customer-side distributed energy storage value is taken under different load characteristics, price policies, energy costs and energy storage technology characteristics, judging the customer-side distributed energy storage trends and potential of further development.
An Adaptive Reclosing Switch Based on Shunt Resistance
Authors: Liu Jian , Lei Yu , Zhang Zhihua
Published: July 2019

In order to solve problems that the low coincidence success rate of the automatic reclosure of distribution network and short-circuit current has a large impact on the system when it coincides with the permanent fault, a shunt resistance type of adaptive reclosing switch is proposed. In order to improve the success rate of reconfiguration of the distribution network. By selecting the appropriate shunt resistance, the switch can not only suppress the magnetizing inrush current, limit the short-circuit current, reduce the system impact, but also use the current characteristics flowing through the shunt resistance to determine whether there is a permanent fault in the downstream, and realize the adaptive reclosing. The shunt resistance type adaptive reclosing switch can be separately applied to the power distribution switch to replace the original reclosing mode, and as a switch with protection function, the safety of the fault handling process is improved.
Electromagnetic Transient Analysis of 500 kV XLPE Submarine Cable Interconnection Project from Zhenhai to Zhoushan
Authors: Xiao Shijie , Ding Xiaoyu , Wang Xiaotong , Ning Kanghong , Chen Hongwei , Peng Mingwei , Wang Xiaojian
Published: July 2019

In Zhenhai-Zhoushan transmission project, 500kV XLPE submarine cable lines are used for the first time in the world. Using electromagnetic transient simulation program(EMTP), electromagnetic transient problems in this project are investigated including electrical parameter of submarine cable lines, power frequency overvoltages, secondary-arc currents and recovery voltages during the single-phase reclosing, power frequency resonance overvoltages, induced voltages and induced currents, switching surges and so on. On the basis, the recommended configuration scheme of HV shunt reactors and neutral reactors is proposed. In addition, it is suggested to install closing resistors of 400ohm on both sides of line breakers in order to restrict switching overvoltages and ensure safe operation of submarine cable lines.
Mechanism and Experimental Study on Insulation Defect Discharge of Transmission Line
Authors: Liu Zhenyao , Gao Song , Jiang Haibo , Guo Rong , Kang Yubin , Chen Xuan
Published: July 2019

Common faults on transmission lines, such as insulator pollution flashover, trees flashover, string breakage failure of insulator will undergo a period of discharge before the occurrence of flashover, which is called insulation defect discharge. In this paper, the process of discharge such as floating discharge, insulator pollution discharge and tree discharge is simulated in the laboratory environment and the high frequency current waveform is monitored. The results show that insulation defect discharge will maintain a long period of time and will not immediately form a flashover fault, in addition, a great deal of high frequency discharge current pulses will be generated during this period. The discharge characteristics and the discharge pulses generated by different type of insulation defect discharge are quite different. Frequency of floating discharge current waveform are very high, while the pulse cluster of pollution discharge is dense, and the current waveform generated by tree discharge has notable dispersity. With the degree of discharge increasing, the parameters such as pulse repetition rate and discharge amount are gradually increasing.
The Strategy of Doubly-fed Induction Generator Low-voltage ride-through Based an Integrated Protection Circuit
Authors: Wang Xiangming , Zhang Huijuan , Zhang Qinrui
Published: July 2019

Aiming at the shortcomings of single-protection circuit in the low-voltage ride-through (LVRT) process of doubly-fed induction generators (DFIG), this paper proposes an integrated protection circuit strategy for LVRT of DFIG based super-capacitor(SC). The integrated protection circuit includes a Crowbar circuit, a rotor series dynamic resistance (SDR) and SC. By adopting different protection circuits in different situations and time divisions, the LVRT capability of the DFIG is comprehensively improved, and the transient current of the rotor current during the protection circuit input is analyzed in each case. Finally, the proposed integrated protection circuit strategy is compared with the traditional single Crowbar circuit and single SDR on the simulation platform MATLAB/Simulink. The simulation results demonstrate the effectiveness of the proposed integrated protection circuit strategy.
Influence of AC System Parameters on DC Current Distribution
Authors: Tong Xuefang , Pan Zhuohong
Published: July 2019

The ground current of HVDC transmission will cause DC bias of transformer in AC system. In order to master the influence of typical AC grid parameters on DC current distribution, a direct field-circuit coupling model of AC and DC power grid is established, and the evaluation parameters of DC current distribution are proposed. The influence of various factors such as the grid density, transformer and transmission line branch resistance, tower-ground wire system on DC current distribution in AC grid are quantitatively analyzed by grid examples. The results show that the denser the grid of a certain voltage level, and the smaller the circuit resistance of transformer and transmission line branch of a voltage level, the larger the DC current of the voltage level and the total DC current of the AC grid. When considering the tower-ground wire system, the DC current entering the AC power grid increases, and the smaller the wire DC resistance and the tower grounding resistance, the more DC current increases. In a line, the tower with the largest grounding current generally appears in the tower 1-4# near the substation with the larger current amplitude. In the calculation process of DC current distribution in large AC grid, ignoring the mutual resistance effect between substations will make the DC current of the AC grid larger, so it is not advisable to neglect the mutual resistance between substations in calculation.
Study on the Policy of Orderly Releasing Plans on Generation and Consumption of Electricity in Northeast China
Authors: Ma Xin , Liu Jicheng , Liu Qiong , Yu Linna , Ren Puchun , Yu Siyu , Chen Jing
Published: July 2019

An important part of China’s power system reform is the implementation of releasing plans on generation and consumption of electricity. This paper discusses the policy of orderly releasing plans on generation and consumption of electricity. By sorting out its relevant policies, interpret those policies from three perspectives. Study the releasing situation of generation and consumption of electricity in northeast China, integrate the implementation plan of the three provinces and one district and lay the foundation for studying the impact of policy and policy suggestions for orderly releasing plans on generation and consumption of electricity.
Identification method based on Zadeh filter models
Authors: Evdokimov I V , Tsarev R Yu , Yamskikh T N , Knyazkov A N , Moor I A , Kapulin D V
Published: July 2019

Mathematical modeling which provides the description of objects and proper organization of control operations in future is an integral stage in the automation of production. One of the approaches to build a mathematical model of an object is to represent nonlinear systems as combinations of inertial and nonlinear inertialess elements. The models thus obtained are called block-oriented. In this paper, we consider nonlinear dynamic objects represented as the models of the Zadeh filter class. In the process of the method development the identification equations were derived for the case when the test signal is a single sinusoid. Then the case of two sinusoids was considered. Such investigations allowed us to identify the patterns and describe the general case for several test components in the signal. The results of digital modeling using the sum of harmonic signals confirm the feasibility and validity of the proposed approach for identifying nonlinear models of the Zadeh filter class.
Optimization of the trajectory of movement of a parallel robot based on a modified AСO algorithm
Authors: Rybak L A , Khalapyan S Y , Malyshev D I
Published: July 2019

The article describes the use of a modified ACO algorithm to optimize the trajectory of a planar 3RPR robot. The trajectories of the motion of agents of the first generation were obtained in accordance with the classical and modified algorithm. The efficiency of using the modified trajectory planning algorithm was demonstrated, which made it possible to reduce the length of the original trajectories and the time required to process them. At the same time, in order to save time, the trajectories of movement obtained during its operation can be subjected to discrete local optimization. The result of the work of the algorithms is a set of tasks reflecting the change in each of the input coordinates of the mechanism over time, which can be directly used during the operation of the robot control system. A detailed description of the algorithm and the results of mathematical modeling are presented.
Technical state evaluation of oil-lubricated parts and units of aircraft gas turbine engines using microwave plasma method
Authors: Drokov V G , Drokov V V , Ivanov N A , Myrishenko V V , Skudaev Y D , Hodunaev A Y
Published: July 2019

The method for technical state evaluation of oil-lubricated units of aircraft gas turbine engines using measurement of wear particle parameters and the microwave plasma method is suggested. Diagnostic features accounting for quantity and composition of wear particles in oil samples and oil filter wash samples have been discovered. Parameter levels for non-defective engines are evaluated. Reference statistical models for non-defective engines, which take into account engine type and engine operating time, are calculated. Distribution laws of parameter values are evaluated, and value normalization functions were found. Actual validity with accuracy up to a unit has been estimated to be 85%, which is confirmed by factory disassembly study of engines, removed from operation by the results of evaluation.
Geomechanical feasibility of underground coal mining technology using control systems of electro-hydraulic shield supports for longwall mining
Authors: Klimov V V
Published: July 2019

The main objective of the research is to assess the possibility of using control systems of electro-hydraulic shield supports for researching geomechanical processes in the rock massif. The research aims to increase the efficiency of longwall mining technology. As a result of the research, changes of pressure distribution in the hydraulic powered shield supports along the width and length of the longwall panel are established. Pressure changes at various speeds of a longwall advance have been established. Recommendations about an increase in efficiency of underground mining of coal seams are made. The paper novelty consists in establishment of dependences of the maximum loads upon a shield on the speed of the longwall advance.
Development of technology for recovery of thermal energy of gases
Authors: Kondrat’ev V V , Sysoev I A , Sysoeva T I , Ershov V A , Gorovoy V O , Ivanov N N
Published: July 2019

The project aims to develop an energy saving method for conversion of thermal to electric energy. The review of engineering solutions in this area demonstrated the rationale for using thermoelectric generator (TEG) modules to produce energy for business use. As a part of the research, ANSYS models were developed and thermal fields of flue walls were studied at different flow speed rates and gas air environment temperatures. A design of the TEG unit consisting of 12 TEG modules, a cooling radiator and a switching unit was developed. A bench for studying the efficiency of converting thermal to electric energy was designed. Experiments using three types of TEG modules were carried out. Capacity values at different temperature gradients were determined. Pilot testing of a high performance thermo-electric generator was carried out within the temperature range under study. It was identified that by increasing the number of TEG units, it is possible to meet technological needs. A system consisting of single inline TEG units was developed. It was used for making circular cross sections in flues. The number of TEG units, the type of modules and the method for their connecting depend on capacity rates, temperature and flue dimensions. The authors filed a patent application. The possibility of research results commercialization in the oil and gas, metallurgy and chemical industries is being explored.
Air magnetic separator for the preparation of forestry seed material and its theoretical justification
Authors: Kozlova E V , Skrypnikov A V , Kozlov V G
Published: July 2019

The preparation of high quality seed material requires cleaning on special seed graders. Seeds of different cultures have particular surface and shape. Taking into account these differences, various plants have been developed and are widely used. The need for magnetic cleaning is caused by the impossibility of high-quality separation of seeds of different forestry crops. The analysis of modern technical means for the preparation of seed material showed that the idea of combining air and magnetic cleaning deserves special attention. In air magnetic separation, various forces influence a seed particle, the magnitudes and direction of which vary depending on the design parameters of the inductor and the position of a particle in the magnetic field of an inductor. It is possible to investigate the movement of a particle in the working channel, as well as to create a mathematical model by accepting some assumptions, the result of which will determine the main regularities of the air magnetic separation process and theoretically study the influence of the structural and technological parameters of the air separator on separation process. The particle motion curves were constructed for various values of magnetic force in the working channel according to the results of the analysis of seed motion trajectories. During the course of the research the graph illustrating the possibility of performing the process of air magnetic separation depending on the ratio of the air flow rate and magnetic force influencing a particle is presented.
Auxiliary equipment for downhole fittings of injection wells and water supply lines used to improve their performance in winter
Authors: Kuleshova L S , Kadyrov R R , Mukhametshin V V , Akhmetov R T
Published: July 2019

The article deals with two methods for eliminating freezing of injection wellhead fittings. The first method involves removing injected water from the well fitting under long well operation stoppage at negative ambient temperatures. Water is removed and air is supplied through the system of valves (a spring loaded valve and a float valve). When pumping water into the injection well, the float valve closes the access to the environment, and the spring-loaded valve is open for injected water. When the injection process stops, the spring-loaded valve supplies remaining water into the well fittings and the surface part of the water supply line and closes; the float valve opens. Air into the free space of the well fittings is supplied through the float valve thereby preventing the wellhead and the surface part of the water supply line from freezing. The second method is used to prevent the mouth of the injection well from freezing. A device is installed inside the casing, which allows heat to be accumulated in summer and winter. Accumulated heat is used to heat up the mouth when the water injection process stops.
Frequency converter power reduction for controlling the hydraulic parameters of the pumping station
Authors: Mukhamadeev E Z , Yagafarova Kh N
Published: July 2019

The article discusses the issue of power reduction for oil and gas equipment. It studies the method for reducing power of a frequency converter to control the hydraulic parameters of a pipeline by replacing a single centrifugal pumping unit with a pumping station consisted of series-installed pumps. The frequency converter is installed on the first stage pump. The method was tested in the water supply system for irrigation of high-temperature aerosol of technical carbon.
Evaluation of the effect of asphalt resin paraffin deposits on oil well performance
Authors: Petrova L V , Yarullin D R
Published: July 2019

The article deals with the problems of field development. The causes of low well performance were identified. Examples and causes of paraffin deposit formation were given. Methods aimed at solving problems of well operation were developed. An innovative method for dealing with asphalt-resin-paraffin deposits was suggested. It involves application of a submersible container with a complex action inhibitor. The formula of the inhibitor is presented. The technological layout of the container with the inhibitor is presented. Technological efficiency of the inhibitor as a method for ASPD prevention was proved.
Optimal design based on probability approach and fracture mechanics
Authors: Pitukhin A V , Skobtsov I G
Published: July 2019

This paper deals with the statistical fracture mechanical method for the optimal design of forest machine components. The problem of optimal design includes the choice of the objective function and independent design variables and establishment of the system limits. The objective function is determined as the mean total cost that includes the initial cost and the cost of failure according to the failure probability. A quasi-brittle fracture occurs under the influence of the stationary random process of loading. Analytical equations of reliability function estimation are obtained. The algorithm of the random search method includes an interval reduction with regard to zone and functional constraints. The approach to the optimal design problem solution can be applied to obtain optimal geometrical sizes and permissible limit defect values of machine components.
Electrothermal processing of tantalum capacitor powders
Authors: Cherednichenko A V , Cherednichenko V S , Bikeev R A , Serikov V A
Published: July 2019

A low-pressure arc discharger with the hollow cathode is a newly developed electrotechnological device for finely dispersed powders of particles having dimensions 50 micron and less. The discharger is useful for putting powder into a high reactive zone of a plasma column and for thermal and mechanical action on particles. In the NSTU, the plain scales of the splinter tantalum powder were gained experimentally. Based on the results of the experiments, several constructive solutions are proposed for the heating of powders with subsequent deformation of tantalum powder particles on the target.
Microprocessor-based watching control system for improved ladder-type rectifier
Authors: Ivanov V V , Myatezh S V , Kapustin A V , Alekseeva I K
Published: July 2019

Currently, the most energy-efficient device designed to convert AC to DC is a zone converter built on the basis of controlled power semiconductor devices: thyristors and transistors. The basis of these converters work is the zone-phase regulation method. The paper discusses the construction of a microprocessor control system for improved four-zone rectifier. The tasks aimed at energy efficiency achievement have been set and solved, the relevance of the tasks is justified. The microprocessor control system development stages including the drivers creation with galvanic isolation for thyristors and transistors control and greed synchronization are shown. Justification and choice of feedback are produced. The control algorithm for power semiconductor devices incorporated in the control program is given. For better understanding of the system operation principle, a block diagram which is based on a program written for the microcontroller is given. That program reflects the control system algorithm. Software modeling of the proposed system is carried out, the modeling results are presented.
Preliminary results of TUSUR University project for design of spacecraft power distribution network: EMC simulation
Authors: Kuksenko S P
Published: July 2019

In this paper, the relevance of the use of mathematical modeling with the electromagnetic compatibility requirements in solving problems of space engineering is shown. Approbation of the software prototype developed in TUSUR is performed by designing the power supply network elements of a spacecraft. The mathematical and software features of the prototype are described.
Definition of distortion power in AC network and analysis of its reasons
Authors: Myatezh S V , Novolodskiy M V , Kitova E T
Published: July 2019

This paper studies the conditions under which such non-active power components as reactive power and distortion power appear in the alternating current power network. By simulating with MatLab Simulink, the validity of formulas obtained by analytical way was tested. The formulas define the components of non-active power based on one of the most well-known theories. The results obtained will be useful for mode optimization in the alternating current networks and for developing effective non-active power compensating technologies.
Grinding closed circuit in centrifugal grinding unit
Authors: Sevostyanov V S , Uralskij V I , Uralskij A V , Sinitsa E V , Uralskaja L S
Published: July 2019

The article presents scientific and technical developments on the creation of a technological module of a closed grinding circuit, the design of which allows improving the quality of the finished product, as well as improving the performance of the grinding unit. The process of organizing a closed cycle using a centrifugal air-through separator with two separation zones is described. The influence of the design parameters of the input and output elements of the pipes on the gas flow rate in the working chambers of the grinding unit using the SolidWorks software in the FlowSimulation module has been studied.
Features of thermal ageing of cables with different type of insulation
Authors: Vlasov A B , Vlasova S V
Published: July 2019

A wide range of temperature and duration of cable routes operation requires the development of objective methods for assessing the properties of cable insulation. While working, preparing and repairing cable routes, it is important to use express methods to determine the technical condition of insulation, to search for diagnostic parameters indicating the process of crack formation. An ongoing monitoring of cable insulation with standard devices controlling electrical resistance and leakage currents is not sufficiently effective for evaluating the performance and predicting the properties of cable insulation. The study is aimed at further testing of the technique by analysing the properties of materials used in cable engineering, as well as comparing the results obtained by various devices manufactured by national and foreign companies. Tests were carried out to assess the quality of insulation based on the monitoring of hardness of the hose insulation and the conductor insulation of KNR and KNREk cables. In the KNREk type cables, the core insulation is also made of the RTI type rubber, but the hose insulation is created on the basis of a material from polyvinyl chloride compound. The method of assessing the quality of insulation and assessing the degree of ageing of cable material is implemented by measuring the hardness of insulation material using the Shore method using portable hardness testers of the following types: TH-200, NOVOTEST TS D-A (TS D-D) up to 100 HSА (HSD). It is shown that the proposed technique makes it possible to identify objective statistical parameters of the material hardness and to diagnose the quality of insulation in operation without dismantling cable routes. The hardness parameters of hose insulation from polyvinyl chloride compound can be controlled by TS D-D devices. The heat resistance of hose insulation of the KNREk type cables is higher than that of the cables of the KNR type, which creates opportunities for their longer operation at high temperatures.
Theory and a posteriori practical methods for calculating the reliability of electrical equipment
Authors: Kuznetsov S M , Orlova I V , Lisichko O I
Published: July 2019

The determination of the current technical resource of the electric transport system is an important characteristic that allows one to define not only the current reliability of the system, but also to predict it for the future. If the maintenance of electrical equipment is carried out to restore the reliability, failure flow is not stopped, then the intensity of equipment failure will be artificially overstated. The timing of service impacts will also be overstated unsuccessfully.
Problems of mathematical modelling of elastic boundary value in the stress-strain state of car body elements
Authors: Gulyaev V A , Kozlov A A , Loginov N Y , Soldatov A A
Published: July 2019

This article considers mathematical modeling problems of elastic boundary value. The stress-strain state mathematical modeling is used to assess the adequacy of theoretical solutions. The conditions of stress-strain state elements of the study mathematical modeling of the car body are given. The obtained analytical dependences make it possible to simulate the stress-strain state of the car body elements in real operating conditions and to compare the experimental and calculated values of stresses, strains and displacements arising under load.
Evaluation of the economic feasibility of the introduction of plasma hardening technologies in the Far North enterprises
Authors: Konyuhov V Yu , Gladkih A M , Chemezov A V
Published: July 2019

The various technologies of plasma surface hardening of the crests of wheel pairs with regard to the conditions of the Far North are considered by the example of Norilsk enterprises. When considering economic issues the cost of repairing wheelsets were considered. The advantages and disadvantages of each method of plasma surface hardening are shown. Criteria for the economic feasibility of their implementation are established. It is shown that from the standpoint of hardening process cost of one wheel, it is preferable to use the plasma quenching technology in the arc mode.
Influence of Fe component from milling yield on characteristics of perlite based geopolymers
Authors: Kozhukhova N I , Zhernovsky I V , Lebedev M S , Sobolev K
Published: July 2019

The mineral and chemical composition of aluminosilicates used in geopolymer systems is critical for optimal structure formation and the overall performance of the geopolymer products. The composition of alumosilicates can be altered during the technological processing, especially, at the stage of fine milling. This study investigated the effect of aluminosilicate contamination with Fe from milling yield, the characteristics of the aluminosilicates with a metal lining, structure formation, and hardened properties of geopolymers based on different natural and technogenic persilicic aluminosilicates. The formation of Fe-phases due to milling yield was detected by the XRF analysis and the XRD investigation revealed the formation of nanosized ferrous hydroxide or bernalite Fe(OH)3(H2O)0.25. The volume of an elemental cell of the nanosized bernalite per Fe atom is 4.5 times larger than that of the metallic iron. This results in the disintegration of the matrix, which was observed by SEM and then confirmed by reduced strength performance of geopolymer composites. Based on this study, the negative effect of Fe-phases from milling and nanosized ferrous hydroxide on structural characteristics and service performance of geopolymer composites based on natural and technogenic raw materials was concluded.
Physico-mathematical model for bellows expansion joint efficiency by different manufacturing technologies
Authors: Novikov I A , Amirkhanov E I , Logunov V V
Published: July 2019

Increasing the reliability and improving of the technical characteristics of bellows and bellows expansion joints widely used in various fields of technology is a recent issue today. To solve this issue, a physico-mathematical model of functioning and measuring the reliability performance of bellows expansion joints is developed. The model includes two mechanisms of fatigue breakdown and wear: the Rehbinder effect and fretting. The developed model allows for calculating cyclic operation life for different bellows expansion joints. The model describes bellows expansion joints by three parameters: growth rate of a microcrack due to the Rehbinder effect, speed of fretting wear, and value of reversible period of microcracks formation. One can experimentally measure these parameters for different constructions and technologies of manufacturing of bellows expansion joints. Today, there are various technologies of bellows expansion joints manufacturing, including promising technologies of modification using fluoro-organic surfactants. The developed model is applied for assessment of different manufacturing technologies. Based on the analysis of the physico-mathematical model, the requirements for technologies are defined that lead to increasing of reliability of bellows expansion joints. The technologies of modification using fluoro-organic surfactants are theoretically proved to lead to increasing of the reliability performance of bellows expansion joints.
Diagnostics of an asynchronous motor powered from a self-commutated voltage inverter
Authors: Zhukovskiy Y L , Korolev N A , Koteleva N I
Published: July 2019

The presented research is focused on two issues. The first one is finding additional parameters that characterize the technical condition of an electric machine according to the current consumption. The second one is increasing of the informativeness of diagnostic methods in conditions of limited access to equipment and incomplete information. The paper discusses a method for diagnosing low and medium power asynchronous electric motors by electrical parameters. It is shown that asynchronous electric motors powered from a self-commutated voltage inverter have contained higher harmonic components in addition to the main harmonic. The non-sinusoidal voltage leads to the emerging of the highest current components in the stator winding of the motor. This is the reason for occurring of a pulsating component of the torque on the motor shaft. Therefore, there are two types of ripple: the one caused by the power supply from the self-commutated inverter and the one caused by defects. The moments’ coincidence of these ripples leads to increasing in the amplitude of oscillations. However, significant noise due to the presence of an autonomous inverter does not allow using the current spectrum to diagnose damage. Analysis of the hodographs of the Park’s vector of the stator current and voltage allows one to exclude harmonic components that were formed by the carrier frequency (and multiple of it). At the same time, analyzing the modulus of the Park’s vector and its spectrum, one can note pulsations of the amplitude values of the vector modulus corresponding to certain damage.
Prospects for the use of supercapacitors in railroad electric transport
Authors: Kuznetsov S M , Artemenko I V
Published: July 2019

In this article we considered a conversion device that ensures matching of the characteristics of the superconducting inductive (SPIN) energy sources and receivers of electric energy of the traditional performance in a power unit of autonomous perspective of the locomotive. Diesel-electric traction is a well-known and established technology for railways operators, but this alternative is non-ecological for the future because only electric traction has a considerable superiority. Besides, diesel-electric engines waste energy when resistive braking is used. This non-regenerative braking decreases the overall efficiency by 10-20%. With these premises, it is important to develop new strategies to increase the energy efficiency of diesel-electric haulage. To reach a better efficiency, a locomotive with energy storage (battery, super-capacitors) is theoretically proposed. Besides, the possibility of using a lower thermal engine with energy storage devices is considered too. This solution reduces diesel consumption and CO2 emissions while being economically viable. It supposes an efficient energy management because the diesel-electric locomotive could act as a dispersed mobile generation (DMG) unit when working under electric overhead lines, and it can be used as a distributed resource for this specific electric power system.
Magnetic lubricating oils based on organosilicon nanofluids
Authors: Bolotov A N , Novikov V V , Novikova O O
Published: July 2019

The results of studying tribotechnical and physicochemical properties of various liquids have proved applicability of a dispersion medium, which is based on organosilicon liquids, for producing new-generation magnetic lubricating oils. The paper gives recommendations for choosing a dispersed magnetic phase. There is an original approach to selecting surfactants for stabilization of a magnetic oil colloidal structure, taking into account their dielectric properties and the effect on friction. The paper describes technological features of the synthesis of lubricating oils based on polyethylsiloxane PES-5 and chlorphenylsiloxane KhS-2-1VV containing nanosized magnetite. It also investigates lubricating properties of magnetic oils based on oligodiethylsiloxane and oligomethyl(chlorophenyl)siloxane under various friction conditions and shows their specific features. It analyzes the influence of various additives and fillers on tribotechnical characteristics of magnetic oils. It also defines a different mechanism of additives effects on frictional contact properties. The results of magnetic oil tests determine the most promising compositions for practical use in tribounits. Finally, there are recommendations on practical application of optimal compositions of magnetic lubricating oils in traditional and perspective tribounits with various operational parameters.
Investigation of the microstructure of laser-deposited layers on cast-iron parts
Authors: Ivanov A , Kolmakova T
Published: July 2019

The gas-powder laser surfacing process of the cast-iron parts’ surfaces with the aim of increasing the wear resistance is investigated. Obtaining a coating with specified parameters (chemical composition, dimensions and quality of the rollers being deposited) depends on the irradiation regimes: power, processing speed, dimensions of the focal spot, powder consumption and the method of its delivery. St3 steel was used as a base material. Self-fluxing powders PG-C3R2, PG-PBH-6-2 and PG-US25-20Fe and their mixtures were used as a material for surfacing. The powders had a particle size of 50-160 microns. During laser heating, the structure is refined: the size of graphite plates is reduced from 150–200 µm to 20–40 µm in the melted zone, then their depth increases to the initial value. In the melted zone, graphite partially dissolves, partially burns out, forming pores. In the areas with the most complete dissolution of graphite plates, an austenite-martensitic structure with a hardness of up to 8.0–9.5 GPa is formed. In areas with a lower degree of dissolution of graphite, a martensite-sorbitol structure is formed with a hardness of 6.5–7.0 GPa. In the area of laser exposure, the hardness of the cast-iron welded parts increases by 3-4 times, which provides a significant increase in wear resistance.
The use of nanomaterials to improve the wear resistance of machine parts under fretting corrosion conditions
Authors: Krasnyy V A
Published: July 2019

The use of nanomaterials in different branches of machinery manufacturing has been studied. Nanomaterials application for improving working properties of machine parts has been described. Fullerene С60 friction properties have been studied; the works of some authors on improving metal resistance with fullerene С60 coating have been analyzed. It has been determined that there is little information about fullerene tribological properties and they are mostly about fullerene С60 as a thin film and additive to lubricating materials in sliding friction with minor normal loads. The test results on fullerene С60 impact as low-friction coating and additive to lubricating oil for reducing steel and brass samples wear in fretting corrosion are given.
Prospects for the use of martensites in the manufacture of adaptive anti-slipping spikes
Authors: Voiku I P , Sergeeva T V , Strikunov A V
Published: July 2019

The article substantiates the relevance of the development of an innovative device, namely an adaptive anti-slipping spike, and the prospects for the use of martensites in its manufacture. The device belongs to the automotive industry, specifically to the anti-slipping spikes. Tire treads of vehicles are equipped with these spikes to increase their adhesion to the roadway. The use of traditional anti-slipping spikes does not allow solving two problems at the same time: to ensure maximum adhesion of the vehicle’s wheel to the road surface and to minimize the destructive effect of anti-slipping spikes on the road surface. These tasks are solved by the fact that the proposed device is made according to the shape and size of traditional anti-slipping spikes but contains a retractable pin. The pin can be operated either by the substances with a negative coefficient of thermal expansion or martensitic materials. The article describes the prospects and features of their use.
Structure of digital and smart factories of the Industry 4.0
Authors: Zakoldaev D A , Shukalov A V , Zharinov I O , Zharinov O O
Published: July 2019

The current task of creating digital factories of the Industry 4.0 through the example of digital factories and smart factories engaged in the item designing is considered. The scheme of competences for the Industry 4.0 company is presented, based on the experience and the performance of the existing companies of the Industry 3.0. The digital factory scheme with project components and its informative support is presented. The smart factory scheme with production components is also given. Based on the results of the analysis of the digital design and manufacturing processes, the set of unique components providing information support to the project and production activity of enterprises is proposed. Implementing general components in the form of ready-to-use services deployed in the community cloud is proposed. Unification of the cloud services components is efficient for the Industry 4.0 companies which are parts of one virtual factory.
On ⅁Γ-complete sets
Authors: Debs Gabriel , Saint Raymond Jean
Published: July 2019

Extending a result of A. Kechris we prove that under suitable assumptions on the class

Γ

\mathbf {\Gamma }

of Borel sets, in particular when

Γ

\mathbf {\Gamma }

is a Baire class, if any

⅁

Γ

\Game \mathbf {\Gamma }

set is reducible to some

⅁

Γ

\Game \mathbf {\Gamma }

set

A
A

by a

⅁

Γ

\Game \mathbf {\Gamma }

-measurable function, then

A
A

is

⅁

Γ

\Game \mathbf {\Gamma }

-complete.