## No 28 (2018)

**Year:**2018**Articles:**13**URL:**https://ered.pstu.ru/index.php/elinf/issue/view/225**DOI:**https://doi.org/10.15593/.v0i28

Articles

NUMERICAL EVALUATION OF THE TEMPERATURE FIELD OF THE CABLE COUPLING AND ITS EFFECT ON THE CABLE LINE CAPACITY

#### Abstract

Laying of power cables with XLPE insulation for 10 kV is carried out in the ground or cable channels, during laying in connection of two cable lengths. The connection is made by means of a coupling. The design of the coupling is similar to the cable design, but radially large in size for the following reasons: bolted connection of the conductors and large insulation thicknesses. When the rated current flows through the core, heat is released according to the Joule-Lenz law. The conductivity of the bolted joint is lower than the conductivity of the core, and also the coupling has a greater thermal resistance than the cable. In this article, taking into account the assumptions made and the boundary conditions, a three-dimensional mathematical model of the processes of heat transfer and electromagnetism in the cable line in conditions of laying the cable with a coupling, in the ground. The numerical realization of the mathematical model was carried out Using the finite element method in one of the ANSYS software packages in the Free environment. Plus 1×400 for a constant voltage of 10 kV. As a result of the numerical solution, there were limited fields in the coupler connection of the power cable and the environment. As a result of analyzing the results of measurements of temperature fields, acceptable permissible current loads were available.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2018;(28):7-17

COMPARATIVE ANALYSIS OF METHODS OF MULTIPLY CONNECTED AUTOMATIC CONTROL SYSTEMS FOR A GAS TURBINE PLANT

#### Abstract

The article explores the possibilities of constructing multiply connected systems for automatic control of gas turbine power stations. It is known that the enterprises of the domestic aircraft engine manufacture produce gas turbine units (GTU) not only for aviation, but also for the construction various capacities power stations. It is known that GTU is efficient only if there is an automatic control system (ACS), so the tasks of improving the SAU GTU are given serious attention. In GTU, intended for power plants, there is a need to provide specified indicators of electric power quality in conditions the power plant constantly changing electric load and changing operating modes, which increases the requirements for automatic control systems. We consider ways to significantly improve the parameters of multiply connected systems of automatic control by using regulators built using fuzzy logic algorithms, the introduction of an adaptive ACS with a reference model and automatic control system with a tunable model, neural networks. The possibilities of their construction are explored, their advantages and disadvantages are analyzed. As a method of adaptation, it is advisable to choose a method based on the Lyapunov function, because search time the shortening for the extremum. As a model GTU uses a complex dynamic model of Aviadvigatel OJSC (Perm), designed to test control algorithms and use as part of semi-standard test benches. As the model of automatic control system, the program code electric power GTU the regular ACS the electric power GTU is used. The models are implemented jointly as part of the software modeling complex KMES and MatLab.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2018;(28):18-31

OPTIMAL TWO-PHASE PULSE-WIDTH MODULATION

#### Abstract

An analytical approach to optimal pulse-width modulation is considered. In this case, the pulse width modulation means the process of approximation of the pulses (modulated) of the required voltage, the smooth (modulating) voltage, which is necessary for the formation of the load current. Current modulation error refers to the difference between the current generated by the modulated voltage function and the current generated by the modulating voltage function. The modulation quality index is interpreted as a numerical integral characteristic of a quadratic modulation (dispersion) error at a certain time interval.Two-phase modulation is a two-half-bridge modulation. For two-phase pulse-width modulation the expression of current dispersion to the load is obtained. A synthesized formula for half-bridge switching functions. It is shown that the two-phase pulse-width modulation algorithm has three free variables, which can be used to find the minimum current dispersion in the load, which is a low-frequency filter. The concept of zero potential function as a free variable, which is optimized, is introduced. We found its expression, which corresponds to the minimum current dispersion in two-phase modulation. Formulas for determining the parameters characterizing the position of pulses of half-bridge potentials at the pulse-width modulation interval are obtained. It is shown that the optimal location of the pulses on the pulse-width modulation period can significantly reduce the current dispersion at a relative modulation frequency of less than 40. When the relative modulation frequency exceeds 40 becomes the optimal modulation with the Central symmetrical position of the pulse interval modulation. The described approach to the two-phase optimal pulse width modulation can be generalized to multi-phase pulse width modulation.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2018;(28):32-49

ADAPTATION OF THE MATHEMATICAL MODEL OF THE COMPUTER SIMULATOR COMPLEX BASED ON THE REAL-TIME DATABASE

#### Abstract

The article discusses the relevance of the use of computer simulator complexes in chemical, petrochemical and oil refining industries, conditioned by the requirements of industrial safety. A brief description of the composition and structure of typical computer simulators is given. The problem of the "aging" of computer simulators is described, which consists in parametric and structural changes in the technological process. To solve the problem of "aging", an algorithm for adapting the mathematical model of the technological process, considered in previous works, is proposed. The work of this algorithm is to create a static model of the technological process, similar to the existing dynamic model in the computer simulator complex, with the subsequent adaptation of this model by known methods of nonlinear optimization, with subsequent substitution of the coefficients found in the dynamic simulator model. For periodic operational correction of the mathematical model of the technological process, the modernization of this algorithm is proposed using real-time database. The work of the algorithm is to create a static model similar to the existing dynamic simulator model, with subsequent tuning of the mode according to the static model and the real-time data obtained from the process object, with a specified periodicity, and then substituting the coefficients found in the dynamic simulator model. The algorithm allows maintaining the current state of the computer simulator complex, corresponding to the real state of the installation, automatically adjusting to parametric changes at the technological object. Also, in the article, further development of this work is proposed to create a forecasting system based on the adapted mathematical model of a computer simulator complex.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2018;(28):50-61

INVESTIGATION OF THE traction effect OF A CYLINDRICAL LINEAR VALVE ELECTRIC MOTORS

#### Abstract

The theoretical and experimental investigation of the traction effect occurring in a cylindrical linear valve motor (CLEM) between a secondary element and an inductor is considered in the article. The force acting to reciprocate the secondary element is the operating force of the cylindrical linear valve motor. The secondary element creates a force force along the axis of the motor, and the traction effect consists in the transverse attraction of the secondary element to the inductor. The forces of mechanical friction of the secondary element about the inductor arise because of the presence of a traction effect between them. As a result of the traction effect, the secondary element begins to touch the surface of the inductor, which leads to a sharp increase in the magnitude of the mechanical friction force between them. As a consequence, there is a sharp weakening of the force effort, which is a worker for the CLEM. Two different designs of the inductor of a cylindrical linear valve motor are considered in the article, their comparison is compared with the magnitude of the specific force. The forces of traction, friction, and force between the secondary element and the inductor are determined for these two different structures. The traction force is due to the displacement of the secondary element of the cylindrical linear valve motor relative to the axis of the inductor, as a result of which the magnetic gap between the inductor and the secondary element becomes uneven in magnitude. In experimental studies, it was found that the tensile force, and hence the mechanical friction, significantly weakens the working force of the CLEM. On the basis of experimental results, we came to the conclusion that it is necessary to change the design of the inducer of CLEM to reduce the traction and mechanical friction forces. The change in the design of the inductor is the use of a non-magnetic intermediate centralizer, which is inserted between two sliding bearings that are located at the ends of each module of the CLEM. In addition, the design of the magnetic flux tube of the high-voltage tube was changed, in which instead of one slot for a three-phase system of windings, three symmetrical grooves were made, each under its phase of a three-phase winding. As a result, the magnetic system of the CLEM became axisymmetric. All these measures taken to change the design of the CLEM have made it possible to sharply reduce the effect of traction, and hence the magnitude of mechanical friction, resulting in a significant increase in the specific force.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2018;(28):62-75

COMPARISON OF ELECTROMAGNETIC PROCESSES CALCULATION METHODS ON THE EXAMPLE OF A CYLINDRICAL LINEAR ELECTRONIC MOTOR

#### Abstract

This article presents a comparison of the two main methods for calculating the electromagnetic processes and the characteristics of electric motors.The first method is based on the theory of electric and magnetic circuits, and the second based on the solutions of the Maxwell equations in differential form.The methods of modeling synchronous motors with permanent magnets are shown in the example of the CLEM.Calculations of electromagnetic fields on the basis of a mathematical model reflecting to a greater or lesser extent the real physical object are the basis for the design of various electric machines. Thus, the choice of the method by which the mathematical model of the engine will be constructed plays an important role in the design of electric machines. As the results of the calculation for these two methods, angular and work characteristics are presented as the most important parameters for engine design.The calculation of electromagnetic fields using the theory of electric and magnetic circuits based on substitution schemes was carried out according to the method of calculating synchronous machines with permanent magnets, presented in the work of I.L. Osin and F.M. Yuferov. Calculation of electromagnetic fields according to the finite element method was realized by the software package ANSYS Maxwell.The angular characteristics are represented by the dependence electromagnetic force F on the values of the angular displacement θ for different values of the supply voltage frequencies.Work characteristics are represented by the dependences of the electromagnetic force F , the phase current I , the power consumption P 1, the efficiency η and the power factor cos(φ) on the power on the rod P 2. The result of the comparison of these two methods revealed a significant deviation of I , P 1 and η, which is related to the saturation of the magnetic circuit, which was not taken into account in the works of I.L. Osin and F.M. Uferov.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2018;(28):76-91

RESEARCH OF TRANSFORMER SUBSTATIONIN COMPLETE WITH TWO SUB-BANDS REACTOR-THIRIST CONTROLLER DEVICE

#### Abstract

The problems associated with the loading of electric networks with reactive power and low-quality power supply to industrial consumers are considered. To solve these problems, a device based on reactor-thyristor keys on the high side of the transformer substation is proposed, which together with a capacitor Bank increases the capacity of electric networks and equalizes the voltage at consumers. To expand the functionality of reactor-thyristor switches, a control method is proposed that provides two-band continuous voltage regulation for consumers with an improved form of load voltage and current, as well as shock-free switching on of a transformer substation under load and its disconnection without the appearance of an electric arc on the mechanical contacts of electrical devices. For the study of the proposed device, complete with a transformer substation, a number of experiments on a mathematical model in the MatLab environment were performed. Analysis of the results of these experiments in stationary and dynamic modes of operation, showed the feasibility of the application of the developed technical solutions for the industrial power supply system. Oscillograms of physical processes on the model show that when the voltage in the network and the load current changes, the device provides a stable voltage at the required level, without creating a shift in the phase of the network current relative to the voltage. Describes the characteristics for the transformer substation in the nominal and with two sub-bands controller device. The proposed method and device for its implementation on the basis of reactor-thyristor keys and a capacitor bank allows for voltage stabilization in consumers, maintain the sinusoidal current in the power transformer and in the network.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2018;(28):92-107

INVESTIGATION OF double-PURPOSE LINEAR INDUCTION MACHINES

#### Abstract

In this paper we describe some of the results of studies of special electric machines for technological purposes, in particular, linear induction machines. In such induction machines the secondary element is the processed materials and products. The expediency of using dual-purpose linear induction machines and the prospects of using linear inductors creating opposite direction traveling magnetic fields are shown. Two-purpose (multi-purpose) linear induction machines can simultaneously perform several operating functions. For example, it is possible to move metal blanks, perform their induction heating and obtain information on the parameters of motion and the position of the blanks. The modes of operation of linear machines with opposite direction traveling magnetic fields are considered with reference to the processing of metal blanks: movement of blanks, their positioning in the working zone, induction heating in running magnetic fields. Traditional methods of induction heating have been studied for many years. However, induction heating in a traveling magnetic field is not fully appreciated with respect to its main advantages and possible industrial applications. The advantages of linear induction machines that create opposite direction traveling magnetic fields are shown: increasing the accuracy of positioning of blanks and equalizing the temperature field during induction heating of metal blanks. The present work is devoted to modeling and studying some peculiar characteristics of this type of multiphase induction heating systems. The main attention is focused on the choice of the three-phase winding of the linear inductor, which provides these advantages. The article presents the results of studies of prototypes of dual-purpose linear induction machines created in the laboratory of the Department of Electrical Engineering and Electrotechnological Systems of the Ural Federal University.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2018;(28):108-121

AUTOMATED EVALUATION OF PARAMETERS FOR ELECTRICAL EQUIPMENT DIAGNOSTIC MODELS USING FUZZY CLUSTERING

#### Abstract

The development of the country's electric power industry is focused on ensuring high reliability and efficient management of power grids with different configurations. The solution of these problems assumes a certain energy-information infrastructure. In addition to electrical equipment, it must include a set of software and hardware for data acquisition, processing and analyzing during monitoring, diagnostic and subsequent management of the grid elements condition and their operating modes. The heterogeneity of the data obtained requires the development of certain mechanisms for their processing that will allow information and diagnostic systems automatically synthesize and adapt diagnostic models to the power supply facilities operation conditions. It is proposed to develop a methodology that allows to determine the parameters of electrical equipment diagnostic models, oriented to high result reliability using data mining algorithms, in particular, fuzzy clustering. The using of fuzzy clustering on the example of the construction of membership functions that evaluate the values of equipment parameters as input variables of diagnostic models was considered. The analysis of various fuzzy clustering algorithms is carried out and a technique for processing data on the equipment operation with the membership functions construction based on the fuzzy matrix partitioning and cluster centers is proposed. The technique allows us to approximate the membership functions by typical curves and choose the most effective variant of the diagnostic model synthesis. A practical example of using the results of clustering in the development of fuzzy models for assessing the condition of the power transformer elements is considered. We obtained a high level of compliance of simulation results with experimental data on the operation of equipment in power supply systems for oil production facilities. This indicates the possibility of using the technique to ensure the accuracy of electrical equipment diagnostics by reducing errors in the recognition of critical and insignificant defects.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2018;(28):122-140

ESTIMATION OF THE TRANSPORT-OPERATIONAL CONDITION OF STRUCTURAL ELEMENTS OF THE CARRIAGEWAY OF BRIDGE CONSTRUCTIONS USING NEIGHBORHOOD MODELS

#### Abstract

Neighborhood models generalize many discrete models and are used to represent complex spatially distributed objects and processes, they are a promising area for modeling of motor transport systems, as well as production systems such as steelmaking, cement production, wastewater treatment processes and others. In this paper, the neighborhood approach is used to model the wear of structural elements of the carriageways of bridge structures. Definitions are given to such concepts as a bridge structure, operational requirement, wear, repair, overhaul, the elements of the bridge sheet group are represented. The purpose of the elements of the bridge structure is described, the most frequently encountered defects are listed, which affect the wear and durability of the bridge structure, the most vulnerable element of the roadway structure of the bridge structure is identified. The main elements of the carriageway, connected with the traffic intensity, are considered. The object of research is the overpass through the railway tracks in the city of Nevinnomyssk, Stavropol Territory. The purpose of the work is to develop a neighborhood model of wear of the elements of the bridge structure, which allows to predict the degree of wear of the elements of the roadway structure. The dependence of the states and outputs of the dynamic neighborhood model in each node at the next instant on the states and inputs at the current time, where the nodes are the parts of the bridge structure, in addition, artificial input and output nodes have been introduced. A linear dynamic discrete neighborhood model is constructed and formulas are given for investigating the process of wear of the elements of a bridge structure. The average absolute identification error is calculated, a conclusion is made about the adequacy of the constructed model. In the programming block of the mathematical package Mathcad, a program was developed that allows parametric identification of a linear dynamic neighborhood model, as well as simulation simulation of the wear process of the elements of a bridge structure. The work is actual, as the developed mathematical model allows to investigate and carry out the transport-operational state of bridge structures, in particular, the damage caused by vehicles.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2018;(28):141-154

IMPLEMENTATION FEATURES OF INFORMATION-MEASURING SYSTEM OF ROBOTIC INSTALLATION

#### Abstract

The production of objects made of polymer composite materials is associated with the need to research the internal structure of manufactured products using non-destructive control methods, including usage of X-rays. The extremely high importance of radiographic research is explained by the specifics of the considered objects which production is based on additive technologies. Additive technologies mean layer-by-layer build-up of the product. Thus, such defects as delamination, resin pockets, etc. can be formed in its internal structure. Often, these defects are small, but can be dangerous during exploitation. The most promising way of automation of the process of X-ray examination of products made of polymer composite materials is to create a robotic unit that automatically performs a set of interrelated operations of X-ray source and receiver positioning. The accuracy of positioning of moving elements determines the minimum size of defects that can be detected in the internal structure of the explored objects. Therefore, the information-measuring subsystem, which is designed for spatial orientation control of the mobile components of the installation, is one of the key functional blocks of the entire system. This article describes the problematic issues of constructing of the information-measuring subsystem of the robotic complex. The mathematical support which is the base for the operation of the inclinometer modules is described. Much attention is paid to hardware testing and investigation of the influence of various power sources on the stability of inclinometer measurement data. The results of the experiments are shown in graphical and tabular form. The article can be useful for developers in the sphere of industrial automation. In addition, the given information can be used by engineers and scientists for the design of control and management systems of unmanned units, because it is necessary to correctly and accurately determine the parameters of spatial orientation for successful functioning of such objects.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2018;(28):155-168

FOUR THEOREMS FOR SYNCHRONOUS MACHINES WITH REACTIVE LOAD

#### Abstract

The current and the moment of the inductive synchronous electric machine under inductive load are considered. For a synchronous machine with an inductive load, Theorem 1 is valid. The amplitude of the current in the inductive load of an inductive synchronous electric machine is independent of the rotational speed. The theorem is proved by equating the second Kirchhoff law and the law of electromagnetic induction with reference to a rotating machine. Theorem 2 is also valid. The torque amplitude for an inductive synchronous electric machine with an inductive load is independent of the rotational speed. The theorem is proved by analyzing the Ampere law with respect to a rotating machine. It is established that, with an active load, the current amplitude depends linearly on the rotational speed. The torque amplitude also depends linearly on the rotational speed. With a capacitive load, the current amplitude depends quadratically on the rotational speed. The torque amplitude also depends quadratically on the rotational speed. The dependence of the power on the nature of the load is established. For inductive loads, the reactive electrical power is linearly dependent on frequency. For a resistive load, the power is quadratically dependent on the frequency. For a capacitive load, the power is cubic depending on the frequency. For a synchronous capacitive machine with a capacitive load, Theorem 3 and 4 are valid. Theorem 3. The voltage amplitude on the capacitive load of a capacitive synchronous electric machine is independent of the rotational speed. Theorem 4. The amplitude of the torque for a capacitive synchronous electric machine with a capacitive load is independent of the rotational speed.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2018;(28):169-178

CALCULATION OF THE CABLE CHANNEL THERMAL FIELD TAKING INTO ACCOUNT THERMAL LOSSES IN THE SHIELD OF CABLES

#### Abstract

In this paper, the process of heat and mass transfer in the cable channel with 18 cable lines, each of which consists of three cables with a core cross-sectional area of 150 mm2 located in the pipe, was studied. Based on the finite element method, a two-dimensional mathematical model of the thermal field of an underground cable channel is developed. The temperature distribution fields in the cable channel and the surrounding ground for different cable lines loading variants were obtained. To assess the effect of heat loss in the copper cable screen the dependences of the maximum temperature of the cable core on the current value are obtained. Options with and without heat loss in the screen are considered. In the work the possibility of replacing a layered cable design for the equivalent layer for the purpose of simplification of the accounting model is analyzed. Maximum temperature values and temperature fields in the cable line for different values of the current load at the multilayer structure and equivalent layer are obtained. In this paper, the question of choosing the location of backup lines is considered. The temperature field for the case of full load of all cables is built to determine the lines, which are in the worst temperature conditions. The expediency of choosing certain lines as backup lines is proved by calculating the maximum temperature of the cable cores. Taking into account all the findings, the maximum load conditions for each cable line, provided that the cable core temperatures do not exceed the maximum permissible values, were selected. The task was solved using the finite volume method in the engineering calculations environment Fluent.

**PNRPU Bulletin. Electrotechnics, Informational Technologies, Control Systems**. 2018;(28):179-193