JournalTOCs

Electrical Engineering and Power Engineering
Number of Followers: 3

This is an Open Access Journal

Open Access journal
ISSN (Print) 1607-6761 - ISSN (Online) 2521-6244
Published by Zaporizhzhia National Technical University

[2 journals]

Improvement of the cold rolling mill diagnostic system based on the data
base of its electromechanical processes
- Authors: Olena Nazarova, Bohdan Vasyliev, Danylo Shokurov
  Pages: 7 - 18
  Abstract: Purpose. To improve the diagnostic system of the cold rolling mill based on the database of its electromechanical processes, by developing a fuzzy decision-making system as to the condition of the rolling mill electrical drives, which will increase the efficiency of the existing diagnostic system. Methodology. Mathematical and computer modeling. Findings.A fuzzy decision-making system about the state of two interconnected electric drives of the unwinding mechanism and the rolling mill has been developed to investigate and prevent the pre-emergency state associated with the break of the rolling metal strip. The specified decision-making system is built on the basis of a database of electromechanical processes of electric drives of the skin-threat single-celled state of cold rolling of the cold rolling shop No. 1 of PJSC "Zaporizhstal". At the input of this system, the voltage of the armature circuit of the unwinding mechanism motor, the armature circuit current of the unwinding mechanism motor, the tension of the rolled metal strip in the area between the unwinder and the rolling cage are set. At the output, the general state of the system is obtained, which depends on the values of the input data. Information on the value of the tensile strength of the rolled metal strip can be obtained on the basis of the pressure data and voltage sensors, which are installed on industrial equipment. Information about the value of the tension force of the rolled metal strip can be obtained both by installing additional measuring devices and indirectly, using mathematical models of the roll current radius and the linear speed of the rolled metal strip. Originality. The system for diagnosing the condition of cold rolling has been improved by introducing a fuzzy decision-making system into its composition based on a database of electromechanical processes of the electric drives of the unwinding mechanism and the cage, which will allow to prevent an emergency condition caused by a break in the rolled metal strip. Practical value. Prevention of breaking of the rolled metal strip on the basis of an improved system for diagnosing the state of cold rolling, which uses information from the database of its electromechanical processes in order to improve the efficiency of the product quality management process. Using complete organized information and experience of operating a cold rolling mill, you can form technical and technological solutions for the modernization of existing and development of new technological equipment and systems for automatic control of electric drives of rolling mills.
  PubDate: 2023-06-30
  DOI: 10.15588/1607-6761-2023-1-1
The power harmonic components distribution study in the power circuit of a
dynamic voltage restorer
- Authors: Maksim Bezzubm, Oleksiy Bialobrzheskyi, Oleg Todorov
  Pages: 19 - 29
  Abstract: Purpose. Investigation of the distribution of harmonic power components in the power circuit of a dynamic voltage restorer. Methodology. On the basis of the differential equations of the power circuit of a dynamic restorer, a search for the relationship between the mode parameters and the parameters of the circuit elements is performed. On the basis of the obtained expressions, a model of a dynamic voltage regulator was created using the methods of mathematical modeling in the visual programming environment.. Findings. The equations that reflect the relationship between the mode parameters of a dynamic voltage restorer and the parameters of circuit elements are obtained. As a result of modeling the mode with different harmonic composition of current and voltage, the following features of the distribution of instantaneous power components are revealed. Originality. It has been established that the presence of different current and voltage harmonics acting in the transformer of a dynamic restorer causes additional power harmonics that are transformed in the windings. It is noted that the low-frequency power harmonics of the LC filter dominate on the capacitor, which is connected in parallel to the transformer winding, while the level of high-frequency components caused by PWM modulation for the capacitor and the filter choke differ slightly. The zero-frequency power component of the storage capacitor corresponds to a tripled zero-time power component at the output of the converter, which is due to its operation in three phases. This cannot be extended to the second and third harmonics of the powers of the converter and the capacitor; these components are absent in the latter, which is due to energy exchange processes between the phases of the converter. Practical value. Using the obtained expressions, the principle of determining the parameters of the elements of the power circuit of a dynamic voltage restorer, in particular, the storage elements, is formulated.
  PubDate: 2023-06-30
  DOI: 10.15588/1607-6761-2023-1-2
Controlling electrical circuit of electric motor on igbt transistors
- Authors: I. Shishkin, Sergii Lushchin
  Pages: 30 - 35
  Abstract: Purpose. Development and analysis of the operation of an electrical circuit for controlling a 700 W direct current electric motor using a contactor on IGBT transistors for operation in diesel locomotives. Methodology. Analytical and computational methods for developing and analyzing the operation of an electrical circuit using a contactor on IGBT transistors. Findings. An electrical circuit for controlling a 700 W DC motor using IGBT transistors was developed. The circuit allows you to replace electromagnetic contactors with IGBT transistors to improve the technical characteristics and performance of the electric motor. The use of IGBT transistors allows you to avoid burning of contact groups in comparison with an electromagnetic contactor. A graphical analysis of the transient processes during switching on and off of the electric motor using a circuit based on IGBT transistors was carried out. The analysis of the load characteristic of the electric motor at start-up shows that in the initial section the voltage increases according to a linear law. After the initial increase in voltage, it reaches the set value and the electric motor operates in the operating mode. The analysis of the load characteristics of the electric motor when it is turned off shows, that when the power is turned off, the motor can’t stop immediately, as the phenomenon of self-induction occurs. When the external voltage is turned off, its change on the electric motor occurs according to the exponential law. It is shown that for controlling the operation of the electric motor, it is more appropriate to use an electric circuit based on IGBT transistors, which provides conditions for more stable and safe operation of the electric motor. Using the electrical circuit allows you to find quickly malfunctions for their further elimination. The electrical circuit allows you to avoid physical wear of its electrical elements. Originality. An electrical circuit for controlling an electric motor based on modern electronic components has been developed, which allows the use of IGBT transistors instead of electromagnetic contactors. On the basis of the analytical and calculation method and graphical analysis, the expediency of using IGBT transistors instead of electromagnetic contactors has been proven. Practical value. The developed electrical circuit can be applied to control a 700 W direct current electric motor for operation in diesel locomotives. The proposed electrical circuit allows to increase the mobility of repairs in the event of a malfunction by replacing the corresponding unit.
  PubDate: 2023-06-30
  DOI: 10.15588/1607-6761-2023-1-3
Automated methodology of calculating parameters for non-traditional
technology of heating mode of hydro-storage power plant station
- Authors: Illia Olishevskyi, Oleksandr Gusev, Hennadii Olishevskyi
  Pages: 36 - 42
  Abstract: Purpose. Justification of the rational parameters of heat pumps and heat accumulators to ensure the efficient operation of the hydro storage power plant (HSPP) in the heating mode. Development of an automated methodology for calculating rational parameters for a complex system of a hydro storage power plant operating in heating mode. Methodology. Mathematical analysis and modeling. Findings. Using the developed automated calculation method, it was analyzed and determined that passing through the heat pump the full flow of water passing through the hydro unit is impractical and ineffective, because the energy consumption in the heat pump compressor is many times higher than the consumption of the hydro unit in pumping mode, which devalues the proposed measure as an energy-saving measure. The use of a heat pump and a heat accumulator at the hydro storage power plant for hot water supply needs will save a third of conventional fuel costs compared to a boiler unit. The developed automated technique allows to calculate the limit and rational values of design and operating parameters of the heat pump and heat accumulator, which ensure the heating mode of operation of the hydro storage power plant to meet the needs of hot water supply. Originality. An automated methodology for calculating the parameters of a complex system has been developed for the hydro storage power plant operating in heating mode. The concept of the maximum heat capacity of the hot water supply of the heat pump is introduced. The concept of the rational heat capacity of the hot water supply of the heat pump is introduced. In addition to the maximum heat capacity and the rational heat capacity modes, the developed method allows you to calculate all the parameters of the heat pump and heat accumulator, which provide the heating mode of the hydro storage power plant, for arbitrary values of the thermal power of hot water supply, with further comparison and analysis of the investigated modes and the selection of the most promising one. Practical value. The technology of using a heat pump and a heat accumulator to transfer the operation of the hydro storage power plant to the heating mode (hot water supply of residential buildings) is substantiated. The possibility of saving conditional fuel when applying the proposed technology is proven.
  PubDate: 2023-06-30
  DOI: 10.15588/1607-6761-2023-1-4