Increasing Noise Immunity of Cables for Fire Protection Systems

Bezprozvannych, G. V.; Pushkar, O. A.

doi:10.20998/2074-272x.2020.4.07

Cited by 4 publications

(4 citation statements)

References 2 publications

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“…Introduction. The rapid growth of digital technologies has prompted cable manufacturers in Ukraine to introduce new technologies and types of cables, in particular, based on twisted pairs of different categories, with an appropriate set of transmission parameters, both for structured cable systems and for security systems -video surveillance, fire and security alarm system [1][2][3][4][5][6]. At the same time, each industrial enterprise to ensure the competitiveness of manufactured products contributes to the automation of both individual technological processes and production as a whole.…”

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confidence: 99%

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Synthesis of constructive-technological decisions of regulation of working capacitance of cables of industrial networks

Bezprozvannych¹,

Kostiukov²,

Pushkar³

2021

Electrical Engineering & Electromechanics

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Introduction. Over the past 10 years, the number of industrial networks has more than doubled. At the physical level, all industrial technology networks are based on twisted pair. Purpose. Synthesis of constructive-technological decisions of regulation of electric capacitance of the insulated conductor at a stage of manufacturing of twisted pair of cables of industrial networks. Methodology. The method of secondary charges to determine the capacitance of the insulated conductor by varying the thickness of the solid and foamed polyethylene insulation. Practical value. Effective regulation is provided on the basis of the obtained dependencies of the effective dielectric constant, the tangent of the dielectric loss angle and the capacitance of the insulated conductor on the degree of foaming and the thickness of the protective film of two-layer insulation. At a degree of porosity of 40 %, the dielectric constant decreases by 25 %, the tangent of the dielectric loss angle – by 33 %, the electrical capacitance of the insulated conductor – by 20 %.

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confidence: 99%

“…The working capacitance of the twisted pair (Fig. 1), the conductors of which are twisted with the corresponding step h, determines the losses in the conductors and in the insulation (see (2)).…”

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confidence: 99%

Synthesis of constructive-technological decisions of regulation of working capacitance of cables of industrial networks

Bezprozvannych¹,

Kostiukov²,

Pushkar³

2021

Electrical Engineering & Electromechanics

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“…To overcome this problem, the authors of [15,16] performed a statistical analysis of the effect of fluctuations in the pitch of twisting the pair on the capacitance of unshielded and shielded cables. The impact of the stochastic nature of the change in capacitance on the attenuation coefficient and electromagnetic interference between twisted pairs has made it possible to substantiate the requirements for the density of the structure and the settings of the technological process of manufacturing shielded cables with twisted pairs [17]. But there are objective difficulties in determining the capacitance of a twisted pair based on the numerical calculation of the electric field, taking into account structural inhomogeneities depending on the design of the cable.…”

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confidence: 99%

Constructing a model of the influence of structural and technological inhomogeneities on electromagnetic energy losses in cables based on a twisted pair

Bezprozvannych

Pushkar

2023

EEJET

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The objects of research reported here were cables based on twisted pairs of various designs. The issue of the emergence of additional losses of electromagnetic energy is related to structural and technological inhomogeneities at the technological stage of cable production. The influence of the working capacitance of the twisted pair on the energy losses in the cables has been substantiated. A methodology was proposed for the numerical calculation of the electric field under the condition of ellipticity of the structural elements of the twisted pair. That has made it possible to determine the distortion of the electric field and the effect of inhomogeneities on the working capacitance of a twisted pair of different designs. Specifically, it was shown that for shielded structures with continuous polymer insulation, the distortion of the electric field and the growth of the working capacitance are observed to a greater extent. The need to find technological solutions to reduce the effect of screen ellipticity on cable capacitance has been emphasized. The effectiveness of capacitance regulation in the presence of inhomogeneities has been confirmed, by using foamed insulation to reduce the loss of electromagnetic energy in the cable. The effect of reducing the working capacitance and increasing additional losses under the simultaneous influence of the ellipticity of the electrical insulation and the protective polymer shell has been established, which necessitates the technological process adjustment in the manufacture of twisted pair. An applied aspect of using the results is the possibility of improving the typical technological process of manufacturing twisted pairs to reduce additional losses of electromagnetic energy at the final technological stage of cable production. The adequacy of the numerical studies was confirmed by experimental dependences of the attenuation coefficient and additional energy losses of the unshielded cable in the frequency range up to 100 MHz

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“…Introduction. For a long time, innovative research and development in the domestic electric power industry was aimed at the development of decentralized local Microgrid electrical systems [1][2][3][4], which use dynamic regulation of the power balance of distributed sources of electricity in conditions of non-stationary consumption by industrial and residential complexes and objects without taking into account electrophysical features of structural elements of cable and conductor products of overhead [5] and cable power transmission lines (PTLs) [6][7][8].…”

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confidence: 99%

Modeling and analysis of electro-thermal processes in installations for induction heat treatment of aluminum cores of power cables

Shcherba,

Podoltsev,

Suprunovska

et al. 2024

Electrical Engineering & Electromechanics

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Introduction. The development of the electric power industry is directly related to the improvement of cable lines. Cable lines meet modern requirements for reliability, they are increasingly used. Problem. Currently, power cables with an aluminum multi-conductor core, which requires heat treatment - an annealing process at the stage of the technological manufacturing process, are widespread. This process makes it possible to desirably reduce the electrical resistance of the wire and increase its flexibility. For effective use of induction heating during annealing of an aluminum core, it is necessary to determine the optimal frequency of the power source of the inductor. Considering the long length of the inductor and the large number of its turns, the numerical calculation of the electromagnetic field, which is necessary for calculating the equivalent electrical parameters of the turns of the inductor and its efficiency, requires significant computer resources. The goal is to develop a computer model for calculating electro-thermal processes in an induction plant for heating (up to the annealing temperature) an aluminum core of a power cable moving in the magnetic field of a long multi-turn inductor, as well as obtaining frequency dependences of the equivalent R, L parameters of such an inductor and determining the optimal the value of the frequency of the power source, which corresponds to the maximum value of the electrical efficiency of the inductor. Methodology. The mathematical model was developed to analyze the coupled electromagnetic and thermal processes occurring in a core moving in a time-harmonic magnetic field of an inductor at a constant speed. The differential equations for the electromagnetic and temperature fields, taking into account the boundary conditions, represent a coupled electro-thermal problem that was solved numerically by the finite element method using the Comsol software package. For a detailed analysis of the electromagnetic processes in the inductor, an additional problem was considered at the level of the elementary cell, which includes one turn of the inductor and a fragment of the core located near this turn. Results. According to the results of the calculation of the electromagnetic field in the area of the elementary cell, the equivalent electrical parameters of one turn of the inductor and the entire multi-turn inductor were calculated depending on the frequency of the electric current. The frequency dependences of the electrical efficiency of the inductor were calculated. Originality. Taking into account the design features of the inductor (its long length and large number of turns), the method of multiscale modeling was used. Electro-thermal processes in the core were studied at the macro level, and the distribution of the electromagnetic field and electric current density in the cross-section of the massive copper turn of the inductor was calculated at the micro level – at the level of an elementary cell containing only one turn of the inductor. The frequency dependences of the equivalent R, L parameters of the inductor, taking into account the skin effect, the proximity effect, and the geometric effect, were obtained, and the quantitative influence of the electric current frequency on these effects was studied. Practical value. The dependence of the electrical efficiency of the inductor on the frequency of the power source was obtained and it was shown that for effective heating of an aluminum core with a diameter of 28 mm, the optimal value of the frequency is in the range of 1–2 kHz, and at the same time the electrical efficiency reaches values of ηind = 0.3–0.33, respectively.

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Increasing Noise Immunity of Cables for Fire Protection Systems

Cited by 4 publications

References 2 publications

Synthesis of constructive-technological decisions of regulation of working capacitance of cables of industrial networks

Synthesis of constructive-technological decisions of regulation of working capacitance of cables of industrial networks

Constructing a model of the influence of structural and technological inhomogeneities on electromagnetic energy losses in cables based on a twisted pair

Modeling and analysis of electro-thermal processes in installations for induction heat treatment of aluminum cores of power cables

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