Contents №5–2015

Analyses and Forecasts

E.B. Vasiliev, Cand. Sc. (Economics), Deputy General Director of JSC VNIIKP; 
N.V. Sakharova, General Director of Electrocable Association

Contact: info@tdvniikp.ru 

Import substitution: the necessary and the realistic

The article analyzes the problems of import substitution in the cable industry. Three aspects are reviewed: 
– import of cable and wire to Russia, 
– import of cable materials to Russia, 
– scientific, technical and financial realities of the import substitution policy in the cable industry both on the part of the government and the manufacturers.

Key words
Import substitution; analysis of export and import; production modernization; structure of imports; scope of delivery; customs regulation.

Science and Technologies

G.V. Greshnyakov, Cand. Sc. (Engineering), Head of Laboratory of NII “Sevkabel”; 
M.V. Doronin, student of SPbPU (Saint-Petersburg State Polytechnical University); 
N.V. Korovkin, Dr. Sc. (Engineering), Head of Department of SPbPU (Saint-Petersburg State Polytechnical University) 

Contact: g.greshnyakov@sevkab.ru

Combined magnetic screens for power cable lines

Magnetic screening of power cable lines with the help of slip screens with gaps is described. The effect of magnetic field redistribution for different gap sizes and different material magnetic properties is studied. Numerical models of single-layer and double-layer screens are developed. Calculations are performed for the magnetic field close to 110 kV single-phase and three-phase cable lines with a magnetic screen and without it.

Key words
Magnetic screening; magnetic field redistribution; cable lines; screening coefficient; screening attenuation; permalloy; magnetically soft alloys; gap; gap opening angle; solid screen

R.G. Kuznetsov, Deputy Manager of Development Department of OOO NPP “Spetskabel”

Contact: profi@spcable.ru  

Measurement of screening parameters of symmetrical cables for SCS

The paper continues the consideration of matters concerning the estimation, analysis and standardization of screening characteristics of symmetrical high-frequency communication cables. The previous paper published in “Cables and Wires” № 3 – 2014 focused on the extension of requirements for cable screening and described briefly the basic screening parameters, some basic designs of cable screens and typical screen characteristics. The estimation of high-frequency cable screening efficiency is associated with the necessity of measuring actual screening parameters of present-day high-frequency communication cables. The use of one of the main methods for the estimation of cable screening efficiency, namely the “triaxial” line method, made it possible to obtain data on the relatively new and important SCS cable parameter – radiation damping, which is characteristic of these cables. Radiation damping depends not only on the cable screening efficiency due to the use of electromagnetic screens against external noise but also on the ability to provide minimal electromagnetic field radiation by the cable itself due to the asymmetry of electromagnetic fields of each insulated conductor in a separate operating cable pair. 

The paper presents the measurement results for some types of NPP “Spetskabel” symmetrical cables for digital communication systems and their comparison with the norms specified in GOST R 54429-2011. This comparison is to show whether some cable types comply with the requirements of GOST R 54429-2011, no other goals were set.

Key words
Radiation damping; screening efficiency; coupling resistance; high-frequency cable; data transmission; standard; measurement methods

A.M. Boev, Associate Professor of National Research University (MEI)
Contact: a_mb@mail.ru

Insulating properties of КМ-120 and БКМ-140 cable paper at liquid nitrogen temperature

Experimental investigations were performed to determine electrical characteristics: breakdown strength, resistivity and dielectric loss tangent of cable insulating paper. Paper containing cellulose fibers is one of the widespread insulating materials that are used in devices operating in the area of cryogenic temperatures. The tests were performed on specimens of two forms (flat and tubular) comprising several layers of 120 m thick paper and 140 m thick microcrepe paper. Dependences of electrical characteristics on the number of paper layers were determined at normal ambient temperature and at liquid nitrogen temperature. It was demonstrated that the КМ-120 cable paper had higher electrical characteristics at liquid nitrogen temperature and thus it should be preferably used as electrical insulation in products with HTSC.

Key words
Cable paper; breakdown strength; liquid nitrogen temperature


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