Power cable

Power cables (SC) differ in design, dimensions, materials used and are selected depending on the conditions of use.

Each SC consists of at least three elements:

• conductive core;
• conductor insulation;
• shell.

To improve the characteristics of the SC, the following elements are included in the design:

• screen;
• belt isolation;
• pillows for armor;
• armor;
• aggregate.

As a material of conductive wires, aluminum or copper is usually used.

The insulation of the conductive core can be made of impregnated paper (see cable with paper insulation ) or polymer (for example, cross-linked polyethylene ).

The power cable with impregnated paper insulation is used in electrical networks with a voltage of 1 to 750 kV and a frequency of 50 Hz .

The cable with XLPE insulation is used both at low and at high voltage, withstands high temperatures, has high strength, helps with network overload ^{[ how? ] to} avoid short circuit , it differs from other cables by lower weight. Specifications:

• operating temperature: −50 ... + 50 ° C ;
• temperature permissible for continuous heating of conductors: +90 ° C;
• maximum permissible temperature during short circuit: from +250 ° C;
• service life: not less than 30 years.

Power cables with impregnated paper insulation in lead or aluminum sheath

Power cables with impregnated paper insulation with copper and aluminum conductors are designed for transmission and distribution of electrical energy at a voltage up to and including 35 kV ( GOST 18410-73 ). Such cables are used for fixed installation and depend on the difference in the level of the route. In order to protect hygroscopic paper insulation, a lead or aluminum sheath is provided in the cable structure. Cables with aluminum sheaths cannot be used under the influence of aggressive media (alkali fumes, concentrated alkaline solutions). In such conditions, it is necessary to use cables in lead sheaths.

Power cables with rubber insulation

Power cables with rubber insulation are used for stationary installation in electric networks with voltage up to 10 kV DC. Cables are designed for laying on routes with an unlimited level difference ( GOST 433-73 ). Advantages of cables with rubber insulation: low hygroscopicity (moisture absorption) and flexibility. However, rubber is not resistant to ultraviolet and ozone; therefore, the cable has steel armor that protects the cable from destructive factors.

Power cables with PVC insulation

Power cables with PVC insulation are designed for fixed installation in power networks with a rated alternating voltage of 0.66 kV, 1-6 kV (GOST 16442-80). PVC-based insulation is one of the cheapest cable insulation, it has elasticity, and thanks to special additives it can acquire the necessary properties, for example, frost resistance and heat resistance ..

Power cables with polyethylene insulation

Power cables with XLPE insulation appeared in the 70s of the 20th century. The appeared cable with XLPE insulation is designed to replace obsolete cables with impregnated paper insulation. Cables are designed for voltage of 6, 10, 15, 20, 30 and 35 kV (first group); 45, 60, 110, 132 and 150 kV (second group); 220 and 330 kV (third group); the cross-sectional area of ​​cables varies from 35 to 200, there are cable products and larger cross-sections -1000 and more mm ² . Compared to paper insulation, cables with PE insulation can withstand higher core temperature, are moisture resistant, have lower weight, do not need to be preheated during installation in winter. (Editing - PE cables must be heated in winter as well. There are restrictions on the temperature ambient air -5 ° C. at -25 laying is prohibited)

AVVG

Power cable with aluminum conductive core, insulation and sheath made of polyvinyl chloride (PVC) plastic compound, without protective cover.

VVG

Power cable with copper conductive core, insulation and sheath made of polyvinyl chloride (PVC) plastic compound, without protective cover. Additional marking of the form (4 × 4) means that the cable is four-core (first number) with a cross section of 4 mm (second number).

AVVG-P

Power cable with aluminum conductive core, insulation and sheath made of polyvinyl chloride (PVC) plastic compound, without protective cover, flat.

VVG-P

Power cable with copper conductive core, insulation and sheath made of polyvinyl chloride (PVC) plastic compound, without protective cover, flat.

AVVGng (A)

Power cable with aluminum conductive core, PVC compound insulation, low flammability PVC sheath.

VVGng (A)

Power cable with copper conductive core, PVC compound insulation, low flammability PVC sheath.

AVVG-Png (A)

Power cable with aluminum conductive core, PVC compound insulation, low flammability PVC compound sheath, flat.

VVG-Png (A)

Power cable with copper conductive core, PVC compound insulation, low flammability PVC compound sheath, flat.

AVVGng (A) -LS

Power cable with aluminum conductive core, insulation and sheath made of PVC compound of low fire hazard. Low Smoke, low smoke and gas emission.

VVGng (A) -LS

Power cable with copper conductive core, insulation and sheath made of PVC compound of low fire hazard. Low Smoke, low smoke and gas emission.

AVBSHv ^[1]

Power cable with aluminum conductive core, insulation made of PVC compound, armored (armor made of two steel galvanized tapes; protective hose made of PVC compound).

Designed for operation in a stationary state at ambient temperature from plus 50 ° С to minus 50 ° С, relative air humidity up to 98% at a temperature up to 35 ° С, including for laying in the open air.

The duration of operation of this cable in emergency mode should not be more than 8 hours per day and not more than 1000 hours per service life.

VBShv

Power cable with copper conductive core, PVC compound insulation, armored (armor from two steel galvanized tapes; PVC compound protective hose) For laying in the ground (trenches), rooms, tunnels, channels, shafts (except for laying in blocks), and also outdoors, if the cable is not subjected to significant tensile forces, if there is a risk of mechanical damage during operation.

AVBShvng (A)

Power cable with aluminum conductive core, PVC compound insulation, armored (armor made of two steel galvanized tapes; protective hose made of low-flammability PVC compound).

VBShvng (A)

Power cable with copper conductive core, insulation made of (PVC) plastic compound, armored (armor of two steel galvanized tapes; protective hose made of low-flammability PVC compound.

AVBShvng (A) -LS

Power cable with aluminum conductive core, insulation from PVC compound of low fire hazard, armored (armor from two steel galvanized tapes; protective hose from PVC compound of low fire hazard).

VBShvng (A) -LS

Power cable with copper conductive core, insulation from PVC compound of low fire hazard, armored (armor from two steel galvanized tapes; protective hose from PVC compound of low fire hazard).

Color Marking

For ease of installation and operation, color marking of the insulation of cable and busbar conductors is introduced, which is established by national standards, based on the functional purpose of each wire or bus. In different countries, the color marking of the insulation of conductors has its own differences. However, many countries adhere to the general principles for the color coding of conductors as set forth in IEC 60445: 2010, the International Electrotechnical Commission standard. In the USSR, the color of the wire strands in the cable was usually not strictly regulated and cable plants produced cables with different color schemes (including the application of color longitudinal stripes) determined by the technical conditions, and often the cable strands were generally single-color. For paper-insulated cables impregnated with oil-rosin, the colors are wound on top of each core of colored paper in one layer (sometimes instead of colored paper stripes, single-color strips are wound on top of each core with Arabic numerals).

Cable lettering

In addition to the color marking of the cable, letter marking is also used, which is the name of the type of cable, which is mandatory for application in accordance with GOST 18620-86. The marking of cables of Russian and foreign production is different, although the principle is the same: each letter in the cable marking indicates the presence of a certain structural element from internal to external, that is, from the material of the current-carrying core to the sheath material.

• Cables, wires, cords, electrical and auxiliary materials. Collection. Part 1. - The official publication. - M: Publishing house of the committee of standards, measures and measuring instruments under the Council of Ministers of the USSR , 1966. - 15,000 copies.
• Cables, wires, cords, electrical and auxiliary materials. Collection. Part 2. - The official publication. - M: Publishing house of the committee of standards, measures and measuring instruments under the Council of Ministers of the USSR , 1966. - 15,000 copies.
• Bustrom J., Campus A., Hampton P., Hake-kala P., Yager K., Smedberg A., Wald D. Copolymer compositions of cross-linked polyethylene (Super Soro) for highly reliable power cables of medium voltage // Cables and wires.- 2005 . -№ 5.-S. 7-12.
• Dementiev V. S. How to determine the location of damage in a power cable Moscow, Energia Publishing House, 1980