RU136626U1 - ELECTRIC POWER CABLE - Google Patents

Abstract

1. Power electric cable with cross-linked polyethylene insulation and a metal screen made of bonded aluminum or aluminum alloy wires, characterized in that the wires in the metal screen are fastened with one or more carbon fiber threads, including woven into a bundle. 2. An electric power cable according to claim 1, characterized in that the wires in the metal shield are made of aluminum or an aluminum alloy modified with rare or rare earth metals, including those with a copper coating. The electric power cable according to claim 1, characterized in that the wires in the metal shield are made of a thermocorrosion-resistant TAC aluminum alloy modified with zirconium.

Description

The utility model relates to cable technology, namely, to the designs of high-voltage power electric cables with XLPE insulation and a metal shield used to transmit electrical energy.

In high-voltage cables with a voltage of 6 kV or more, a metal screen as part of a combined shield of electrically conductive materials placed on top of the insulation shunts the distortions of the electric field that arise due to the presence of insulation defects. It was found that the electric strength of the insulation of power cables during shielding increases by 20%, and the pulse strength by 5%.

A known design of a power electric cable with insulation made of cross-linked polyethylene for a voltage of 10, 20 and 35 kV according to TU 16.K71-335-2004, year 2004, Russia, having a metal screen made of copper wires fastened with a copper tape. Disadvantages of a metal screen made of copper wires and copper tape: accelerated destruction of insulation under the influence of copper ions, as well as a large mass and high cost.

Also known is the design of a power electric cable with insulation made of cross-linked polyethylene according to Russian patent No. 87037 for a utility model having a metal screen made of aluminum or aluminum alloy wires.

The closest in parameters to the utility model is an electric power cable with cross-linked polyethylene insulation according to patent No. 113862, Russia, (prototype) containing a metal screen made of aluminum or aluminum alloy wires fastened with a tape of electrically conductive material. The electric cable according to the prototype (Fig.) Consists of a multi-wire conductive core 1, a screen along the core 2, insulation 3, a combined screen 4, a separation layer 5, a plastic sheath 6. The electric power cable according to the prototype is made according to the following technology. A screen 2 of an electrically conductive polymer cross-linked composition with a thickness of at least 0.3 mm is applied by extrusion onto a copper or aluminum conductive core 1. On top of the screen 2, insulation 3 is made of cross-linked polyethylene. The thickness of the insulation depends on the brand of cable. On top of the insulation, a combined screen 4 is applied, consisting of an electrically conductive polymer cross-linked composition with a thickness of at least 0.3 mm, a layer of electrically conductive polymer tape and a metal screen of aluminum wires with a nominal diameter (0.7-2.0) mm, fastened with an aluminum tape with a thickness of 0 , 2 mm and a width of 20 mm. On top of the combination screen, a separation layer 5 of at least 0.2 mm thick is applied from crepe or cable paper tapes or polymer tapes. On top of the separation layer, a sheath 6 made of high density polyethylene or polyvinyl chloride plasticate is extruded.

The disadvantages of the prototype include:

- reduced mechanical strength of the metal screen in the overload and short circuit mode;

- reduced corrosion resistance of the metal screen;

- increased complexity of manufacturing a metal screen.

All these disadvantages of the prototype significantly reduce the reliability and manufacturability of cables with insulation made of cross-linked polyethylene.

The technical task of the utility model is to develop a power electric cable that is not inferior to the prototype in basic characteristics, but more reliable and technologically advanced.

The technical result is achieved by the fact that the wires in the metal screen of the cable are fastened with one or more carbon fiber threads, including woven into a bundle.

A common feature of the prototype and the proposed technical solution is the presence of a metal screen of fastened aluminum or aluminum alloy wires. At the same time, the proposed cable differs from the known one using fastening carbon fiber threads in the metal screen.

Unlike other electrically conductive materials (metal and metal-plastic tapes, wire and yarn) used to fasten the wires of the metal screen of the cable, carbon fiber (carbon) filaments have a high specific strength exceeding the strength of steel. Carbon filaments do not lose strength at high temperatures (above 100 ° C) and at the same time conduct electric current well. Carbon threads are not subject to corrosion. The amount of solid carbon fiber in one spool is significantly greater than a metal tape. In this regard, the number of technological stops during the manufacture of a metal cable shield is reduced.

Advantages of the new cable:

- high mechanical strength of the metal screen, including at elevated temperatures;

- high corrosion resistance of the metal screen;

- high reliability and durability;

- high technology.

Restrictions on the choice of the brand of aluminum or aluminum alloy for metal shield wires are imposed by the conditions for the manufacture, installation and operation of the cable:

- manufacture of wire from wire rod by drawing method;

- cable operation in overload mode;

- the required physical and mechanical characteristics of the wires of the metal shield: maximum breaking strength and elongation, minimum creep, minimum electrical resistance, maximum heat resistance and durability.

The above requirements are met by aluminum and its alloys modified with rare or rare-earth metals or mixtures thereof. The most affordable and cheapest are aluminum alloys modified with zirconium. The authors of the utility model suggest using wire rod made of heat-resistant aluminum alloy of the TAS brand for the manufacture of wires of a metal shield according to TU 1712-043-50289046-2012, the year 2012, Russia, modified with zirconium.

The wires of the metal shield can be coated with copper, which allows the use of standard connecting and grounding fittings.

The construction and manufacturing technology of the cable according to the utility model are similar to the construction and manufacturing technology of the cable according to the prototype, with the exception of the construction of the combined screen, in which instead of an aluminum tape one or several carbon fiber threads are used, including woven into a bundle.

Utility power cables have undergone comprehensive tests at cable plants in the Russian Federation with positive results. Production of these cables has been established.

Claims (3)

1. Electric power cable with cross-linked polyethylene insulation and a metal screen made of bonded aluminum or aluminum alloy wires, characterized in that the wires in the metal screen are fastened with one or more carbon fiber threads, including woven into a bundle. 2. The electric power cable according to claim 1, characterized in that the wires in the metal shield are made of aluminum or an aluminum alloy modified with rare or rare earth metals, including those with a copper coating. 3. The electric power cable according to claim 1, characterized in that the wires in the metal shield are made of a thermocorrosion-resistant TAC aluminum alloy modified with zirconium.

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