RU128388U1 - ELECTRIC POWER CABLE ARMORED - Google Patents

Abstract

1. Armored electric power cable, containing a conductive core, including a sealed water-blocking tape or thread, a core screen of a conductive cross-linked polyethylene composition, core insulation of cross-linked polyethylene, a pillow-shield of conductive polymer, a separation layer of conductive tapes or conductive water block tapes or without tapes, a non-magnetic metal armor shield, a release layer of paper or polymer tapes, or electrically conductive water-blocking tapes and laminas aluminopolymer tape, or fire retardant tapes or without it, and an outer polymer shell, characterized in that the pillow-screen is made of two layers and contains the first layer adjacent to the insulation of the electrically conductive cross-linked polyethylene composition and the second layer of an electrically conductive elastomer, and the armor-shield is made single-layer of wires of aluminum or its alloys, including those modified with rare or rare-earth metals, including those coated with copper, fastened with a tape of electrically conductive materials or without it. 2. The electric power cable according to claim 1, characterized in that, as the second layer of the cushion screen, it contains an ATEPep electrically conductive alkenedienic thermoplastic elastomer.

Description

The utility model relates to cable technology, namely, to designs of high voltage power electric armored cables with XLPE insulation and a metal shield, used for transmission and distribution of electric energy and laying in places with the possibility of radial and axial tensile loads and mechanical damage.

Known designs of power cables with insulation made of cross-linked polyethylene according to patents No. 87037 and No. 113862, Russia, containing a metal screen made of aluminum or aluminum alloy wires. The scope of these cables is limited, as they are not protected from radial and axial tensile loads and mechanical damage due to lack of armor.

The closest in parameters to the utility model is an armored power cable according to patent No. 85738, Russia, (prototype), containing a conductive core, a shield along the core, insulation, a pillow made in the form of a screen of conductive polymer, two-layer tape armor made in the form of an electric non-magnetic metal screen. In addition, each armor layer is applied in the opposite direction.

The main disadvantages of the prototype:

- limiting the scope of the cable due to the reduced stability of the tape armor to axial tensile loads;

- increased complexity of applying armor;

- low manufacturability associated with increased accuracy of applying tape armor;

- the possibility of damage to the pillow-screen and insulation of the conductive core with tape armor during bending of the cable and breakdown of the cable insulation;

- the possibility of partial discharges during bending and peeling of the pillow-screen from the insulation of the core;

- reduced performance cable with tape armor due to the increased bending radius of the cable.

The disadvantages of the prototype significantly reduce the operational characteristics, reliability and scope of power armored cables.

The technical task of the utility model is to develop an armored electric power cable that is not inferior to the prototype in terms of basic characteristics, but is more technological, high-quality and highly reliable, designed for cable lines laid in soils subject to displacement, and for underwater cable lines.

The technical result is achieved by the fact that the cable cushion-shield is made of two layers and contains a first layer adjacent to the insulation from an electrically conductive cross-linked polyethylene composition and a second layer from an electrically conductive elastomer, and the armor-shield is made of a single layer of aluminum or aluminum alloy wires, including modified rare or rare earth metals, including those coated with copper, fastened with a tape of electrically conductive materials or without it ..

A common feature of the prototype and the proposed technical solution is the presence of a cushion-screen made of conductive polymer and an armor-screen made of non-magnetic metal. At the same time, the proposed cable differs from the known one by the use of a two-layer cushion-screen, containing the first layer adjacent to the insulation, from an electrically conductive cross-linked polyethylene composition and a second layer of an electrically conductive elastomer, and a single-layer armor shield made of aluminum or aluminum alloy wires, including those modified with rare or rare-earth metals, including those coated with copper, fastened with a tape of electrically conductive materials or without it. A two-layer cushion-screen allows providing on the one hand high adhesion to insulation, high mechanical strength of the screen and increased electrical strength of the insulation, on the other hand, high elastic properties of the cushion to absorb the radial mechanical loads from the armor while maintaining electrical conductivity. A single-layer armor shield made of aluminum or aluminum alloy wires, compared with a tape armor shield, can significantly increase the protection of the cable from axial tensile loads and mechanical damage and expand the scope of application of power armored cables. When using a single-layer wire armor shield, the manufacturability increases and the complexity of cable manufacturing is reduced, the operating characteristics and reliability of the cable are increased. The fastening tape provides electrical contact between the wires of the armor shield over the entire cable surface. This increases the electrical strength of the insulation. The tape also fixes the wires of the armor shield at a certain distance from each other and prevents the displacement and overlap of the wires when a separating layer and a plastic sheath are applied to the cable. This significantly improves the manufacturability of cable manufacturing and increases the efficiency of the wire armor screen. The armor shield can be made of aluminum or its alloy wires modified with rare or rare-earth metals, for example: zirconium, scandium, yttrium, cerium, lanthanum, vanadium, hafnium, or mixtures thereof. Small additives (up to 0.5 wt.%) Of the rare and rare-earth metals listed above can significantly increase the strength, heat resistance and corrosion resistance of aluminum and its alloys without reducing electrical conductivity. For example, the addition of cerium in an amount of 0.5 wt.% Increases the strength and heat resistance of aluminum almost twice. This reduces corrosion by 10 times and significantly increases the electrical conductivity of aluminum. The addition of 0.3 wt.% Yttrium increases the conductivity of aluminum by 7.5%, and also increases its strength and heat resistance. The addition of 0.4 wt.% Scandium increases the strength of aluminum by 35%. This increases the electrical conductivity and heat resistance of aluminum. The addition of zirconium to 0.5 wt.% Allows you to significantly (2-2.5 times) increase the heat resistance of aluminum and its alloys without reducing electrical conductivity. Aluminum and its alloys modified with rare or rare-earth metals have practically no creep under load. The copper coating of the wires of the armor shield can increase the reliability of grounding the screen.

As electrically conductive elastomers for the second layer of the cushion screen, cross-linked elastomers (rubber) based on natural and synthetic rubbers, thermoplastic elastomers and polyurethanes filled with electrically conductive carbon black can be used. The main criteria when choosing an electrically conductive elastomer:

- high elasticity, including at low temperatures;

- high strength and wear resistance;

- high adhesion to an electrically conductive cross-linked polyethylene composition;

- increased electrical conductivity;

- high chemical, thermal and climatic resistance, moisture resistance;

- high manufacturability and the possibility of recycling;

- long operational period;

- low cost.

All these requirements are met to a greater extent by the conductive alkene diene thermoplastic elastomer ATEPep according to TU 2294-044-50289046-2012, commissioned year 2012, Russia, developed by the authors of the utility model.

Restrictions on the choice of the electrically conductive material of the fastening tape for the manufacture of an armor shield from aluminum wires of power cables with XLPE insulation are imposed by the conditions for the manufacture and operation of this material and cable:

- mechanical load on the electrically conductive tapes when applied to the cable;

- difficult-deformed state of electrically conductive tapes in the composition of the finished cable when it is repeatedly bent during storage, transportation, laying and operation;

- long-term thermal load on electrically conductive tapes at temperatures up to 90 ° C in the composition of the cable during its operation;

- thermomechanical load on the electrically conductive tapes in the cable during storage at a temperature of ± 50 ° C in the drums, as well as the required physical and mechanical characteristics of the electrically conductive material: thickness, density, maximum breaking strength and elongation, minimum electrical resistance, maximum moisture resistance, heat resistance and durability;

- price.

To perform the shielding properties and ensure sufficient dielectric strength, the electrically conductive material must have the following characteristics:

- the material should be uniform and uniform in thickness;

- the thickness of the material should be minimal, not more than 200 microns;

- the electrical resistance of the material should be no more than 3.5 × 10 ^-8 Ω · m;

- the material should remove heat well;

- The material must not break when applied to the cable.

The above requirements correspond to tapes made of aluminum and aluminum alloy, copper tapes and aluminum-polymer tapes. The lightest and cheapest metal screens are obtained using aluminum and aluminum alloy tapes.

An armored electric power cable according to a utility model (Fig.) Contains a conductive core (TJ) 1, including a sealed water-blocking tape or thread, a shield 2 along a core of an electrically conductive cross-linked polyethylene composition, insulation 3 made of cross-linked polyethylene, a two-layer cushion shield 4 s the first layer adjacent to the insulation of the electrically conductive cross-linked polyethylene composition and the second layer of electrically conductive elastomer, the separation layer 5 of electrically conductive tapes, or electrically conductive water-blocking tapes or without n it, a single-layer armor shield 6 of aluminum or its alloy wires, including those modified with rare or rare-earth metals, including those coated with copper, a fastening tape 7 of electrically conductive materials or without it, a separation layer 8 of paper or polymer tapes, or electrically conductive water-blocking tapes and laminated aluminopolymer tapes, or without fire retardant tapes and an outer protective sheath 9 made of polyethylene or PVC compound.

The cable proposed by the authors of the utility model is manufactured according to the following technology. The conductive core 1 is twisted on a twisting machine from one or several concentric coils of round aluminum or copper wires in a spiral in alternating directions with a certain twisting pitch. In this case, one wire is placed in the center of the core. The last twist of the wires should have the right direction of torsion. During twisting, TPG is sealed with crimp rollers. When the core is compacted, the diameter of the cable decreases and its operational characteristics increase. In order to ensure longitudinal sealing of TPG, water blocking tapes or threads are introduced when twisting into the core between the wires. A screen 2 of an electrically conductive cross-linked polyethylene composition with a thickness of at least 0.3 mm is applied to the conductive core 1 by extrusion. To prevent penetration of the electrically conductive composition of polyethylene during the extrusion process into the conductive core between the core and the screen, a separation layer of electrically conductive polymer tape with an overlap of (10-15)% can be applied on winding machines. On top of the screen 2 extruded insulation 3 of cross-linked polyethylene. The thickness of the insulation depends on the brand of cable. On the insulation 3 is extruded the first layer of the cushion screen 4 of an electrically conductive cross-linked polyethylene composition with a thickness of at least 0.3 mm. The overlay of the screen 2 along the core, insulation 3 and the first layer of the pillow-screen 4 is carried out in one pass on a continuous vulcanization line such as EPL-50 from Maillefer, Finland. The simultaneous application in the process of triple extrusion and the simultaneous stitching of all three layers provides high adhesion strength between the screens and insulation, as well as high dielectric strength due to the absence of gas inclusions in the insulation and on the border with the screens. With this technology, the adhesion strength between the screens and the insulation is comparable to the insulation strength. A second layer of an electrically conductive elastomer is applied to the first layer of the cushion screen 4, for example, of an ATEPep brand electrically conductive alkenediene thermoplastic elastomer having a polyolefin base similar to the first layer of the cushion screen. This increases the adhesion strength of the first and second layer of the pillow-screen. The thickness of the second layer of the pillow-screen is selected depending on the brand of cable. On top of the cushion screen 4, a separation layer 5 of electrically conductive tapes or electrically conductive water blocking tapes can be applied on winding machines. On top of the cushion shield 4 or on top of the separation layer 5, the armor shield 6 is made in a spiral from aluminum wires or its alloys, including those modified with rare or rare-earth metals, including those coated with copper. The diameter of the wires and their number are selected depending on the brand of cable. The overlay of the armor screen is performed on twisting machines with an increased pitch. The wire armor shield 6 can be fastened on twisting machines with tape 7 from electrically conductive materials from the group: copper, aluminum, aluminum alloys, aluminum-polymer tape. On top of the armor screen 6, a separating layer 8 of paper or polymer tapes, or electrically conductive water-blocking tapes and laminated aluminum-polymer tape or fire-retardant tapes can be applied on winding machines. On top of the armor screen 6 or the separation layer 8, an outer protective sheath 9 of polyethylene or PVC compound is applied by extrusion.

The materials used for the manufacture of the proposed cable are mass-produced.

Advantages of the new cable:

- high manufacturability in manufacturing;

- high operational characteristics;

- increased reliability and durability;

- wider scope;

- reduced cost.

Armored electrical power cables with cross-linked polyethylene insulation for voltages of 10 kV and higher with a single-layer armor shield made of aluminum alloy wires fastened with aluminum tape and a two-layer cushion shield made of electrically conductive polymers passed comprehensive tests at cable plants in the Russian Federation with positive results. Production of these cables has been established.

Claims (2)

1. Armored electric power cable, containing a conductive core, including a sealed water-blocking tape or thread, a core screen of a conductive cross-linked polyethylene composition, core insulation of cross-linked polyethylene, a pillow-shield of conductive polymer, a separation layer of conductive tapes or conductive water block tapes or without tapes, a non-magnetic metal armor shield, a release layer of paper or polymer tapes, or electrically conductive water-blocking tapes and laminas aluminopolymer tape, or fire retardant tapes or without it, and an outer polymer shell, characterized in that the cushion is a two-layer cushion and contains a first layer adjacent to the insulation of the electrically conductive cross-linked polyethylene composition and a second layer of electrically conductive elastomer, and the armor-shield is made single-layer of wires of aluminum or its alloys, including those modified with rare or rare-earth metals, including coated with copper, fastened with a tape of electrically conductive materials or without it. 2. The electric power cable according to claim 1, characterized in that, as the second layer of the cushion screen, it contains an ATEPep electrically conductive alkenediene thermoplastic elastomer.

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