RU113862U1 - ELECTRIC POWER CABLE - Google Patents

Abstract

1. An electric power cable with XLPE insulation and a metal screen made of aluminum or aluminum alloy wires, characterized in that the wires in the metal screen are additionally fastened with a conductive tape. ! 2. Power cable according to claim 1, characterized in that it contains a tape of aluminum or an aluminum alloy as a fastening tape. ! 3. Power cable according to claim 1, characterized in that it contains a copper tape as a fastening tape. ! 4. Power cable according to claim 1, characterized in that it contains an aluminum-polymer tape as a fastening tape.

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 cable with plastic insulation for a voltage of 6 kV according to GOST 16442-80, year of entry 1982, Russia, having a combined screen. This standard applies to power cables with aluminum or copper conductors, with plastic insulation, in plastic or aluminum sheath, with or without protective covers, intended for the transmission and distribution of electrical energy in stationary installations for a rated alternating voltage of up to 6 kV of a frequency of 50 Hz. Non-metallic electrically conductive materials are used as a combined shield of cables with plastic insulation, on top of which a metal shield of copper tapes or copper foil is applied.

Also known is the design of a power cable with cross-linked polyethylene insulation for voltage of 10, 20 and 35 kV according to TU 16.K71-335-2004, year of entry 2004, Russia, which has a combined insulation screen with a metal screen made of copper wires fastened with a copper tape. Disadvantages of a metal screen made of copper wires and copper tape: large mass and high cost.

The closest in parameters to the utility model is a power cable with cross-linked polyethylene insulation according to patent No. 87037, Russia (prototype), which contains a metal screen made of aluminum or aluminum alloy wires as a part of a combined screen. 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 shield 4, a separation layer 5, a plastic sheath 6. Electric power cables according to the prototype are made according to the following technology. A screen 2 of an electrically conductive polymer crosslinked composition with a thickness of at least 0.3 mm is applied by extrusion onto a copper or aluminum conductive core 1. To prevent the penetration of the electrically conductive polymer composition into the conductive core with a cross section of 1000 mm ² and above, a layer of conductive polymer tape with an overlap of (10-15)% is laid between the core and the screen. Over 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 screen of aluminum wires with a nominal diameter (0.7-2.0) mm. On top of the combined 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 dielectric strength;

- reduced manufacturability.

All these disadvantages of the prototype significantly reduce the quality, reliability and manufacturability of cables with XLPE insulation.

The technical task of the utility model is the development of a power electric cable that is not inferior to the prototype in basic characteristics, but more technological, high-quality and highly reliable.

The technical result is achieved in that the wires of aluminum or aluminum alloy in the metal screen of the cable are additionally fastened with a tape of electrically conductive material.

A common feature of the prototype and the proposed technical solution is the presence of a metal screen made of aluminum or aluminum alloy wires. At the same time, the proposed cable differs from the known one by using a fastening tape of an electrically conductive material in a metal screen made of aluminum wires or an aluminum alloy. A fastening tape ensures the continuity of the metal shield over the entire cable surface. This increases the electrical strength of the insulation. The tape also fixes the aluminum wires of the metal screen 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 metal screen.

Advantages of the new cable:

- high dielectric strength;

- high manufacturability and quality.

Restrictions on the choice of the electrically conductive material of the fastening tape for the manufacture of metal shields 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 force 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.

The essence of the proposed utility model is illustrated by the following examples. Table 1 shows the options for samples of electrically conductive materials for fastening tapes and their main characteristics. Designations of electrically conductive materials:

- A5 aluminum tape - A5 technical aluminum tape in accordance with GOST 618-73, Russia;

- tape AMts - tape from aluminum alloy AMTs according to GOST 618-73;

- APK-1 tape - polyethylene with a single-sided polyethylene layer according to TU 1811-021-00463800-2008, commissioning year 2008, Russia;

- Ml tape - copper tape according to GOST 1173-2006, Russia.

Table 2 shows the quality indicators of samples of a single-core electric cable of the PvPu1 × 800 / 35-10 kV brand according to TU 16.K71-335-2004, commissioned year 2004, Russia, with cross-linked polyethylene insulation and a combined insulation screen, including a metal shield from A5 aluminum wires with a diameter of 1.5 mm, in the amount of 32 pcs., with a total cross section of 56 mm ² (alternative to a screen of copper wires with a cross section of 35 mm ² ), according to the prototype, and fastening tape from A5 aluminum 10 mm wide, according to the new cable design. Three options of the fastening tape 100, 150 and 200 microns thick were used. The design and manufacturing technology of all cable samples, including the prototype, in the above examples were similar, except for the design of the metal screen. Unlike the prototype, the new cable design contains a fastening tape made of an electrically conductive material, laid on top of the aluminum wires of the metal screen in a spiral with a gap.

From table 1 it can be seen that the most cheap and high-quality electrically conductive material for the bonding tape is aluminum tape A5.

From table 2 it is seen that the highest quality and manufacturability is electric cable with a metal screen made of aluminum wires fastened with aluminum tape A5 thickness (150-200) microns.

Power electric cables with cross-linked polyethylene insulation for voltages of 10 kV and higher with a metal screen made of aluminum wires fastened with aluminum tape have passed comprehensive tests at cable plants in the Russian Federation with positive results. Production of these cables has been established.

Table 1 Name of characteristics Variants of samples of electrically conductive materials Tape aluminum A5 Tape AMTS Tape APK1 Tape M1 Thickness, microns one hundred 150 200 170 200 one hundred Weight 1 m ² , g 270 405 540 464 455 890 Temporary resistance, MPa, not less than GOST 11701-84 60 60 60 110 fifty 240 Relative elongation,%, not less 25 25 25 25 thirty 36 Electrical resistivity, Ohm · m, according to GOST 7229-76 2.7 · 10 ^-8 2.7 · 10 ^-8 2.7 · 10 ^-8 3.45 · 10 ^-8 2.7 · 10 ^-8 1.7510 ^-8 price, rub. for 1 kg 120 120 120 150 160 440

table 2 Quality indicators for electric cables PvPu1 × 800 / 35-10 cable with a metal shield from aluminum. wires (prototype) PvPu1 × 800 / 35-10 cable options with A5 aluminum fastening tape according to Table 1. 100 μm 150 microns 200 microns The level of partial discharges at an alternating voltage of 15 kV with a frequency of 50 Hz, according to GOST 20074-83, no more than 10 pC 7.8 5,4 5.1 4,5 Breakdown test with an alternating voltage of 25 kV at a frequency of 50 Hz for 10 minutes, according to GOST 2990-78 Sustained Withstood Resistance to winding (multiple bending), according to TU 16.K71-335-2004 No metal screen wire breaks Cracking fastener tape There are no tears or cracks in the fastening tape There are no tears or cracks in the fastening tape

Continuation of table 2 Quality indicators for electric cables PvPu1 × 800 / 35-10 cable with a metal shield from aluminum. wires (prototype) PvPu1 × 800 / 35-10 cable options with A5 aluminum fastening tape according to Table 1. 100 μm 150 microns 200 microns The level of partial discharges at a voltage of 15 kV with a frequency of 50 Hz after a bending test, not more than 5 pC 6.2 5,0 2,8 2.6 Test after bending for breakdown with an alternating voltage of 40 kV at a frequency of 50 Hz for 5 min, according to GOST 2990-78 Could not resist Could not resist Withstood

Continuation of table 2 Quality indicators for electric cables PvPu1 × 800 / 35-10 cable with a metal shield from aluminum. wires (prototype) PvPu1 × 800 / 35-10 cable options with fastening tape made of aluminum A5 according to Table 1. 100 μm 150 microns 200 microns Manufacturability and quality Manufacturability and quality are low Manufacturability and quality are low High manufacturability, quality and profitability Workability and quality are high

Claims (4)

1. An electric power cable with cross-linked polyethylene insulation and a metal screen made of aluminum or aluminum alloy wires, characterized in that the wires in the metal screen are additionally fastened with a tape of electrically conductive material. 2. Electric power cable according to claim 1, characterized in that as a fastening tape it contains a tape of aluminum or aluminum alloy. 3. The electric power cable according to claim 1, characterized in that as a fastening tape it contains a copper tape. 4. The electric power cable according to claim 1, characterized in that as a fastening tape it contains an aluminum polymer tape.