RU2815923C1 - High-voltage three-phase coaxial cable - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention relates to high-voltage electric cables for transportation of electric power of increased frequency. Technical result is achieved by the fact that the high-voltage cable consists of four conductors for three-phase current of increased frequency, three of which are insulated with fluoroplastic. First conductor is single-core or multi-core and is located in the centre of a high-voltage three-phase coaxial cable. Subsequent conductors are made in the form of braiding or single-core. Each conductor is superimposed concentrically on insulation of the previous conductor. Cable additionally comprises two aramid bearing cables longitudinally laid on fourth conductor, wherein the fourth conductor and two longitudinally laid aramid bearing cables are covered with an outer insulating shell of light-stabilized cross-linked polyethylene.

EFFECT: higher reliability and safety of electric power transmission via high-voltage three-phase coaxial cable by elimination of sagging and stretching.

1 cl, 2 dwg

Description

The invention relates to electrical engineering, mainly to high-voltage electrical overhead cables for transporting electricity, called overhead power lines, and can be used to transmit electrical energy of high frequency up to 12000 Hz in power networks with a nominal alternating voltage of up to 2000 V.

A superconducting cable is known (patent for invention RU No. 2340969, MPK N01 V 12/02, published on December 10, 2008) containing a frame made of normally conducting metal, a first superconducting layer formed around the outer circumference of the frame, an electrical insulating layer formed around an outer circumference of the first superconducting layer, a second superconducting layer formed around the outer circumference of the electrical insulating layer, and a normal conductive metal layer formed between the electrical insulating layer and the second superconducting layer.

The disadvantages of this superconducting cable are the use of conductors made of superconducting materials, circulation of coolant through the cable to achieve the required operating temperature of the conductors.

A known three-phase coaxial heating cable (patent for invention RU No. 2516219, IPC N05 V 3/56, published May 20, 2014) containing three cores, each of which is covered with an external sealed thermoelectric insulating sheath and has internal and external conductors connected in series between each other and coaxially placed with an annular gap between them filled with an internal thermoelectric insulating shell, and a common protective shell.

The disadvantage of this technical solution is that the invention relates to electric heating cables, namely to the designs of three-phase coaxial heating cables, which are intended for heating objects of various shapes. Due to its design and insulation characteristics, this cable is not intended for transmitting high voltage electricity.

A coaxial cable is known for the transmission and distribution of electrical energy (patent for utility model RU No. 81370, IPC N01 V 9/04, published on March 10, 2009), containing an internal conductor, insulation of the internal conductor, on which an external multi-core conductor of aluminum wires, and an outer insulating sheath, the inner conductor is made of single-core or stranded copper or aluminum wires twisted together into a core, part of the cores of the inner and outer conductors is made of galvanized steel wires, and the number of steel wires is determined by the required breaking force that must withstand cable.

The disadvantages of this coaxial cable for the transmission and distribution of electrical energy is the lack of the required number of conductors and, as a consequence, the impossibility of transmitting electricity through a three-phase power transmission system.

The closest in technical essence to the claimed technical solution is a high-voltage three-phase coaxial cable (patent for invention RU No. 2790859, IPC N01 V 9/02, published on February 28, 2023), containing a first conductor made of single-core or multi-core copper or aluminum wires and located in the center of the cable, subsequent conductors are made of single-core or braided with copper or aluminum wires, superimposed concentrically on the insulation of the previous conductor, three conductors are insulated with fluoroplastic, and the fourth conductor is covered with an outer insulating sheath of light-stabilized cross-linked polyethylene.

The disadvantages of this high-voltage three-phase coaxial cable are its stretching and sagging during operation on overhead power lines, which reduces the reliability and safety of power networks.

The technical objective of the proposed invention is to increase the strength of the cable and the safety of operation of power networks with the ability to transmit high-frequency electricity via a high-voltage three-phase coaxial cable.

The technical result of the proposed invention is to increase reliability by eliminating sagging and stretching of a high-voltage three-phase coaxial cable.

This is achieved by the fact that a high-voltage coaxial three-phase cable contains four conductors, three of which are insulated with fluoroplastic, conductors made of copper or aluminum wires are arranged coaxially, the first conductor is made single-core or multi-core and is located in the center of the high-voltage three-phase coaxial cable, subsequent conductors are made in the form of a braid or single-core, each conductor is superimposed concentrically on the insulation of the previous conductor, according to the invention, additionally contains two aramid load-bearing cables laid longitudinally on the fourth conductor, and the fourth conductor and two aramid load-bearing cables longitudinally laid on it are covered with an outer insulating sheath of light-stabilized cross-linked polyethylene.

The essence of the invention is illustrated by drawings, where in Fig. 1 shows a schematic diagram of the cable (longitudinal), Fig. 2 - schematic diagram of the cable (transverse).

The design of the proposed high-voltage three-phase coaxial cable, including conductors No. 1-4, contains (see Fig. 1-2):

1. Outer insulating shell made of light-stabilized cross-linked polyethylene;

2. Conductor No. 4;

3. Insulation of conductor No. 3 made of fluoroplastic;

4. Conductor No. 3;

5. Insulation of conductor No. 2 made of fluoroplastic;

6. Conductor No. 2;

7. Insulation of conductor No. 1 made of fluoroplastic;

8. Conductor No. 1;

9. Aramid support cable.

The high-voltage three-phase coaxial cable (Fig. 1 and Fig. 2) consists of four conductors for three-phase high-frequency current and two supporting cables 9, conductors 8,6,4 - for three phases L1, L2, L3, and conductor 2 - depending from the selected grounding system. Conductor 8 is made of single-core or stranded copper or aluminum wires and is located in the center of a high-voltage three-phase coaxial cable. Subsequent conductors 6, 4 and 2 are made of single-core or braided copper or aluminum wires, superimposed concentrically on the insulation 7, 5 and 3 of the previous conductor, respectively. Two supporting cables 9, made of aramid threads, are laid longitudinally on the conductor 2 and covered with an outer insulating sheath of light-stabilized cross-linked polyethylene 1.

High voltage three phase coaxial cable works as follows.

PTFE insulation 7, 5 and 3 provides protection against short circuit between conductors 8, 6; 6, 4 and 4, 2. The outer insulating sheath 1 made of light-stabilized cross-linked polyethylene prevents harmful external influences on the high-voltage three-phase coaxial cable in contact with the environment, and also protects people from electric shock of high frequency in direct contact with the conductor 2.

Aramid cable 9 accepts all load-bearing loads, increasing the reliability of high voltage three-phase coaxial cable without compromising flexibility.

Thus, the load-bearing loads are distributed without reducing the efficiency of use of the conductor material, without increasing the electrical resistance when transmitting electrical energy of increased frequency in the proposed high-voltage three-phase coaxial cable.

The use of the invention makes it possible to increase the reliability and safety of high-frequency power transmission via a high-voltage three-phase coaxial cable by eliminating sagging and stretching, as well as increasing its service life.

Claims (1)

A high-voltage coaxial three-phase cable containing four conductors, three of which are insulated with fluoroplastic, conductors made of copper or aluminum wires are arranged coaxially, the first conductor is made single-core or multi-core and is located in the center of the high-voltage three-phase coaxial cable, subsequent conductors are made in the form of braided or single-core, each the conductor is superimposed concentrically on the insulation of the previous conductor, characterized in that it additionally contains two aramid load-bearing cables laid longitudinally on the fourth conductor, wherein the fourth conductor and two aramid load-bearing cables laid longitudinally on it are covered with an outer insulating sheath made of light-stabilized cross-linked polyethylene.