RU2515275C1 - Gas-insulated power transmission line - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: gas-insulated power transmission line contains a cylindrical shell (1) filled with gas and a current-carrying tube (2) placed in it and fixed by base insulators (3) mounted at the inner surface of the shell (1). A butt end (4) of the base insulator (3) is entered into the current-carrying tube (2) through an opening (5) in its wall and covered by a screened tip (6) which top (7) is fixed in the wall of the current-carrying tube (2) opposite the above opening (5). The opening (5) is wider than the screened tip (6) and its edge (8) is flanged so that it can be fixed in the opening (5). The current-carrying tube (2) and the screened tip (6) can be made of the same metal.

EFFECT: even distribution of the electric field intensity both in the body and at surface of the base insulators.

2 cl, 1 dwg

Description

Technical field

The invention relates to the electric power industry, and in particular to structures of gas-insulated power transmission lines (hereinafter referred to as GIL) of ultra-high voltage.

State of the art

Known ultra-high voltage GIL, comprising a sheath and a current-carrying core coaxially located in it, supported by an insulating structure, which is a dielectric layer covering the current-carrying core, and insulating spacers emerging from this layer in the radial direction, distributed uniformly around the perimeter of the core, and the volume of the insulating gas is at least 50% of the volume of the solid dielectric [DE No. 213453, 07/06/1971].

This design of ultra-high voltage GIL has a number of drawbacks, which are the difficulty of manufacturing high-quality solid insulation due to its large volume and complex shape, installation of the current lead itself, and the development of the insulation surface with high field strength, which increases the likelihood of breakdown of insulation, as on the surface of a solid dielectric , and in its thickness.

An ultrahigh-voltage GIL is also known, containing a cylindrical shell in which conductive elements are located, separated from the shell by both bushing and support insulators, the latter can have through holes for filling internal volumes of GIL with gas [SU No. 660136, 04/01/1977]. This design provides high electrical strength of the gas insulation, and the use of support insulators ensures the manufacturability of the installation and dismantling of GIL. However, in this design, supporting insulators have high values of the electric field strength both on their surface and inside the solid dielectric, which reduces the operational reliability of the GIL.

The closest technical solution is an ultrahigh-voltage GIL containing a cylindrical shell filled with gas and a current-conducting pipe coaxially placed in it, fixed with support insulators mounted on the inner surface of the shell [Tech. Japanese journal Hitachi Review, v.28 (1979), No. 5, p. 27]. In this GIL, selected as a prototype, the supporting insulators have internal electrodes for attaching a current-carrying pipe, which reduce the electric field near the surface of the supporting insulators, however, the electric field in the body of the supporting insulators of the prototype remains high, which affects the reliability of the GIL.

Disclosure of the invention

The technical result of the invention is a uniform distribution of electric field strength both in the body and on the surface of the supporting insulators. The consequence of this is the ability to reduce the dimensions of insulators and GIL as a whole, keeping local values of electric field strength within acceptable limits, or, maintaining the dimensions, to increase the electric strength of GIL.

The subject of the invention is a GIL containing a cylindrical shell filled with gas and placed in it at least one current-carrying pipe fixed with support insulators mounted on the inner surface of the shell, characterized in that the end face of at least one support insulator introduced into the current-carrying pipe through an opening in its wall and covered by a shielding tip, the apex of which is fixed in the wall of the current-carrying pipe opposite the specified hole, while the hole in the wall of the current-carrying Pipes wider than the shield cap, the edge of which a flange to be secured in said hole.

This allows you to get the above technical result.

The invention has a development, which consists in the fact that the current-carrying pipe and the shielding tip are made of the same metal.

This avoids their electrochemical interaction.

The implementation of the invention in view of its development

Figure 1 as an example schematically shows a linear section of a single-phase GIL in the context.

The GIL in FIG. 1 contains a cylindrical shell 1 filled with gas, and a current-carrying pipe 2 placed therein, fixed with support insulators 3 mounted on the inner surface of the shell 1. The end face 4 of the insulator 3 is inserted into the pipe 2 through an opening 5 in the pipe wall 2 and covered by a shielding tip 6, the apex of which 7 is fixed in the wall of the current-carrying pipe 2 opposite the corresponding hole 5.

The hole 5 in the wall of the pipe 2 is made wider than the shielding tip 6. The edge 8 of the tip 6 is flanged with the possibility of fixing the tip 6 in the hole 5.

The pipe 2 and the tip 6 are made of the same metal, for example copper.

During the operation of the GIL, the shell 1 is grounded, and the pipe 2 is connected to the source (at the GIL input) and to the consumer (at the GIL output) of an ultrahigh (500 kV and more) voltage. The electric field between the conductive pipe 2 and the metal tip 6 in contact with it, on the one hand, and the grounded sheath 1, on the other hand, is uneven. Its tension has local maxima in the body and on the surface of insulator 3, as well as near the edge 8 of tip 6 at the so-called “triple point”, where metal, solid insulation, gas insulation are in contact. The shielding conductive tip 6 “pulls” the electric field from the solid insulation and thereby reduces the voltage values in the body of the insulator 3 and on its surface. Flanging edge 8, in turn, reduces the value of the electric field near the “triple point”.

Similarly, the invention can be implemented in a GIL with several current-carrying pipes 2, for example, in a three-phase GIL.

Claims (2)

1. Gas-insulated power line containing a cylindrical shell filled with gas, and placed in it, at least one current-carrying pipe, fixed with support insulators mounted on the inner surface of the shell, characterized in that the end face of at least one reference the insulator is introduced into the current-carrying pipe through an opening in its wall and is surrounded by a shielding tip, the apex of which is fixed in the wall of the current-carrying pipe opposite the specified hole, while the hole in the current wall the traveling pipe is wider than the shielding tip, the edge of which is flanged with the possibility of fixation in the specified hole. 2. The gas-insulated line according to claim 1, in which the current-carrying pipe and the shielding tip are made of the same metal.

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