DE3112022A1 - Electrical installation or apparatus - Google Patents

Abstract

Electrically conductive parts (2, 4), on which the calculable field intensity is at a maximum, are provided with electrically conductive layers (6 and 8) which form a smooth surface. If these parts are provided with an insulating envelope (34), the inner surface of the envelope (34) can also be provided with the conductive layer (36). By means of this coating of critical installation parts, field intensity peaks are avoided and the safety distance can be selected to be correspondingly smaller. <IMAGE>

Description

SIEMENS AKTIENGESELLSCHAFT Our mark

Berlin and Munich VPA 8 | p 7 5 \ g

Electrical system or device

The invention relates to an electrical system or an electrical device carrying high voltage Elements.

For medium-voltage systems with a voltage of more than about 1 kV, especially in high-voltage systems, electrical safety is known to be due to the Determines the field strength occurring on the individual elements. Especially in the construction of pressurized gas insulated Systems one is forced to keep the dimensions as small as possible so that one can deal with the voltage utilization can approach the limit of the permissible field strength. Depending on the surrounding medium, the permissible values differ. However, since one has both of the surface shape of the electrically conductive Divide certain field strength as well as the field strength determined by the surface roughness, which lead to field strength peaks must take into account, a certain additional safety distance must be maintained. This limits the operating voltage permissible for a given arrangement. You can, for example In pressurized gas-insulated systems, the influence of the surface roughness on the field strength due to high requirements keep the surface quality small. However, this increases the manufacturing costs.

Plastics are known which become electrically conductive through the addition of finely divided metal or carbon can be made, so-called conductive elastomers.

Kin 2 Koe / 23-3.1981

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Such plastics, which are generally easy to process in the liquid state, are used in electronic devices has been applied to the surface of electrically conductive parts for the area of low voltage in order to reduce the 5 to compensate for surface roughness and thereby improve the contact between adjacent surfaces for the current transfer (Insulation / Circuits, Febr. 1975, Pages 41 to 43).

The invention is based on the task of taking into account the influence of the surface roughness to reduce the safety allowance required for the field strength.

This object is achieved according to the invention in that electrically conductive parts, on which by surface curvature or a field strength increase occurs due to surface roughness, with an electrically conductive one Layer are provided, which forms a smooth surface. With such preferably adhesive conductive Layers are particularly the inner surface of the housing and the conductor in high-voltage systems, especially in compressed gas insulated high-voltage systems.

For coating electrically conductive plastics, vorzugsx-xeise conductive Slastomsr® ρ or conductive casting resins as well as coatings or rubber "suitable Specifically, these layers are made of a material having a large surface tension _9, the VOA liquid passes into a more solid state and by its © surface tension forms a smooth surface.

In systems whose electrically conductive parts have a insulating sheath are provided, may be appropriate

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the space between the conductor surface and the inner surface of the sheath with the electrically conductive one Layer provided, in particular filled out.

A particularly advantageous embodiment of the system is obtained in that these are electrically conductive Elements that are provided with a cover, the inner surface of the cover with the conductive Material is coated.

To further explain the invention, reference is made to the drawing, in which FIG. 1 shows an exemplary embodiment one ; electrical device according to the invention is schematically illustrated. The figures 2 and 3 each show a particular embodiment of an electrical device according to the invention.

According to Figure 1, an electrical conductor 2 is a compressed gas insulated High-voltage system surrounded by a hollow cylindrical casing 4, for example from Sheet steel can exist and the conductor 2 surrounds concentrically at a distance a. The distance a becomes determined by the range to be switched on at a given voltage of, for example, 220 kV, as well as the maximum Field strength. Un the influence of surface roughness to exclude the field strength at least approximately, the surface of the conductor 2 with a Layer 6 made of electrically conductive material, in particular an electrically conductive elastomer, is provided. Under certain circumstances, it may be expedient to also liner the inner surface of the casing 4 8 to be provided, for example from a hardenable plastic or from a higher Temperature liquid plastic can exist. the

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Thickness of the layers 6 and 8 wii d chosen so that the conductive layer covers the peaks of the surface roughness, for example a weld seam, smoothly.

In a system with electrically conductive parts 20, for example profile conductors, ν ie with an electrically insulating sheath 24 are provided, can preferably the space between the inner surface of the envelope and the surface of the conductor 20 with electrically conductive material: 6 must be filled out. By this filling 2.6 Hohlräime are avoided and the Influence of the surface roughness -.- it on the field strength locked out.

In systems with profile conductors 3 ^r >, which are seen with an electrically conductive sheath 34 ', which are subsequently pushed onto the conductor 30 and thereby form a gap between the surface of the conductor 30 and the inner surface of the sheath 34, preferably the inner surface of the envelope 34 can be provided with a liner 36. In this case, the cavity 38 formed between part of the surface of the conductor 30 and the free surface of the lining 36 is located between two electrically conductive surfaces, which are thus at the same potential the surface roughness on the field strength is excluded,

3 claims
3 figures

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Claims (3)

- * - VPA 81 P 7 5 1 9 DE Claims fiJ Electrical system with high voltage leading Elements, marked! that electrically conductive parts (2, 4), on which by surface curvature or surface roughness a field strength increase occurs, provided with an electrically conductive layer (6 or 8) that forms a smooth surface. 2. Electrical system or Gerf-t according to claim 1 with electrically conductive elements, which are seen with an electrically insulating cover \, characterized in that the Gap between the conductive parts (20) and the envelope (24) with electrically conductive Material (26) is filled (Fig. 2). 3. Electrical system or device according to claim 2, characterized in that the inner surface of the casing (34) facing the conductive parts (30) with an electrically conductive one Lining (36) is provided. BATH ORIGINAL