RU2169420C1 - External grounding device - Google Patents

Abstract

FIELD: electrical engineering; grounding industrial units and electrical installations. SUBSTANCE: device has conductor running from industrial unit, grounding net driven in earth through certain depth, grounding frame placed under net over its perimeter at depth of hazard-zone radius where current may spread over earth surface. Grounding net and grounding frame are rigidly fixed together over their perimeters by means of vertical insulated conductors. EFFECT: reduced amount of excavation work. 4 dwg _

Description

 The present invention relates to electrical engineering and can be used to ground industrial facilities with electrical installations using remote grounding devices made of horizontal electrodes, grounding electrodes.

There are various types of contour and remote grounding devices designed for grounding electrical installations (AS USSR 513432, 877675, 881921, 930462, 552278, etc.)
The disadvantages of these devices are the design complexity and the presence on the surface of the earth of dangerous zones of current spreading fields due to the presence of dangerous "step voltage".

 Known grounding device made in the form of a grounding grid embedded in the soil to a depth of the radius of the danger zone of the current spreading field.

R _op = (1/7 - 1/8) R _max ,
where R _max is the maximum radius of the current spreading field, R _max = 15 - 20 m (Pat. 2011250 RF, class H 01 R 4/66, H 02 B 1/16).

The disadvantage of this prototype is the significant amount of earthwork required to lay the grounding device in the ground. This is explained by the fact that for laying the mesh into the ground, it is necessary to form a foundation pit with dimensions equal to the length and width of the mesh with a depth of R _op = 2.0 - 2.5 m.

 The task of the invention is to eliminate this drawback.

 The solution to this problem is achieved by the implementation of the grounding device in the form of a hollow prism turned upside down, the bottom of which is made in the form of a mesh, the sides and ends are in the form of vertical insulated wires, the shell is in the form of a frame.

The novelty lies in the fact that the grounding grid is located at a depth less than the radius _Rop , along the perimeter of which a grounding frame is located at a depth of _Rop below, rigidly connected by vertical insulated wires around the perimeter to the grounding grid.

 This design makes it possible to reduce the amount of earthwork for laying the grounding grid into the ground, since it is necessary to form a foundation pit with a depth of 0.5 - 0.8 m under the grid (Nikitin L.I. Labor protection and fire protection in the forest industry. - M .: Forest industry, 1974, p. 234). rather than 2.0 - 2.5 m.

Laying the grounding frame to a depth of R _{o is} necessary to exclude the formation of a dangerous zone of the current spreading field along the perimeter of the grounding grid. Inside this grid, due to the equalization of the potentials of the earth's points from adjacent grid elements, “step voltages” and dangerous zones of the current spreading field will be safe. The laying of the grounding frame in the ground can be carried out in a narrow gap formed by earth-moving machines.

 Making vertical wires insulated is necessary to prevent the formation of dangerous zones of current spreading fields on the earth's surface as from vertical grounding conductors.

 In FIG. 1 and 2 show the arrangement of the grounding device in the ground, in FIG. 3 and 4 - a General view of the grounding device.

The remote grounding device consists of a conductor 1 (Fig. 1 and 2), going from the production facility, grounding grid 2, located in the ground at a depth h, a grounding frame 3, located below the grid according to its dimensions at a depth of the radius of the danger zone of the current spreading field at the surface of the earth R _op and vertical insulated wires 4, rigidly connected to the grounding grid and frame.

 The operation of the remote grounding device is as follows. When the current is closed to the electrical installations of the production facility, the current through the conductor 1 (Fig. 1 and 2) enters the grounding grid 2, into the insulated wires 4 and into the grounding frame 3, spreading in the ground relative to the grounding device in all directions at the same distance.

Claims (1)

A remote grounding device containing a grounding grid embedded in the ground, characterized in that the grounding grid is located at a depth of a smaller radius R _{op of the} dangerous zone of the current spreading field on the earth's surface, and an additionally introduced grounding ground is located along the perimeter of the grounding grid at a depth equal to R _op frame, wherein the grounding grid and grounding frame rigidly interconnected along the perimeter additionally introduced vertical insulated wires, a R _op (1,7 - 1,8) R _max, where R _max - maximum field radius ra percolation current on the ground surface.

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