CN112540236A - Method and device for shielding corridor electric field exceeding low potential of overhead transmission line - Google Patents

Abstract

The invention discloses an over-standard low potential shielding method and device for an electric field of an overhead transmission line corridor, wherein the over-standard position is determined through the ground electric field intensity, so that a shielding treatment area is determined, the shielding treatment area is used as a central area, and a square shielding body earth screen with the side length not less than 2 times of the distance between phase leads at two sides of the overhead transmission line is selected for laying the earth screen, so that the distribution distortion of the electric field lines of the corridor is changed, the shielding safety is improved, and the space of the electric transmission line corridor is saved.

Description

Method and device for shielding electric field exceeding standard and low potential in overhead transmission line corridor

technical field

The invention relates to the technical field of electric field shielding in an overhead transmission line corridor, in particular to a method and a device for shielding an electric field exceeding the standard and low potential in an overhead transmission line corridor.

Background technique

With the improvement of public awareness of environmental protection, people's attention to the influence of power frequency electric field strength of overhead transmission lines is increasing year by year. "Electromagnetic Environmental Control Limits" (GB8702-2014) stipulates that the public exposure limit of electric field intensity is E=200/f (frequency) V/m when the frequency is 0.025kHz ~ 1.2kHz. For overhead transmission lines, the frequency is 50Hz, and the limit The value is 4kV/m. At the same time, it is also stipulated that the farmland, garden land, pasture land, livestock and poultry breeding land, breeding water surface, roads and other places under the overhead transmission line route should be satisfied. The control limit of the electric field strength at a frequency of 50Hz is 10kV/m m.

In the current design regulations for 110kV-1000kV overhead transmission lines, the distance between the overhead transmission line and the ground corridor is estimated based on the ground potential of the surface of the ground object, and the local resistivity difference between ground objects and soil is not considered, resulting in the local electric field strength on the ground exceeding the public exposure. The limit of 4kV/m makes the electric field intensity environmental evaluation unqualified after the construction of the overhead transmission line is completed. It is necessary to carry out the treatment of the electric field exceeding the standard, and the completion acceptance of the project can only be completed after the treatment is qualified. The current method for controlling the electric field that exceeds the standard is to use the high-potential shielding of the electric field in the corridor of the overhead transmission line. However, this method induces large voltage and induced current, which has a large potential safety hazard, and additionally occupies the space of the corridor of the overhead transmission line.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is that the induced voltage and the induced current are relatively large in the existing treatment methods for exceeding the standard electric field, and there is a great potential safety hazard. At the same time, the space of the overhead transmission line corridor is additionally occupied. Therefore, the present invention provides an overhead transmission line. The method and device for shielding the corridor electric field exceeding the standard and low potential can improve the shielding safety and save the space of the transmission line corridor.

The present invention is achieved through the following technical solutions:

A method for shielding an electric field exceeding a standard and a low potential in a corridor of an overhead transmission line, comprising:

Obtain the ground electric field intensity at each measurement point of the overhead transmission line corridor and the distance between the phase conductors on both sides of the overhead transmission line;

Take the position of the measurement point where the ground electric field strength exceeds the preset value of the strength as the over-standard position;

Carry out resistivity detection on the soil at the position exceeding the standard, and determine that the soil area corresponding to the minimum resistivity is the shielding treatment area;

The shielding treatment area is taken as the central area, and the grounding net of the shielding body is selected according to the distance between the phase wires on both sides of the overhead transmission line, so as to complete the laying of the grounding net of the shielding body.

Further, the mesh of the ground mesh of the shielding body is square, and the side length is greater than 0 and less than or equal to 0.5m.

Further, the ground mesh of the shielding body is square.

Further, the side length of the square is not less than twice the distance between the phase conductors on both sides of the overhead transmission line.

Further, the material of the ground mesh of the shielding body is a conductive material.

Further, the laying depth of the ground net is not more than 0.5 meters.

Further, the overhead transmission line is an overhead transmission line with an AC voltage level of 110kV, 220kV, 330kV, 500kV, 750kV or 1000kV; or,

The overhead transmission line is a 500kV or 800kV DC voltage level overhead transmission line.

An overhead transmission line corridor electric field exceeding standard and low potential shielding device, comprising:

The data acquisition module is used to acquire the ground electric field intensity of each measurement point of the overhead transmission line corridor and the distance between the phase conductors on both sides of the overhead transmission line;

The exceeding standard position determination module is used to take the position of the measurement point where the ground electric field strength exceeds the preset value of the strength as the exceeding standard position;

The shielding treatment area determination module is used to detect the resistivity of the soil at the position exceeding the standard, and determine the soil area corresponding to the minimum resistivity as the shielding treatment area;

The shielding body grounding network selection module is used to select the shielding body grounding network according to the distance of the phase conductors on both sides of the overhead transmission line with the shielding management area as the central area, so as to complete the shielding body grounding network laying.

The invention provides a method and a device for shielding the electric field exceeding the standard and low potential in the corridor of an overhead transmission line. The excessive position is determined by the ground electric field strength, so as to determine the shielding treatment area, and the shielding treatment area is taken as the central area, and the side length is not less than the overhead transmission line. The ground grid of the square shielded body with twice the distance of the phase conductors on both sides is laid for the ground grid to change the distribution distortion of the electric field lines in the corridor, improve the shielding safety, and save the space of the transmission line corridor.

Description of drawings

The accompanying drawings described herein are used to provide further understanding of the embodiments of the present invention, and constitute a part of the present application, and do not constitute limitations to the embodiments of the present invention. In the attached image:

FIG. 1 is an application scenario diagram of a method for shielding an overhead transmission line corridor with an electric field exceeding the standard and low potential.

FIG. 2 is a flow chart of a method for shielding an overhead transmission line corridor with an electric field exceeding a standard and a low potential shielding according to the present invention.

3 is a distribution diagram of electric field lines in a corridor with uniform distribution of soil resistivity according to an embodiment of the present invention.

FIG. 4 is a distribution diagram of electric field lines in a corridor with uneven soil resistivity distribution according to an embodiment of the present invention.

Fig. 5 is a distribution diagram of the corridor electric field line of soil resistivity after laying a shielded ground net in an embodiment of the present invention.

FIG. 6 is a schematic block diagram of a low-potential shielding device for an overhead transmission line corridor electric field exceeding the standard and low potential according to the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and the accompanying drawings. as a limitation of the present invention.

The method for shielding the electric field exceeding the standard and the low potential in the corridor of an overhead transmission line provided by the present invention is applied in the application scenario shown in FIG. 1 . Among them, D represents the distance between the phase conductors on both sides of the overhead transmission line.

Example 1

The present invention provides a method for shielding the electric field exceeding the standard and low potential in an overhead transmission line corridor, as shown in FIG. 2 , which specifically includes the following steps:

S10: Obtain the ground electric field strength of each measurement point in the overhead transmission line corridor and the distance between the phase conductors on both sides of the overhead transmission line.

S20: The position of the measurement point where the ground electric field strength exceeds the preset strength value is taken as the over-standard position.

The preset intensity value refers to a preset electromagnetic environment public exposure control limit, and the preset intensity value in this embodiment is set to 4kV/m.

S30: Perform resistivity detection on the soil at the position exceeding the standard, and determine the soil area corresponding to the minimum resistivity as the shielding treatment area.

S40: Take the shielding treatment area as the central area, and select the shielding body grounding network according to the distance between the phase wires on both sides of the overhead transmission line to complete the laying of the shielding body grounding network.

Further, the meshes of the ground mesh of the shielding body can be set to be square, rectangular or circular. However, using a circular shape is inconvenient for construction; if a rectangular shape is used, the length should be larger than the width, which wastes materials. Therefore, in this embodiment, a square mesh is used, and the side length is greater than 0 and less than or equal to 0.5m.

Further, the ground net of the shielding body is square.

Further, the side length of the square is not less than twice the distance between the phase conductors on both sides of the overhead transmission line.

Further, the material of the ground mesh of the shielding body is a conductive material. Since there are corrosive substances in the ground, in order to avoid corrosion and from an economical point of view, the ground mesh of the shielding body in this embodiment is made of stainless steel.

Further, the depth of the ground net laying shall not exceed 0.5 meters.

Further, the overhead transmission line is an overhead transmission line with an AC voltage level of 110kV, 220kV, 330kV, 500kV, 750kV or 1000kV. Alternatively, the overhead transmission line is a 500kV or 800kV DC voltage level overhead transmission line.

Specifically, when the soil resistivity distribution of the overhead transmission line corridor is uniform, the distribution of the electric field lines in the corridor is as shown in Figure 3, which is uniformly distributed without distortion; when the soil of the overhead transmission line corridor contains metals, coal mines and other substances, the soil When the resistivity distribution is uneven, the distribution of electric field lines in the corridor is shown in Figure 4. The distribution of electric field lines on the soil surface with low resistivity is distorted, and the electric field intensity exceeds the preset intensity value. Through the above-mentioned method of shielding the electric field in the corridor of overhead transmission line with excessive electric field and low potential, lay a stainless steel square shielded ground grid with a depth of not more than 0.5 meters, a mesh size of not more than 0.5 m, and a side length of not less than 2 times the distance between the phase conductors on both sides of the overhead transmission line. , so that the distorted electric field lines are evenly distributed. Figure 5 shows the distribution of the electric field lines in the corridor after laying the shielded ground net. It can be seen from Figure 5 that the electric field lines in the corridor after laying the shielded ground net are evenly distributed.

Example 2

As shown in FIG. 6 , the difference between this embodiment and Embodiment 1 is that an overhead transmission line corridor electric field exceeding standard and low potential shielding device is provided, including:

The data acquisition module 10 is used for acquiring the ground electric field intensity of each measurement point of the overhead transmission line corridor and the distance between the phase conductors on both sides of the overhead transmission line.

The exceeding-standard position determination module 20 is used for taking the position of the measurement point where the ground electric field intensity exceeds the preset intensity value as the exceeding-standard position.

The shielding treatment area determination module 30 is configured to perform resistivity detection on the soil in the exceeding standard position, and determine the soil area corresponding to the minimum resistivity as the shielding treatment area.

The shielding body grounding network selection module 40 is used to select the shielding body grounding network according to the distance between the phase conductors on both sides of the overhead transmission line with the shielding treatment area as the central area, so as to complete the laying of the shielding body grounding network.

Those skilled in the art can clearly understand that, for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. Module completion, that is, dividing the internal structure of the device into different functional units or modules to complete all or part of the functions described above.

The specific embodiments described above further describe the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (8)

1. an overhead transmission line corridor electric field exceeding standard low potential shielding method, is characterized in that, comprises: Obtain the ground electric field intensity at each measurement point of the overhead transmission line corridor and the distance between the phase conductors on both sides of the overhead transmission line; Take the position of the measurement point where the ground electric field strength exceeds the preset value of the strength as the over-standard position; Carry out resistivity detection on the soil at the position exceeding the standard, and determine that the soil area corresponding to the minimum resistivity is the shielding treatment area; The shielding treatment area is taken as the central area, and the grounding net of the shielding body is selected according to the distance between the phase wires on both sides of the overhead transmission line, so as to complete the laying of the grounding net of the shielding body. 2 . The method for shielding the electric field exceeding the standard and low potential in an overhead transmission line corridor according to claim 1 , wherein the mesh of the ground net of the shielding body is square, and the side length is greater than 0 and less than or equal to 0.5m. 3 . 3 . The method for shielding the electric field exceeding the standard and low potential in the corridor of an overhead transmission line according to claim 1 , wherein the ground net of the shielding body is square. 4 . 4 . The method for shielding the electric field exceeding standard and low potential in an overhead transmission line corridor according to claim 3 , wherein the side length of the square is not less than twice the distance between the phase conductors on both sides of the overhead transmission line. 5 . 5 . The method for shielding an electric field exceeding standard and low potential in an overhead transmission line corridor according to any one of claims 1 to 4 , wherein the material of the ground net of the shielding body is a conductive material. 6 . 6 . The method for shielding the electric field exceeding the standard and low potential in an overhead transmission line corridor according to claim 1 , wherein the depth of laying the ground grid does not exceed 0.5 meters. 7 . 7. The method for shielding the electric field in the corridor of an overhead transmission line according to claim 1, wherein the overhead transmission line is an overhead transmission line with an AC voltage level of 110kV, 220kV, 330kV, 500kV, 750kV or 1000kV; or , The overhead transmission line is a 500kV or 800kV DC voltage level overhead transmission line. 8. An overhead transmission line corridor electric field exceeding standard and low potential shielding device is characterized in that, comprising: The data acquisition module is used to acquire the ground electric field intensity of each measurement point of the overhead transmission line corridor and the distance between the phase conductors on both sides of the overhead transmission line; The exceeding standard position determination module is used to take the position of the measurement point where the ground electric field strength exceeds the preset value of the strength as the exceeding standard position; The shielding treatment area determination module is used to detect the resistivity of the soil at the position exceeding the standard, and determine the soil area corresponding to the minimum resistivity as the shielding treatment area; The shielding body grounding network selection module is used to select the shielding body grounding network according to the distance of the phase conductors on both sides of the overhead transmission line with the shielding management area as the central area, so as to complete the shielding body grounding network laying.

Images