CN205846263U - Grounding body structure based on graphite-based flexible ground body - Google Patents

Abstract

The utility model provides a grounding body structure based on a graphite-based flexible grounding body, which includes a grounding body body and a plurality of needle-punched graphites, one end of the needle-punched graphite is connected to the grounding body body, and the angle between the needle-punched graphite and the grounding body body Not 0; several needle-punched graphites are connected to the same or different positions of the grounding body body, but at most two sections of needle-punched graphite are connected at the same position, and the grounding body body and several needle-punched graphites are in the same plane; the grounding body body and Acupunctured graphite is a graphite-based flexible grounding body. The diameters of the needled graphite and the grounding body are the same or different, and the length of the needled graphite is 1% to 25% of the length of the grounding body. The utility model connects needle-punched graphite on the traditional graphite-based flexible grounding body to make full use of the spark effect, thereby reducing the impact grounding resistance of the graphite-based flexible grounding body.

Description

Grounding body structure based on graphite-based flexible grounding body

technical field

The utility model belongs to the technical field of lightning protection and grounding of electric power systems, in particular to a grounding body structure based on a graphite-based flexible grounding body.

Background technique

The grounding device of the transmission line is the basic guarantee and important measure to maintain the safe and reliable operation of the power system and to ensure the safety of electrical equipment and operating personnel. A ground electrode with good impact characteristics can provide effective protection for transmission lines, thereby avoiding power outages caused by lightning strikes, which is of great significance to the safe operation of the power system and the reliability of power supply.

With the development of my country's power grid and the improvement of the stability of the power system, the proportion of accidents caused by lightning strikes is increasing in all power system failures. When lightning strikes the line, if the impact grounding resistance of the grounding electrode is high, a high dangerous voltage will be formed at both ends of the line insulator string, which not only poses a threat to the personal safety of the grid operators, but also damages electrical equipment and even cause more serious accidents. Due to the constraints of technical conditions, the early power system grounding design ignored the impact characteristics of the grounding electrode and only focused on its power frequency characteristics. For a long time, the design of tower grounding electrodes has been based on the regulations "Grounding of AC Electrical Installations" (DL/T621-1997). The basic principle of grounding design in the regulations is to regard the product of the power frequency grounding resistance and the impact coefficient as the impact grounding resistance. This describes the impact characteristics of the grounding device under the action of lightning current. However, under the action of lightning current, it is the impact grounding resistance, not the power frequency grounding resistance, that reflects the impact performance of the tower grounding electrode. In order to avoid accidents and improve the impact grounding characteristics of the grounding electrode, it is very necessary to systematically optimize the structure of the grounding electrode.

Under the action of the impact current, the grounding device generates a transient electromagnetic field around it. If the electric field strength of the soil near the grounding electrode exceeds the critical breakdown field strength of the soil, spark discharge will be generated in the soil near the grounding conductor. The soil Being broken down, the formation of spark discharge greatly reduces the voltage drop near the ground electrode, and the size of the ground electrode seems to increase a bit, thereby reducing the impact ground impedance, which is the spark effect. Adding needle-like conductors on the grounding electrode can strengthen the distortion of the local space electric field intensity between soil particles, promote the generation of spark effects, and theoretically reduce the impact grounding resistance of the grounding body. In addition, graphite-based flexible grounding bodies have been more and more widely used in tower grounding due to their advantages in corrosion resistance, anti-theft, impedance reduction, easy construction, cost reduction, and environmental protection. For this reason, it is of great significance to study how to reduce the impact grounding resistance of graphite-based flexible grounding bodies for the safe and stable operation of transmission lines.

Utility model content

The purpose of the utility model is to provide a grounding body structure based on graphite-based flexible grounding body which can reduce impact grounding resistance.

A grounding body structure based on a graphite-based flexible grounding body, including a grounding body body and a plurality of needle-punched graphites, the plurality of needle-punched graphites are connected to the same or different positions of the grounding body body, and at most two sections of needle-punched graphite are connected to the same position; The included angle between the graphite and the grounding body is not 0°, and the grounding body and several needle-punched graphites are on the same plane; the grounding body and the needle-punched graphite are both graphite-based flexible grounding bodies, and the needle-punched graphite and the grounding The diameter of the grounding body is the same or different, and the length of the needle-punched graphite is 1% to 25% of the length of the grounding body.

The quantity of needle-punched graphite is determined according to the length of the grounding body body. Generally, the longer the body length of the grounding body, the more the needle-punched graphite. The number of needle-punched graphite is generally 1-10.

The diameter of the needle-punched graphite is preferably 10 mm to 30 mm.

The included angle between the needle-punched graphite and the body of the grounding body is preferably 45°-90°.

Preferably, the distance from the connection position of the needle-punched graphite to the head end of the grounding body is not greater than half the length of the grounding body.

In the grounding body structure of the utility model, the grounding body body and the needle-punched graphite are connected through connecting pieces, and the connecting pieces are U-shaped grooves, hoops or screws; the connecting pieces are made of non-metallic materials such as plastics and epoxy resins. Or copper, galvanized steel and other metal materials. In the specific implementation, the connector can be selected according to the needs, but the connection must be reliable, and the contact resistance between the needle-punched graphite and the grounding body should be reduced as much as possible.

When applying, it is necessary to consider the actual conditions such as the local soil resistivity, the length of the grounding body, the diameter of the grounding body and its embedding method, etc., and determine the number, diameter, length, and distance between the needle-punched graphite and the grounding body through multiple simulation optimizations. Connection point position, connection direction and other parameters.

Compared with the prior art, the utility model has the following advantages and beneficial effects:

The needle-punched graphite is connected to the traditional graphite-based flexible grounding body to make full use of the spark effect, thereby reducing the impact grounding resistance of the graphite-based flexible grounding body.

Description of drawings

Fig. 1 is the concrete structural representation of the utility model.

In the figure, 1-grounding body, 2-needled graphite, 3-injection point.

specific embodiment

A specific embodiment and technical effects of the present utility model will be described in detail below in conjunction with FIG. 1 .

Example 1

The grounding body 1 has a length of 40m and a diameter of 28mm. The resistivity of the local soil is 1000Ω·m. It is laid horizontally with a buried depth of 2m. The impulse grounding resistance calculation considering the spark effect is carried out, the impulse grounding current waveform is set to 2.6/50μs, and the peak value is 50kA, and the impulse grounding resistance R of the grounding body 1 is obtained = 28.86Ω. In this embodiment, the grounding body 1 is equivalent to the traditional graphite-based flexible grounding body.

Example 2

The grounding body body 1 has a length of 40m and a diameter of 28mm, and the needle-punched graphite 2 has a length of 2.5m and a diameter of 28mm. The included angles between the two sections of needle-punched graphite 2 and the grounding body body 1 are both 90°, as shown in FIG. 1 . The resistivity of the local soil is 1000Ω•m, and it is laid horizontally with a buried depth of 2m, so that the grounding body 1 and the needle-punched graphite 2 are at the same level. The calculation of the impulse grounding resistance considering the spark effect is also carried out, the impulse grounding current waveform is set to 2.6/50μs, and the peak value is 50kA, and the impulse grounding resistance R ₁ of the graphite-based flexible grounding body of this embodiment is obtained =27.65Ω. Compared with the traditional graphite-based flexible grounding body without needle-punched graphite, the impact grounding resistance of the graphite-based flexible grounding body with needle-punched graphite in this embodiment is reduced.

The above-mentioned embodiments are used to specifically illustrate the present application. Although the text is described by specific terms, the protection scope of the present application cannot be limited with this. Those who are familiar with this technical field can understand the spirit and principles of the present application. It is changed or modified to achieve equivalent purposes, and such equivalent changes and modifications should be covered within the scope defined by the scope of the claims.

Claims (8)

1. A grounding body structure based on graphite-based flexible grounding body, characterized in that: Including the grounding body and several needle-punched graphites, several needle-punched graphites are connected to the same or different positions of the grounding body, and at most two sections of needle-punched graphite are connected at the same position; the angle between the needle-punched graphite and the grounding body is not 0°, And the body of the grounding body and several needle-punched graphites are in the same plane; The grounding body and the needle-punched graphite are graphite-based flexible grounding bodies, the diameters of the needle-punched graphite and the grounding body are the same or different, and the length of the needle-punched graphite is 1% to 25% of the length of the grounding body. 2. The grounding body structure based on graphite-based flexible grounding body as claimed in claim 1, characterized in that: The number of needle-punched graphite is 1-10. 3. The grounding body structure based on graphite-based flexible grounding body as claimed in claim 1, characterized in that: The diameter of the needle-punched graphite is 10mm-30mm. 4. The grounding body structure based on graphite-based flexible grounding body as claimed in claim 1, characterized in that: The included angle between the needle-punched graphite and the grounding body is 45°-90°. 5. The grounding body structure based on graphite-based flexible grounding body as claimed in claim 1, characterized in that: The distance from the needle-punched graphite connection position to the head end of the grounding body is no more than half the length of the grounding body. 6. The grounding body structure based on graphite-based flexible grounding body as claimed in claim 1, characterized in that: One end of the needle-punched graphite is connected to the main body of the grounding body through a connecting piece. 7. The grounding body structure based on graphite-based flexible grounding body as claimed in claim 6, characterized in that: The connecting parts are U-shaped grooves, hoops or screws. 8. The grounding body structure based on graphite-based flexible grounding body as claimed in claim 6, characterized in that: The connecting piece is made of non-metal material or metal material.