CN203277669U - Mountable hollow aluminum alloy tube grounding device - Google Patents

Abstract

An assemblable grounding device for a hollow aluminum alloy tube, comprising a closed ring on which multiple sets of grounding bodies are welded, the grounding body includes at least one unit grounding body, and the unit grounding bodies are connected by matching sleeves, The grounding body of the unit is an aluminum alloy hollow tube; the casing is one or more of axial casing, "Y" type casing, and "T" type casing, and the closed ring is welded with 4 sets of grounding bodies, one end of the grounding body is welded on the closed ring, and the other end can be expanded and extended by using a casing as required; the length of the unit grounding body is 1m, and both ends are processed with threads, and the casing There are threads matching the two ends of the unit grounding body inside. The grounding body of the utility model adopts a hollow aluminum alloy tubular structure, which is light in weight, has good electrical and thermal conductivity, and strong corrosion resistance. in various environments.

Description

Assembled hollow aluminum alloy tube grounding device

technical field

The utility model belongs to the technical field of lightning protection and grounding for high-voltage transmission line engineering, in particular to an assemblable hollow aluminum alloy tube grounding device.

Background technique

With the development of the economy, the connection between society and electricity is getting closer, and the requirements for the reliability of power supply are getting higher and higher. However, high-voltage transmission lines have long distances, large spans, wide geographical distribution, and very complicated meteorological conditions, so the probability of tripping and power outages caused by lightning strikes is very high. Especially with the development of science and technology, the reduction of overvoltage inside the power system and the reduction of accidents caused by it, the line tripping accident caused by lightning strikes occupies an increasingly important position, which poses a major threat to the safe and stable operation of the power grid. According to statistics, jumping accidents caused by lightning strikes account for more than 50% of the total accidents in the power grid. Especially in mountainous areas with heavy thunderstorms, high soil resistivity, and complex terrain, the accident rate caused by lightning strikes on transmission lines is higher and brings huge losses.

The grounding resistance value of the transmission line tower is an important technical index of the lightning protection grounding system and the main parameter to measure the grounding effect, which directly affects the lightning protection effect of the system. For transmission lines located in mountainous areas, due to high soil resistivity, complex topography, inconvenient transportation, and difficult construction, the grounding resistance of towers is generally high. When the lightning strikes the top of the tower and the lightning protection line, the lightning current will enter the ground through the grounding device of the tower. In the case of a high grounding resistance of the tower, a high counter-attack overvoltage will be generated, which will cause damage to the insulator, and breakage of the overhead ground wire and the wire, resulting in Accidents such as line tripping.

For reducing the grounding resistance, the measures often used in the project mainly include increasing the area of the grounding grid, increasing the size of the grounding body, increasing the buried depth of the grounding body, external grounding, using natural grounding bodies, replacing soil, and using resistance reducing agents, etc. . However, these resistance reduction measures have their relative application conditions. Only by adopting different methods for different regions and different soil conditions can the grounding resistance be effectively reduced.

At present, the material used in the grounding design is hot-dip galvanized round steel or flat steel. However, due to the low corrosion resistance of steel in the soil, the consumption is large and the service life is short, accidents are prone to occur due to grounding corrosion and fracture. At the same time, in order to solve the grounding problem of towers in areas with high soil resistivity, a large round steel or flat steel grounding network must be used, which requires a large amount of construction work and also faces corrosion problems. For this reason, there are currently some new materials or structures such as conductive cement or grounding modules, such as "a resistance-reducing grounding module" with patent No. ", but these methods are expensive, and even have environmental damage.

Contents of the invention

The technical problem to be solved by the utility model is to provide an assemblable hollow aluminum alloy tube grounding device, which has a simple structure, good corrosion resistance, is suitable for a large number of engineering applications and various geological conditions, and can reduce the grounding resistance of towers in areas with high soil resistivity grounding device.

In order to solve the above-mentioned technical problems, the technical proposal of the present invention is: an assemblable grounding device for hollow aluminum alloy tubes, including a closed ring on which multiple groups of grounding bodies are welded, and the grounding bodies include at least one unit grounding The unit grounding bodies are connected through matching sleeves, and the unit grounding bodies are aluminum alloy hollow tubes.

The bushing is one or more of axial bushing, "Y" bushing, "T" bushing, and the axial bushing is a bushing connecting two unit grounding body joints, The Y-shaped bushing is used as the bushing to realize the horizontal expansion of the three unit grounding bodies, and the "T" type bushing is the bushing to realize the vertical expansion of the three unit grounding bodies.

Four sets of grounding bodies are welded on the closed ring, one end of the grounding body is welded on the closed ring, and the other end can be extended by using a casing as required. Since the tower of the transmission line has four legs, four sets of grounding bodies are used to correspond to it, and the effect is better.

The length of the unit grounding body is 1m, and both ends are processed with threads, and the inside of the bushing is provided with threads matching the two ends of the unit grounding body. The length is set to 1m, which is not only light and easy to move, but also convenient to count, and can quickly count the total length of the grounding body.

The closed ring is made of aluminum alloy material, and the closed ring can be a circular ring or a square closed ring or other shapes, and it only needs to allow the legs of the entire tower to be located therein.

Using the horizontal plane radially extending grounding body structure of the present invention, the simulation calculation results of the same specification round steel grounding body are analyzed as follows.

DL/T621-1997 "Grounding of AC Electrical Installations" stipulates that the grounding resistance of horizontal grounding electrodes of different shapes can be calculated by the following formula

${\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;L</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ln</span>}\frac{{\mathrm{<span\; class="notranslate">\; L</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; hd</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; )</span>$

In the formula, R _h is the grounding resistance of the horizontal grounding electrode, the unit is Ω; L is the total length of the horizontal grounding electrode, the unit is m; h is the buried depth of the horizontal grounding electrode, the unit is m; d is the diameter of the horizontal grounding electrode Or equivalent diameter, in m; A is the shape factor of the horizontal grounding electrode.

According to the grounding device design method of the electric power standard "use electric grounding technology", design the appropriate size of the grounding body of the grounding device. Under the same structural size, the simulation is carried out by using the traditional grounding material round steel and the hollow aluminum alloy tubular structure of the utility model. The data calculation results are compared in Table 1.

Table 1

It can be seen from Table 1 that the grounding resistance value calculated by the grounding device of the present invention will be significantly smaller than the grounding resistance value of the conventional grounding device. Moreover, with the increase of soil resistivity, the optimization effect of the aluminum alloy tubular grounding device of the present invention becomes more and more obvious.

From the structural research, according to the electric power standard DL/T621-1997 Appendix A "Calculation of artificial grounding electrode power frequency grounding resistance", the shape factor A of the horizontal plane grounding electrode can adopt the values listed in Table 2.

Table 2

It can be seen from Table 2 that the shape factor A of the horizontal grounding electrode is equal to 0 when three lines meet at one point; when four lines meet at one point, A=0.89; when five lines meet at one point, A=2.19; bigger.

可知，A值越大，接地电阻R_h越大，也就是接地材料的利用率越低，接地效果越差。而本实用新型对结构进行优化采用的是“Y”型接地型式，当水平接地极总长度、接地极埋深和接地极等效直径都相同时，其形状系数最优。在采用“Y”型接地型式的基础上，将接地材料换成本实用新型所使用的空心铝合金管状结构，从理论上分析可得将使接地优化效果达到最大。且采用“Y”型接地型式还有一个优点是占地面积小，也即施工土石方量小。如土壤电阻率1500Ω·m时，传统的接地装置的占地面积约为6750m²，“Y”型接地型式占地约为2200m²。Calculated from the grounding resistance Rh

It can be seen that the larger the value of A is, the larger the grounding resistance _Rh is, that is, the lower the utilization rate of the grounding material is, and the worse the grounding effect is. However, the utility model optimizes the structure and adopts the "Y" type grounding type. When the total length of the horizontal grounding pole, the buried depth of the grounding pole and the equivalent diameter of the grounding pole are all the same, its shape factor is optimal. On the basis of adopting the "Y" type grounding type, replacing the grounding material with the hollow aluminum alloy tubular structure used in this utility model can maximize the grounding optimization effect from theoretical analysis. Another advantage of adopting the "Y" type grounding type is that it occupies a small area, that is, the amount of earth and stone for construction is small. For example, when the soil resistivity is 1500Ω·m, the traditional grounding device occupies an area of about 6750m ² , and the "Y" type grounding type occupies an area of about 2200m ² .

The main body of the utility model is a closed ring made of aluminum alloy material, a hollow tubular grounding body and various threaded sleeves for connection, wherein the grounding bodies used are all aluminum alloy hollow tubular structures.

The beneficial effects of the utility model are:

1) Replace the traditional grounding body material round steel with aluminum alloy material. In this way, compared with other material grounding bodies, it has the characteristics of good economic performance and not easy to rust, thus increasing the service life of the grounding device and effectively protecting against lightning The role of the grounding body; especially for the long-term operation of the common grounding body, the grounding performance is reduced or invalidated due to corrosion or aging. The use of aluminum alloy materials can give full play to its oxidation resistance to ensure the long-term effective operation of the grounding body and meet the It meets the lightning protection and grounding requirements in areas with high soil resistivity, and can be widely applied to the practical application of a large number of line tower grounding projects.

2) Compared with the solid round steel as the grounding body, the hollow aluminum alloy tube adopted has a larger circumference than the round steel when the same material weight is used, which increases the distance between the tube and the soil. The contact area is larger, which can better discharge the lightning current into the ground; in addition, the hollow tubular structure can attach impurities such as underground humus and groundwater, thereby improving the electrical characteristics of the soil around the grounding body and reducing the grounding resistance.

3) The unit grounding body is processed and produced according to the standard length. The length of each unit grounding body is fixed at 1m, which is convenient to carry and easy to count. Extension, suitable for high soil resistivity areas under various construction conditions; according to different requirements, the assembly and connection of grounding bodies can be carried out, and it is suitable for soil areas with different earthwork engineering conditions.

4) According to the power standard "Calculation of Power Frequency Grounding Resistance of Artificial Grounding Electrodes", the "Y" structure grounding body is three wires meeting at one point, and the shape factor of its horizontal grounding electrode is 0. Except for horizontal extension, the shielding between grounding bodies The smallest, that is, a connection method with the smallest grounding resistance.

5) Compared with the current grounding project where the grounding device is designed as a whole, earthwork excavated and laid as a whole, the prefabricated structure is very convenient in terms of design, material transportation and construction.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

Fig. 1 is a schematic diagram of the radial extension structure of the utility model in the horizontal plane.

Fig. 2 is a schematic diagram of the horizontal plane "Y" extension structure of the utility model.

Fig. 3 is a schematic diagram of the "T"-shaped three-dimensional extended structure of the utility model in the horizontal and vertical directions.

Fig. 4 is a schematic diagram of the hollow aluminum alloy tube of the grounding body of the present invention.

Fig. 5 is a schematic diagram of the bushing of the two-pipe joint of the grounding body of the present invention.

Fig. 6 is a schematic diagram of the three-pipe "Y" joint casing of the grounding body of the present invention.

Fig. 7 is a schematic diagram of the casing of the three-pipe "T" joint of the grounding body of the present invention.

Fig. 8 is an assembly drawing of the two-section hollow aluminum alloy tube grounding body of the present invention.

Detailed ways

The grounding device for an assembling hollow aluminum alloy tube provided by the utility model includes a closed ring 1 on which multiple sets of grounding bodies 2 are welded. The supporting casing 4 is connected, and the unit grounding body 3 is an aluminum alloy hollow tube.

The casing 4 is one or more of axial casing, "Y" type casing and "T" type casing.

Example 1:

An assemblable hollow aluminum alloy tube grounding device, which includes a closed ring 1 made of aluminum alloy, 4 sets of grounding bodies 2 connected to the closed ring, the unit grounding body 3 in the grounding body 2 is a hollow tubular structure, and its outer The diameter is 39mm, and the inner diameter is 32mm. One end of the unit grounding body is welded to the closed ring, and the other end is connected to the outside by a sleeve.

According to the needs, the grounding body can be extended radially in the horizontal plane by using the axial bushing, the horizontal size of the grounding body can be expanded by using the "Y" type bushing, or the vertical extension of the grounding body can be made by using the "T" type bushing. Any combination of the three bushings can also be used in one grounding body at the same time.

During construction, when the device is located in an area with a soil resistivity of 1500Ω·m or more, the length of each grounding electrode in the "Y" structure is recommended to be 11m, and the angle between each unit grounding body is 120°. And all the tower legs are located in the closed loop. When the soil geology is difficult to excavate horizontally, the form of vertical drilling can be adopted, that is, the "T" structure is adopted, and the casing is used to connect the unit grounding body to extend vertically downward.

When installing grounding, the grounding body 2 is located in the grounding groove 5, and the grounding bodies are all made of aluminum alloy hollow tubular structure, so as to reduce the grounding resistance and prevent the grounding body from rusting. The gap between the grounding body and the grounding groove is filled with backfill soil, and the backfill soil is filled until it is level with the ground, and compacted in layers.

Example 2:

China Three Gorges University and Sanmenxia Power Supply Company of Henan Provincial Electric Power Company conducted on-site measurement on April 25, 2013 for the reconstruction project of the 63# tower grounding device of the 110kV Zhuming Line around Lushi and Lingbao in the south of Sanmenxia. One of the legs of the tower was backfilled with large stones The ground grid is difficult to dig; the other 3 are extended with two ground connection plates, the ground grid at each leg is buried at a depth of about 1m, the soil quality is the surface layer of 100-450mm soil, and the bottom is rocky mountain or rock-concrete, so it is impossible to install a vertical ground electrode . Therefore, the "Y" structure assembled grounding device is adopted, and the measured soil resistivity is 1673Ω·m. The grounding body of the hollow aluminum alloy tube is 216m in total, and the total length of the grounding body is 216m. Assemble, share 8 "Y" type bushings, and the measured grounding resistance of the grounding device is 18.2Ω.

Claims (5)

1. An assemblable hollow aluminum alloy tube grounding device, characterized in that it includes a closed ring (1), on which there are multiple sets of grounding bodies (2) welded, and the grounding body includes at least one unit grounding body ( 3), the unit grounding bodies are connected through matching sleeves (4), and the unit grounding bodies (3) are aluminum alloy hollow tubes. 2. Assemblable hollow aluminum alloy pipe grounding device according to claim 1, characterized in that: the casing (4) is an axial casing, a "Y" type casing, and a ", T" type casing one or more of them. 3. The assembleable hollow aluminum alloy tube grounding device according to claim 1, characterized in that 4 sets of grounding bodies (2) are welded on the closed ring. 4. The assembleable hollow aluminum alloy tube grounding device according to claim 1, characterized in that: the length of the unit grounding body is 1m, and both ends are processed with threads, and the inside of the casing (4) is provided with Threads that mate with both ends of the unit's grounding body. 5. The assembleable hollow aluminum alloy tube grounding device according to any one of claims 1-4, wherein the closed ring is made of aluminum alloy.

Images