CN205543271U - Novel three -dimensional earth mat - Google Patents

Abstract

A new type of three-dimensional ground grid, including a grounding ring, the grounding ring includes an inner grounding ring and an outer grounding ring, the inner grounding ring and the outer grounding ring are concentric circles on the same horizontal plane, and a horizontal grounding body is arranged on the grounding ring, The horizontal grounding body passes through the center of the grounding ring and intersects both the inner grounding ring and the outer grounding ring; the intersection of the horizontal grounding body and the inner grounding ring is provided with a vertically downward inner ring vertical grounding electrode, and the horizontal grounding At the intersection of the body and the outer ground ring, a vertical ground electrode of the outer ring is provided vertically downward. The utility model provides a novel three-dimensional ground net, which can effectively reduce the grounding resistance of the wind power generator ground net, reduce step voltage and contact voltage, thereby improving the lightning protection level of the wind power generator and the safety of staff in the wind farm.

Description

A new three-dimensional ground net

technical field

The utility model relates to the field of overvoltage and lightning protection grounding, in particular to a novel three-dimensional grounding net.

Background technique

The grounding resistance of the wind turbine ground grid is an important technical parameter to measure the lightning protection performance of the wind turbine generator. Reducing the ground grid resistance of the wind turbine generator can significantly improve the lightning protection level of the wind turbine generator and the safety of the staff in the wind farm. In the study of the electrical performance of wind turbines, the long-standing problem is that the grounding resistance of the ground grid of wind turbines under high resistivity soil is relatively high, and as the distance between adjacent wind turbines becomes farther, the grounding resistance of adjacent wind turbines should be adopted. The resistance reduction measures of internet connection are no longer applicable. In order to meet the lightning protection requirements of a single wind turbine, this patent proposes a new three-dimensional ground grid composed of double rings, multiple vertical electrodes and bifurcated ground electrodes, which can effectively reduce the grounding resistance of the wind turbine ground grid, Step voltage and contact voltage can improve the lightning protection level of wind turbines and the safety of workers in wind farms.

In the overvoltage and lightning protection grounding project of wind turbines, a ground grid is usually set up for wind turbines to discharge lightning current. Since wind turbines are generally installed in high mountains or wild areas, the environment is relatively harsh, and the soil resistivity The current way to improve the lightning protection performance of wind turbines is to interconnect the ground grids of multiple wind turbines, but with the increase of the capacity of wind turbines and the height of the fuselage, the distance between adjacent wind turbines The farther and farther away, the method of reducing resistance by interconnecting multiple wind turbines to the ground grid will lead to an increase in cost.

When a wind turbine is struck by lightning, a strong surge current flows along the tower, and finally the lightning current leaks into the ground through the ground grid. In this transient process, due to the existence of the grounding resistance of the grounding network, the ground potential will be greatly elevated, and dangerous touch voltage and step voltage may be generated. In addition, between the power cable and the shielding layer and the wind turbine There may be a large voltage difference between the high-voltage winding and the low-voltage winding of the transformer. This voltage may break down the insulation of the cable or transformer winding, damage the electronic or electrical equipment installed in the tower, and may damage the wind turbine in the distance. affect the safe and stable operation of the system. At present, there are no regulations on the lightning protection grounding of wind turbines at home and abroad. The current lightning protection design of wind turbines basically refers to the practices of other industries (such as construction, electric power and electronic communication). At present, the lightning protection and grounding acceptance of wind turbines is still based on whether the power frequency grounding resistance of the ground grid is qualified or not. However, under the action of high-frequency and large-scale lightning current, spark effects and inductance effects will occur during the leakage current of the ground grid. , at this time, the power frequency characteristics cannot truly reflect the lightning protection effect of the ground network, and the impact characteristics of the ground network need to be considered. In high-resistivity soil areas, the soil conductivity is poor, lightning current is difficult to spread in the soil, the impact grounding resistance is large, the step voltage and contact voltage are large, and the normal and safe operation of the wind turbine and the personal safety of the staff Security is a threat.

The Chinese patent "A grounding device for reducing the grounding resistance of wind turbines (CN204577627U)" provides a grounding device in which a ring and multiple electrodes are connected in parallel. The resistance reduction effect is obvious, but the construction is inconvenient.

The Chinese patent "Grounding body for reducing grounding resistance of wind turbines (CN202523855U)" provides a steel cage grounding body, which has an obvious effect of reducing resistance, but the grounding device is large in size, requires more materials, and has relatively high engineering costs.

Contents of the invention

The technical problem to be solved by the utility model is to provide a new three-dimensional ground grid, which can effectively reduce the grounding resistance of the ground grid of the wind power generator, reduce the step voltage and contact voltage, thereby improving the lightning protection level of the wind power generator and the wind farm safety of staff inside.

In order to solve the above technical problems, the technical solution adopted by the utility model is: a new three-dimensional ground grid, including a grounding ring, the grounding ring includes an inner grounding ring and an outer grounding ring, and the inner grounding ring and the outer grounding ring are in the same Concentric circles on the horizontal plane, a horizontal grounding body is provided on the grounding ring, the horizontal grounding body passes through the center of the grounding ring, and intersects both the inner grounding ring and the outer grounding ring; the intersection of the horizontal grounding body and the inner grounding ring is set There is a vertically downward inner ring vertical grounding electrode, and a vertically downward outer ring vertical grounding electrode is provided at the intersection of the horizontal grounding body and the outer grounding ring.

Preferably, the outer ground ring is provided with horizontal short conductors, and the horizontal short conductors are evenly distributed on the outer ground ring.

Preferably, the outer ground ring is further provided with a horizontal ray electrode, the horizontal ray electrode is evenly arranged on the outer ground ring, and the extension line of the horizontal ray electrode passes through the center of the outer ground ring.

Preferably, the middle of the horizontal ray electrode is provided with a vertically downward middle vertical ground electrode, and the end of the horizontal ray electrode is provided with a vertically downward end vertical ground electrode.

Preferably, the middle part of the horizontal ray electrode is further provided with a short ground electrode in the middle part, and the end part of the horizontal ray electrode is further provided with bifurcated electrodes.

Preferably, the distance between the inner ground ring and the outer ground ring is 5-15m.

Preferably, there are multiple horizontal grounding bodies, which are evenly arranged on the grounding ring.

The utility model has the following advantages:

1) The grounding resistance of the wind turbine ground grid is effectively reduced by using parallel connection;

2) The effective grounding area is increased within the limited grounding area, which accelerates the diffusion of lightning current in the soil;

3) The increased vertical electrodes speed up the diffusion of lightning current in the soil and reduce the grounding resistance, step voltage and contact voltage;

4) The added short conductors and bifurcations enhance the spark effect.

Description of drawings

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

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

In the figure: inner grounding ring 1, outer grounding ring 2, horizontal grounding body 3, horizontal short conductor 4, inner ring vertical grounding electrode 5, outer ring vertical grounding electrode 6, horizontal ray electrode 7, middle vertical grounding electrode 8, end A vertical ground electrode 9, a short ground electrode 10 in the middle, and a bifurcated electrode 11.

detailed description

As shown in Figure 1, a new type of three-dimensional ground grid includes a ground ring. The ground ring includes an inner ground ring 1 and an outer ground ring 2. The inner ground ring 1 and the outer ground ring 2 are concentric circles on the same horizontal plane. A horizontal grounding body 3 is provided on the grounding ring, and the horizontal grounding body 3 passes through the center of the grounding ring and intersects both the inner grounding ring 1 and the outer grounding ring 2; the intersection of the horizontal grounding body 3 and the inner grounding ring 1 is provided with The vertically downward inner ring vertical ground electrode 5 , and the vertically downward outer ring vertical ground electrode 6 is provided at the intersection of the horizontal ground body 3 and the outer ground ring 2 . The outer ground ring 2 is provided with horizontal short conductors 4 , and the horizontal short conductors 4 are evenly distributed on the outer ground ring 2 . The outer ground ring 2 is also provided with a horizontal ray electrode 7 , which is evenly arranged on the outer ground ring 2 , and the extension line of the horizontal ray electrode 7 passes through the center of the outer ground ring 2 . The middle part of the horizontal ray electrode 7 is provided with a vertically downward middle vertical ground electrode 8 , and the end of the horizontal ray electrode 7 is provided with a vertically downward end vertical ground electrode 9 . The middle part of the horizontal ray electrode 7 is also provided with a middle short ground electrode 10 , and the end part of the horizontal ray electrode 7 is also provided with a bifurcated electrode 11 . The distance between the inner ground ring 1 and the outer ground ring 2 is 5-15m. There are multiple horizontal grounding bodies 3, which are evenly arranged on the grounding ring.

In this embodiment, the diameter of the inner grounding ring 1 is selected to be 15m, the diameter of the outer grounding ring 2 is 25m, the number of horizontal grounding bodies 3 is 4, and the number of horizontal short conductors 4 depends on the size of the ring. 24 horizontal short conductors 4 are installed. The length of the horizontal short conductors 4 is 0.2m-0.6m to increase the diffusion area. The inner ring vertical grounding electrode 5 and the outer ring vertical grounding electrode 6 are provided, and the lengths of the inner ring vertical grounding electrode 5 and the outer ring vertical grounding electrode 6 are determined according to the soil conditions in actual engineering.

In actual engineering, this patent is buried 1m below the ground surface. When struck by lightning, the inner grounding ring 1, the outer grounding ring 2, the horizontal grounding body 3, the horizontal short grounding body 4, the inner ring vertical grounding electrode 5, and the outer ring Vertical grounding electrodes 6, horizontal ray electrodes 7, middle vertical grounding electrodes 8, end vertical grounding electrodes 9, middle short grounding electrodes 10, and bifurcated electrodes 11 diffuse lightning current into the soil to reduce wind turbine grounding resistance and contact voltage , The effect of step voltage, thereby improving the lightning protection level of wind turbines and the safety of staff in wind farms.

Above-mentioned embodiment is only the preferred technical scheme of the present utility model, and should not be considered as the restriction to the present utility model, and the protection scope of the present utility model should be the technical solution described in the claims, including the technology in the technical solution described in the claims. An equivalent alternative to the feature is the scope of protection. That is, equivalent replacement and improvement within this scope are also within the protection scope of the present utility model.

Claims (7)

1. a novel solid earth mat, including ground loop, described ground loop includes interior ground loop (1) and external ground ring (2), inside connects Ground ring (1) and external ground ring (2) are the concentric circular being in same level, it is characterised in that: on ground loop, it is provided with level Grounding body (3), horizontal grounding objects (3), through the center of circle of ground loop, all intersects with interior ground loop (1) and external ground ring (2)；Described Horizontal grounding objects (3) is provided with internal ring vertical grounding electrode (5) straight down with the point of intersection of interior ground loop (1), and described level connects Terrain (3) is provided with outer shroud vertical grounding electrode (6) straight down with the point of intersection of external ground ring (2).

A kind of novel solid earth mat, it is characterised in that: described external ground ring (2) is provided with level Short conductors (4), horizontal short conductors (4) is uniformly distributed on external ground ring (2).

A kind of novel solid earth mat the most according to claim 1 or claim 2, it is characterised in that: it is additionally provided with on described external ground ring (2) Horizontal rays electrode (7), horizontal rays electrode (7) is uniformly arranged on external ground ring (2), the prolongation of horizontal rays electrode (7) Line is through the center of circle of external ground ring (2).

A kind of novel solid earth mat, it is characterised in that: the middle part of described horizontal rays electrode (7) Being provided with middle part vertical grounding electrode (8) straight down, the end vertical that the end of horizontal rays electrode (7) is provided with straight down connects Earth polar (9).

A kind of novel solid earth mat, it is characterised in that: the middle part of described horizontal rays electrode (7) Being additionally provided with short circuit earth polar, middle part (10), the end of horizontal rays electrode (7) is additionally provided with divergent electrode (11).

A kind of novel solid earth mat, it is characterised in that: described interior ground loop (1) and external ground ring (2) at a distance of 5-15m between.

A kind of novel solid earth mat, it is characterised in that: described horizontal grounding objects (3) has multiple, all Even it is arranged on ground loop.