KR101688024B1 - Electrical ground connection method using ground cylinder - Google Patents

Abstract

The present invention relates to a method of manufacturing a semiconductor device comprising the steps of connecting a ground lead wire to a grounding cylinder, burying the grounding cylinder and ground lead wire at a position of 75 cm or less from the ground surface, and burring the grounding cylinder and ground lead wire, Wherein the grounding cylinder is made of a conductive material and the inner space has a tapered shape in which an upper portion is opened to load the soil and a side surface of the cylinder is narrowed from the upper portion to the lower portion.

Description

Technical Field [0001] The present invention relates to a grounding method using a grounding cylinder,

 The present invention relates to a grounding method using a grounding cylinder, and more particularly, to a grounding method using a grounding cylinder. More particularly, the present invention relates to a grounding method using a grounding cylinder, When a lightning strike such as a ground fault due to disconnection or a lightning strikes in a power plant or a building occurs, it is detected quickly and the electric path is correctly shut off, or the abnormal potential is set to 0 (zero = zero potential to prevent electric shocks caused by electric shocks, to prevent damage to power equipment and equipment due to long-term over-current overcurrent, to prevent the occurrence of fires in power facilities and buildings, In order to maintain the safety of facilities and auxiliary structures at the highest level in an economical, efficient and naturally adaptive manner, It relates to a grounding method using a cylinder.

The electric wires (transmission and distribution) that are constructed by machining are used to secure the safety of the lightning strikes. The wire is connected to the top of the support along with the power line at the bottom. This wire is installed at every pylon (tower) In parallel.

(1-wire or 2-wire) machined wire installed at the top of the transmission tower and 1 wire processed wire installed at the top with a power distribution line is used as the wire without bare wire. OHGW-Over Head Ground Wire.

The function of the ground branch is to receive (absorb) the brain primarily when the brain is generated from the upper side or the side of the wire, quickly discharge (discharge) to the ground under zero potential through the ground pole installed for each support, It is a facility that protects power facilities from brain spikes by restoring zero potential to uncharged areas.

The brain shielding rate of the processed branch line is close to 100%, so that the power line in operation is virtually not applied to the direct brain.

* The branch line uses steel wire twisted steel wire, and the reason why it uses wire wire is because of economic reasons and strength, not for electrical reasons.

On the other hand, in case of the neutral method or the one-wire grounding method, one power line is grounded every electric pole and the sickness is sideways along with the power line separately from the ground line installed at the top of the electric line. Even in this case, the wires must be bare wires without insulation, and the grounded wires should be installed under the voltage applied wires regardless of the vertical / horizontal arrangement of the wires. This wire is called a neutral wire or a ground wire.

There are 22,900V-Y extra-high voltage distribution lines, which are neutral point grounding type, and 220 / 380V-Y low voltage method, which is supplied to power receiving sites.

There is usually no current in the ground wire installed at the top of the wire. The neutral current (neutral line) of the neutral grounding system always flows a current equal to or less than the current flowing through the power line (since the three-phase power distribution line always receives a slight unbalanced load during the phase, the vector sum current of the three- In the case of a fully balanced load, no current may flow, but this is rarely the case).

In the case of a single phase, the voltage line and almost current always flow. Neutral lines in the single-phase mode also serve as ground and power lines (negatively "-" lines).

In addition to grounding of ground wire and neutral wire, the conductor wire is also used to connect the ungrounded conductor [iron tower body, inner iron core of enclosures, transformer, switchgear, condenser and other devices) Etc.] shall be connected to the neutral wire (ground wire) electrically and collectively. In addition, lightning arrester (L.A) should be installed and grounding of lightning arrester should be provided for power line when a direct lightning strike or induction lightning strikes power line at a certain interval.

A ground wire, a lightning arrester, and a working neutral wire (ground wire) installed at the top of the wire, in addition to the inner side of the steel tower or the inner space or outer surface of the pole (concrete pole) Lower the ground down to 75cm below ground (70cm until now, now change to 75cm) Extend the ground wire from the depth to the outside of the support so that the support does not touch the earth electrode (if the support is steel, It is regulated to ground using a standardized grounding pole.

Grounding of ground wire, lightning arrester, neutral wire (ground wire) should be separate ground wire down to the ground, ground electrode should be buried at a certain distance apart, separate independent ground or one ground wire, The standard for whether to put the ground electrode down into a common ground will change from time to time.

Here, regardless of whether each ground is made as a separate ground or a common ground and the distance between the support and the ground electrode, the ground electrode is grounded using the ground electrode of a standard product.

Of course, there is no legal restriction to use the standardized grounding pole in the construction of the individual. When grounding the basic grounding of a private building or factory or grounding the lightning rod, it is necessary to lay a wide copper plate, Can be grounded with grounding pole. However, it is common to use standardized grounding pole because electric works must leave the construction work to a professional company having license for electric work.

However, it is true that the ground pole, which is used frequently by electric power companies or electric construction companies, is inevitably ineffective in terms of economics, ease of construction, and the use of standardized / standardized grounding pole.

When constructing the transmission line (transmission and distribution) in the ground instead of the processing, only the ground wire (OHGW) installed at the top as the working wire is omitted, but the other is grounded with the same standard as the processing line.

The following table shows standardized / standardized ground poles that are used in large quantities by electric power companies (KEPCO) and electric construction companies.

<Types of Grounding Pole>

  Ground pole name   Size (Unit mm)   Weight (kg)    Unit Price (won)     Remarks grounding
worker bee Dong rod  14 x 1,000     -     4.286
1 total unit price
Approximately 7,100 won
Lead terminal       -     2,805 Conductivity
concrete
Ground plate Ground plate  200 x 1,000 x 40    18.679    47,793 Total weight Approximately 20kg
Total price approx. 53,000 won Lead terminal       -     0.099     4,621 Conductivity
concrete
Grounding rod Grounding rod  100 x 1,000    19.286    63,575 Total weight Approximately 20kg
Total unit price approx. 67,000 won Lead terminal       -     0.316     3,495 circle
concrete
Earth pole Attach lead terminal  30 x 420    10.500    67,000 Weight per unit of about 10kg Price 67,000 won

* The grounding enclosure has various sizes with different diameters and lengths. Currently, the standard used in KEPCO is 14 (diameter) mm x 1,000 mm (length).

In addition to the ground pole in the above table, recently, an earth pole made of carbon material has been developed. However, it is difficult to use it as a ground pole of a power facility which is expensive because the unit price is more than 150,000 won per unit. But it is used only in a very limited number of places where it is very difficult to obtain a specified ground resistance due to high resistivity.

Grounding has been developed since the 1970s and has been used as grounding pole for almost all electric power facilities. Grounding pole made of conductive concrete has recently been developed and is being used limitedly. It has a higher unit price than the grounding pole, It is an evaluation that it takes a lot of manpower and the change (increase) of grounding resistance due to durability or aging change is not verified surely and it is not enough to replace enclosure as earth pole.

The grounding pole, which is still the most widely used in power construction sites, is also grounded, due to its low unit cost and easy construction.

The construction of this grounding cylinder (cans) is not made due to the problem of the above grounding electrodes which are already commercialized, or due to the incompatibility of the grounding pole. It is also possible to lower the manufacturing cost of the grounding pole, The grounding cylinder is considered as a grounding pole which can reduce the grounding resistance constantly / dramatically by using the natural conditions, saving the manpower of the grounding work and, above all, complying with the natural conditions beyond the environment friendly ones.

1. It is characterized in that the earthing pole which is mainly composed of the current grounding is used in parallel with the grounding and the grounding cylinder to compensate mutual weakness, thereby obtaining the lowest grounding resistance at the lowest construction cost.

Concrete ground poles made of conductive concrete, which is high in price and heavy in construction, are excluded.

2. Basically, the material of the body constituting the cylinder is characterized by using the most electrically smooth copper plate (t = about 0.3 mm).

The upper cylinder has a diameter of about 300 mm, a height of 200 mm, and a tapered shape with a smaller diameter as it goes down. A cylindrical cylinder having a bottom diameter of 200 mm is made.

The upper part of the cylinder is machined around 22 mm² (2 mm x 7 strand) or 25 mm² or 38 mm² on the upper part of the cylinder.

The electric wire, which is electrically connected to the upper part of the cylinder, makes the 200-300 mm protruding out of the cylinder to connect the ground wire from the support and the ground wire by sleeve compression or wire connection.

The thickness of the copper plate does not greatly affect the ground resistance, but the ground resistance value is determined by the surface area in contact with the ground. Therefore, the thickness of the copper plate should be such that the cylinder is not deformed by a light external impact, and a thickness of the copper plate of 0.5 mm or more is sufficient to make the cylinder more rigid.

The copper plate of the cylinder body is rolled around the upper wire, and the zinc plated steel sheet of appropriate thickness (about 1 mm) is worn on the surface to reinforce the physical strength of the electrically connected part (to prevent the cylinder from squeezing) The shape of the container is reinforced so that it can not be deformed even under a considerable impact, and the electrical connection between the wire and the copper plate therein is strengthened.

The joints on the side of the cylinder body and the joints of the side and bottom surfaces may be welded together, or the joints of both sides of the cylinder body should be folded about 5 mm to bend.

3. If the stainless steel plate is used as the material of the cylinder to make the manufacturing cost of the cylinder lower and to prevent the rust (oxidation), the cylinder will be more durable and the rust will not occur even if it is buried in the ground for a long time, .

4. To lower the manufacturing cost Here, the use of the galvanized steel plate can make the cylinder more rigid, and even if it is buried in the ground, it can not be oxidized (rusted), corrosion is prevented, and manufacturing cost can be drastically reduced.

5. Regardless of the metal material of the cylinder body, the wire that is rolled around the top should be copper wire.

6. Cylinders are cylindrical cylinders which have no difference in diameter between upper and lower sides. If they are manufactured in such a form, loss of raw materials can be minimized, but they can not be stacked and stored.

The main purpose of making the shape of the tapered shape is to allow the cylinders to be stacked and transported, so the figures given above are merely examples, not absolute figures.

The cylinder can be made to have a suitable surface area, but the diameter reduction rate can be made in a tapered form with a minimum diameter reduction ratio that allows the container to be superimposed, stored and transported.

7. The earth electrode does not need to be made of metal with high conductivity such as copper (conductivity 99-100% or more) or aluminum (60%). In general, metals that are not conductive but metal that are conductive are sufficient.

Therefore, there is no reason to increase the grounding resistance by making the grounding cylinder of stainless steel plate or galvanized steel plate.

Metal that does not rust and does not corrode even if buried in the ground for a long time is enough.

On the other hand, aluminum plates are not suitable for earth electrodes which are easily corroded and oxidized and buried in the ground even though the electrical conductivity is high and the value is low.

Concrete can not exceed the conductivity of stainless steel or galvanized steel sheets, no matter how conductive it is.

1. Economics

1-1 Grounding The unit price (including lead terminal) per unit is 7,100 won.

It is most common to install one enclosure at the low-voltage end of the distribution line, and to install two enclosures in parallel or two at the high-voltage pole.

Korea has a high population density and high power demand density. Therefore, low pressure poles are rarely found in residential and urban areas, except for the low pressure pole installed in the paddy fields for pumping water for agricultural water, agricultural water in rural areas.

Most of the poles in residential and urban areas are high pressure poles and low pressure is sick under high pressure.

And Jeonju in the urban area is a pavilion with a transformer installed at about 1/3 of the whole Jeonju.

The electric pole (main transformer) and the pole with the lightning arrester are installed by connecting two enclosures directly connected with two enclosures in parallel.

- When 2 enclosures are directly connected: 4,286 x 2 + 2,805 = 11,377 won

- The price of two bundled units: (4,286 + 2,805) x 2 = 14,182 won

- 2 bundles directly attached 2 bundles Thermal installation price 11,377 x 2 = 22,754 won

In other words, except for a small number of low voltage poles erected in the mountains and fields of farming and fishing villages, the material cost of the ground poles for grounding one pole of the pole is 11,377 ~ 22,754 won in most poles.

1-2 Material cost for manufacturing 1 grounding cylinder (manufacturing cost calculation data)

  - Copper plate (0.3t) Wholesale price: 10,300 won / kg

  - Electric wire 22mm² Wholesale unit price: 1,164 won / m

  - Specific gravity of grains: about 9.0 (8.5 ~ 8.9 depending on the content of grains)

  - Copper requirements per grounding cylinder

For the convenience of calculation, the cylinder is not a tapered form, but a circular can with a bottom and a bottom 250 mm in diameter and 200 mm in height is closed. The surface area is 250 x 3.14 x 200 + (250/2) ² x 3.14 = 206,000 mm) ²

- Calculate the total area of the copper plate to be 220,000 (mm) ² considering the area for bending connection of side and bottom joints and the allowance area of copper plate for inserting the electric wire at the top.

- Copper plate volume = 220,000 (mm) ² (copper plate area) x 0.3 mm (copper plate thickness) = 66,000 (mm) ³.

- 66,000 (mm) ³ = 66 (cm) ³

- multiply the total volume of the copper plate 66 (cm) ³ by the specific gravity 9

- The required weight of copper plate per grounding cylinder is 66 (cm) ³ x 9 = 594 Approximately 600g (gram)

In other words, the weight of the copper plate required to manufacture one grounding cylinder with 0.3t of copper plate is 0.6kg.

- The length of the copper wire (lead wire) to be connected to the cylinder by crimping around the cylinder top is 300mm x 3, 14 = 940mm = 94cm

If the length of the wire protruding from the cylinder is about 20 cm, the total length of the wire is about 1.3 m.

- Pure material cost for one cylinder

0.6kg x 10,300 won / kg + 1.3m x 1,164 won / m = 6,180 won + 1,513 won = 7,693 won

    That is, when one grounding cylinder is manufactured from 0.3t copper plate, the net material cost is about 8,000 won per piece.

- If you cut the copper plate to the specified area, the part of the sparkle will occur between them, but it will be re-used as the copper plate. If you get the obesity, you can play it as a new copper plate.

- It is possible to produce 100% automation of the grounding cylinder, which is produced by welding or pressing by cutting the plate of copper plate by a predetermined dimension than the enclosure manufactured by plating copper on the surface of steel bar or pressing copper plate.

- Calculation of manufacturing cost excluding material cost is omitted because there is no production experience yet.

2. Ground reduction effect

The factors determining the ground resistance are determined by the resistivity of the soil to be grounded, the degree of moisture absorption of the soil, and the contact area between the earth and the earth electrode, as described above.

2-1 Specific resistivity of soil (land)

This is an intrinsic property of the soil and is a constant constant.

However, it is possible to reduce the resistivity partly by artificially adjusting the resistivity, but it is not practical because it is expensive and lowering the resistivity by applying the reducing agent is costly, and the effect is not continuous and causes environmental problems.

That is, the resistivity of the earth is a constant, not a variable depending on the type of earth electrode.

The resistivity of the earth is irrelevant to the type of earth electrode or the shape of the material.

2-2 Moisture absorption of soil

Is a key point of the present invention.

It was confirmed that the resistivity of the earth decreased or increased to one-tenth of that of the same soil depending on the moisture absorption state.

The core of the function of the grounding cylinder is to take in the rain that nature gives itself and keep it in the 4 season cylinders so that the soil in the cylinder is always kept wet with water and the humidity is continuously supplied to the surrounding soil, It is an invention starting from the idea of falling.

Although the grounding has many advantages, it is a function that can not be followed.

In the grounded enclosure, the thin bar is embedded vertically in the ground, and the humidity of the surroundings rises at the moment of rain, but when the rain stops, the ground resistance continues to increase as the water immediately seeps into the ground and the humidity in the surroundings decreases.

The same manufacturing cost will sustain the lowest ground resistance among the earth electrodes having the same earth contact area semi-permanently.

2-3 Contact area between ground electrode and earth

Even if the ground electrode of the same material is buried in the same soil, the earth resistance varies in reverse proportion to the contact area with the earth.

- Grounding enclosure 1 surface area

[(14 mm; enclosed diameter) / 2] ² x 3.14 x 1,000 (enclosed length) = 153,860 (mm) ²

- Surface area of one ground cylinder approx. = 206,000 (mm) ²

- The surface area of one ground cylinder is more than 20% larger than that of the grounded enclosure, and the inside and outside of the cylinder are brought into contact with the soil together, so that the surface area contacting the actual soil is doubled.

- Even without taking into account the resistivity reduction factors caused by the water inside the cylinder, the cylinder will have a better ground resistance reduction effect compared to the grounding at the contact area.

2-4 Convenience of construction and examination in terms of manpower (product)

- Do not compare with the grounding pole made of concrete (no comparison)

- The manpower (goods) and the difficulty for grounding are similar to the enclosed cylinder.

- No special skill or effort required.

The enclosure can be poured (pounded) at the desired place, then the soil (backfill of the soil), the cylinder is seated at the desired place, the soil is filled, the water is poured sufficiently, .

3. Fault factors in grounding using grounding and grounding cylinders

3-1 Grounding is not an independent construction for grounding only.

It is an incidental construction after building a steel tower, building a pole, installing ground equipment, or seating a manhole structure.

Therefore, there is no need for separate excavation work only for grounding work. Before constructing a pit for digging the base of a steel tower or building a pole, it is necessary to place the ground pole at the top of the ground pole at 75 cm below the surface.

3-2 The grounding cylinder has a volume of about the size of a large can, and there is no restriction on the grounding.

However, the grounding enclosure has many obstacles.

It is very difficult to install in a rocky area or a mixed area of gravel, and many obstacles (electric power / telecommunication cable, water supply and sewage, city gas, etc.) are densely buried under the road in the city area.

If you do not check it, you will be put into place and other facilities will be destroyed, and the power cable or gas pipe line will be destroyed, causing a big accident.

This is why it is very difficult and sensitive to put the grounding enclosure in the urban area.

I can not do it with a manpower. I am excavated by shoveling the place to be enclosed, check it with a thin wire, and then put it in place.

4. Comprehensive Review

Grounding Enclosures and grounding cylinders are complementary, and grounding cylinders are not such grounding electrodes that completely replace the grounding enclosure.

Urban areas and dense populations are mostly clayey soils with little rocky or sandy areas.

When installing poles in such places, avoid using the enclosures that may cause damage to other facilities and close the ground with a grounding cylinder. The same is true for the fields and plains.

On the other hand, if it is difficult to obtain the desired grounding resistance value at about 75cm below the ground surface as a satiny or sandy area, it is necessary to embed the grounding pole in the ground deeply It is good to choose the method of.

In this case, ground fault of high-voltage line falling on the ground surface is detected by a grounding cylinder buried 75cm below the ground surface, and deep grounding of grounding pole to obtain specified grounding resistance is made by connecting several grounding enclosures in series. Ground parallel with ground cylinder.

Grounding of the high voltage line falling on the surface of the earth is to provide the grounding cylinder, and the role of the grounding pole to obtain the specified grounding resistance is to provide an electrical role sharing so that the grounding is enclosed.

As a general summary, ground resistances are relatively low, such as residential areas, urban areas, and fields, so grounding is done by a grounding cylinder in areas where a given grounding resistance can be obtained as 1 to 3 grounding poles near 75 cm below the ground surface, It is difficult to obtain a predetermined grounding resistance even if the number of the grounding electrodes is increased by the number of the grounding electrodes (parallel), so that the grounding in the vicinity of the surface layer (75 cm below the grounding surface) And the ground connection can be put in the ground, so that it is possible to obtain desired grounding resistance by connecting the grounded enclosures which are relatively easy to penetrate and connecting them in parallel.

As the average grounding resistance decreases, the overall safety of the power plant will improve.

Quality of life will improve as safety improves.

  BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating a grounding system using a grounding cylinder according to an embodiment of the present invention; FIG.

For reference, the factors determining the ground resistance related to the present invention are as follows.

1. Factors determining ground resistance

1-1 Resistivity of Earth

Clay or loess is the lowest resistivity, followed by clay, loess and sand, followed by sand, and the highest resistivity is rocky. In other words, the thinner and harder the particles are, the lower the resistivity.

<Resistivity according to kind of soil>

     Types of soil       Resistivity [Ω.m]   Remarks   Swamp and mud       80 ~ 200 Source of data
Published by KEPCO
Safety management inspection techniques and examples
(Protective relay, spare power supply, grounding, explosion proof) Booklet 134p
Issued on March 1, 2013   Clay, sand      150-300      Sandy      250 to 500   Sandstone and rocky areas   10,000 to 100,000

Earth resistivity is an invariant constant that determines the earth resistance to a fixed value that can not be changed before a large earthquake occurs.

1-2 Humidity of the earth

Even in the case of the same geology, when the humidity is high in the soil after rain, the resistivity of the land lowers, and the resistivity of the land increases proportionally as the dryness of the soil increases due to the permeation of water into the underground or evaporation. Is as shown in Table 2 above)

&Lt; Specific resistivity according to the change of humidity of the soil &

Soil moisture
[%]                           Resistivity [Ω.m]   Sandy loam   Topsoil (upper soil)     Red soil 2 1,800 - - 4 600 2,000 - 6 380 1,300 - 8 290 900 - 10 220 560 2,000 12 170 360 1,800 16 130 190 180 20 90 110 130 24 70 90 110 28 60 80 100

* Humidity is an important variable that determines the grounding resistance as the value changes from time to time according to climatic conditions.

1-3 The ground resistance is inversely proportional to the contact area between the earth electrode and the land

Even if the ground electrode of the same material is buried in the land of the same condition, the grounding resistance decreases in inverse proportion to the area where the earth electrode contacts the ground, and the grounding resistance increases as the contact surface becomes narrower. It is the same logic as Ohm's law that the electric resistance is inversely proportional to the cross-sectional area of a conductor even if it is made of the same material.

2. Relationship between Soil and Ground Resistance

2-1 Since all the soil was created in the beginning, various kinds of rocks and ores were crushed by weathering for a long time, and the physical deformation and chemical degeneration became clay or loam. , And it is the rock that is not exposed to weathering and keeps the original shape.

Therefore, even pure clay or loam, pure soil that has been completely removed from impurities and moisture is close to non-conductive, such as sand or rock.

2-2 However, clay and loess are very small in particle size (0.005-0.002mm in diameter) and have adsorption, plasticity and viscosity properties.

2-3 The low resistivity of clay or loess is not because of the high conductivity of the soil, but because clay or loess has a large amount of organic matter, which is a byproduct of plants and animals that have floundered billions of years on earth, Because of the adsorbability and viscosity of organic matter and moisture absorbed once, it has a characteristic that it is preserved for a long time and has a relatively low resistivity than sand or rock. In addition, clay and loess are dense with almost no empty space for air due to organic matter and moisture mixed with soil. Pure air, which is not allowed to breathe moisture, is close to non-conducting, so if air is mixed between the soil, the resistivity of the land is increased.

2-4 On the other hand, sand or gravel has little adsorption plasticity viscosity, so that even if the water seeps in due to rain, it flows into the underground or evaporates, and the space between them is filled with air close to the nonconductor, The overall resistivity is much higher than clay or loess, and the dry rock mass is very close to non-conducting due to its high electrical resistivity.

3. Role of ground resistance reducing agent

Typically, there is an Earth-Ron in the form of a white powder similar to wheat flour.

The powder itself is a conductive material and has the property of preserving the moisture for a long time if the water is once drained like clay or loess. In other words, applying a reducing agent to the sand or gravel layer is not only a conductive material itself, but also has the effect of converting the sand to clay.

However, if a large amount of the reducing agent is sparged, a considerable cost is incurred, and in the long run, the reducing agent is diluted in the rainwater permeated by the reducing agent and penetrated into the ground, thereby reducing the effect of reducing the ground resistance.

Above all, the abatement agent is a chemical substance that ultimately pollutes the soil, causing environmental problems, and Korea and the rest of the world are gradually regulating the use of abatement agents.

4. Reason for grounding pole to be 75cm below ground

In general, the grounding resistance is lowered as the grounding electrode is deeply buried under the ground surface.

Since the clay component increases and the humidity becomes higher as it penetrates deeply to a certain depth, the ground resistance becomes lower as the depth of the ground electrode becomes the same.

In addition, when a power line is hit by a lightning strike on the earth electrode, or when an electrical contact is made with a live part (iron or neutral wire on a support) due to insulation breakdown of a high voltage line or a high-low voltage interlock, an excessive fault current flows, (Voltage drop) multiplied by the ground resistance of the ground electrode causes a considerably higher potential rise around the ground electrode. At this time, if the ground electrode is buried directly under the ground surface, there is a great risk that the person or the animal passing over the ground electrode excessively raises the electric potential of the ground surface to be subjected to electric shock.

If the ground electrode is deeply buried in order to reduce the grounding resistance and reduce the potential rise of the surface of the earth, when the high-voltage line is disconnected from the ground electrode, the distance between the ground surface and the ground electrode where the high- A ground fault can not be detected smoothly.

These two are in conflict.

So, for a long time, the depth of the power line has been found to be 50 ~ 100cm below the ground surface to meet these two opposite conditions. KEPCO has recently defined this depth as 75cm above the ground surface, Roe has a ground pole embedded in the ground surface at 75cm. However, this depth is a depth that can be slightly changed again at any time, not the value of the constant.

5. Characteristics of the grounding cylinder (grounding can)

In terms of economics, it is the same as the grounded enclosure with the lowest manufacturing cost, or rather it reduces the cost of the construction of the power plant by lowering the cost of construction of the power plant, which is costly and reduces the grounding resistance A grounding cylinder that can sustain the excellent grounding resistance reduction effect more than the reducing agent depending on the natural phenomenon (rain) without using the reducing agent which is not continuous effect and causes the environmental problem.

It is simply expressed as a metal plate (copper plate or other metal plate) that receives rainwater flowing from the ground, and it can be stored in its own container (bowl).

The grounding cylinder acts as a grounding electrode such as a grounding plate or a copper plate or a conductive concrete grounding pole. In addition, the incidental rainwater permeates into the ground and is stored in the container like soil, so that the soil in the grounding electrode is always wet with water. In the surrounding soil, the water in the container continuously supplies moisture to raise the humidity of the soil around the grounding cylinder.

The water in the grounding cylinder is grounded so that the upper part of the cylinder is to be seated at the initial stage of construction. The upper part of the cylinder is 75cm below the ground surface. The ground is fixed so that it is horizontal. Then the grounding line is lowered from the upper part of the support to the lead wire drawn from the cylinder , Or winding connection) to seat the cylinder.

Next, fill the fine soil with the gravel removed around the cylinder, fill the cylinder with fine soil, and then compaction with a compaction machine, or tread the ground with a man's foot, pour water in and around the cylinder, Cover the soil and fill it up.

After the construction is completed, rainwater from the sky will constantly replenish the water in the cylinder.

Even if it does not rain for a long time due to drought, the water in a cylinder 75cm below the ground surface will not evaporate almost because of the topsoil covering 75cm thick. Even in winter, the soil will not freeze up to 75cm depth. And soil mixed.

The detailed description will be described later.

For reference, the scope of application of the present invention is as follows.

1. All earth electrodes (copper plates, waste wires, enclosed conductors, conductive concretes, carbon products, etc.) that have been used by electric power companies or electric power companies in the world until now have the ground contact area Use the phenomenon that the surface resistivity of the ground electrode is increased as much as possible and the resistivity of the soil becomes lower as it penetrates deep into the ground. The uppermost part of the ground electrode should be buried at 75cm below the surface specified by the relevant regulations. It is limited to the method of deeply asking, and the method of spraying a low hygroscopic agent around the grounding pole in the point that the soil resistance becomes low as the soil contains a lot of water.

As a method of increasing the contact area between the ground electrode and the ground, there is a method of laying the copper plate widely or connecting several grounding coils in parallel. As a method of deepening the grounding pole in the ground, And a method of raising the moisture content of the soil includes a method of spraying a reducing agent (chemical agent) having a strong hygroscopicity around the ground electrode.

All of them involve a lot of cost and effort, and their effects are not continuous and they cause environmental problems.

2. A grounding cylinder was devised as a solution to all of these conditions at once.

The grounding pole is made in the form of a vessel instead of the plate or rod form which has been used up to now, and it is buried in the underground (75cm) of the prescribed depth so that the grounding pole receives nature's rainwater, It will bring up dramatically.

As a hygroscopic property of the reducing agent, a high humidity that can not be followed is maintained constantly, and the wet clay itself becomes a conductor, and the surface of the earth electrode is naturally widened.

3. Scope of application

3-1 Material of cylinder

In this application, for example, a representative copper plate is used as an example and a stainless steel plate or a fused zinc plated steel plate is used as an example for lowering the production cost. However, a metal non-ferrous metal conductor or its alloy which is not rust- It may also be made by bonding more than two metals.

3-2 The shape is a tapered cylinder (can) that is easy to manufacture and store, but it can be any shape or shape that can serve as an earth pole and have the form of a container to store rainwater that permeates into the ground.

The present invention proposes a study on a method for lowering the ground resistance (resistance) more economically. (Ground fault due to disconnection of high-voltage cable, contact between live part and ground due to damage or destruction of insulator of cable or cable), and (power line) It is important to note that the lower the grounding resistance, the better the safety of the power distribution system as well as the transmission and distribution lines and the power system as well as the safety of the power system (the entire system) It is true.

However, it is not so easy to lower the grounding resistance to the specified value. Moreover, since the cost and effort are high, the minimum legal grounding resistance value limit (upper limit value) is prescribed for the power system, the electric equipment and the structure to be protected from lightning. As the ground resistance is minimized, safety from electric accidents can be improved. Therefore, the upper limit of the legal ground resistance can be changed according to the technological development and the safety demanded by the age.

The provision of the legal grounding resistance is only a requirement that the grounding resistance be lowered to at least the value below and the goal of the ultimate grounding resistance is to ensure that the grounding resistance is as close as possible to all the grounding resistors converging to "zero ohms" Lowering.

Prior to the 1970s, ground copper plates and waste wires were mainly used as earth electrodes. However, there is a disadvantage to excavate a large area with manpower in order to place a ground copper plate with a large area on the ground. In today's world, due to the fact that many burials are densely buried underground, The ground copper plate is not used frequently except for special cases.

Then, grounded enclosures were developed in which a thin copper plate was physically pressed around the iron bar to replace the ground copper plate. However, it is not easy to install the grounding obstacle when obstacles such as rocks come out. Especially, in urban areas, many obstacles (power cable, communication cable, gas pipe, water supply and drainage pipe, etc.) are destroyed. .

Even if the electric facilities buried with the grounded enclosures are removed, the enclosures often become difficult to remove (pull out). This is a waste of resources and an obstacle to other constructions. (The newly developed conductive concrete earth pole is also the same would.)

Although the above described grounding copper plate and grounding are described, water (moisture) is required for more efficient grounding resistance. Therefore, in the past 1970s, grounding pole (copper plate, enclosed) was buried in order to further reduce the grounding resistance, and charcoal powder, ) Were sprinkled around the ground pole. However, this is not a legitimate method and is not a permanent method. Also, since the change of ground resistance is long due to the passage of time, it temporarily reduces the ground resistance. However, the ground resistance has increased in the course of time.

The next development was the chemical called Earth-Ron, a ground resistance reducing agent. This is a flour-like powder in the form of flour, which is sprayed around the earthing electrode when it penetrates, and it has the effect of reducing the grounding resistance in the mid- and long-term because it is damp for long time. However, after a long time, And the ground resistance was increased again after a certain period of time. In addition, the use of Asrons has been prohibited in recent years because it has been judged to pollute the soil.

The present invention provides a grounding method for providing an eco-friendly and low-cost effective grounding resistance.

The present invention is based on the idea that the ground resistance is basically determined by the resistivity of the soil, but the ground resistance is lower as the soil contains a lot of moisture.
So far, all earth electrodes (waste wires, copper plates, enclosed concrete, concrete plates) that have been used by all over the world have temporarily reduced ground resistance when there is much water in the soil after rain, but when the soil is dry after drying, And the ground resistance value rises again according to the rise.
In order to improve it, it is practically impossible (cost, product) to replace the soil around the ground pole largely, and as an alternative means, the chemical called "ASTRON" was administered around the ground electrode. In the mid-term, the ground resistance was reduced. However, when the seal passed, the water penetrated into the underground, and the ASTRON itself was washed in the rainwater and penetrated into the ground, so that the effect of reducing the ground resistance was not maintained. And the cost is also very low.
In order to improve this dramatically, the ground electrode itself is made into a container form, and the rain that falls from nature penetrates into the underground. The rainwater is received by itself and stored in the ground. The surrounding soil is always wetted with water or moisture, In view of attaining the effect of reducing the resistance, it is essential and essential for the present invention to make the earthing electrode into a container form (grounding cylinder = earthing can).
A grounding method using a grounding cylinder used as a storage means for storing a ratio according to an embodiment of the present invention includes the steps of connecting a grounding lead to the grounding cylinder used as a storage means for storing the rain, And a ground lead line at a position of 75 cm from the surface of the ground; and filling and grounding the grounding cylinder and the ground lead, wherein the grounding cylinder is made of a conductive material, And the side surface of the cylinder is tapered so as to be narrowed from the upper part to the lower part.

1 is a grounding cylinder 10 used in the grounding method of the present invention. A grounding method according to an embodiment of the present invention uses a grounding cylinder buried under the ground surface. The grounding cylinder is made of a conductive material such as iron or copper in order to discharge a voltage transmitted from a lightning stroke or the like to the underground. The upper part of the internal space of the grounding cylinder (10) is opened so that the soil can be loaded. At this time, the upper part of the grounding cylinder is generally formed into a circular shape and is sized according to the upper diameter (a). The lower part of the grounding cylinder has a lower diameter (c) and the lower diameter (c) is smaller than the upper diameter (a). The lower diameter (c) is smaller than the upper diameter (a) so that the side surface of the cylinder has a tapered shape narrowing from the upper part to the lower part, whereby more moisture is collected through the upper part of the cylinder, Gathered. The height (b) of the grounding cylinder determines the inclination of the side of the grounding cylinder.

<Hole of grounding cylinder>

The grounding cylinder 10 may include at least one hole formed on the bottom surface or the side surface. The holes serve to continuously supply moisture to the soil outside the can while the water flowing in the grounding cylinder flows out of the can and flows along the side of the can. Soils with such moisture have good grounding properties.

It is not necessary to drill a large number of holes in a relatively rich region like Korea, but a large number of holes may be considered for a grounding cylinder buried in a place where rain is low (desert or the like).

The diameter of the hole is 0.1 mm or less, preferably 0.01 to 0.1 mm, and the hole is drilled as small as possible so that water flows down over a long period of time. The hole diameter, the hole position and the number of holes can be changed at each manufacturing time.

<Shape of Grounding Cylinder>

The difference between the upper diameter and the lower diameter of the grounding cylinder includes two purposes. The first is to reduce the storage volume by making it easier to fold the grounding cylinder and the second is to increase the upper surface area of the grounding cylinder so that the rainwater penetrating through the soil can be accepted as much as possible in the grounding cylinder . Even if the overall surface area of the grounding cylinder is made the same, the larger the diameter of the upper part, the more favorable condition is to receive the rainwater.

<Size of grounding cylinder>

In one embodiment of the present invention, the grounding cylinder may have a top diameter of 30 cm x height (key) of 20 cm x bottom diameter of 20 cm. However, this is only an approximate measure as an embodiment of the present invention, and the size (dimension) of the grounding cylinder is a variable value which can be changed according to the request of the customer. As another example, the grounding cylinder according to the present invention may have a top diameter of 30 cm or more, a bottom diameter of 20 cm or less, and a height of 20 cm or less.

The grounding cylinder of the present invention can increase the standard (outer shape) and compensate for the disadvantage of the soil resistivity value in a region where the resistivity value of the soil is high (Jeju Island, sandy soil, mountain slope, (Small) standard in areas with low resistivity values (such as marshy areas and clayey areas), and the optimum manufacturing cost is obtained so that desired ground resistance can be obtained. It can be divided into several steps. These specifications can be determined according to the needs of the consumer (for example, electric power companies, electric contractors, etc.).

(If the present invention is practically used, the size of the grounding cylinder should be standardized to about 3 to 5).

<Installation of Grounding Cylinder>

A grounding lead (20) is connected to the grounding cylinder, and this grounding lead is connected to the ground surface to transmit an excessive current due to lightning or the like to the grounding cylinder.

The grounding method according to the present invention includes the steps of connecting a ground lead wire to a grounding cylinder, burying the grounding cylinder and the ground lead wire at a position of 75 cm or less from the ground surface, and burring the grounding cylinder and the ground lead wire .

The grounding cylinder and the ground lead wire can be electrically connected by compression connection using copper sleeves or by crimping the wire strands and winding them together.

In winter, the freezing line of the soil is about 50cm (below Seoul). The ground lead may therefore be at least 50 cm long to be connected to the ground or other grounding equipment. When the grounding cylinder is installed at a distance of 50 cm or less from the surface of the earth, the water contained in the grounding cylinder is not frozen even during the winter season, so that the effect of lowering the grounding resistance for four seasons can be exhibited.

These grounding cylinders can lift the safety of buildings (steel towers, high-rise buildings, etc.) exposed to the risk of electric power facilities and lightning to several stages.

10: Grounding cylinder
20: Ground lead wire

Claims (5)

Connecting a ground lead wire to a grounding cylinder;
Burying the grounding cylinder and the ground lead; And
And grounding and grounding the grounding cylinder and the ground lead,
The grounding cylinder is made of a conductive material,
The upper diameter of the grounding cylinder is not less than 25 cm and not more than 35 cm, the lower diameter is not less than 20 cm and not more than 30 cm, and the height is not less than 20 cm and not more than 30 cm.
The grounding cylinder is opened at the top so as to load the soil in the inner space when the grounding cylinder is buried, and the side surface of the grounding cylinder is tapered so that the side surface of the grounding cylinder is narrowed from the top to the bottom And a second container
One end of the ground lead wire is welded or press-connected to the upper portion of the grounding cylinder. In order to prevent collapsing of the grounding cylinder and to enhance the electrical connection between the grounding cylinder and the ground lead, one end of the ground lead wire is connected to the connecting portion of the ground lead wire and the grounding cylinder A zinc-plated steel sheet was covered and re-pressed,
And a hole formed in the bottom surface or side surface of the grounding cylinder at a size of 0.01 mm to 0.1 mm to continuously supply moisture to the soil around the grounding cylinder according to the humidity of the soil around the grounding cylinder,
Wherein the grounding resistance is reduced in proportion to an increase in moisture content around the grounding cylinder. The method according to claim 1,
Wherein the welding of the grounding cylinder and the ground lead wire is an electric welding or a spot welding.
The method according to claim 1,
Wherein the grounding cylinder has an upper diameter of 25 cm or more and 35 cm or less and a lower diameter of 20 cm or more and 30 cm or less and a height of 20 cm or more and 30 cm or less and is characterized in that desert and Jeju Island Wherein the grounding cylinder has a bottom diameter of 1.0 m, an upper diameter of 1.05 m, and a height of 1.0 m in a special geological region including the ground.
The method according to claim 1,
Wherein the ground lead line is 20 cm or 25 cm or 30 cm depending on the bottom diameter standard of the cylinder.
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