JP2001052831A - Executing method of ground electrode work - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an executing method of ground electrode work, enabling the work to be executed at a low cost without requiring large-scale installation work. SOLUTION: A work executing method is employed having a form inserting process for inserting a form 3 made of metal into an electrode installing hole vertically formed in the ground 'e' where a ground electrode is installed, a wire inserting process for inserting a bare wire 4 from a power distribution mast 2 into the form 3 made of metal after the form inserting process, a conductive-powder filling process for filling the form 3 made of metal with a carbonic conductive powder 6 mixed with cement after the form inserting process, and a form removing process for pulling out the form 3 made of metal after the conductive-powder filing process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of constructing electric equipment and lightning rods to be installed on concrete poles and the like for electric power distribution / telegraph / telephone information communication and electric railways, and a method of constructing a ground electrode of a ground wire.

[0002]

2. Description of the Related Art A pole such as a distribution pole usually has a diameter of 50 cm.
In this method, an earth auger excavates a pillar hole having a depth of 1 m to 3 m, and a concrete pillar having a diameter of 20 cm to 40 cm is inserted into the hole. Most of the pillars such as distribution poles are mostly roads and sidewalks, so it is not possible to excavate a wide area. Be constrained. Accordingly, as a ground electrode used in the conventional method, a rod-shaped electrode of 14 mmφ × 1.5 m is often used, but there is a limit in reducing the ground resistance with this ground electrode. This is because the surface area of the electrode is determined by the size of the rod-shaped electrode, and the effective ground area (volume)
It is difficult to take a large contact area in the
This is because the surface of the rod-shaped electrode is smooth, and the contact with the soil becomes a continuous point contact, which makes it difficult to make a close contact. In such a case, for example, the following construction methods (1) to (5) have been sought to reduce the ground resistance as much as possible. A drug-based grounding resistance reducing agent is injected around the rod-shaped electrode. A plurality of buried ground wires will be laid radially from the distribution pole. A plurality of carbon-based strip-shaped electrodes are buried at a position about 1 m away from the distribution pole, and connected in parallel with these. A required length of deep buried electrode is constructed by a boring machine and connected in parallel with this.

[0003]

However, in a layer having a high ground resistivity, such as a gravel layer and a bedrock layer, there may be a case where the acquisition of the prescribed grounding resistance value is abandoned due to the relationship between the land area and the construction cost. are doing. In addition, in the above construction method, due to the characteristics of the grounding resistance reducing agent, since there is a problem that the aging of the grounding resistance value and corrosion of the metal electrode occur,
In recent years, its usage has decreased. Due to the lateness of such ground electrode construction technology, JIS standard A4
Even when it is difficult to comply with the provisions of Article 201-1981 and Article 18 of the Electrical Equipment Technical Standard, a large-scale installation work is required to comply with the provision, and there has been a problem that a great deal of cost is required.

[0004] The ground electrode construction method of the present invention has been made in view of the above circumstances, and an object thereof is to provide a method that can be carried out at low cost without requiring large-scale installation work.

[0005]

The ground electrode construction method of the present invention employs the following means to solve the above problems. In other words, the method for forming a ground electrode according to claim 1 is a method for forming a ground electrode for a building pole such as a distribution pole, for forming an electrode installation hole vertically in the ground on which the ground electrode is to be formed. A mold inserting step of inserting a mold, an electric wire inserting step of inserting an electric wire from the pole into the electrode forming mold after the mold inserting step, and the electrode forming after the electric wire inserting step. In the forming form, a conductive powder filling step of filling a conductive powder mixed with a coagulant, and having a form removing step of pulling out the electrode forming form after the conductive powder filling step. I do.

According to the method for applying a ground electrode according to the first aspect of the present invention, the outer surface of the ground electrode after the application is subjected to earth pressure by adjusting the mixing amount of the coagulant to bring the ground electrode after the application into a semi-solid state. In addition, the inner electrode can be made thicker in the horizontal direction by its own weight and can be made to closely match the inner wall surface of the electrode installation hole, so that the ground resistance of the ground electrode can be extremely low. Further, since the ground electrode is provided perpendicular to the ground, the ground surface area required for providing the ground electrode is only a point, and the problem of difficulty in securing land can be solved. Also, by forming the electrode installation hole perpendicular to the ground, the ground electrode after construction is also formed perpendicular to the ground, so for example, even if a crack occurs in a part of the longitudinal direction,
Using the shaking and vibration of the pillars, the cracks can be rubbed together for natural restoration. That is, when the ground electrode is viewed in a plan view, it becomes a point and the earth pressure and the self-weight pressure can be concentrated, so that the earth pressure and the self-weight pressure applied to the ground electrode can be effectively concentrated at the crack. In addition, concentrated contact of the grounding and the earth pressure / self-weight pressure is applied to the cracked portion to act to fill the crack. Also, when filling conductive powder into the narrow and long electrode installation hole,
By inserting the electrode forming mold first, it is possible to spread the conductive powder evenly and deeply into the electrode installation hole.

According to a second aspect of the present invention, in the method of the first aspect, the coagulant is cement, and 10 to 15% by weight based on 100% by weight of the conductive powder. It is characterized by mixing.

According to the ground electrode construction method of the second aspect, the strength required for maintaining the shape of the electrode can be maintained, and at the same time,
If the ground electrode is damaged, the damaged portion can be maintained as soft as can be naturally repaired by earth pressure or own weight. That is, if the amount of the cement is less than 10% by weight, it is difficult to maintain the shape due to insufficient strength. Conversely, if the amount is more than 15% by weight, the strength is too high and the natural restoration ability is lost. % Is preferable.

According to a third aspect of the present invention, there is provided the ground electrode mounting method according to the first or second aspect, wherein the ground electrode after the installation is placed in the electrode forming mold in the wire insertion step. A reinforcing net for reinforcing the wire is inserted together with the electric wire.

According to the ground electrode construction method of the third aspect, when the sway or vibration of the building pole is transmitted to the ground electrode, this force acts to bend the ground electrode along the longitudinal direction. Then, there is a possibility that the bending force may cause breakage such as a crack in the middle of the ground electrode in the longitudinal direction. However, in the ground electrode after construction of the present invention, the strength is maintained such that the breakage does not easily occur by inserting the reinforcing net. .

[0011] Further, in the ground electrode construction method according to the fourth aspect, in the ground electrode construction method according to the third aspect, the reinforcing net is a metal net and is fixed to the electric wire so as to be able to conduct electricity.

[0012] According to the method for constructing a ground electrode according to the fourth aspect of the present invention, by providing a reinforcing net between the electric wire and the conductive powder, the area where the electric wire contacts the conductive powder is limited to the case where only the electric wire is used. The current path can be made relatively large, and furthermore, the energization path extending in the width direction extends over substantially the entire length of the ground electrode, so that the electric resistance between the electric wire and the conductive powder can be kept low. Therefore, the ground resistance between the electric wire and the ground can be kept extremely low.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the method for applying a ground electrode according to the present invention will be described with reference to the drawings, but it is needless to say that the present invention is not limited to this. In the following description, an example will be described in which a distribution pole is built as a building pole, and a gap formed in a building pole hole where the distribution pole is built is used as an electrode installation hole for installing a ground electrode. First, a mold insertion step of vertically forming an electrode installation hole on the ground where the ground electrode is to be constructed and inserting an electrode forming mold is performed. As described above, the electrode installation hole is a part of a pillar hole. Since this is already formed, the process is started from the insertion of the electrode forming mold. That is, as shown in FIG. 1, after installing the distribution pole 2 in the pole hole 1 formed on the ground e,
In order to form a uniform grounding electrode in the gap formed between the pole hole 1 and the distribution pole 2 (usually about 3 cm to 10 cm and a depth of 1 m to 3 m, which is an electrode installation hole). Metal Form 3 for Forming Ground Electrode (Form Form for Electrode)
Insert The metal mold 3 is formed of, for example, a long tube having a rectangular cross section made of a steel plate, and its cross-sectional shape and length depend on the shape of the electrode installation hole to be constructed. May be changed as appropriate.

Next, as shown in FIG. 2, a wire mesh 5 (reinforcement mesh; this wire mesh) to which a bare electric wire 4 from the distribution pole 2 is welded and fixed in the metal mold 3 after the mold insertion step. 5 will be described later). Further, as shown in FIG.
Then, a conductive powder filling step of filling a carbon-based conductive powder 6 mixed with a coagulant therein is performed. This carbon-based conductive powder 6
Is hardly solidified by itself, so it is difficult to maintain a constant shape for many months. Therefore,
A coagulant is blended in advance with the carbon-based conductive powder 6 in order to give strength enough to maintain a certain shape.

Good results can be obtained by using Portland cement as the coagulant. Further, the cement mixing ratio is preferably 10 to 15% by weight, more preferably 12 to 13% by weight, based on 100% by weight of the carbon-based conductive powder 6. If the weight ratio of the cement is 10% by weight or less, it is difficult to maintain the shape due to insufficient strength, and if it is 15% by weight or more, the strength is too high and the natural restoration ability is lost. And finally, after the conductive powder filling step, a mold removing step of pulling out the metal mold 3 is performed. That is, as shown in FIG. 4, only the metal mold 3 is pulled out upward, and the space above the ground electrode 7 is filled with the soil 8, thereby completing the construction of the ground electrode 7 for the distribution pole 2.

Meanwhile, the distribution pole 2 always generates considerable shaking and vibration due to shaking due to an earthquake, wind pressure, and the like.
At this time, the ground electrode 7 buried in the vicinity of the power distribution pole 2 may be damaged or deformed or cracked by the pressure of the soil. (Since the shape is elongated vertically, cracks running in the horizontal direction are particularly problematic.) .). However, the ground electrode 7 of the present embodiment is
As described above, since the carbon-based conductive powder 6 is in a semi-solidified state instead of a completely solidified state by mixing an appropriate amount of cement, a change in ground resistance caused by damage such as a crack is naturally repaired. Have the ability.

The reason why the ground electrode 7 has the ability to naturally repair damage such as cracks will be described in detail below. The damage of the ground electrode 7 is caused by the shaking and vibration generated by the power distribution pole 2. Therefore, even after the damage occurs, the shaking and vibration is applied to the ground electrode 7. Therefore, natural restoration is performed by using the shaking and vibration. That is, for example, FIG.
As shown in (1), when the shaking of the distribution pole 2 is transmitted to the ground electrode 7 (to the carbon-based conductive powder 6) and a crack 9 is formed, the crack 9 is constantly subjected to earth pressure and its own weight pressure from above. At the same time as pressure is applied (arrow F1), the crack 9
Are broken (arrow F2), and the gap g formed in the crack 9 is filled with the surrounding carbon-based conductive powder 6 (semi-solidified state), so that the restoration is naturally performed.

As described above, the ground electrode 7 of the present embodiment
, The wire mesh 5 is inserted together with the bare electric wire 4. As shown in FIG. 6, the wire mesh 5 is for making it less likely to cause damage such as cracks or breakage, and has, for example, a long flat plate shape of 225 mm in width × 2000 mm in length. The length dimension is not limited to 2000 mm, and is preferably substantially equal to the entire length of the ground electrode 7 to be constructed. Further, the width dimension is also the same, and is not limited to 225 mm, and is preferably substantially equal to the width dimension of the ground electrode 7 to be constructed (when the shape of the ground electrode 7 is a cylindrical shape, its outer diameter dimension). . By setting the length and width of the wire mesh 5 in this manner, the wire mesh 5 can be extended to every corner of the ground electrode 7.
Will be prevalent. The bare wire 4 is fixed to the wire mesh 5 at the center in the width direction so as to be able to conduct electricity over the entire length. The fixing of the bare wire 4 is performed by welding the bare wire 4 to the wire mesh 5 at regular intervals (welded portions indicated by reference numeral 10).

The ground electrode 7 thus reinforced by the wire mesh 5
However, if the power pole 2 is excessively swayed and vibrated, the cracks 9 and the like may be damaged. In this case, if the content of the cement is too large (exceeding the above-mentioned weight ratio) and the carbon-based conductive powder 6 is completely solidified, the damaged portion cannot be naturally repaired.
Then, since the wire mesh 5 is passed through the damaged portion, there is no change in the ground resistance. However, for example, when a current due to a lightning strike or the like flows into the ground electrode 7 through the bare wire 4,
Since only the wire mesh 5 can be energized at the damaged portion, a large current flows here and there is a possibility that the fuse may be heated and melted due to insufficient current capacity. However, as described above, the cement distribution ratio is adjusted appropriately (the carbon-based conductive powder 6 is added in a weight ratio of 100%).
%, The cement content is 10 to 15%, and more preferably 12 to 13%), so that the carbon-based conductive powder 6 can be semi-solidified and the damaged portion can be repaired naturally. In addition, even if a temporarily damaged portion occurs, the wire mesh 5 is repaired immediately, thereby reducing the possibility of the wire mesh 5 fusing.

According to the ground electrode construction method of the present embodiment,
A mold insertion step of inserting the metal formwork 3 into a gap vertically formed between the distribution pole 2 and the pole hole 1, and inserting a bare electric wire with the wire mesh 5 fixed in the metal formwork 3. Wire insertion process,
Carbon-based conductive powder 6 mixed with a coagulant in metal mold 3
The following (1) to (3) can be achieved by adopting a construction method having a conductive powder filling step of filling the mold and a mold removing step of pulling out the metal mold 3.

(1) The ground electrode 7 (carbon-based conductive powder 6) after application is adjusted to a semi-solid state by adjusting the amount of cement mixed, so that the outer surface of the ground electrode 7 is leveled by earth pressure or own weight pressure. It is thicker in the direction and closely matches the soil.
Can be made extremely low. Therefore, there is no need to bury multiple rod-shaped electrodes to obtain a low grounding resistance or to increase the burial depth to increase the length of the rod-shaped electrodes, as in the past, so It is possible to carry out the construction at low cost without requiring any complicated construction work. Further, since the ground electrode 7 is provided perpendicular to the ground e, the ground surface area required for providing the ground electrode 7 is only a point, and the problem of securing land can be solved.

(2) By forming the ground electrode 7 so as to be perpendicular to the ground e after construction, even if a crack 9 is generated in a part of the longitudinal direction, for example, shaking or vibration of the distribution pole 2 is prevented. It is possible to repair the natural part by using the damaged part. That is, when the ground electrode 7 is viewed in a plan view, since the earth pressure and the self-weight pressure can be concentrated as points, the earth pressure and the self-weight pressure applied to the ground electrode 7 can be effectively concentrated at the crack location. Can be. Concentrated pressurization of earth pressure and self-weight is applied to this damaged portion and acts to fill it, so that it is possible to perform natural restoration. (3) When filling the carbon-based conductive powder 6 into the narrow and long gap formed between the pole hole 1 and the distribution pole 2 installed therein, the metal mold 3 is inserted first. By doing so, it is possible to spread the carbon-based conductive powder 6 evenly and deeply into the gap.

According to the ground electrode application method of the present embodiment, the cement mixing amount is 10 to 15% by weight, more preferably 12 to 15% by weight, based on 100% by weight of the carbon-based conductive powder 6.
By setting it to 13% by weight, the strength required for maintaining the shape of the ground electrode 7 can be maintained, and at the same time, the damaged portion when the ground electrode 7 is damaged is soft enough to be naturally repaired by earth pressure or own weight pressure. It is also possible to maintain it.

Further, according to the ground electrode installation method of the present embodiment, the wire mesh 5 for reinforcing the ground electrode 7 after installation is inserted together with the bare wire 4 into the metal mold 3 in the wire insertion step. As a result, the sway and vibration of the power distribution pole 2 are transmitted to the ground electrode 7.
Even if it is attempted to bend the ground electrode 7, it is possible to maintain the ground electrode 7 at such a strength that breakage such as a crack is not easily generated.

Further, according to the ground electrode construction method of the present embodiment, the reinforcing mesh for reinforcing the ground electrode 7 is the wire mesh 5, which is welded and fixed to the bare wire 4 so as to be able to conduct electricity.
Can have a larger area in contact with the carbon-based conductive powder 6 than when the wire net 5 is not used as the bare wire 4 alone, and furthermore, a current path in the width direction over substantially the entire length of the ground electrode 7. Is formed so that the electric resistance between the bare electric wire 4 and the carbon-based conductive powder 6 can be kept low. Therefore, the ground resistance between the bare wire 4 and the ground e can be kept extremely low.

Example 1 In order to investigate the effect of the wire mesh 5 (reinforcement mesh), the installation form E of the ground electrode by the construction method reinforced by the wire mesh 5 of the above embodiment, and other installation forms A to
Embodiment 1 in which comparison with D is performed will be described below with reference to FIG. In this electrode breakdown test, a ground resistivity of 5
A sand layer of 00 Ω · m was used as an experimental place, and five identical concrete columns (not shown) were built here, and ground electrodes of installation forms A to E were constructed for each of these concrete columns.
Each concrete pillar is 13m long and 37.7cm in diameter.
And the depth of embedding was 2.4 m. Then, the tip portions (upper end portions) of these concrete pillars were stretched five times each in the front-rear and left-right directions in the horizontal plane, 20 cm each.

In the installation mode A, one rod-shaped electrode 11 having a diameter of 14 mmφ and a total length of 1500 mm is set at a distance of 7 mm from the ground e.
It is buried vertically downward from a depth of 50 mm (the depth dimension from the ground e to the lowermost end of the ground electrode is about 2250 mm). In addition, the installation mode B has a diameter 14
Two rod-shaped electrodes 12 each having a diameter of 1,500 mm and a total length of 1,500 mm are connected in series so as to be able to conduct electricity, and are buried vertically downward from a depth of 750 mm from the ground e (depth dimension from the ground e to the lowermost end of the ground electrode). Is about 3750 mm). The installation mode C is the same as the above-described embodiment, except that the wire mesh 5 is not inserted, and the 38 mm ² × 1 bare electric wire 1 is used.
3 (2000 mm) is embedded together with the carbon-based conductive powder 6. The outer shape of the ground electrode after the construction is a long plate having a thickness of 40 mm x a width of 300 mm x a length of 2000 mm, and the depth from the ground e to the lowermost end of the ground electrode is about 2750 mm. In addition, the installation mode D is the same as the construction method of the above embodiment, except that the wire mesh 5 is not inserted and 38 mm ²
X One bare electric wire 14 is formed into a loop shape having a length dimension of 2000 mm and a width dimension of 300 mm, and is buried together with the carbon-based conductive powder 6. The outer shape of the ground electrode after the construction is a long plate having a thickness of 40 mm x a width of 300 mm x a length of 2000 mm, and the depth from the ground e to the lowermost end of the ground electrode is about 2750 mm. In addition, the installation form E uses the construction method of the above embodiment,
38 mm ² × one bare electric wire 15 welded and fixed to the copper wire mesh 5 is inserted and buried together with the carbon-based conductive powder 6 (depth from the ground e to the lowermost end of the ground electrode). The dimensions are 2750 mm).

Table 1 below summarizes the test results of the electrode destruction tests in each of the installation modes A to E.

[0029]

[Table 1]

As shown in the table, in the installation mode A,
The ground resistance before and after the electrode breakdown test was constant at 358 Ω, and did not change, and there was no breakage or cracking. Further, in the installation mode B, the ground resistance before and after the electrode destruction test was constant at 199Ω and did not change, and no breakage or cracking occurred. In the installation mode C, the ground resistance before the electrode breakdown test was 8
In contrast to 7.9 Ω, after the test, significant damage occurred, and the ground resistance increased to 243.7 Ω. In the installation mode D, the ground resistance before the electrode breakdown test was 79.0Ω, but after the test, a crack was generated and the ground resistance increased to 99.5Ω.

In the installation mode E constructed by the construction method of the present invention, despite the fact that a crack is generated,
An extremely low ground resistance of 3.7Ω was successfully maintained before and after the test. This is because the wire mesh 5
This is because, by fixing by welding, the contact area between the bare electric wire 15 and the carbon-based conductive powder 6 is increased, and at the same time, the ground electrode is reinforced to prevent large breakage. According to the above-described electrode destruction test, by providing a wire mesh in the ground electrode, a constant ground resistance is maintained before and after the test, as in the case of using a rod-shaped electrode having rigidity (for example, installation forms A and B). Reinforcing ability that does not cause large breakage like installation mode C was confirmed.

[Example 2] In order to confirm the effect of reducing the grounding resistance of the ground electrode by the construction method of the present invention, the installation form I constructed by the construction method of the above embodiment and the construction form by the conventional construction method The description of the second embodiment in which the ground resistances are compared with F to H will be described below with reference to FIGS. In the second embodiment, the embedding depth is 750 mm or less, and the width is 5 mm.
The ground resistance that can be obtained within 0 cm × 5 m depth × 10 m length and within a required volume of 25 m ³ was compared. Reference numeral 20 is a concrete column having the same specifications as the concrete column described in the first embodiment.

The installation form F has a diameter of 14 mm and a total length of 1.
Four sets of three 500 mm rod-shaped electrodes 16a connected in series are prepared, and these are laid at an interval of 3300 mm and buried at a depth of 75 mm.
Four points are vertically driven at 0 mm or less, and their upper ends are connected to each other by a copper wire 16b so as to be able to conduct electricity.
In the installation form G, a bare wire 17 having a length of 38 mm ² and a length of 10 m is laid in a horizontal direction at an embedding depth of 750 mm or less (embedded ground wire). Installation form H
Is a horizontal buried carbon-based electrode 18 having a thickness of 4 cm × a width of 50 cm × a length of 10 m, which is laid horizontally at a burying depth of 750 mm. The installation mode I is 40 mm thick × 400 mm wide using the construction method of the above embodiment.
Four electrodes 19a of mm × 5000 mm in length are embedded so that the interval between them is 3300 mm. The burial depth of these electrodes 19a is 750 mm or less, and they are installed in the vertical direction, respectively, and wire meshes 19b similar to the wire mesh 5 are inserted into the inside thereof.

Table 2 below summarizes the results of the comparison test of the grounding resistance reduction effect of the above installation modes F to I.

[0035]

[Table 2]

As shown in the table, the grounding resistance of installation type F is 11.7Ω, and the grounding resistance of installation type G is 17.3Ω.
Ω, the ground resistance of the installation form H was 8.3 Ω, and the ground resistance of the installation form I was 3.1 Ω. Accordingly, the installation mode I according to the construction method of the present invention is compared to the installation mode F (11.
(7Ω−3.1Ω) /11.7Ω×100=73.5% of the ground resistance reduction rate is achieved. Similarly, when compared with the installation mode G, (17.3Ω-3.1Ω) /17.3Ω×
A ground resistance reduction rate of 100 = 82.1% is achieved.
Similarly, when compared with the installation mode H, (8.3Ω-3.1
Ω) /8.3Ω×100=62.7% of the ground resistance reduction rate is achieved. From the above comparative test results, it was confirmed that the installation form I according to the construction method of the present invention can obtain the lowest ground resistance within a common required volume as compared with the installation forms F to H according to the conventional construction method. did it.

[Example 3] For the purpose of verifying the difficulty of construction, construction time, construction cost, and the effect of reducing the grounding resistance, installation forms J and K according to the construction method currently adopted as a standard construction method, and the present invention. The description of Example 3 in which the comparison is made with the installation forms L to O according to the construction method described above is continued below.

The installation form J is a rod electrode having a diameter of 14 m.
A rod-shaped electrode with mφ and a total length of 1500 mm is buried at a depth of 750
mm (not shown. Reference symbol J corresponds to reference symbol J in Table 3 below. The same applies to the following installation modes K to O). In the installation mode K, a strip electrode is added to the rod electrode, and a strip electrode having a width of 50 cm and a length of 5 m is connected to the ground electrode of the installation mode J. Installation form L is 40mm thick x 300mm wide
× It is a vertical plate-like electrode having an external dimension of length 2800 mm.

The installation mode M is a vertical plate-like electrode, and the ground electrode of the installation mode L is provided with a ground electrode of an installation mode P described later at an interval of 3 m. The installation mode N is a vertical plate-shaped electrode, and is formed by further adding a ground electrode of the installation mode P to the ground electrode of the installation mode M at an interval of 3 m. The installation mode O is a vertical plate-like electrode, and the installation mode P is further added to the ground electrode of the installation mode M.
Are applied at intervals of 3 m (see FIG. 12). The installation form P is a vertical plate-like electrode, in which a ground electrode having an outer dimension of 40 mm in thickness × 400 mm in width × 5000 mm in length is constructed using the construction method of the above embodiment. Table 3 below shows a comparison result of the grounding resistance reduction effect of each of the installation modes J to O.

[0040]

[Table 3]

As shown in the table, in the installation mode J according to the conventional construction method, a ground resistance of 79.6Ω was obtained, but even if the installation mode K was adopted to further reduce this, 25 It could only be reduced to about 0.8Ω. However, in the installation mode L according to the construction method of the present invention, 24.6 Ω, in the installation mode M, 13.1 Ω, and the installation mode N
In the installation mode O, a ground resistance as low as 9.6 Ω and 7.4 Ω was successfully obtained. The ground resistance 7.4 Ω of this installation mode O is 71.7 with respect to the conventional installation mode K.
Achieved a ground resistance reduction rate of 3%.
As can be seen from the fact that the grounding resistance reduction rate of 90.7% has been achieved, the construction method of the present invention is effective in obtaining a ground resistance extremely lower than the current standard construction method. Was proved.

[0042]

According to the method for applying a ground electrode according to the first aspect of the present invention, a mold inserting step of inserting an electrode forming mold into a vertically formed electrode installation hole; An electric wire insertion step of inserting an electric wire into the mold, a conductive powder filling step of filling a conductive powder mixed with a coagulant in an electrode forming mold, and a mold removing step of pulling out the electrode forming mold. By adopting the method, the following (1) to (3)
Becomes possible.

(1) By adjusting the mixing amount of the coagulant to make the ground electrode after construction into a semi-solid state, the outer surface of the ground electrode becomes thicker in the horizontal direction due to the earth pressure or the weight of its own weight. Since it closely matches the wall surface, the ground resistance of the ground electrode can be made extremely low. Accordingly, since the ground resistance can be reduced without increasing the shape of the ground electrode, a plurality of rod-shaped electrodes are buried or the length of the rod-shaped electrode is increased in order to obtain a low ground resistance as in the related art. Therefore, since it is not necessary to increase the burial depth, it is possible to perform the construction at a low cost without requiring a large-scale installation work. Furthermore, since the ground electrode is provided perpendicular to the ground, the ground surface area required for providing the ground electrode is only a point, and it is possible to solve the difficult problem of securing land. (2) By forming the electrode installation hole perpendicular to the ground, the ground electrode after construction is also formed perpendicular to the ground. Therefore, even if a crack occurs in a part of the longitudinal direction, for example, the sway or vibration of the building pole It is possible to repair the natural parts by rubbing the cracked parts using the method. That is, when the ground electrode is viewed in a plan view, it becomes a point and the earth pressure and the own weight pressure can be concentrated, so that the earth pressure and the own weight pressure applied to the ground electrode can be effectively concentrated at the crack location. So, in this crack,
Since the rubbing and the concentrated pressure of the earth pressure / self-weight pressure are applied and act to fill the pressure, natural restoration can be performed. (3) When filling the narrow and long electrode installation hole with the conductive powder, the electrode forming mold is inserted first,
It is possible to spread the conductive powder evenly and deeply into the electrode installation hole.

Further, according to the method for applying a ground electrode according to the second aspect, the amount of cement mixed is set to 100% by weight of the conductive powder.
10 to 15% by weight with respect to the electrode, the strength required for maintaining the shape of the electrode can be maintained, and at the same time, the location where the ground electrode is damaged can be repaired naturally by the earth pressure. It is also possible to maintain.

According to the third aspect of the present invention, the reinforcing mesh for reinforcing the ground electrode after the construction is inserted together with the electric wire into the electrode forming mold in the electric wire inserting step. Therefore, even if the ground electrode is bent by transmitting the swing or vibration of the pole, the ground electrode can be maintained at a strength that does not cause breakage such as a crack.

Further, according to the ground electrode construction method of the fourth aspect, the reinforcing mesh is a wire mesh, which is fixed to the wire so as to be able to conduct electricity, so that the area where the wire contacts the conductive powder can be reduced.
It can be larger than when only electric wires are used,
Furthermore, since the energization path extends over substantially the entire length of the ground electrode, the electric resistance between the electric wire and the conductive powder can be kept low. Therefore, it is possible to keep the ground resistance between the electric wire and the ground extremely low.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a ground electrode construction method of the present invention, and is a cross-sectional view showing a mold insertion step.

FIG. 2 is a view showing a continuation of the construction method, and is a cross-sectional view showing an electric wire insertion step.

FIG. 3 is a view showing a continuation of the construction method, and is a cross-sectional view showing a conductive powder filling step.

FIG. 4 is a view showing a continuation of the construction method, and is a cross-sectional view showing a formwork removing step.

FIG. 5 is a cross-sectional view illustrating natural restoration when a crack occurs in the ground electrode constructed by the construction method.

FIG. 6 is a front view showing a wire mesh used in the construction method.

FIG. 7 is a cross-sectional view showing an installation mode according to the construction method of the present invention used for the electrode breakdown test and an installation mode according to another construction method.

FIG. 8 is a cross-sectional view of a ground electrode, showing an installation mode according to a conventional construction method for confirming the effect of reducing ground resistance.

FIG. 9 is a cross-sectional view of a ground electrode, showing another installation form according to a conventional construction method for confirming the effect of reducing the ground resistance.

FIG. 10 is a cross-sectional view of a ground electrode, showing another installation form according to a conventional construction method for confirming the effect of reducing the ground resistance.

FIG. 11 is a view showing an installation mode according to the construction method of the present invention constructed to confirm the effect of reducing the ground resistance of the ground electrode, and is a cross-sectional view of the ground electrode.

FIG. 12 is a cross-sectional view of a ground electrode in an installation form according to the construction method of the present invention, constructed for the purpose of verifying the difficulty of construction, the construction time, the construction cost, and the effect of reducing the ground resistance.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electrode installation hole (building pole hole) 2 ... Distribution pole (building pole) 3 ... Metal formwork (electrode forming formwork) 4 ... Bare electric wire (electric wire) 5 ... Wire mesh (reinforcement mesh, wire mesh) 6: carbon-based conductive powder (conductive powder) 7: ground electrode e: ground

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[Procedure amendment]

[Submission date] April 3, 2000 (200.4.3)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

[0005]

The ground electrode construction method of the present invention employs the following means to solve the above problems. In other words, the method for forming a ground electrode according to claim 1 is a method for forming a ground electrode for a building pole such as a distribution pole, for forming an electrode installation hole vertically in the ground on which the ground electrode is to be formed. A mold inserting step of inserting a mold, an electric wire inserting step of inserting an electric wire from the pole into the electrode forming mold after the mold inserting step, and the electrode forming after the electric wire inserting step. In the forming mold, there is a conductive powder filling step of filling a semi-solidified conductive powder mixed with a coagulant, and a mold removing step of pulling out the electrode forming mold after the conductive powder filling step. It is characterized by the following. ────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] September 14, 2000
4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

[0005]

The ground electrode construction method of the present invention employs the following means to solve the above problems. In other words, the method for forming a ground electrode according to claim 1 is a method for forming a ground electrode for a building pole such as a distribution pole, for forming an electrode installation hole vertically in the ground on which the ground electrode is to be formed. A mold inserting step of inserting a mold, an electric wire inserting step of inserting an electric wire from the pole into the electrode forming mold after the mold inserting step, and the electrode forming after the electric wire inserting step. to use mold inside, closed and conductive powder filling step of filling a conductive powder in a semi-solidified state mixed with coagulant, and a mold removal step of withdrawing the electrode forming mold after the conductive powder filling step Wherein the coagulant is cement and the conductive
10-15% by weight is mixed with 100% by weight of the powder,
It becomes a semi-solid state ground electrode after construction, and earth pressure and own weight pressure
With the ability to naturally repair changes in ground resistance
It is characterized by being .

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

According to the method for applying a ground electrode according to the first aspect of the present invention, the outer surface of the ground electrode after the application is subjected to earth pressure by adjusting the mixing amount of the coagulant to bring the ground electrode after the application into a semi-solid state. In addition, the inner electrode can be made thicker in the horizontal direction by its own weight and can be made to closely match the inner wall surface of the electrode installation hole, so that the ground resistance of the ground electrode can be made extremely low. Further, since the ground electrode is provided perpendicular to the ground, the ground surface area required for providing the ground electrode is only a point, and the problem of difficulty in securing land can be solved. Also, by forming the electrode installation hole perpendicular to the ground, the ground electrode after construction is also formed perpendicular to the ground, so for example, even if a crack occurs in a part of the longitudinal direction,
Using the shaking and vibration of the pillars, the cracks can be rubbed together for natural restoration. That is, when the ground electrode is viewed in a plan view, it becomes a point and the earth pressure and the self-weight pressure can be concentrated, so that the earth pressure and the self-weight pressure applied to the ground electrode can be effectively concentrated at the crack location. In addition, concentrated contact of the grounding and the earth pressure / self-weight pressure is applied to the cracked portion to act to fill the crack. Also, when filling conductive powder into the narrow and long electrode installation hole,
By inserting the electrode forming mold first, it is possible to spread the conductive powder evenly and deeply into the electrode installation hole. In addition, the coagulant is cement,
Mix 10-15% by weight with respect to 100% by weight of powder
With this, while maintaining the strength necessary to maintain the shape of the electrode,
If the ground electrode is damaged, determine the location of the damage
Maintain softness that can be naturally restored by pressure
Can also be. That is, this cement mixing amount is 10 weight
%, It is difficult to maintain the shape due to insufficient strength
If it is more than 15% by weight, the strength is too high
10 to 15 weights
It is preferable to be within the range of the amount%.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Deleted

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Deleted

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Deleted

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Deleted

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Deleted

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0012

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[Procedure amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0044

[Correction method] Change

[Correction contents]

Further, the amount of cement mixed with the conductive powder 100
By setting the amount to 10 to 15% by weight with respect to the weight%, the strength required for maintaining the shape of the electrode can be maintained, and at the same time, if the ground electrode is damaged, it is soft enough to be naturally repaired by earth pressure. It is also possible to maintain it.

[Procedure amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0045

[Correction method] Deleted

[Procedure amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0046

[Correction method] Deleted

Claims (4)

[Claims] 1. A method of installing a ground electrode for a building pole such as a distribution pole, the method comprising: forming an electrode installation hole vertically in the ground where the ground electrode is to be installed; and inserting an electrode forming mold. An insertion step, an electric wire insertion step of inserting an electric wire from the pillar into the electrode forming mold after the mold insertion step, and a solidification in the electrode forming mold after the electric wire insertion step. A ground electrode applying method, comprising: a conductive powder filling step of filling a conductive powder mixed with an agent; and a mold removing step of pulling out the electrode forming mold after the conductive powder filling step. 2. The method according to claim 1, wherein the coagulant is cement, and 10 to 15% by weight is mixed with 100% by weight of the conductive powder. . 3. The ground electrode installation method according to claim 1, wherein a reinforcing net for reinforcing the ground electrode after the installation is inserted together with the electric wire into the electrode forming mold in the electric wire insertion step. A method for constructing a ground electrode, comprising: 4. The method according to claim 3, wherein the reinforcing net is a metal net and is fixed to the electric wire so as to be able to conduct electricity.