JPH11149948A - Earth electrode buried in deep in multistage and computation of earthing resistance of earth electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To bury a plurality of earth electrodes at different earth depth in a single dug hole. SOLUTION: A plurality of earth electrodes 1, 2, 3 kept as insulated electric wires to different depth points from the surface of the ground and made naked electric wires at the lower part are buried in a dug hole H. In this case, at the time of boring the dug hole H, the drilling pipe itself is used as an earth electrode and the earthing resistance is measured for every depth point as the depth is deepened and then the earthing resistance RE1 of an earth electrode 1 is computed from a calculation expression: RE1 =(RT1 ×RL1 )/(RT1 -RL1 ), wherein RT1 is the measured earthing resistance value RT1 corresponding to the depth T1 at the lower end of the insulated electric wire part of the earth electrode 1 and RL1 is the measured earthing resistance value RL1 corresponding to the depth L1 at the lower end of the necked electric wire part of the earth electrode 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multistage deeply buried ground electrode capable of easily measuring a ground resistance and a method of calculating the ground resistance.

[0002]

Conventionally, when a ground electrode is buried at a large depth in the ground, when measuring the ground resistance, the electrode is buried in a pit obtained by boring the ground. The method of measuring the ground resistance has been used. By the way, in recent years, avoiding grounding near the ground surface, an insulated wire from the ground surface to a certain depth and a ground wire as a bare wire below the insulated wire, or a separate electrode material connected to the lower end of the insulated wire as a ground electrode Sometimes. In this case, the grounding resistance may change depending on the depth, and it is necessary to determine the burial depth, the length of the bare wire, etc. in consideration of them, and if the basic data used for the calculation is insufficient, the Extra work must be taken, extra work may be performed, and the construction period and construction costs may increase.

[0003]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an invention according to claim 1 is to provide an insulated wire from the ground surface to different depths from each other, and to provide a grounded wire underneath as a bare wire or a grounding pole component. Two or more ground electrodes each having a portion are buried in a trench.

According to a second aspect of the present invention, when boring a hole in which the multi-stage deeply buried ground electrode of the first aspect is buried, the drill pipe itself is used as a ground electrode every time the depth increases, and the ground resistance at each depth is increased. Then, from the measured ground resistance R _T corresponding to the depth of the lower end of the insulated wire portion of the ground electrode and the measured ground resistance R _L corresponding to the depth of the lower end of the ground electrode, the ground resistance of the ground electrode is determined. R _E is calculated by the following formula: R _E = (R _T ×
R _L ) / (R _T -R _L ).

According to a third aspect of the present invention, in the first aspect of the present invention, an auxiliary ground electrode for measuring a ground resistance is buried in the trench.

According to a fourth aspect of the present invention, in the first or the third aspect of the present invention, two or more excavations having the same depth are excavated, and a combination of ground electrodes having the same configuration is buried in each of the excavations. The same ground electrodes are connected in parallel to form ground electrodes.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an embodiment according to the first and third aspects of the present invention. In the figure, H is a pit having a diameter D and a depth L3. Depth L in this hole H
The ground electrodes 1, 2, and 3 are buried by 1, L2, and L3, respectively. The ground electrodes 1, 2, and 3 are respectively located at a depth T1,
Up to T2 and T3 are covered with an insulating material, and the remaining lengths E1, E2 and E3 up to the depths L1, L2 and L3 thereunder are constituted by bare wires or ground wires.

That is, each of the electric wires 1, 2, and 3 has a length E1, E2, and E3 at its lower end as an effective grounding portion. The section S1 in the drawing is a ground potential spread prevention insulating section between the effective ground portion of the ground electrode 1 and the effective ground portion of the ground electrode 2, and similarly, the section S2 is the effective ground of the ground electrode 2. This is an insulating portion for preventing the spread of ground potential between the portion and the effective ground portion of the ground electrode 3. In this way, the three ground electrodes 1,
2 and 3 are buried, and the ground resistance can be measured by using these three ground electrodes 1, 2, and 3 as mutual auxiliary electrodes. Reference numerals 4 and 5 in the figure denote auxiliary grounding electrodes buried for grounding resistance measurement. A grounding electrode part having a length of about 0.5 to 1.0 m is formed at the tip of the fine wire. Can be

[0009] The grounding work of this embodiment includes forming ground electrodes in various underground geology, burying the ground electrodes deep underground, preventing various potentials on the ground surface from spreading deep into the ground, Since the construction involves construction and the grounding pole configuration involves construction methods, the common names are "multi-stage deep burial grounding", "multi-stage deep burial ground", and "multi-stage deep burial earth". ”,“ Multi-stage multi-grounding ”,“ Multi-stage multi-stage grounding ”,“ Multi-stage multi-stage grounding ”,
"Multi-level grounding", "Multi-level grounding", "Multi-level grounding", "Multi-level grounding", "Multi-level grounding", "Multi-level grounding", "Multi-level grounding",
"Multi deep grounding", "Multi deep deep", "Multi deep deep grounding", "Multi deep deep ground", "Multi deep deep earth", "Multi deep deep earth", "Multi deep deep buried clean ground" Construction, multi-stage deep buried clean grounding, multi-stage clean grounding, multi-stage clean grounding, multi-stage deep clean grounding,
“Multi-stage deep clean grounding”, “Multi-stage deep clean grounding”, “Multi-stage deep clean grounding”, “Multi-stage deep clean grounding”, “Multi-stage deep clean grounding”, “Multi-stage deep clean ground”, “Multi-stage deep ground” It can be read as `` clean earth work '', `` multi-stage grounding with built-in grounding measurement electrode '', `` multi-stage deep grounding boring work '', and because it has the same meaning, `` grounding work '' It can be read as "grounding method".

Next, a description will be given of a method of calculating the ground resistance according to the second aspect. When the value of the ground resistance of the ground electrodes 1, 2, and 3 in the trench H of FIG. 1 is to be obtained, first, when the trench H is first drilled, every time the drill pipe is extended, Then, the ground resistance of the drill pipe is measured, and the value of the ground resistance at each depth is recorded as a measurement table. Next, for example, the ground resistance at the length E1 from the depth T1 to the depth L1 in the case of the ground electrode 1 is R _E1 , the measured resistance up to the depth T1 is R _T1, and the measured resistance up to the depth L1 is R _L1 . Then, the ground resistance _RE1 is obtained by the following equation.

[0011]

## EQU1 ## R _E1 = (R _T1 × R _L1 ) / (R _T1 −R _L1 )

The ground resistances R _E2 and R _{E3 of the} ground electrodes 2 and _{3 are}
Can be similarly calculated. In this way, the hole H
By measuring the grounding resistance on the ground while boring, the maximum depth of the pit H for obtaining the required grounding resistance can be predicted in advance, and boring to an unnecessarily large depth is eliminated. , Shortening the construction period and reducing costs.

Next, an embodiment according to claim 4 will be described. This embodiment differs from the embodiment of FIG.
When a ground resistance of a sufficiently low value cannot be obtained with only one trench H, one or more other trenches H are further provided, and ground electrodes having the same configuration are buried in each of them, and these are paralleled to each other. They are connected to obtain a desired ground resistance value. FIG. 2 is a sectional view showing an embodiment according to the fourth aspect of the present invention. In the figure, Ha and Hb are both diameter D and depth L3.
And ground electrodes 1 and 2, each having the same dimensions as the ground electrodes 1, 2, 3 and the auxiliary ground electrodes 4, 5 in FIG.
a, 2a, 3a, ground electrodes 1b, 2b, 3b, auxiliary ground electrodes 4a, 5
a, 4b, 5b are buried.

The ground electrodes 1a, 2a, 3a and the ground electrodes 1b,
2b and 3b are connected in parallel to each other at the top and
Extracted as a few. The ground resistance obtained here has a resistance value that is approximately １ ／ of that in the case of one excavation hole H. Further, in the embodiment of this drawing, when the grounding resistance of each of the a grounding system and the b grounding system is to be measured, the ground resistance can be easily measured by using another system as an auxiliary grounding pole for measurement. can do.

In order to obtain a lower value of the ground resistance, it is possible to increase the number of trenches and increase the number of parallel ground poles. The second embodiment can be referred to as "multi-stage parallel grounding", "parallel multi-stage grounding work", or "parallel multi-stage clean earth". These names are obtained by adding “parallel” to the names of the embodiment in FIG.

In FIG. 1, when a large current flows through the ground electrode 1, an induced voltage is induced in the ground electrodes 2 and 3 by the magnetic flux φ generated in the portion up to the depth L1. The induced voltage is about 0.235 V at a current value of 100 A per 10 m, and the induced voltage generated at the other ground electrodes 2 and 3 buried in the trench H is small and negligible. Safety is maintained. In addition, if the insulating portions of the ground electrodes 1, 2, and 3 are provided with a waterproof measure, the corrosion resistance against natural corrosion and electric corrosion in the insulated inner wire portion is improved.

[0017]

As described above, according to the first aspect of the present invention, two or more insulating wires are provided from the ground surface to different depths from each other, and a grounding portion is formed below the insulated wires using a bare wire or a grounding pole component. By embedding the ground electrode in the trench, the ground electrode can be buried in any depth at multiple stages.

According to the second aspect of the present invention, in the first aspect of the present invention, when boring a borehole, a ground resistance is measured at each depth by using a drill pipe itself as a ground pole, and the measured value is measured. To calculate the ground resistance of the buried ground electrode. As a result, the depth of the hole for embedding the ground electrode is obtained in advance, so that the hole is not drilled to an excessive depth.

According to the third aspect of the present invention, in the first aspect of the present invention, the earth resistance can be easily measured by burying the auxiliary earth electrode for earth resistance measurement in the borehole.

According to a fourth aspect of the present invention, in the first or the third aspect of the present invention, two or more excavations having the same depth are excavated, and a combination of ground electrodes having the same configuration is embedded in each of the excavations. By connecting the same ground electrode in parallel on the ground surface to form a ground electrode, it is possible to cope with a case where a predetermined ground resistance cannot be obtained with one trench.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment according to the first and third aspects of the present invention.

FIG. 2 is a sectional view showing an embodiment according to the invention of claim 4;

[Explanation of symbols]

 1, 2, 3 Ground electrode 4, 5 Auxiliary ground electrode 1a, 2a, 3a Ground electrode 1b, 2b, 3b Ground electrode 4a, 5a Auxiliary ground electrode 4b, 5b Auxiliary ground electrode H, Ha, Hb

Claims (4)

[Claims] 1. An insulated wire extending from the ground surface to different depths from each other, and two or more ground electrodes having a ground portion formed underneath by using a bare wire or a grounding pole component material are buried in a borehole. Multi-stage deep buried ground electrode. 2. A boring hole in which the multi-stage deeply buried ground electrode according to claim 1 is buried, wherein a ground resistance is measured at each depth by using a drill pipe itself as a ground electrode each time the depth increases. Next, from the measured ground resistance R _T corresponding to the depth of the lower end of the insulated wire portion of the ground electrode and the measured ground resistance R _L corresponding to the depth of the lower end of the ground electrode, the ground resistance R _E of the ground electrode is calculated as follows: calculation formula _{R E = (R T × R} L) / (R T -
R _L ), and calculating the ground resistance of the multi-stage deeply buried ground electrode. 3. The multi-stage deeply buried ground electrode according to claim 1, wherein an auxiliary ground electrode for measuring ground resistance is buried in the trench. 4. The multi-stage deeply buried ground electrode according to claim 1, wherein two or more pits having the same depth are excavated, and a combination of ground electrodes having the same configuration is buried in each of the digging holes. Wherein the same ground electrode is connected in parallel to form a ground electrode.