JPS635187Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an auxiliary grounding device installed at the base of a transmission line tower.

In order to prevent lightning damage to power transmission lines, it is generally recommended to use a counterpoise, which is a 30-50m long conductor extending parallel or radially from the base of a steel tower and buried at a depth of 30-50cm underground. There are two types of grounding systems: the distributed grounding system, which has a mesh-like conductor buried near the base of the tower, and the centralized grounding system, which buries a mesh conductor near the base of the tower. As is known.

These grounding devices are buried in the earth, and their surge impedance is particularly influenced by the earth's resistivity. In places where the earth's resistivity is high,
It is often extremely difficult to reduce the value of surge impedance. It has been theoretically calculated that the surge impedance during lightning strikes can be lowered by using both the distributed grounding method and the concentrated grounding method in soils with such poor conditions.

Therefore, the purpose of this invention is to provide an auxiliary grounding device of a distributed grounding type which can be used in conjunction with a counterpoise, and which is attached to each tower pedestal of a steel tower. A grounding conductor consisting of a covered wire is provided extending radially in a direction of about 45° to the counterpoise, which extends parallel to each other, and assists in grounding the counterpoise. A grounding conductor body consisting of a bare wire connected to the tip of the conductor and extending in the same direction, and a sharp-shaped tip attached to the tip of each grounding conductor body and driven almost perpendicularly into the ground. The present invention provides a concentrated distribution type auxiliary grounding device equipped with a small rod, thereby making it easier to lower surge impedance.

In the following, the invention will be explained with reference to the illustrated embodiments.

As shown in FIG. 1, a mounting plate 3 is fixed to the leg 1 of the steel tower near its foundation 2. The mounting plate 3 has five bolt holes 4, as shown in FIG.
4', 4'', and its five bolt holes 4, 4',
It is recommended that two of the 4" holes 4 be used to attach this mounting plate to the tower pedestal, the central one 4' is for mounting the counterpoise, and the remaining two 4" holes are used for attaching the ground conductor. . Using two bolt holes 4″,
Four ground conductors 5 are attached, and the ground conductors 5 are extended radially as shown in FIG.

As shown in more detail in FIG. 1, the grounding conductor 5 is a covered wire with a mounting terminal 6, which is crimped to the mounting plate, and this covered wire is used near the tower base to prevent corrosion over time. , from terminal 6 above ground to underground
It extends about 1.5 m, and its tip is connected to the ground conductor main body part 8 by a connecting body 7. The main body part 8 made of bare copper wire is generally several meters long, and a small rod 9 which can be driven into the ground almost perpendicularly is crimped and connected at the tip part with a connector 10. Lower end 11 of small rod 9
It has a sharp shape so that it can be easily driven into the ground. A counterpoise 12 is installed in the hole 4' of the mounting plate 3 and extends in parallel as shown in FIG.

In this way, by using the auxiliary grounding device in combination with the counterpoise 12, it is possible to easily lower the surge impedance at the time of lightning strike even in the ground where conditions are poor. Other local grounding devices may be difficult to install due to the location of the steel tower, but this idea uses short grounding conductors in a radial pattern, making installation easy and workable. The small rod has a sharp tip and can cause a large amount of current to flow to the ground due to discharge, making the grounding effect even greater.

Corrosion over time is always a problem with grounding devices.
This idea uses relatively stable copper material and uses coated wires near the steel towers, which are particularly corroded, to increase corrosion resistance.

[Brief explanation of the drawing]

Fig. 1 is a side view showing one embodiment of the auxiliary grounding device of this invention, Fig. 2 is a side view of the mounting plate, and Fig. 3 is a plan view of the auxiliary grounding device of this invention in combination with a counterpoise. . 1... Steel tower legs, 2... Foundation, 3... Mounting plate, 4, 4', 4''... Bolt holes, 5... Grounding conductor, 6... Mounting terminal, 7... Connection body, 8... Ground conductor main body, 9... Small rod, 10... Connector, 11... Lower end of small rod, 12... Counterpoise.

Claims (1)

[Scope of utility model registration request] The counterpoises are attached to each tower pedestal of the steel tower and extend radially in a direction of approximately 45° relative to the counterpoises, which are attached to the above-mentioned tower pedestals and extend parallel to each other. a grounding conductor consisting of a covered wire that assists in grounding;
A grounding conductor main body made of a bare wire connected to the tip of each grounding conductor and extending in the same direction, and a sharp tip that is attached to the tip of each grounding conductor and driven into the ground almost perpendicularly. An auxiliary grounding device characterized by comprising a small rod shape.