JPH0538031A - Structure for suppressing potential rise of steel tower - Google Patents

Abstract

PURPOSE:To suppress the potential rise at the top of a steel tower, to reduce the probability of the occurrence of ground faults and to make a lightening arrester smaller and light in weight by suppressing energy acting on the lightening arrester even though a large surge current enters into the lightening arrester. CONSTITUTION:A covered lead wire 6 is connected from the top of the main body of a steel tower 1 to the ground G, and a supporting arm 2 of the steel tower is connected to the covered lead wire 6 with a covered lead wire 8 for short-circuiting purpose.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention suppresses an increase in the electric potential of a steel tower when a steel tower or an overhead ground wire is struck by lightning, thereby preventing a ground fault accident. It is about structure.

[0002]

2. Description of the Related Art Generally, when a steel tower or an overhead ground wire is struck by lightning, the electric potential of the steel tower rises and the electric potential of the tip of a supporting arm of the steel tower rises. Then, the potential difference between the transmission line supported by the tip of the support arm via the support insulator and the support arm increases, and the arc horns on the ground side and the charging side mounted on both ends of the support insulator. Then the flashover occurs and a ground fault occurs. In order to solve this, conventionally, as shown in FIG. 9, a ground wire 21 is connected to the lower end portion of the tower main body 1 to suppress the potential rise of the tower. Also, the tower main body 1
When the grounding resistance of the grounding wire 21 of the base portion of 1 exceeds the target value, the buried ground wire 22 may be provided.

Further, a shunt line 23 is connected to an overhead ground wire 5 located at the top of the tower 1, and a power transmission line 4 mounted on a support arm 2 of the tower via a support insulator 3 is bypassed to be grounded to the ground. A structure for suppressing potential rise is also considered.

[0004]

However, the above-described potential suppressing structure by the ground wire 21 or the buried ground wire 22 is
Both of them can suppress the electric potential rise of the steel tower to some extent, but they are not sufficient and there is a problem that the effect of reducing the ground fault cannot be satisfied.

Further, although the potential suppressing structure by the shunt line 23 can suppress the potential of the tower, the shunt line 23 is installed outside the tower, so that the installation space is increased and a surge occurs during a lightning strike. Since the electric current flows through the shunt line 23 arranged outside the steel tower, there is a problem in safety.

Further, a lightning arrester device for power transmission is also mounted on the support arm 2 of the steel tower. However, when a lightning surge current having a large amount of electric charges enters, the processing energy at the time of operation becomes large and a large lightning arrester device is provided. There was also a problem that was needed.

An object of the present invention is to provide a structure for suppressing the increase in the electric potential of the steel tower which can suppress the increase in the electric potential of the steel tower due to a lightning stroke.

[0008]

In order to achieve the above object, the invention according to claim 1 connects a metal conductor to the ground between the tower top of the tower and the ground, and supports the tower and the metal conductor. The means of connecting the middle part of the with a short-circuit conductor.

The invention according to claim 2 has a means of connecting a capacitor in parallel between the ground and the connection point of the lowermost short-circuit conductor and the metal conductor in claim 1. The invention according to claim 3 provides a power cable having a ground shield coating for the metal conductor between the ground and the connection point of the lowermost short-circuit conductor and the metal conductor in claim 1. ing.

According to a fourth aspect of the present invention, in the second aspect,
A means of connecting a resistance element whose voltage-current characteristic is non-linear to the capacitor in parallel is adopted. According to a fifth aspect of the present invention, in any one of the first to third aspects, the metal conductor and the short-circuit conductor are formed in a pipe shape or a stitch pipe shape.

Further, the invention according to claim 6 is defined by claims 1 to 1.
3. In any one of 3 above, the metal conductor and the short-circuit conductor are formed by plating a good conductor such as copper, zinc, aluminum or the like or an alloy thereof on the outer periphery of a reinforcing core material such as steel or iron by metallikon, cast coating or coating plating. The means to do so.

[0012]

According to the invention described in claim 1, by taking the above means, when a surge current due to a lightning strike enters the overhead ground line or the top of the tower, it is shunted to the main body of the tower and also flows to the metal conductor to be grounded. Therefore, the increase in the electric potential of the steel tower is significantly suppressed. When the rise in the electric potential of the steel tower is suppressed in this way, the lightning surge potential difference between the support arm and the power transmission line is also suppressed, and it is possible to prevent flashover between them and prevent ground faults. Further, since the electric potential rise of the steel tower is suppressed, it is possible to reduce the processing energy of the surge current due to the lightning strike when the lightning protection insulator device is installed,
The lightning protection device can be downsized.

Further, according to the second aspect of the invention, when the lightning surge current enters the metal conductor, the current is shunted to the capacitor and temporarily stored, so that the potential peak at the top of the tower can be lowered. it can.

According to the third aspect of the invention, when a lightning surge current enters the metal conductor, the current is shunted by the capacitor function between the power cable and the ground shield coating and temporarily stored. The potential peak at the tower top can be lowered.

According to the fourth aspect of the present invention, the potential peak is reduced by charging the capacitor, but the charge is given by the electrostatic capacitance × voltage, and when the saturated charge amount is reached, the reduction effect is lost. Since the charged electric charge of the capacitor is absorbed as Joule energy and the overvoltage that cannot be withstood to the capacitor is suppressed, the electric potential at the top of the tower can be suppressed efficiently.

According to the fifth aspect of the invention, since the metal conductor and the short-circuit conductor are formed in a pipe shape or a knitted pipe shape, the width of the lightning surge current flowing through the metal conductor becomes large, and the current is quickly grounded. The potential rise can be efficiently suppressed.

Further, in the invention according to claim 6, a metal conductor or a short-circuit conductor is plated on the outer periphery of a reinforcing core material such as steel or iron with copper, zinc, aluminum or an alloy thereof by metallikon, cast coating or coating plating. Since it is formed, the width of the lightning surge current flowing through the metal conductor becomes large, and the current can be quickly grounded to efficiently suppress the potential rise.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, upper and lower three-stage support arms 2 are horizontally supported on the upper part of the tower main body 1 in a symmetrical manner. Power transmission lines 4 are respectively supported by these support arms 2 via support insulators 3. or,
An overhead ground wire 5 is supported on the tower top of the steel tower body 1.

A covered lead wire 6 as a metal conductor for grounding the overhead ground wire 5 to the ground G is vertically arranged at the center of the tower main body 1, and the ground wire is provided at the lower end of the lead wire 6. A ground rod 7 for grounding is connected to G. The vicinity of the base end of each support arm 2 and the coated lead wire 6 are electrically connected by a coated lead wire 8 as a short-circuit conductor for short-circuiting the support arm 2 and the coated lead wire 6. As shown in FIG. 2, the coated lead wire 6 and the short-circuited coated lead wire 8 are connected by a connection terminal 9.

Usually, the surge current caused by lightning strikes directly into the overhead ground wire 5 provided on the top of the tower main body 1 or the top of the main body 1. This surge current is grounded from the ground rod 7 to the ground G through the coated lead wire 6. Therefore, the rise of the electric potentials of the tower main body 1 and the support arm 2 is suppressed, and the probability that the lightning surge current enters the transmission line 4 due to the flashover of the support insulator 3 is reduced. The probability of occurrence is also reduced, and the probability of occurrence of a ground fault accident is reduced.

As shown in FIG. 3, when the potential of the tower top portion due to the lightning surge current is compared with the conventional ground wire system, it is understood that the embodiment of the present invention is significantly lowered. Further, when the lightning protection insulator device is mounted in the vicinity of the support insulator 3, the potential increase of the tower main body 1 and the support arm 2 is suppressed. Therefore, when a surge current having a large processing energy enters, the potential increase thereof occurs. Therefore, it is possible to design the capacity of the lightning protection insulator device to be small and to downsize it.

Next, another embodiment of the present invention will be described with reference to FIGS. In this embodiment, a capacitor C is connected in parallel in the middle of the coated lead wire 6.
According to this embodiment, when a lightning surge current enters the coated lead wire 6, the current is shunted to the capacitor C and temporarily stored, so that the two-dot chain line in FIG. As shown by, the potential peak at the tower top can be further lowered.

Further, another embodiment of the present invention will be described with reference to FIGS. In this embodiment, in addition to the structure of the embodiment shown in FIG. 5, a resistor element 11 having a non-linear voltage-current characteristic is connected in parallel to the circuit of the capacitor C. In this embodiment, although the potential peak is reduced by charging the capacitor C, the charging charge Q is given by (electrostatic capacitance × voltage), and when the saturated charge amount is reached, the reduction effect is lost, so that the capacitor Since the charged electric charge is absorbed as Joule energy by the resistance element 11 and the overvoltage which cannot be tolerated is further applied to the capacitor, it can be reduced as shown by the chain double-dashed line in FIG. It can be efficiently suppressed.

Next, another example of the coated lead wire 6 will be described with reference to FIGS. Lead wire 6 shown in FIG.
Is formed in a knitted pipe shape, the width in which the lightning surge current flows is increased, the lightning surge current is easily grounded, and the potential rise can be efficiently suppressed.

The lead wire 6 shown in FIG. 7 is obtained by forming a metal conductor 14 on the outer periphery of a reinforcing core material 13 such as steel or iron by metallikon, casting coating or coating plating of copper, zinc, aluminum or an alloy thereof. Is. Also in this embodiment, the width of the lightning surge current increases, the lightning surge current is easily grounded, and the potential rise can be efficiently suppressed.

In another example shown in FIG. 8, the outer periphery of the lead wire 6 is covered with a ground shield coating 15 to provide a function as a capacitor between the core wire 6a of the lead wire 6 and the shield coating 15. In this embodiment as well, as in the case where the capacitor C is used, since it is shunted to the ground shield coating 15 and temporarily stored, the potential peak at the tower top can be lowered.

The present invention is not limited to the above embodiment, and for example, the lead wire 8 for short-circuiting the support arm 2 is used.
It is also possible to embody it by arbitrarily changing the connection position of (1) to an arbitrary position between the front end portion and the base end portion of the support arm 2 without departing from the gist of the present invention.

[0028]

As described in detail above, the invention according to claim 1 can suppress the rise in the electric potential at the top of the tower, reduce the probability of occurrence of a ground fault, and install a lightning arrester. In this case, there is an effect that even if a surge current with large processing energy enters, the energy acting on the lightning arrester can be suppressed and the lightning arrester can be made smaller and lighter.

According to the second aspect of the invention, when the lightning surge current enters the metal conductor, the current is shunted to the capacitor and temporarily stored, so that the potential peak at the top of the tower can be lowered. it can.

According to the third aspect of the invention, when a lightning surge current enters the metal conductor, the current is shunted by the capacitor function between the power cable and the ground shield coating and temporarily stored. The potential peak at the tower top can be lowered.

Further, in the invention according to the fourth aspect, since the charged electric charge of the capacitor is absorbed as Joule energy by the resistance element and further the overvoltage which cannot be endured to the capacitor is suppressed, the potential at the top of the tower is efficiently increased. Can be suppressed.

Further, in each of the fifth and sixth aspects of the invention, the width of the lightning surge current flowing through the metal conductor becomes large, and the current can be quickly grounded to effectively suppress the potential rise.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a connection portion between a coated lead wire and a short-circuited lead wire.

FIG. 3 is a graph showing the relationship between time and the electric potential at the top of a steel tower.

FIG. 4 is a front view showing another embodiment of the present invention.

FIG. 5 is a front view showing another embodiment of the present invention.

FIG. 6 is a perspective view showing another example of the metal conductor.

FIG. 7 is a perspective view showing another example of the metal conductor.

FIG. 8 is a perspective view showing another example of the metal conductor.

FIG. 9 is a front view showing a conventional example.

[Explanation of symbols]

1 steel tower body, 2 support arm, 5 overhead ground wire, 6 coated lead wire as metal conductor, 7 ground rod, 8 coated lead wire as short-circuit conductor.

Claims (6)

[Claims] 1. A potential increase control of a steel tower, wherein a metal conductor is grounded between the top of the steel tower and the ground, and a support arm of the steel tower and an intermediate portion of the metal conductor are connected by a short-circuit conductor. Construction. 2. The structure for suppressing a potential increase in a steel tower according to claim 1, wherein a capacitor is connected in parallel between the ground and the connection point between the lowermost short-circuit conductor and the metal conductor. 3. The electric potential of a tower according to claim 1, wherein the metal conductor between the ground and the connection point of the lowermost short-circuit conductor and the metal conductor is a power cable having a ground shield coating. Rise control structure. 4. The structure of claim 2, wherein a resistance element having a non-linear voltage-current characteristic is connected in parallel to the capacitor. 5. The method according to any one of claims 1 to 3,
A structure for suppressing a potential increase in a steel tower, wherein the metal conductor and the short-circuit conductor are formed in a pipe shape or a knitted pipe shape. 6. The method according to any one of claims 1 to 3,
The metal conductor, the short-circuit conductor, steel, steel, iron or the like on the outer periphery of the reinforcing core, copper, zinc, good conductor such as aluminum or their alloys formed by metallikon, cast coating or coating plating Potential rise suppression structure.