JPH06119840A - Lightning protection insulator set - Google Patents

Abstract

PURPOSE:To lessen allotted responsibility per phase at the time of a lightning stroke and also reduce size and cost, by making control voltage, generated in a current limiting element when rated current at the time of a lightning stroke is flowed, have a given value. CONSTITUTION:When thunderbolt surge current is flowed to a transmission line 7 due to a lightning stroke, the current is flushed over to an earth side discharge electrode 23 via a series gap G2 from a wire clamp 8 and a charge side discharge electrode 13. Moreover the current is flowed to a current limiting element 17 from an electrode fitting 18, and is flowed in a supporting arm 2 via an electrode fitting 19 and a fitting adapter 14 on an earth side to be discharged to the ground from a tower body. In this case, limiting voltage, the voltage drop part of the element 17 generated by thunderbolt surge current, is made higher than the 50% flush-over voltage value of the gap G2 and lower than the 50% flush-over voltage value of a horn gap G1. Consequently, the thunderbolt surge current is diverted to a near lightning protection insulator set without the flush-over of the gap G1, reducing size and cost by lessening the withstand quantity of one phase of a lightning protection insulator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention, when a normal lightning surge current flows through a transmission line, discharges it rapidly to the ground,
The present invention relates to a lightning arrester device capable of suppressing and blocking a subsequent flow that occurs thereafter to prevent a ground fault accident, and more particularly to a gap type lightning arrester device.

[0002]

2. Description of the Related Art Conventionally, in order to reduce accidents due to lightning, a lightning arrester having a current limiting element having a non-linear voltage-current characteristic between a ground side and a voltage applying side has been widely used. In the case of this lightning protection insulator, the current limiting element mainly made of zinc oxide discharges the lightning surge current at the time of a lightning stroke to the ground due to its characteristics, and also suppresses and interrupts the subsequent current to prevent a ground fault accident.

There are a gap type lightning arrestor and a gapless lightning arrester in this lightning arrestor. In the case of a gapless lightning insulator, since there are no gaps and they operate instantly, a plurality of lightning arrestors operate for one stroke. Therefore, the diversion effect is large, the burden of responsibility per phase is small, and the size of the lightning protection insulator itself can be made small. However,
If it breaks down once, a permanent ground fault will occur and it will not be possible to retransmit power. For this reason, in recent years, the gap type lightning arrestor is often used. Even if this gap type lightning arrestor fails, the gap keeps the insulation, and if it is turned on again, power can be transmitted.

[0004]

However, since the above-mentioned gap type lightning arrestor has a series gap,
Discharge delay occurs and the voltage at which flashover starts is high. In the voltage-current characteristics shown in FIG. 3, the limiting voltage of the conventional lightning arrester is lower than the 50% flashover voltage of the series gap, as shown in (b), and the lightning surge current is temporarily applied to the specific lightning insulator. When it flows, it is rarely distributed to other lightning protection insulators. That is, the number of movements of the lightning protection insulator during a lightning stroke is small. Therefore, it is necessary to use a large-diameter current limiting element with a large capacity for lightning strikes with a long duration and multiple lightning strikes, as the duty of energy sharing for each phase of the lightning arrestor is strict. there were.

The present invention has been made by paying attention to the problems existing in such a conventional technique. The purpose of the present invention is to reduce the burden of responsibility for each phase at the time of lightning stroke, to reduce the size and An object is to provide a lightning protection insulator device that can reduce costs.

[0006]

In order to achieve the above object, in the present invention, a horn gap is formed by arc horns on the grounding side and the charging side, and a supporting insulator is hung from a supporting arm of a steel tower. The voltage-current characteristic has a built-in non-linear current limiting element, and has a lightning arrester suspended on the support arm, and the discharge electrode is fixed to the charging side of the support insulator, In a lightning arrester device in which a ground side discharge electrode is electrically connected to the voltage applying side and a series gap is formed between the ground side discharge electrode and the voltage applying side discharge electrode, the rated current at the time of lightning strike The gist is that the limiting voltage that sometimes occurs in the current limiting element is greater than the 50% flashover voltage value of the series gap and smaller than the 50% flashover voltage value of the horn gap.

[0007]

With the above structure, the lightning surge current generated at the time of a lightning strike flashes over from the discharge electrode on the charging insulator side of the supporting insulator to the discharge electrode on the grounding side, and from the steel tower to the ground via the current limiting element of the lightning insulator and the supporting arm. Is discharged. At this time, the limiting voltage, which is the voltage drop of the current limiting element caused by the lightning surge current, is larger than the 50% flashover voltage value of the series gap and smaller than the 50% flashover voltage value of the horn gap. Therefore, the lightning surge current is shunted to the adjacent lightning arrester device without flashing over the horn gap.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a lightning protection insulator device mounted on a suspension type support insulator will be described below with reference to the drawings.

The connecting metal fitting 1 is fixed to the tip of the support arm 2 of the steel tower, and the suspension insulator string 3 is supported by the U-clevis link 4 and the upper horn mounting metal 5 so as to be swingable in the line direction and the orthogonal direction. ing. Suspension insulator series 3 is a suspension insulator 6
Are connected in series to form a support insulator. An electric wire clamp 8 for gripping the power transmission line 7 is supported by a lower horn mounting bracket 9 at the lower end of the suspension insulator string 3 via a connecting link 10. Arc horns 11 and 12 are attached to the lower and upper horn mounting brackets 9 and 5 for suppressing damage to the surface flashover of the suspension insulator series 3, and a horn gap G1 is formed between them. Also, the discharge electrode 1 on the charging side
3 is fixed to the horn mounting bracket 9 separately from the arc horn 11.

The mounting adapter 14 is fixed to the tip of the support arm 2 by a bolt 15, and a lightning arrester 16 is provided on the lower surface of the tip of the adapter 14 and a ground side electrode fitting 19 described later.
It is fixed by hanging.

The lightning protection insulator 16 is provided with an insulating cylinder (not shown) formed in a cylindrical shape from a tension-resistant material such as FRP, and the current limiting element 17 is housed in series inside the insulating cylinder. Cap-shaped electrode fittings 18 and 19 on the charging side and the grounding side are fitted to both ends of the insulating cylinder, and a rubber mold 20 is integrally formed on the outer periphery of the insulating cylinder. A rubber mold 20 is attached to the electrode fittings 18 and 19 on the grounding side and the charging side.
Arc ring 2 to reduce damage when the surface flashes
1 and 22 are mounted respectively. A discharge electrode 23 on the grounding side is fixed to an electrode metal fitting 18 on the charging side located at the lower end of the lightning protection insulator 16, and a series gap G2 is formed between the discharge electrode 23 on the charging side and the discharge electrode 13 on the charging side. is doing.

The current limiting element 17 is mainly made of zinc oxide whose voltage-current characteristic is non-linear. This current limiting element 1
The voltage-current characteristics of No. 7 are shown in FIG. Here, (a) is the voltage-current characteristic of the current limiting element 17 of the present embodiment, and (b) is the characteristic of the current limiting element of the conventional example. Further, (c) is a voltage-time characteristic in a support insulator having an arc horn interval of about 4000 mm, and (d) is a series gap G of the lightning protection insulator 16.
2 is a voltage-time characteristic. As can be seen from this characteristic diagram, the limiting voltage V _Ir of the current limiting element 17 is about 1.5 times that of the conventional voltage. This characteristic is realized by changing the resistance value of the current limiting element 17, that is, by changing the composition or increasing the number of series connection of the current limiting elements. On the other hand, the limiting voltage V _Ir generated when the rated current Ir flows is larger than the 50% flashover voltage value of the series gap G2 and smaller than the 50% flashover voltage value of the horn gap G1.

Next, the operation of the embodiment configured as described above will be described. Now, as shown in FIG. 2, when a lightning surge current flows through the power transmission line 7 due to a lightning stroke, this current flows from the wire clamp 8 and the discharge side discharge electrode 13 to the series gap G.
The discharge electrode 23 is flashed over to the ground side discharge electrode 23 via the line 2. Further, it flows from the electrode metal fitting 18 to the current limiting element 17, then flows to the support arm 2 via the electrode metal fitting 19 on the ground side and the mounting adapter 14, and is discharged from the tower body 24 to the ground. In the transient state in which the lightning surge current flows, after the elapse of a predetermined time, the electric potential of the power transmission line 7 of the second tower body 24a is the voltage −
The voltage is raised to the limit voltage V _Ir shown in the current characteristic. Then, after a slight delay, the limit voltage V _Ir is transmitted through the power transmission line 7 and is adjacent to the first tower body 24b and the third tower body 24c.
Will be applied to the series gap G2. However, since the limit voltage V _Ir is larger than the 50% flashover voltage value of the series gap G2, the series gap G2 is flashed over and the lightning surge current is shunted. To be discharged. On the other hand, since the limit voltage V _Ir is smaller than the flashover voltage value of the horn gap G1, there is no flashover between the arc horns 11 and 12 of the supporting insulator.

FIG. 4 shows the number (e) of lightning protection insulators that operate during a lightning stroke, the processing energy (f) at that time, and the maximum discharge current (g). According to this characteristic diagram, at the time of the lightning strike of the lightning protection insulator 16 of this embodiment, the three lightning protection insulators 16 operate, and the processing energy at that time is reduced to 2/3 as compared with the conventional case. The maximum discharge current is also reduced to 2/3.

As described above, in the lightning protection insulator device of this embodiment, a plurality of lightning protection insulators 16 can be operated at the time of a lightning stroke, and the maximum discharge current can be reduced. Therefore, the withstand voltage of one phase of the lightning protection insulator 16 is reduced. The size and cost can be reduced.

The present invention is not limited to the configuration of the above-mentioned embodiment, and for example, it is applied to a voltage class other than that of the embodiment, is applied to a suspension type lightning arrester, and the like, and deviates from the spirit of the present invention. It is also possible to embody it by arbitrarily changing it within the range that does not.

[0017]

According to the present invention, the limiting voltage generated when the rated current at the time of lightning strikes is 50% of the series gap.
Greater than the flashover voltage value and 50% of the horn gap
Since it is smaller than the flashover voltage value, the shunt effect can be increased despite the gap type. Therefore, it is possible to reduce the withstand voltage of one phase of the lightning protection insulator and to reduce the size and cost.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a lightning protection insulator device embodying the present invention.

FIG. 2 is an explanatory diagram showing an operating state of a plurality of lightning protection insulator devices.

FIG. 3 is a characteristic diagram showing voltage-current characteristics of a current limiting element.

FIG. 4 is a characteristic diagram showing the number of operating lightning insulators, processing energy, and maximum discharge current during a lightning strike.

[Explanation of symbols]

2 support arms, 3 suspension insulators which are support insulators, 7
Power transmission line, 11 charging side arc horn, 12 grounding side arc horn, 13 charging side discharge electrode, 17 current limiting element, 2
3 ground side discharge electrode, 24 tower body, G1 horn gap, G2 series gap.

Claims (1)

[Claims] 1. A grounding-side and power-charging side arc horn forms a horn gap, and a built-in support insulator suspended from a support arm of a tower and a current limiting element having a non-linear voltage-current characteristic are provided. It has a lightning arrester suspended on the support arm, the discharge electrode is fixed to the charging side of the support insulator, the ground side discharge electrode is electrically connected to the charging side of the lightning insulator, the In a lightning arrester device in which a series gap is formed between the ground side discharge electrode and the charging side discharge electrode, the limiting voltage generated in the current limiting element when the rated current at the time of lightning strikes is A lightning arrester device characterized by being larger than a 50% flashover voltage value and smaller than a 50% flashover voltage value of a horn gap.