JPH06283248A - Lightning arrester - Google Patents

Abstract

PURPOSE:To improve response speed to outside surge and prevent occurrence of insulation failure between carbon trigger wires due to sputtering at the time of discharge of a lightning arrester tube by installing groups of carbon trigger wires reciprocally at a prescribed distance while setting them face to face. CONSTITUTION:Groups of carbon trigger wires, which consist of a plurality of carbon trigger wires 12 in parallel and gathered closely and which are set in a ceramic cylindrical body 10 from one end to the other end of the cylindrical body 10 wherein an earth electrode and a line electrode are attached to one end and to the other end, respectively. Consequently, since the number of the carbon trigger wires of the same electrode can be increased, the response speed of an arrester tube can be improved. Also, the distance between groups of the carbon trigger wires of different electrodes can be set wide and thus the occurrence of insulating failure among carbon trigger wires due to sputtering at the time of discharge of the arrester tube is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightning arrester, and more particularly to a structure of a carbon trigger wire provided on a ceramic cylinder of the lightning arrester.

[0002]

2. Description of the Related Art A lightning arrester is constructed by brazing and sealing an earth electrode and a line electrode to the end face of a ceramic cylinder, and also an inert gas such as argon gas is sealed inside. When a surge enters, it discharges between the line electrode and the ground electrode and acts to protect electrical equipment from external surges. Therefore, in order for the lightning arrester to exert a reliable protection function, it is necessary to reliably respond to an external surge of a predetermined voltage or more to discharge, and a standard such as a discharge start voltage is defined.

FIG. 4 shows a ceramic cylinder 1 used for a lightning arrester.
Indicates 0. The ceramic cylindrical body 10 is formed of a ceramic body into a cylindrical shape as shown in the drawing, and is provided with a carbon trigger wire 12 on its inner wall. In general, a lightning arrester is provided with a carbon trigger wire in order to speed up the response speed to a surge and to stabilize the discharge starting voltage of the lightning arrester.

The carbon trigger wire 12 is provided by drawing from the end surface of the ceramic cylindrical body 10 to the end surface on the opposite side, as shown in the drawing, and before reaching the end surface on the opposite side.
Has stopped the tip of. FIG. 5 shows a state in which the ceramic cylindrical body 10 is expanded. 5A shows an example in which four carbon trigger wires 12 are provided, and FIG. 5B shows an example in which eight carbon trigger wires 12 are provided. The carbon trigger wires 12 are arranged at regular intervals as shown in the figure. It is formed by pulling it out from the end face. This carbon trigger wire 12 is for improving the response speed to the external surge by making it easier for discharge to occur between the electrode and the electrode when the external surge enters the arrester. Normally, when a carbon trigger wire is provided, it is formed on the inner surface of the ceramic cylindrical body 10 by drawing a line with a pencil.

[0005]

By the way, it is effective to increase the number of carbon trigger wires in order to increase the response speed to the surge applied to the lightning arrester.
As shown in, as the number of carbon trigger wires increases, the distance between adjacent carbon trigger wires decreases,
As a result, there is a problem that insulation failure is likely to occur between the carbon trigger wires due to the influence of sputtering when the arrester discharges. Since the electrode material is sputtered and adheres to the inner wall of the ceramic cylinder when the arrester discharges, the narrower the distance between the carbon trigger wires, the worse the insulation between the carbon trigger wires.

Insulation defects that occur between the carbon trigger wires due to discharge of the arrester affect the durability of the arrester, and those that easily cause insulation defects between the carbon trigger wires have low durability. . According to the present invention, when the carbon trigger wire is provided on the arrester in this way, it is possible to suppress the influence of the sputtering caused by the discharge of the arrester and maintain the suitable insulation between the carbon trigger wires, and thereby the sufficient durability is provided. You can get sex
An object of the present invention is to provide a lightning arrester having excellent characteristics of fast response speed.

[0007]

The present invention has the following constitution in order to achieve the above object. That is, a plurality of carbon trigger wires are arranged in parallel and close to each other on the inner surface of the ceramic cylinder whose one end is sealed with a ground electrode and the other end is sealed with a line electrode. It is characterized in that the provided carbon trigger wire groups are alternately opposed to each other with a predetermined interval.

[0008]

By forming a carbon trigger wire group by drawing a plurality of carbon trigger wires close to each other, the number of carbon trigger wires of the same electrode can be increased, thereby improving the response speed of the arrester. it can. Furthermore, since the spacing between the carbon trigger wire groups of different electrodes can be widened, it is possible to effectively prevent the occurrence of insulation failure between the carbon trigger wires due to sputtering when the arrester discharges.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is an explanatory view showing a state in which a ceramic cylindrical portion is developed by a lightning arrester according to the present invention.
Similarly to the conventional example, the arrester according to the present invention is also constructed by alternately drawing the carbon trigger wires 12 from the opposite end faces of the ceramic cylindrical body. However, in the present invention, a plurality of carbon trigger wires 12 are arranged in parallel and close to each other. It is characterized in that the carbon trigger wire groups drawn by the above method are alternately provided from the respective end surfaces facing each other in the circumferential direction.

The embodiment shown in FIG. 1 (a) is an example in which a carbon trigger wire group is formed of two carbon trigger wires 12 each, and four carbon trigger wire groups are provided. FIG. 1B is an example in which a carbon trigger wire group is formed by three carbon trigger wires 12. FIGS. 1 (c) and 1 (d) are examples formed by two carbon trigger wire groups, FIG. 1 (c) is an example formed by four carbon trigger wires 12, and FIG. This is an example formed by the carbon trigger wire 12 of the book.

As shown in FIG. 1, if a carbon trigger wire group is formed by closely arranging carbon trigger wires, the number of carbon trigger wires provided on the inner wall surface of the ceramic cylinder 10 can be increased and the carbon trigger wire can be increased. Since the space between the groups of wires can be widened, it is possible to effectively prevent the occurrence of insulation failure between the carbon trigger wires due to sputtering when the arrester is discharged.

FIGS. 2 and 3 show the results of an actual discharge test conducted with an arrester of the type shown in FIG. 1 (a) provided with two carbon trigger wires. Figure 2 is based on a 5 amp alternating current test (5 times / 1 second) at 3 minute intervals, DC (2KV / s)
The voltage is the discharge start voltage at impulse voltage (500 V / μs). In the figure, DC is a DC voltage test, IM
P indicates the result of the impulse test. The maximum value, the minimum value and the average value of the discharge start voltage are shown respectively. The left side of the figure shows the measured value at the start of the test, and the right side shows the measured value at the end of the life test. Fig. 3 shows the surge current waveform of 8 / 20μs, 5KA (± 5
The results of measuring the discharge start voltage with the DC voltage and the impulse voltage when the voltage is applied 10 times / total 10 times) are shown. Similar to the above example, the measured values at the start of the test and at the end of the life test are shown.

The above-mentioned discharge test is the most strict test as the standard test of the arrester, but since the test result maintains performance almost the same as at the start of the test even at the end of the test, the arrester is discharged. It maintains sufficient insulation between the carbon trigger wires, and maintains a suitable discharge initiation characteristic even for impulse tests showing the response speed of the arrester. It was possible to obtain a good test result that no deterioration occurred.

Since the lightning arrester of this embodiment is formed by pulling a plurality of carbon trigger wires close to the inner wall surface of the ceramic cylindrical body, a carbon trigger wire is drawn in comparison with the conventional lightning arrester. Although it takes time, it has the advantage that the conventional device can be used as it is, and it has an excellent performance that can not be obtained with conventional products that can maintain the insulation property between carbon trigger wires and improve the response speed. Obtainable. In the above description, a two-pole lightning arrester has been described as an example, but it can be similarly applied to a three-pole lightning arrester. Further, the number of carbon trigger wires provided in the carbon trigger wire group, the number of carbon trigger wire groups, and the like may be appropriately set according to the product standard such as the discharge start voltage.

[0015]

As described above, according to the lightning arrester of the present invention, the response speed to an external surge can be improved, and the insulation failure between the carbon trigger wires can be prevented by the sputtering when the lightning arrester discharges. It is possible to effectively prevent the occurrence of lightning, and it is possible to obtain a remarkable effect such as to obtain a lightning arrester having excellent characteristics.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a developed ceramic cylinder body of a lightning arrester.

FIG. 2 is a graph showing the results of a discharge durability test of an arrester by applying an AC voltage.

FIG. 3 is a graph showing the results of a discharge durability test of a lightning arrester by applying a current surge.

FIG. 4 is an explanatory diagram showing a configuration of a ceramic cylindrical body of the arrester.

FIG. 5 is an explanatory view showing a developed ceramic tube body of a lightning arrester of a conventional example.

[Explanation of symbols]

 10 Ceramic cylinder 12 Carbon trigger wire

Claims (1)

[Claims] 1. A plurality of carbon trigger wires are arranged in parallel with each other from the one end side to the other end side of the ceramic cylindrical body on which the ground electrode is sealed at one end and the line electrode is sealed at the other end. A lightning arrester characterized in that a group of carbon trigger wires provided close to each other are alternately opposed to each other at a predetermined interval.