JPH0142484B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a lightning arrester, and more particularly to an improvement of a zinc oxide type lightning arrester with improved explosion-proof performance.

[Technical background of the invention and its problems]

There have been various types of lightning arresters, one of which is a so-called zinc oxide type gear press arrester that uses a zinc oxide nonlinear resistor as a characteristic element that does not have a series gap.

This type of gear press arrester will be explained with reference to FIG.

In FIG. 1, reference numeral 1 denotes a zinc oxide-based nonlinear resistor formed by stacking a plurality of zinc oxide elements, and the nonlinear resistor 1 is supported in the longitudinal direction by an insulating rod 2. Moreover, the lower end portions are fixed to the lower terminal plate 3a and the upper terminal plate 3b. A characteristic element 4 is composed of the nonlinear resistor 1, the insulating rod 2, the lower terminal plate 3a, and the upper terminal plate 3b. This characteristic element 4 has a characteristic of exhibiting low resistance above a predetermined voltage value and exhibiting high resistance below it. This characteristic element 4 is then housed within the insulator tube 5. On the other hand, the lower end of this insulator tube 5 includes a lower pressure relief membrane 6a, a lower outlet conductor 7a, and a lower pressure relief chamber 8a.
The lower terminal plate 3a of the characteristic element 4 is supported by a support 11 in the sealed portion, and the lower outlet conductor 7a is electrically connected to the lower terminal plate 10a. Enables electricity to be applied. The upper end of the insulator 5 is sealed by an upper lid body 10b having an upper pressure relief membrane 6b, an upper outlet conductor 7b, an upper pressure relief chamber 8b, and an upper outlet 9b, and the upper characteristic element is attached to the sealed portion. 4 upper terminal board 3
b is supported by a spring 12, and the upper lead conductor 7b
This makes it possible to conduct electricity electrically.

In addition, in the above, the lower pressure evacuation chamber 8a and the upper pressure evacuation chamber 8
b serves to avoid the pressure of the gas released from the lower pressure relief membrane 6a and the upper pressure relief membrane 6b, and to guide the discharged gas to the lower outlet 9a and the upper outlet 9b which are opposed to each other.

In the lightning arrester configured as described above, the upper lead conductor 7b is connected to the power system, and the lower lead conductor 7a is grounded. When excessive surge energy occurs in the power system, it is guided to the characteristic element 4 through the conductive spring 12 from the upper outlet conductor 7b of the upper lid body 10b, and this characteristic element 4 is Since it has a characteristic of exhibiting a low resistance value above a voltage value and a high resistance value below a predetermined voltage value, it can absorb the surge energy. When this surge energy is absorbed, the characteristic element 4 is destroyed, the inside of the insulator tube 5 is short-circuited by the arc current, a ground fault occurs in the power system, and the pressure inside the insulator tube 5 increases. Therefore, the lightning arrester is required to have an explosion-proof structure so that the insulator tube 5 does not explode and scatter due to the increase in internal pressure.

In order to prevent explosion and scattering due to such a pressure increase inside the insulator tube 5, it is necessary to bring out the arc column inside the insulator tube 5 to the outside of the insulator tube 5 as quickly as possible. For this purpose, it is necessary that the lower and upper pressure shielding membranes 6a and 6b be destroyed by the pressure increase inside the insulator tube 5 or the heat caused by the arc as soon as possible after the short circuit is caused by the arc inside the insulator tube 5. be. In the lightning arrester shown in Figure 1,
The arc generation point is the lower pressure protection film 6b and the upper pressure protection film 6.
Since the distance is near point a, there is little time delay in destroying the lower and upper pressure shielding films 6b and 6a.

By the way, in the above-mentioned lightning arrester, the insulator tube 5 is
A certain length dimension is required to ensure the specified withstand voltage characteristics even when the external surface is contaminated, but in some cases, the characteristic element 4 for the insulated tube 5 is
The length dimension of may become smaller. In such a case, as shown in FIG.
A metal cylinder 13 is interposed between the characteristic elements 4 and 4.
It is conceivable that the lower lid body 8a is separated from the lower lid body 8a.

In the lightning arrester shown in FIG. 2, when excessive surge energy occurs in the power system, the characteristic element 4 is destroyed and an arc is generated. and the upper terminal plate 3b, and the lower lid body 8a
This occurs between the sealed portion and the lower terminal plate 3a. Therefore, the heat of the arc generated between the upper terminal plate 3b and the upper lid body 8b effectively acts on the upper pressure shielding film 6b since they are close to each other. The arc generated between the lower terminal plate 3a and the lower lid body 8a is
Since they are separated by a large distance, the resulting heat does not effectively act on the lower pressure relief membrane 6a, and the lower pressure relief membrane 6a
It takes a certain amount of time for a to be destroyed.
Further, after the lower pressure-protecting membrane 6a is destroyed, the speed of high-pressure, high-temperature ionized gas jetted out from the lower blow-off port 9a slows down, and the amount of jetted gas also decreases. Therefore, the upper air outlets 12 facing each other
b. The formation of an arc column between the lower outlet ports 12a was delayed, and the pressure increase inside the insulator tube 5 increased by the amount of delay, which caused a problem in terms of explosion-proof performance.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a lightning arrester with high explosion-proof performance that can provide effective explosion-proofing even when the length dimension of the insulator tube is larger than that of the characteristic elements. With the goal.

[Summary of the invention]

The lightning arrester according to the present invention has two characteristic elements consisting of a zinc oxide type nonlinear resistor housed inside the insulator tube.
dividing and connecting these with a conductive intermediate support, and sealing the upper and lower terminal plates of each of the divided characteristic elements at the top and bottom of the insulated tube;
The above object is achieved by arranging the upper pressure relief membrane and the lower pressure relief membrane formed on the lower lid body in close proximity to each other.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 3 is a block diagram showing one embodiment of a lightning arrester according to the present invention. In FIG. 3, the same parts as in FIGS. 1 and 2 are given the same reference numerals, and the explanation thereof will be omitted, and only the different parts will be explained here. 3 differs from FIGS. 1 and 2 in the configuration of the characteristic element 14 housed inside the insulator tube 5. In FIG. That is, this characteristic element 14 includes a first zinc oxide type nonlinear resistor 16a provided with a lower terminal plate 15a, and a second zinc oxide type nonlinear resistor 16b provided with an upper terminal plate 15b. , are connected by a cylindrical conductive intermediate support 17 made of metal or the like via intermediate terminal plates 15c1 and 15c2. And this characteristic element 14
are the lower terminal plate 15a and upper terminal plate 15b.
are configured to be close to the lower pressure avoidance membrane 6a and the upper pressure avoidance membrane 6b, respectively.

Next, the operation of the embodiment configured as described above will be explained. Now, when excessive surge energy occurs in the power system, it is guided from the upper outlet conductor 7b of the upper lid body 10b to the characteristic element 14 via the conductive spring 12, and the surge energy is thereby absorbed. Ru. In this case, each of the first and second zinc oxide nonlinear resistors 16a, 16b
If one of them is destroyed early, the limiting voltage of the lightning arrester will decrease, and an excessive surge current will be transmitted to the other zinc oxide nonlinear resistor 1, which is destroyed at the early stage.
6a or 16b, and the other nonlinear resistor 16a or 16b is also destroyed almost simultaneously.

At this time, the arc connects to the lower terminal plate 15a,
It is formed between the sealing part of the lower lid body 10a and between the upper terminal board 15b and the sealing part of the upper lid body 10b. Therefore, the arc generation point is the lower pressure-retaining film 6a.
Since the arc heat effectively acts on the lower pressure protection film 6a and the upper pressure protection film 6b, there is no time delay in destroying them. Therefore, the high-temperature, high-pressure ionized gas generated inside the insulator tube 5 does not have a slow blowout speed or a small blowout amount, and the lower blowout port 9a and the upper blowout port 9a are opposite to each other. It flows out from the outlet 9b. Therefore, since the arc column is formed without any delay between the lower outlet 9a and the upper outlet 9b, the increase in internal pressure of the insulator tube 5 is reduced accordingly, and the original explosion-proof performance can be effectively exhibited. It becomes possible.

〔Effect of the invention〕

As described above, according to the present invention, the characteristic element consisting of a zinc oxide-based nonlinear resistor is divided into two parts and connected by a conductive intermediate support, and the arc generation position is set by the pressure relief membranes at the upper and lower ends of the porcelain tube. Since the structure is close to that of the insulator, even if the length of the insulator tube is larger than that of the characteristic element, it is possible to create a lightning arrester with extremely high explosion-proof performance that can provide effective explosion-proofing. Can be provided.

[Brief explanation of drawings]

1 and 2 are block diagrams showing a conventional lightning arrester, and FIG. 3 is a block diagram showing an embodiment of the lightning arrester according to the present invention. 1...Zinc oxide nonlinear resistor, 2...Insulating material,
3a...lower terminal board, 3b...upper terminal board, 4...
...Characteristic elements, 5...Insulator pipe, 6a...Lower pressure relief membrane,
6b... Upper pressure relief membrane, 7a... Lower lead-out conductor,
7b... Upper outlet conductor, 8a... Lower pressure escape chamber,
8b... Upper pressure relief chamber, 9a... Lower outlet, 9
b...Upper outlet, 10a...Lower lid, 10
b... Upper lid body, 11... Support body, 12... Spring, 13... Metal cylinder, 14... Characteristic element, 15
a...Lower terminal board, 15a...Lower terminal board, 15
b... Upper terminal plate, 15c1, 15c2... Intermediate terminal plate, 16a... First zinc oxide nonlinear resistor, 16b... Second zinc oxide nonlinear resistor,
17... Conductive intermediate support.

Claims (1)

[Claims] 1. A zinc oxide-based non-linear resistor is used as a characteristic element housed inside the insulator tube, and an upper lid body that seals the upper opening of the insulator tube has an upper pressure relief membrane and an upper outlet conductor; In a lightning arrester which has a lower pressure protection film and a lower outlet conductor in the lower lid body that seals the lower opening, the above characteristic elements are obtained by dividing the zinc oxide non-linear resistor into two parts and 1. One end of each of the second zinc oxide-based nonlinear resistors is disposed close to the upper pressure relief membrane and the lower pressure relief membrane, and the other ends are connected by a conductive intermediate support. A lightning arrester characterized by: