JPS59726Y2 - Lightning arrester for enclosed switchgear - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to improvements in lightning arresters for enclosed switchgear.

Conventional sealed switchgear lightning arresters whose characteristic element is an element consisting of a non-linear or linear resistor whose main component is a metal oxide have a characteristic element consisting of a plurality of stacked elements 1, as shown in Figure 1. It is housed in an insulating cylinder 4 via a spring 2 and a pipe spacer 3 (not shown), and an arc discharge port 6 and a punched part 7a as shown in FIGS. A shield 7 etc. with a
It is also housed in an external tank 9.

If an abnormally excessive current flows through such a lightning arrester due to some kind of accident, an arc will occur inside the arrester, causing a sudden rise in internal pressure, and this arc will eject from the discharge port in the top cover and from the punched part in the shield. Although it further ejects into the external tank, the ejected debris fills the external tank, and the external tank has an explosion-proof structure to prevent damage.

Since the external tank is still intact even after such an arc short circuit, it is unclear whether it is normal at first glance or whether the explosion has already been completed and it is no longer usable, and there are points that need to be improved in terms of maintenance management.

In addition, the internal pressure rise due to the arc during this explosion is large, and it is difficult to handle the energy by simply shorting the arc with the conventional structure. It is necessary to consume the abnormal arc energy as much as possible, and there are points that need to be improved.

The purpose of this invention was made in view of the above points, and it is an excellent maintenance management method that can determine whether a lightning arrester has already exploded due to an accident and has become unusable.
Another object of the present invention is to provide a safe and reliable sealed type switchgear lightning arrester that prevents damage to an external tank by consuming arc energy during an internal explosion through a metal short circuit.

Hereinafter, the present invention will be explained with reference to the embodiments shown in FIGS. 4 to 7.

The same parts as in FIGS. 1 to 3 are given the same reference numerals.

As shown in FIG. 4, a characteristic element 21 is formed by stacking a plurality of elements 1 made of non-linear resistors mainly composed of metal oxides.
is housed in an insulating tube 4 via a tube spacer 3 and a spring 2, an arc discharge port 6 is provided in a top cover 5 at the top of the insulating tube, and a shield 7 is attached to cover this top cover 5 to alleviate the electric field. The inner element 22 is then formed.

This internal element 22 is housed in a tank 9 together with an insulating gas 11 such as SF6 gas, the upper part of this internal element is led to the high pressure side by a conductor 15a via an insulating spacer 15, and the lower part is provided on the tank bottom plate 12. It is led to the ground side via the ground terminal 16.

As shown in FIGS. 5 and 6, the shield 7 on the head is provided with a movable shield part 8 in a part of the shield 7, and at a set position of the tank 9 corresponding to the movable shield part 8, for example, a rubber A fastener 10 made of a system member is attached.

Next, the operation of the lightning arrester of the present invention constructed as described above will be described.

If an arc is generated in the insulating cylinder 4 due to some accident, the pressure increases abnormally, and the arc is ejected from the discharge port 6 in the upper cover 5.The movable shield part 8 is blown up by the discharge pressure, and the external tank Collision contact with 9.

At this time, the movable shield part 8 is fixed to a fastener 10 provided on the inner wall of the external tank 9, and the high pressure side and the ground side are short-circuited.

It is unclear from the appearance of the tank whether the arrester has already stopped functioning due to an internal explosion, but if it is short-circuited at the movable shield part 8 as described above, it will cause damage between the high voltage and the ground. Whether or not the function has stopped can be easily determined by measuring insulation resistance or the like.

In addition, by short-circuiting the external tank 9 on the high-pressure side and the ground side by the movable shield portion 8, excessive energy of the arc at the time of internal explosion can be handled, and damage to the tank can be prevented.

In addition, in the above embodiment, the movable shield provided in the shield part is not provided with a punching part, but if the movable shield can be contacted and fixed in the event of an explosion, a punching part of an appropriate size may be provided in the movable shield part. .

Further, this movable shield may be provided at several locations as appropriate.

Further, although the single-phase type has been described above, the present invention can also be applied to a three-phase all-in-one type sealed switchgear lightning arrester.

In other words, in this case, the movable shield parts of each phase are prevented from falling inwardly during each internal explosion and causing a short circuit between phases, and by falling toward the tank side in each phase in the same way as the present invention, The effect of this can be obtained.

Furthermore, although the present invention has been described with respect to a lightning arrester that houses a non-linear resistor element whose main component is a metal oxide, it goes without saying that the present invention can also be applied to a lightning arrester that incorporates a gap and characteristic elements.

As described above, according to the present invention, by providing a movable shield in the shield, if an internal explosion occurs for some reason, the movable shield will be blown up by the arc ejection pressure, collide with the external tank, and be fixed by the fastener. Since the high-voltage side and the ground side are short-circuited, whether or not a post-surge arrester can be used can be determined by measuring insulation resistance from the outside.

Further, since excessive internal energy can be disposed of by short circuiting caused by the movable shield, it is possible to provide a lightning arrester for a sealed switchgear that is safe and reliable and prevents damage to the external tank.

[Brief explanation of the drawing]

Figures 1 to 3 show the main parts of a conventional lightning arrester, respectively.
Figure 1 is a sectional view, Figure 2 is a plan view taken along the line ■■-■■ in Figure 1, Figure 3 is a side view taken along the line III-III in Figure 2, and Figures 4 to 7. 4 shows the main parts of the earth arrester of the present invention, FIG. 4 is a partially cutaway sectional view, and FIG.
FIG. 6 is a plan view taken along the line V, and FIG. 6 is a side view taken along the line VI-VI in FIG. 1... Element, 4... Insulating tube, 5...
...Top lid, 6...Discharge port, 7...Shield, 8...Movable shield, 9...
External tank, 10... Fastener, 11...
・Insulating gas, 12...tank bottom plate, 15...
...Insulating spacer, 16...Grounding terminal section, 2
1...Characteristic element, 22...Internal element.

Claims (1)

[Scope of utility model registration request] A characteristic element is housed in an insulating cylinder, and an internal element comprising a top cover with a discharge port at the top of the insulating cylinder and a shield surrounding the top cover is housed in a lightning arrester tank together with an insulating gas, wherein the shield At least one movable shield is provided in the tank, and when an internal explosion occurs due to an abnormal current, the movable shield opens due to the internal pressure of the arc, and one end of the movable shield collides with the inner wall of the tank and is fixed. Lightning arrester for enclosed switchgear.