JPH0828142B2 - Lightning arrester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention rapidly discharges a lightning surge current to a ground when a power transmission line or a distribution line flows, and further suppresses a commercial frequency follow-up current generated thereafter. The present invention relates to a lightning protection insulator capable of suppressing and blocking.

(Problems to be Solved by Conventional Techniques and Inventions) As a conventional antistatic insulator, as shown in FIG. 7, a ring-shaped current limiting element 32 is fitted on a tension insulating rod 31, and the tension insulating Cap fittings 33 and 34 are provided at both ends of the rod 31, and the current limiting element 32 is provided.
There is a structure in which the current limiting element 32 is hermetically enclosed while the outer periphery of the current limiting element 32 is covered with an insulating outer body 36 made of porcelain while the elastic body 35 is held elastically between the cap metal fittings 33, 34. It was

However, in the above-mentioned lightning protection insulator, since the mantle 36 is made of porcelain, if the source element 32 becomes conductive due to unexpected lightning strike or other reasons, a high temperature and high pressure arc occurs, so that it releases the pressure. As a means of this, it is necessary to provide a rupture plate that ruptures with a constant pressure on the cap fitting 33, and therefore the pressure release structure becomes complicated,
Not only is the manufacturing cumbersome, but there is also a problem with airtight reliability due to the method of adhering or closely contacting the rupture plate.

In order to solve this problem, the applicant of the present application has proposed a lightning protection insulator shown in FIG. This lightning insulator has cap metal fittings 38 and 39 fitted and fixed to both end openings of a pressure-resistant insulating cylinder 37 having a tubular shape, and the current limiting element 32 is accommodated in the pressure-resistant insulating cylinder 37.
While electrically connecting to the cap fittings 38, 39,
At least one pressure release hole 37a is provided through the pressure-resistant insulating cylinder 37 so as to correspond to both ends of the current limiting element 32, and the arc fitting member 40 is provided in the cap fittings 38 and 39. It is provided so as to correspond to the outside, respectively.
Provided is a lightning protection insulator in which the outer periphery and the gap between the withstand voltage insulating cylinder 37 and the current limiting element 32 are molded with a rubber organic insulating material 41.

However, this lightning protection insulator has a withstand voltage insulation tube 37 and a current limiting element 32.
Since the organic insulating material 41 made of rubber is filled in the gap g between the and, in the unlikely event that the current limiting element 32 becomes conductive due to some reason, the pressure-proof insulating cylinder is set to the pressure generated by the arc. Since it is necessary to endure it, the thickness must be increased, and there is a problem that the lightning protection insulator becomes large.

The object of the present invention is to solve the problems existing in the above-mentioned conventional techniques, and in the unlikely event that a lightning surge current intrudes into the lightning protection insulator, which is beyond the assumption, or the current limiting element becomes conductive due to other causes. In this case, the pressure relief plug provided with the high-temperature, high-pressure arc on the insulator tube can be quickly and reliably melted and scattered to release the pressure, and the insulator tube can be made thinner to reduce the size of the lightning protection insulator. , To provide a lightning protection insulator which has excellent applicability to existing equipment.

(Means for Solving the Problems) In order to solve the above problems, the present invention hermetically fits and fixes the ground-side electrode fittings and the power-supply-side electrode fittings on both ends of the insulator-insulated porcelain tube. The sealed space of the porcelain tube accommodates a current limiting element having a non-linear voltage-current characteristic with a predetermined gap from its inner peripheral surface, and electrically connects the upper and lower ends of the electrode fitting and the current limiting element. Insulating gas is sealed in the closed space, and further, at least a part of the porcelain insulator is provided with a pressure relief hole penetrating it so as to be located between the insulating folds. In practice, a pressure-release plug having a non-moisture-permeability and air-tightness is fitted and fixed in an air-tight manner, and a concave portion communicating with the closed space is formed in the pressure-release plug.

(Operation) In the present invention, a pressure release hole is provided between the insulating folds provided with the insulator tube,
Since the pressure relief plug is fitted and fixed there, the pressure relief pressure can be strictly controlled by optimally setting factors such as the diameter, thickness and material of the pressure relief plug. The pressure can be minimized, and therefore, the pressure applied to the porcelain insulator is reduced, and the wall thickness of the decomposition pipe can be made thin to miniaturize the lightning arrester.

In particular, in the present invention, since the depression is formed in communication with the pressure relief plug in the closed space, high-temperature, high-pressure gas enters the depression from the enclosed space, and gas pressure easily acts on the inner top surface of the pressure relief plug. As a result, the above-mentioned various elements of the pressure relief plug can be set more optimally. In the structure where the pressure relief plug is not formed with the recess, the gas easily flows in the longitudinal direction in the sealed space,
Since there is no gas wraparound, the pressure for melting and breaking the pressure relief plug cannot be applied efficiently.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

As shown in FIG. 2, at the upper end of the cylindrical porcelain tube 1 made of weatherproof reinforced resin (for example, ERP) integrally formed with a large number of insulating folds 1a on the outer periphery, the inner and outer two-layered fitting tubular portion 1b is formed. Are formed. The lower cylindrical portion of the ground-side electrode fitting 3 is fitted and fixed to the fitting tubular portion 1b with an adhesive 2, and the outer peripheral surface of the electrode fitting 3 is a mounting adapter attached to a support arm of a steel tower (not shown). The flange portion 3a attached to the is integrally formed.

In addition, a bottomed cylindrical electrode metal fitting 4 having a bottom shape is hermetically fitted and fixed to the fitting cylinder portion 1b formed at the lower end portion of the porcelain bushing 1 by an adhesive 2 and is attached to the lower surface of the electrode fitting 4. Although not shown in the figure, a bracket 4a for attaching the arc horn on the power supply side attached to the power transmission line side and the arc horn on the ground side facing each other with a predetermined air discharge gap is integrally formed.
The porcelain bushing 1 and the electrode fittings 3 and 4 may be insert-molded at the same time by a molding die.

A fitting cylindrical portion 4b is formed on the inner bottom surface of the electrode-side metal fitting 4 on the power-charging side, and the lower end of the conductor fitting 5 on the power-charging side is fitted and fixed thereto. On the upper surface of the conductor fitting 5, a current limiting element 6 composed mainly of zinc oxide having a non-linear voltage-current characteristic is formed.
Are stacked in series, and a grounded conductor fitting 7 which also serves as a spring receiver and has a bottomed cylindrical shape is supported on the upper end surface of the source element 6.

On the other hand, a tightening ring 8 is screwed into the threaded portion 3b formed on the inner peripheral surface of the ground-side electrode fitting 3, and between the intermediate conductor 9 fitted in the ring 8 and the conductor fitting 7. A coil-shaped spring 11 having a shunt 10 for energizing is interposed. Due to the resilience of the spring 11, the current limiting element 6 is pressed and fixed between the conductor fitting 5 on the voltage applying side and the conductor fitting 7 on the ground side.

Furthermore, an insulating hermetically sealed body 13 is provided in the opening of the ground-side electrode fitting 3 so as to cover the insulating ring 8 and the intermediate conductor 9.
Are hermetically fitted and fixed by the adhesive 2.

A gas filling hole 4c is formed in the electrode metal fitting 4 on the side of charging, and nitrogen gas or hexafluoride is introduced into the closed space R formed between the porcelain tube 1 and the current limiting element 6 from the filling hole 4c. A gas having excellent insulating properties such as sulfur (SF6) is enclosed, and after the enclosure, it is sealed with a tight plug 14.

Further, as shown in FIGS. 1 and 2, circular or elongated pressure release holes 1c are formed between the insulating folds 1a, 1a of the porcelain tube 1 at a plurality of positions, and the pressure release holes 1c are made of aluminum. A pressure release plug 15 made of a metal such as copper and having a bottomed cylindrical shape is hermetically fitted and joined by an adhesive 2. Then, when the inside of the closed space R becomes a predetermined temperature and a predetermined pressure or more,
The pressure release plug 15 melts and bursts so that pressure can be released.

A recess 16 is formed in the pressure release plug 15 so as to communicate with the closed space R. The wall thickness of this pressure release plug 15 is, for example, 0.
It should be about 05-0.2 mm.

Next, the operation of the lightning protection insulator configured as described above will be described.

When a lightning surge current flows through a transmission line with the lightning protection insulator attached to a tower, the current is flashed from an arc horn (not shown) on the transmission line side to an arc horn (not shown) at the lower end of the lightning protection insulator. , Electrode metal fitting 4, conductive metal fitting 5, current limiting element 6, conductor metal fitting 7, shunt 1 on the voltage applying side
After passing through 0, the intermediate conductor 9 and the tightening ring 8, it flows to the grounded side electrode fitting 3 and further to the steel tower through a mounting adapter (not shown) to be discharged to the ground.

Further, the subsequent current generated thereafter is suppressed and cut off by both arc horns and the current limiting element 6.

According to the present invention, the pressure relief hole 1c is provided so as to be located between the insulating pleats 1a, 1a in the porcelain bushing 1, and the pressure relief wire 15 is hermetically fitted and joined thereto. By controlling factors such as wall thickness, the pressure release pressure is minimized, the pressure acting on the porcelain bushing 1 is reduced, and the wall thickness of the porcelain bushing 1 is reduced to reduce the size and weight of the lightning protection insulator. be able to.

In particular, in the above-described embodiment, since the recess 16 communicating with the closed space R is formed in the pressure release plug 15, the high-temperature and high-pressure gas enters from the closed space R so as to wrap around the recess 16 and enter the pressure release plug 15. The high-pressure gas efficiently acts on the top surface, and as a result, the above-described effects can be further improved.

In the above-described embodiment, since the insulating gas is sealed in the closed space R between the porcelain bushing 1 and the current limiting element 6, a large-scale unexpected lightning surge current is applied to the current limiting element 6 by any chance. Even when the current limiting element 6 becomes conductive and a high-temperature and high-pressure arc is generated, the arc pushes away the insulating gas in the space R and quickly propagates to the pressure relief plug 15. Since a high-pressure arc rapidly breaks or melts the pressure release plug 15 and is released to the outside, the pressure inside the porcelain tube 1 is higher than that when the insulating space R is filled with an insulating filler. The rise can be reduced, the wall thickness of the main body of the porcelain insulator 1 can be further reduced, and the lightning protection insulator can be miniaturized.

The present invention can also be embodied as follows.

(1) At least one pressure release hole 1c may be provided, but when a plurality of pressure release holes 1c are provided, it is desirable to arrange them in a zigzag manner from the viewpoint of mechanical strength of the porcelain insulator 1.

(2) Although the resin porcelain insulator was used in the above embodiment, a porcelain insulator is used.

Effects of the Invention As described in detail above, the present invention melts the pressure relief plug in the event that a current limiting element becomes conductive due to unexpected lightning strikes or other causes, and a high temperature / high pressure arc occurs. There is an effect that the lightning arrester can be downsized by destroying and quickly releasing the pressure, facilitating the pressure control of the pressure relief plug, reducing the pressure rise of the porcelain tube, making it thinner.

In particular, in this invention, since the depression is formed in the pressure relief plug so as to communicate with the closed space, high-temperature, high-pressure gas enters from the enclosed space so as to circulate into the depression and enters the inner top surface of the pressure relief plug at high temperature and high pressure. The gas described above efficiently acts, and as a result, the above-mentioned effects can be promoted.

[Brief description of drawings]

FIG. 1 is a semi-longitudinal sectional view showing an embodiment of a lightning arrester of the present invention, FIG. 2 is a partially cutaway perspective view of an insulator tube, FIG. 3 is a sectional view taken along the line AA of FIG. 1, and FIG. 1 is a sectional view taken along the line BB in FIG. 1, FIG. 5 is a sectional view taken along the line CC in FIG. 1, and FIGS. 6 and 7 are vertical sectional views showing a conventional example. 1 ... Insulator, 1a ... Insulation pleats, 1b ... Fitting cylinder, 1c ...
Pressure relief hole, 3 ... grounding side electrode fitting, 4 ... voltage applying side electrode fitting, 5 ... conductive fitting, 6 ... current limiting element, 7 ... conductor fitting, 8 ... tightening ring, 9 …… Intermediate conductor, 10 …… Shunt, 11 …… Spring, 13 …… Insulation sealing body, 14 …… Seal plug, 15…
… Press release plug, 16 …… recessed part, R …… closed space.

Claims (2)

[Claims] 1. A ground-side electrode fitting and a power-supply-side electrode fitting are airtightly fitted and fixed to both ends of an insulating pleated porcelain tube, and the sealed space of the porcelain tube has a predetermined distance from its inner peripheral surface. With a voltage-current characteristic accommodates a non-linear current limiting element, the electrode fitting and the upper and lower ends of the current limiting element are electrically connected, an insulating gas is sealed in the sealed space, and At least a part of the porcelain tube is provided with a pressure release hole penetrating it so as to be positioned between the insulating folds, and a pressure release plug having practically non-moisture impermeable and airtight properties is airtightly provided in the pressure release hole. A lightning protection insulator, wherein the lightning protection insulator is fitted in and fixed to the pressure relief plug, and a recess communicating with the closed space is formed inside the pressure relief plug. 2. The lightning arrester according to claim 1, wherein the pressure relief plug is formed of a thin non-moisture-permeable metal plate such as aluminum or copper and adhered to the inner peripheral surface of the pressure relief hole. insulator.