JP3612519B2 - Lightning arrestor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting arrester excellent in safety and reliability, which is capable of quickly discharging out a high-temperature/high-pressure gas flow generated by an internal arc and surely guiding it to an external path so as to protect an insulating tube against damage when a ground fault occurs. <P>SOLUTION: A pressure releasing opening 19a and a sloping plate 20a located at a position opposite to the opening 19a in a radial direction are provided to a guide 20 inside an arc guide 19. When an arc occurs inside the insulating tube 13 to generate a high-temperature/high-pressure gas flow, the gas flow breaks pressure release plats 15 as it is passing through the communicating openings 14a and 14b of lids 14 and flows into guides 20 inside the arc guides 19. At this point, the gas flow hits against the sloping plates 20a and then is guided to the openings 20b and pressure release openings 19a of the guides 20. <P>COPYRIGHT: (C)2003,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lightning arrester in which an internal element formed by laminating a plurality of non-linear resistors mainly composed of zinc oxide is housed inside a soot tube, and more particularly to an arc generated inside a soot tube during a lightning arrester ground fault and The present invention relates to a lightning arrester that prevents explosion explosion of the soot tube by releasing the accompanying high-temperature, high-pressure gas flow to the outside of the soot tube and causing it to flash externally.
[0002]
[Prior art]
In general, a lightning arrester plays an important role in promoting insulation coordination within a substation and improving insulation reliability. In particular, in recent years, an element using a zinc oxide element having excellent protective properties as an internal element in a soot tube has become widespread. By the way, when a lightning arrester has a ground fault, an arc is generated inside, and accompanying this, the temperature and pressure in the soot pipe rapidly rise, and the soot pipe may be damaged. In particular, when the soot tube is an insulator-type soot tube made of porcelain, there is a risk that the soot tube may be broken and scattered to the surroundings as well as the cracks in the soot tube.
[0003]
Therefore, conventionally, a lightning arrester has been proposed in which high temperature and high pressure gas is discharged to the outside of the soot tube and an internal arc is transferred to an external flash to prevent explosion. A conventional example of such a lightning arrester will be specifically described with reference to FIGS. 4 (a) and 4 (b).
[0004]
FIG. 4A shows a longitudinal sectional view of an example of a conventional lightning arrester, and FIG. 4B shows a partial plan view. As shown in FIG. 4A, the lightning arrester 11 has an internal element 12 concentrically housed inside a cylindrical soot 13. The internal element 12 is configured by laminating a plurality of non-linear resistors mainly composed of zinc oxide, and is connected to an electric device (not shown). The soot tube 13 is filled with gas, and a pair of upper and lower lids 14 and 14 are provided at the openings at the upper and lower ends, which are the axial ends of the soot tube 13.
[0005]
The lid 14 is formed with communication ports 14a and 14b that communicate with the inside of the tub tube 13, respectively. The communication ports 14a and 14b are both semicircular, and are bilaterally symmetric as shown in FIG. Further, a crushable pressure release plate 15 that closes the communication ports 14a and 14b, a packing 16, and a presser plate 17 that presses the pressure release plate 15 are provided on the outside of each lid 14. The structure is kept airtight.
[0006]
In addition, a pair of upper and lower steel pipe flanges 18 are disposed in the openings at the upper and lower ends of the steel pipe 13, and a pair of upper and lower arc guides 19 are installed on each steel pipe flange 18. These arc guides 19 are made of, for example, a hollow, substantially disk-shaped member made of aluminum or an aluminum alloy, and gas is taken into the inside from the soot tube 13 through the communication ports 14a, 14b. Each arc guide 19 is formed with a pressure release port 19a for releasing the gas in the arc guide 19 to the outside. The upper and lower pressure release ports 19 a in FIG. 4A are arranged horizontally so as to face each other along the axial direction of the soot tube 13.
[0007]
Furthermore, an iron guide 20 is housed in each arc guide 19 as an example. As shown in FIG. 4B, the guide 20 has a U shape with a planar shape having an opening 20 b, and is raised vertically to the presser plate 17. The opening 20b of the guide 20 is formed on the pressure relief port 19a side, from which the gas inside the arc guide 19 is guided to the pressure relief port 19a.
[0008]
Here, when the lightning arrester 11 performs an over-responsibility operation exceeding the capability, the lightning arrester 11 causes a flashing or penetration failure, and a short-circuit current flows. Therefore, an arc is generated inside the soot tube 13, and the inside of the soot tube 13 becomes high temperature. Further, since a shock wave is also generated along with the arc, the pressure inside the soot tube 13 rapidly increases, and a high-temperature and high-pressure gas flow is produced inside the soot tube 13. The gas flow passes through the communication ports 14 a and 14 b of the lid 14, crushes the pressure release plate 15, and is ejected into the arc guides 19. Further, the gas flow is guided to the opening 20b of the guide 20, directed to each pressure release port 19a, and discharged through the pressure release port 19a to the outside.
[0009]
At this time, in FIG. 4A, a gas flow is released downward from the upper pressure release port 19a and a gas flow is released upward from the lower pressure release port 19a. Since the pressure release ports 19a face each other, the two gas flows collide and merge between the pressure release ports 19a. As a result, a closed circuit can be formed between the pressure release ports 19a, and the arc generated inside the soot tube 13 can be transferred to an external flash. As a result, even when the pressure inside the soot tube 13 suddenly rises, it is possible to prevent the soot tube 13 from being damaged and exploding.
[0010]
[Problems to be solved by the invention]
However, the above prior art has the following problems. That is, the direction of the gas flow when passing through the communication ports 14 a and 14 b is the vertical direction (the axial direction of the vertical tube 13), and the arc guide 19 is colliding with the top plate or bottom plate of the arc guide 19 and the wall surface of the guide 20. Inside, the direction is changed in the horizontal direction (a direction perpendicular to the axial direction of the vertical tube 13). Then, after passing through the opening 20b of the guide 20, the direction is changed again in the vertical direction and exits to the discharge port 19a.
[0011]
That is, the gas flow generated in the soot tube 13 undergoes a 90-degree turn twice from the communication ports 14a, 14b to the discharge port 19a. As a result, turbulent flow and stagnation are likely to occur in the gas flow, and a phenomenon occurs in which the flow velocity of the gas flow at the time of exiting from the upper and lower pressure release ports 19a is significantly slower than that at the beginning of gas flow generation. If the flow velocity of the gas flow from the pressure release port 19a is slow, it becomes difficult to collide and merge between the pressure release ports 19a, and it is difficult to generate an external flash.
[0012]
The present invention has been made in consideration of such circumstances, and its purpose is to quickly release a high-temperature and high-pressure gas flow caused by an internal arc to the outside in the event of a ground fault, and to an external flash. It is an object of the present invention to provide a lightning arrester excellent in safety and reliability that can reliably achieve the transition and prevent damage to the duct.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is characterized in that a cylindrical soot tube filled with gas is provided therein, and an internal element formed by laminating a plurality of non-linear resistors in the soot tube. A lid having a communication port communicating with the interior of the soot tube and an arc guide for taking in gas inside the soot tube through the communication port are disposed at both axial ends of the soot tube, respectively. Closed crushable pressure release plates are installed, and each arc guide is formed with pressure release ports that discharge the gas in the arc guide to the outside so as to face each other along the axial direction of the soot tube. In the lightning arrester provided with a guide having an opening for guiding the gas from the inside of the soot tube to the pressure relief port, a base end portion is fixed in a position opposite to the pressure relief port in the radial direction. Tilt toward the pressure relief port The tip of the inclined plate on the pressure release side is in contact with the surface of the arc guide facing the communication port, and on the extension line at the center of the vertical tube and near the pressure release port. It is characterized by being arranged so as to be on the extension line of the edge of the communication port.
[0014]
According to the first aspect of the present invention, when an arc is generated inside the soot tube during a lightning arrester ground fault and a high-temperature and high-pressure gas flow is generated in the soot tube, this gas flow breaks the pressure relief plate through the communication port of the lid, It flows into the arc guide and collides with the inclined plate of the guide. The gas flow is guided toward the opening of the guide by the inclined plate, and smoothly flows to the pressure release port while joining the gas flow immediately after passing through the communication port. As described above, in the first aspect of the invention, the gas flow can smoothly flow from the communication port to the pressure release port, and turbulence and stagnation can be suppressed. Therefore, the gas flow can be blown out from the pressure release port at a high speed without decelerating, and the gas flows are surely merged. Thereby, the arc inside the soot tube can be easily transferred to the external flash, and it is possible to prevent the soot from being damaged. In addition, since the tip of the inclined plate exceeds the extension of the center of the soot tube, at least half of the gas flow exiting the communication port directly hits the inclined plate, so that the inclined plate has a sufficient amount of gas flow. Can be guided to the opening side, and the occurrence of turbulence and stagnation can be reliably suppressed. In addition, since most of the gas flow does not directly collide with the top plate (bottom plate) of the arc guide, an excessive load is not applied to the arc guide, and the arc guide is made of a lightweight member such as aluminum or aluminum alloy. Even when formed, sufficient durability can be secured.
[0015]
Furthermore, since the tip of the inclined plate does not exceed the extended line of the edge near the pressure release port at the communication port, the inclined plate does not fall too much to block the entire communication port. For this reason, the gas flow exiting the communication port does not collide with the inclined plate having a very steep angle, and the direction of the gas flow from the communication port to the opening can be smoothly changed. Further, when the inclined plate is arranged as described above, the gas flow from the communication port does not collide with only one of the inclined plate or the top plate (bottom plate) of the arc guide at a high speed. Therefore, the collision energy to the member is also reduced, there is no possibility that the arc guide or the inclined plate is deformed or damaged, and the safety is high.
[0016]
According to a second aspect of the present invention, in the lightning arrester according to the first aspect, when the discharge port area of the arc guide is 100%, the communication port area of the lid and the opening area of the guide are 50 to 150%. It is characterized by having been formed.
According to the second aspect of the present invention, since the size of the communication port of the lid and the opening of the guide is suppressed to 1.5 times or less of the pressure release port, the size of the communication port and the guide is smaller than the size of the pressure release port. The opening is not too large. Therefore, a gas flow larger than the outflow amount from the pressure release port does not flow into the pressure release port, and excessive pressure is concentrated and the guide arc is not damaged, and the gas flow is quickly injected from the pressure release port. Can be made.
[0017]
On the other hand, since the size of the opening of the lid and the opening of the guide is secured more than half of the pressure relief opening, a sufficient amount of gas flow should be supplied from the communication opening and the opening to the pressure relief opening. Can do. As a result, a decrease in the flow rate of the gas injected from the pressure release port can be prevented, and an external flash can be reliably achieved.
[0018]
According to a third aspect of the present invention, in the lightning arrester according to the first or second aspect, a shield ring is disposed at a pressure relief port of the arc guide.
According to the third aspect of the present invention, by providing the shield ring, the electric field at the pressure release port during normal use of the lightning arrester is relieved, and the occurrence of partial discharge outside the lightning arrester can be suppressed. Further, when the gas flow generated inside the soot pipe is injected from the pressure release port, the shield ring can be easily blown from the pressure release port by the gas flow. At this time, since metal vapor is generated from the melted portion, it becomes a conductor, and an external flash can be achieved more easily.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of an embodiment of the present invention (hereinafter referred to as an embodiment) will be specifically described with reference to FIGS. In addition, the same code | symbol is attached | subjected about the same or equivalent part as the prior art example shown in FIG. 4, and description is abbreviate | omitted.
[0020]
(1) First Embodiment (1-1. Configuration)
The first embodiment includes claims 1 and 2, and in FIG. 1, (a) is a longitudinal sectional view of a lightning arrester according to the first embodiment, and (b) is a plan view of an essential part thereof. is there. As shown in the drawing, the guide 20 in the arc guide 19 is provided with an inclined plate 20a at a position opposite to the pressure release port 19a in the radial direction (the right side in FIG. 1A). The inclined plate 20a is configured to linearly incline in the direction of the pressure release port 19a.
[0021]
That is, the inclined plate 20a is integrally formed with the guide 20 by inclining the surface facing the opening 20b on the inner side of the U-shaped guide 20 and welding to both parallel surfaces sandwiching this surface. . As the material of the inclined plate 20a, iron is suitable because of its high strength and melting point, and a rolled steel plate having excellent strength is particularly desirable. In particular, when the guide 20 is made of iron as described in the prior art, if the inclined plate 20a is made of iron, the welding strength when the inclined plate 20a is welded to the guide 20 is excellent. Further, the thickness dimension of the inclined plate 20a is preferably 3 mm or more. If the thickness is 3 mm or more, various voltage classes are obtained from the viewpoint of strength and heat resistance against high-temperature and high-pressure gas flow. It is applicable to.
[0022]
Next, the arrangement configuration of the inclined plate 20a will be described using the enlarged view of FIG. In the following description, the end of the inclined plate 20a near the pressure relief port 19a is the distal end (left side end in FIG. 2), and the end opposite to the pressure relief port 19a in the radial direction is the base end (right side end in FIG. 2). Part). The tip of the inclined plate 20a is in contact with the top plate (bottom plate) of the arc guide 19 and extends over the extended line L1 at the edge of the communication port 14a near the pressure relief port 19a beyond the extended line L1 at the center of the vertical tube 13. It is arranged in between. FIG. 2 shows a state immediately after exceeding the extension line L1 and a state reaching the extension line L2. On the other hand, the base end portion of the inclined plate 20a is fixed in the vicinity of the edge portion on the opposite side to the pressure release port 19a in the communication port 14b.
[0023]
Furthermore, the opening area of the pressure release port 19a, the communication ports 14a and 14b, and the opening 20b of the guide 20 has the following relationship. That is, in the first embodiment, when the area of the pressure release port 19a of the arc guide 19 is 100%, the areas of the communication ports 14a and 14b of the lid 14 and the area of the opening 20b of the guide 20 are 50 to 150%. Preferably, when the opening area of the pressure release port 19a is 100%, the sum of the opening areas of the communication ports 14a and 14b is 100%, and the opening area of the opening 20b of the guide 20 is 70 to Each is formed to be 95%.
[0024]
(1-2. Effects)
In 1st Embodiment which has the above structure, when a short circuit current flows into the internal element 12 at the time of the earth fault of the lightning arrester 11, an arc will generate | occur | produce inside the soot pipe 13, and a high-temperature / high pressure gas flow will arise. The gas flow passes through the communication ports 14 a and 14 b of the lids 14, crushes the pressure release plates 15, and flows into the guides 20 arranged in the arc guides 19. Here, the gas flow collides with the inclined plate 20a and is guided to the opening 20b side of the guide along the inclined surface.
[0025]
The gas flow guided to the inclined plate 20a smoothly joins with the gas flow immediately after passing through the communication ports 14a and 14b, and turbulence and stagnation do not occur when the direction of the gas flow is changed. Therefore, the gas flow in the guide 20 can pass through the opening 20b without being decelerated and can be jetted to the outside from the pressure release port 19a. As a result, the gas flows from the pressure release port 19a collide and merge between the pressure release ports 19a, and a reliable closed circuit can be formed. Thereby, the arc inside the soot tube 13 can be easily transferred to the external flash between the upper and lower pressure release ports 19a. According to such 1st Embodiment, the explosion scattering of the soot pipe 13 can be prevented beforehand, and the improvement of safety | security and reliability can be aimed at.
[0026]
Moreover, in the first embodiment, since the tip of the inclined plate 20a exceeds the extension of the center of the vertical tube 13, the inclined plate 20a is one of the two communication ports 14a and 14b. It covers the mouth 14b. That is, at least half of the gas flow exiting the communication ports 14a and 14b directly hits the inclined plate 20a, and the inclined plate 20a can guide a sufficient amount of gas flow to the opening 20b side, Generation of turbulence and stagnation can be reliably suppressed. In addition, since most of the gas flow does not directly collide with the top plate (bottom plate) of the arc guide 19, an excessive load is not applied to the arc guide, and the arc guide is made of a lightweight member such as aluminum or aluminum alloy. Even when formed, sufficient durability can be ensured.
[0027]
Further, since the tip of the inclined plate 20a does not exceed the extended line of the edge of the communication port 14a near the pressure relief port 19a, the inclined plate 20a does not fall too much so as to cover the entire communication ports 14a and 14b. For this reason, the gas flow that has exited the communication ports 14a and 14b does not collide with the inclined plate 20a having a very steep angle, and the direction of the gas flow from the communication ports 14a and 14b toward the opening 20b is smoothly changed. be able to.
[0028]
Furthermore, when the inclined plate 20a is arranged as described above, the gas flow from the communication ports 14a and 14b may collide with only one of the inclined plate 20a or the top plate (bottom plate) of the arc guide 19 at a high speed. Absent. Therefore, the collision energy to the member is also reduced, there is no possibility that the arc guide 19 and the inclined plate 20a are deformed or damaged, and the safety is high.
[0029]
Further, in the first embodiment, the sum of the opening areas of the communication ports 14a and 14b of the lid 14 and the opening area of the pressure release port 19a of the arc guide 19 are made equal, and the guide 20 located between them is located. The size of the opening 20b is set to be slightly small, about 70 to 95% of both. That is, the gas flow exiting from the communication ports 14 a and 14 b is slightly blocked by the opening 20 b of the guide 20. Therefore, the space in the guide 20 serves as a pressure accumulating chamber, and the pressure in the guide 20 becomes higher than the pressure release port 19a. The gas flow that has passed through the opening 20b is blown out at a higher speed than the upper and lower pressure relief ports 19a, and the tips of the gas flow from the upper and lower pressure relief ports 19a can easily approach each other. Is easily achieved.
[0030]
By the way, in the first embodiment, when the area of the pressure release port 19a of the arc guide 19 is 100%, the areas of the communication ports 14a and 14b of the lid 14 and the area of the opening 20b of the guide 20 are 50 to 150%. It is stopped within the range. Thereby, it is possible to secure the communication ports 14a and 14b and the opening 20b having appropriate sizes with respect to the pressure release port 19a. That is, when the sizes of the communication ports 14a and 14b and the opening 20b are less than 50% of the pressure release port 19a, it is difficult to sufficiently supply the gas flow to the pressure release port 19a. Conversely, if the size of the communication ports 14a and 14b and the opening 20b exceeds 150% of the pressure release port 19a, an excessive gas flow from the communication ports 14a and 14b and the opening 20b to the pressure release port 19a. Concentration causes the arc guide 19 to be damaged.
[0031]
In any case, such a situation where the gas flow to the pressure release port 19a is insufficient or excessive causes the flow rate and flow rate of the gas flow from the pressure release port 19a to be reduced, and external flashing is less likely to occur. . Therefore, in the first embodiment, by limiting the size of the opening 20b of the communication ports 14a and 14b to the above range with respect to the pressure release port 19a, the gas flow flows from the pressure release port 19a at a high speed and in a large amount. And an external flash can be easily realized.
[0032]
(2. Second Embodiment)
(2-1. Configuration)
The second embodiment corresponds to claim 3 and is characterized in that a shield ring 21 is disposed on the outer peripheral portion of the pressure release port 19a of the arc guide 19 as shown in FIG. The shield ring 21 has a thickness smaller than the thickness of the arc guide 19 and is made of an aluminum-based alloy, preferably an aluminum magnesium alloy, which has a low melting point and easily generates metal vapor.
[0033]
(2-2. Effects)
Generally, in the lightning arrester 11 used at a high voltage, partial discharge is more likely to occur than the high-voltage side metal part. In the second embodiment, when the surge arrester 11 is in a normal use state, that is, when a surge flows through the internal element 12 inside the soot tube 13 without generating a high-temperature and high-pressure gas flow inside the soot tube 13, the pressure release port that becomes a protruding portion There is a possibility of partial discharge from the tip of 19a. Therefore, in the second embodiment, the shield ring 21 is disposed on the outer periphery of the pressure release port 19a on the high pressure side. Thereby, the electric field in the pressure release port 19a can be relieved and generation | occurrence | production of partial discharge can be prevented.
[0034]
Further, when an arc is generated inside the soot tube 13, a gas flow is released from the pressure release port 19a. At this time, the low melting point shield ring 21 is easily blown. Since metal vapor is generated in the shield ring 21 made of an aluminum magnesium alloy, this exists between the upper and lower pressure release ports 19a. Therefore, this metal vapor becomes a conductor, and an external flash can be achieved more easily.
[0035]
In the second embodiment, the shield ring 21 is made of aluminum or an aluminum alloy. However, when the arc guide 19 is made of aluminum or an aluminum alloy, the welding of both is easy. There is an advantage such as.
[0036]
(3. Other embodiments)
The present invention is not limited to the above embodiment, and the shape and material of each constituent member can be appropriately changed. For example, regarding the material of the inclined plate 20a, not only iron but also excellent thermal conductivity is provided. Copper or a copper alloy containing copper as a main component, specifically, brass which is an alloy of copper and zinc may be used. In this case, the thickness dimension is desirably 3 mm or more. Furthermore, aluminum or an aluminum alloy mainly composed of aluminum may be used. In this case, the thickness dimension is desirably 4 mm or more.
[0037]
The inclination angle of the inclined plate 21a can be appropriately changed in accordance with the internal dimensions of the arc guide 19 and the guide 20, and the shape of the inclined surface is not limited to a linear shape, but may be an arcuate curved surface or a “h” character. It may be bent into a shape.
[0038]
The soot tube in the present invention may be made of polymer as well as porcelain. If the soot tube is made of porcelain, its explosion and scattering can be suppressed, so that particularly excellent reliability and safety can be exhibited. However, even if the soot tube is made of a polymer, the same effect is obtained in that the damage is prevented.
[0039]
Furthermore, since the present invention has a simple structure in which an inclined plate is provided in the guide portion, it can be easily attached to a conventional lightning arrester, and the transition from existing equipment to the present invention is very easy.
[0040]
【The invention's effect】
As described above, according to the present invention, when a ground fault is caused by a simple configuration in which an inclined plate that is inclined in the direction of the discharge port is provided at a position opposite to the discharge port of the arc guide in the radial direction. A high-temperature and high-pressure gas flow due to the internal arc is quickly released to the outside, and the transition to the external flashing can be reliably achieved to prevent the damage of the soot tube, resulting in a safe and reliable lightning arrester. be able to.
[Brief description of the drawings]
1A is a longitudinal sectional view of a lightning arrester according to a first embodiment of the present invention, and FIG. 1B is a plan view of a holding plate and a guide plate shown in FIG.
FIG. 2 is an enlarged side view of an inclined plate according to the first embodiment.
FIG. 3 is a longitudinal sectional view of a lightning arrester according to a second embodiment of the present invention.
4A is a longitudinal sectional view of a conventional lightning arrester, and FIG. 4B is a plan view of a presser plate and a guide plate shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Lightning arrester 12 ... Internal element 13 ... Dust pipe 14 ... Cover 14a, 14b ... Communication port 15 ... Pressure release plate 16 ... Packing 17 ... Holding plate 18 ... Dust pipe flange 19 ... Arc guide 19a ... Pressure release port 20 ... Guide 20a ... Inclined plate 20b ... Guide opening 21 ... Shield ring

Claims (3)

A cylindrical soot tube filled with gas is provided therein, and internal elements formed by laminating a plurality of non-linear resistors are accommodated in the soot tube, and both end portions in the axial direction of the soot tube respectively A lid having a communication port for communication and an arc guide for taking gas inside the pipe through the communication port are arranged, and a crushable pressure release plate for closing the lid is installed at the communication port, and each arc guide has an arc. Pressure release ports for releasing the gas in the guide to the outside are formed facing each other along the axial direction of the soot tube, and each arc guide has an opening for guiding the gas from the inside of the soot tube to the pressure relief port In a lightning arrester provided with a guide having
Said inside guide an inclined plate to which the base end portion to the position of the discharge pressure port in a radial direction opposite inclined fixed the release pressure port direction,
The tip of the inclined plate on the side of the pressure relief port is in contact with the surface of the arc guide facing the communication port, on the extension line at the center of the soot tube and on the edge of the communication port near the pressure relief port. A lightning arrester characterized by being placed between the extension lines. 2. The structure according to claim 1, wherein when the pressure release area of the arc guide is 100%, the communication opening area of the lid and the opening area of the guide are 50 to 150%. The described lightning arrester. The lightning arrester according to claim 1 or 2, wherein a shield ring is disposed at a pressure release port of the arc guide.

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