JPH03280379A - Fault indicator for lightning arrestor insulator - Google Patents

Abstract

PURPOSE:To provide a fault indicator for arrestor insulator having high reliabil ity for a long period by connecting a resistance element to be destroyed by the failure earth current to the coupling part electrically, and allowing a pres sure release cover to separate or beak with destruction of the resistance element. CONSTITUTION:A case 2 is fitted with coupling parts 8, 9 put in series connec tion between the power-transmission line side and the earth side. The case 2 accommodates a resistance element 17 while in electrical connection with the two coupling parts 8, 9, wherein the resistance element 17 has non-linear voltage-current characteristic and fails with the faulty earth current. An opening 15 provided in this case 2 is covered with a pressure release cover 5 and fixed. When the resistance element 17 is broken by faulty earth current, the pressure release cover 5 is separated from the case 2 or breaks. Thus a fault indicator for arrestor insulator is accomplished provided with a high reliability for a long period of time.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a failure indicator for a lightning arrester, and more specifically, it is a failure indicator that is used when an abnormal current exceeding a predetermined current flows through a lightning arrester device and the lightning arrester is damaged. , relates to a failure indicator for a lightning arrester that indicates this failure.

[Conventional technology]

In power transmission lines, lightning arresters are known that have a built-in current-limiting element with nonlinear voltage-current characteristics, in order to allow lightning surge current to flow to the ground and to limit and interrupt the subsequent flow of operating voltage. ing. However, lightning surge current that exceeds the maximum discharge capacity of the current limiting element may damage the lightning arrester.
When the current limiting element deteriorates due to long-term use, the current limiting effect of the current limiting element is lost and it is no longer able to limit and cut off lightning surge current.
Fault ground fault current flows.

Conventionally, as a fault indicator to indicate a fault in the lightning arrester, a current transformer (CT) operated by the fault ground fault current was attached to the ground side of the lightning arrester, as shown in Japanese Patent Application Laid-Open No. 62-209373. The explosives built into the display device were detonated from this current transformer via lead wires, and the resulting energy was used to expose the display body to indicate a malfunction in the lightning arrester.

[Problem to be solved by the invention]

However, since the conventional gunpowder-type failure indicator uses gunpowder that is sensitive to moisture, it has not been reliable enough for long-term use. Further, there are problems such as the need for an expensive current transformer and the inability to reduce costs.

An object of the present invention is to provide a fault indicator for a lightning arrester that is reliable over a long period of time and can reliably indicate a fault.

[Means to accomplish the task]

In the invention of claim 1, in order to achieve the above object, case 2
A connecting part 8 connected in series between the power transmission line side and the ground side,
9, and a resistor element 17 having a non-linear voltage-current characteristic and damaged by faulty ground fault current is housed in the case 2 while being electrically connected to both the connecting parts 8 and 9, An opening 15 provided in the case 2 is covered and fixed with a pressure release cover 5, and the pressure release cover 5 is separated from the case 2 or damaged when the resistance element 17 is damaged.

In the invention of claim 2, in order to achieve the above object, case 2
A connecting part 8 connected in series between the power transmission line side and the ground side,
9, and in the case 2, a resistive element 17 having a non-linear voltage-current characteristic and having a maximum discharge withstand capacity smaller than the maximum discharge withstand capacity of the current-limiting element built in the lightning arrester 34 is provided, and the resistor element 17 is connected to both the above-mentioned. It is electrically connected to part 8゜9 and stored, and case 2
The opening 15 provided in the opening 15 is covered and fixed with a pressure release cover 5,
The pressure relief cover 5 is separated from the case 2 or damaged when the resistance element 17 is damaged.

[Effect]

In the invention of claim 1, since the connecting portion 8°9 is provided in the case 2, it can be connected in series with the lightning insulator disposed between the power transmission line side and the ground side, and the lightning surge current can be connected to the ground. Can be discharged.

Furthermore, when a fault ground fault current flows through the resistance element 17, since the resistance element 17 has nonlinear voltage-current characteristics,
Thermal runaway occurs within a short period of time, resulting in reliable destruction. Since this destruction of the resistance element 17 is accompanied by an explosion, the pressure release cover 5 is separated from the case 2 or damaged. Pressure release cover 5 is case 2
If the lightning arrester 34 is separated or damaged, this condition can be visually recognized from the outside, and a failure of the lightning arrester 34 is indicated. In particular, the fault indicator is activated by the fault ground fault current that flows after the lightning arrester is damaged, so if the fault indicator is activated, it will definitely indicate that the lightning arrester is damaged and will prevent malfunction. do not have.

In the invention of claim 2, since the resistive element 17 is a resistive element with a maximum discharge withstand capacity smaller than that of the current limiting element built in the lightning arrester 34, a large lightning surge comparable to the maximum discharge withstand capacity of the current limiting element can be avoided. When current flows, the resistive element 17 undergoes thermal runaway and is destroyed before the current limiting element.

In particular, there is a high possibility that the current limiting element has deteriorated even if it is not visually damaged due to a lightning surge current that is comparable to the maximum discharge withstand capacity of the current limiting element. Therefore, if the failure indicator indicates a failure, a deteriorated lightning arrester that requires replacement can also be displayed, and the lightning arrester that should be inspected or replaced can be reliably displayed.

[Example 1] Hereinafter, Example I of the invention of claim I will be described in detail based on FIGS. 1 to 5.

The invention according to claim 1 is a case in which a fault indicator l is activated by a fault ground fault current.

In this embodiment 1, the case 2 of the fault indicator 1 is constructed by sealingly fixing each end of a cylinder 3 with a cover 4 and a pressure relief cover 5, and a connecting conductor plate 6 on both sides of the main body 2. 7 are connected and fixed, and connecting portions 8.9 are formed at each end of the connecting conductive plates 6, 7 to connect in series with the lightning arrester.

The cylindrical body 3 is made of thick insulating porcelain, and is formed into a bottomed cylindrical shape with the minus side open.

A thick flange 10 is integrally formed on the opening edge of the cylinder 3, and a flange 12 having an inclined surface 11 that widens toward the bottom is integrally formed on the outer circumference of the bottom side. has been done. Moreover, in the center of the bottom surface 13 of the cylinder body 3,
An opening 15 having a smaller diameter than the inner circumferential surface 14 of the body of the cylinder 3 is provided.

The cover 4 is made of a conductive metal plate, and is bent along the outer edge of the flange 10 to have a U-shaped cross section.
The open side of the cylinder 3 is covered and fixed. In addition, flange I
A backing 16 is inserted between O and the cover 4 to ensure the airtightness of the case 2. Further, the pressure release cover 5 is made of a thin conductive metal plate, and its peripheral edge is formed by the flange 12.
is bent along the slope 11 of
The bottom side of the cylinder 3 is covered and fixed. Therefore, the fixation of the pressure release cover 5 is weaker against internal pressure than the fixation of the cover 4, which has a U-shaped cross section. Note that a backing 16 is inserted between the flange 12 and the cover 4 to ensure the airtightness of the case 2.

Connecting conductive plates 6, 7 are protruded and fixed to the central portions of the covers 4, 5 by means such as welding.

The connecting conductive plates 6 and 7 are flexible thin plates, and connecting holes 8 and 9 are provided at both ends of the connecting conductive plates 6 and 7, respectively, to connect the case 2 in series between the power transmission line side and the ground side. It is formed in four places.

Further, a cylindrical resistance element 17 having a diameter slightly smaller than the inner diameter of the cylinder 3 is housed inside the cylinder 3 which is made airtight by the covers 4 and 5.

This resistance element 17 is mainly composed of zinc oxide, which exhibits non-linear voltage-current characteristics, and electrical energy exceeding a predetermined value per unit time causes thermal runaway and is destroyed with thermal shock. It has properties. That is, the resistance element 17 has a characteristic of being destroyed explosively with thermal shock.

Between the cover 4 and the resistance element 17 is a plate-shaped spring holder 18 formed to have approximately the same diameter as the resistance element 17.
19 are provided respectively, and the resistive element 17 is pressed and fixed against the bottom surface 13 by a coiled spring 20 interposed between the spring receiving fittings 18 and 19. Furthermore, a conductive material 21 made of flexible aluminum foil or copper foil is interposed between the spring holders 18 and 19 on the outside of the spring 20, so that the electrical connection between the two spring holders 18 and 19 is Connection is secured. Therefore, the resistance element 17 and the cover 4 are sufficiently electrically connected.

In addition, inside the opening 15, a plate-shaped spring holder 22, 23 is provided.
are provided respectively, and a coiled spring 24 interposed between the spring receivers 22 and 23 presses and biases the resistance element 17 and the center portion of the pressure release cover 5. Furthermore, a conductive material 25 made of flexible aluminum foil or copper foil is interposed between the two spring holders 18 and 19 on the outside of the spring 24, so that the electrical connection between the two spring holders 22 and 23 is Connection is secured. Therefore, the resistance element 17 and the pressure release cover 5 are electrically connected sufficiently.

Next, an example in which the lightning arrester 26 is constructed by installing the failure indicator l of the first embodiment configured as described above will be described with reference to FIGS. 2-3.

A suspension insulator 29 is suspended and fixed to the support arm 27 of the steel tower via a connecting fitting 28. A wire clamp 31 is connected to the lower part of the suspension insulator 29 via a connecting fitting 30.
A power transmission line 32 is supported by this electric wire clamp 31 .

Further, a mounting adapter 33 is supported by a cantilever on the support arm 27, and a lightning arrester 34 is suspended from the bottom surface of the distal end of the mounting adapter 33 in parallel with the suspension insulator 29. The lightning arrester 34 consists of a voltage-resistant insulating tube (not shown), a mounting bracket 35 on the installation side that is fitted and fixed to both upper and lower ends of the insulating tube, a discharge electrode fitting 36 on the energized side, and a voltage-current characteristic built into the voltage-resistant insulating tube. A current limiting element made of zinc oxide with linearity (not shown).

) and a rubber mold 37 provided on the outer periphery of the voltage-resistant insulating cylinder.

In addition, the discharge electrode 3 on the installation side is attached to the tip of the discharge electrode metal fitting 36.
8 is supported, and is arranged to face the discharge electrode 39 on the power supply side, which is fixedly attached to the connecting fitting 30 on the side of the suspension insulator 29, with a predetermined air discharge gap G therebetween.

As shown in FIGS. 2 and 3, the mounting bracket 35 of the lightning arrester 34 is fixed to the mounting adapter 33 with a mounting bolt 40, and is connected to a grounding terminal 42 protruding from the upper end of the lightning arrester 34 via an insulated terminal 41. In this case, a plate-shaped mounting bracket 43 to which the power supply side of the fault indicator 1 is attached is fixedly tightened with a mounting bolt 44 . Further, on the upper surface of the mounting adapter 33, a plate-shaped mounting bracket 45 for mounting the ground side of the failure indicator 1 is secured by a mounting bolt 46. In addition, the connection holes 8 and 9 formed in the connection conductive plates 6 and 7 of the failure indicator l and the bolt insertion holes (
Not shown. ) and are connected and fixed by mounting bolts 47.

Next, the resistance element 17 built into the failure indicator l attached to the lightning arrester 26 will be explained.

FIG. 4 shows the relationship between the current limiting element built into the lightning arrester and the resistance element 17 built into the fault indicator. In FIG. 4, a failure indicator incorporating a resistive element 17 with a large maximum discharge withstand capacity a is selected for the maximum discharge withstand capacity a of the current limiting element. Therefore, even if a surge current exceeding the maximum discharge withstand capacity of the current limiting element flows, the current limiting element is destroyed and the resistive element 17 does not operate. However, when an AC overcurrent flows through the resistance element, the AC overcurrent takes a very long time (and thus the amount of energy is very large) compared to the lightning surge current, which is in microseconds, so the resistance element 17 is activated. Destruction occurs with thermal shock due to thermal runaway.

Note that the resistance element 1 having the same varistor voltage as the current limiting element
In order to cause the resistive element 17 to perform this operation using the resistor 7, it is possible to make the cross-sectional area of the resistive element 17 larger than that of the current limiting element.

Furthermore, if the maximum discharge withstand capacity of the resistor element 17 is set to be much larger than the maximum discharge withstand capacity of the current-limiting element, the operation start time of the resistor element 17 becomes longer. It is desirable that the difference in maximum discharge capacity is as small as possible, and considering manufacturing variations, 5.
It is sufficient to increase it by about %.

Next, the lightning arrester 2 equipped with the fault indicator 1 as described above is
6, its effect will be explained.

Now, when a lightning surge current flows through the power transmission line 32, as shown in FIG. It flows to the discharge electrode 38. Then, it flows through the current limiting element, passes through the grounding terminal 42, the mounting bracket 43, the fault indicator 1, the mounting bracket 45, and the mounting adapter 33, flows to the support arm 27 of the steel tower, and is discharged to the ground. The subsequent flow of the operating voltage that occurs thereafter is limited and interrupted by the current limiting element built into the lightning arrester 34, thereby preventing ground faults. At this time, the lightning surge current flows through the failure indicator 1 from the right connecting conductive plate 6 to the cover 4, the spring receiver 18, the conductive member 21, and the spring receiver 19 to the resistance element 17 in FIG. Then, from the resistance element 17 to the spring holder 22 and the conductive material 2
5. It flows from the pressure release cover 5 to the left connecting conductive plate 7 via the spring receiver 23.

Since the resistance element 17 is selected to be larger than the maximum discharge withstand capacity of the current-limiting element built into the lightning arrester 34, it is possible to allow the surge current to flow without the failure indicator l operating against lightning surge current. can.

Next, if the current limiting element built into the lightning arrester 34 is destroyed and becomes conductive, it will no longer be possible to block the follow-on current following the electric shock, and the current will flow through the resistance element 17 of the fault indicator l. An alternating current overcurrent flows to the support arm 27 of the steel tower. Since the AC overcurrent at this time has a very long time compared to the lightning surge current in microsecond units, the amount of energy is extremely large and exceeds the AC overcurrent withstand capacity of the resistance element 17. As a result, the resistance element 17 undergoes thermal runaway and is destroyed with thermal shock. With this explosive destruction of the resistance element 17, the internal pressure inside the airtight case 2 suddenly increases, and the pressure release cover 5 is caused by the biasing force of the spring 24, as conceptually shown in FIG. extends at the bent portion 5a and separates or partially peels off from the flange 12. In addition, the flexible connecting conductive plate 6
, 7 are fixed by mounting fittings 43, 45, the pressure relief cover 5 abuts against the cylinder body 3 in a staggered manner, giving the appearance of being separated or peeled off. From this appearance, it can be visually confirmed that the failure indicator 1 has been activated, and a failure of the lightning arrester 34 is displayed.

Furthermore, both ends of the flexible connecting conductive plates 6 and 7 are attached to mounting brackets 43.
45, and the pressure release cover 5 is not significantly separated from the cylinder body 3, so the spring receivers 18, 19
, the spring 20 , the conductive material 21 , the destroyed objects of the resistance element 17 , the spring receivers 22 , 23 , the spring 24 , the conductive material 25 , etc. remain in the opening 15 . Therefore, it is possible to reduce the number of dangerous objects falling onto the ground due to the activation of the failure indicator 1.

In this first embodiment, the resistive element 17 that is destroyed by a faulty ground fault current is electrically connected to the connecting parts 8 and 9, and the fault indicator 1 is activated by the faulty ground fault current. If the display 1 indicates a failure, it can certainly indicate that the lightning arrester 34 is damaged, and there will be no erroneous display.

[Example 2] Next, a second embodiment of the invention according to claim 2 will be described.

Here, the configuration of the second embodiment is almost the same as that of the first embodiment.

Therefore, descriptions of items common to Example 1 will be omitted, and only items that are different will be described.

Here, if a lightning surge current comparable to the maximum discharge withstand capacity flows through the current limiting element built into the lightning arrester 34, even if the current limiting element is not clearly destroyed in appearance, it will deteriorate significantly and lose its current limiting effect. You may have lost it. Such a deteriorated lightning arrester cannot exhibit a normal current limiting effect against the next lightning surge. For this reason, in the second embodiment, as shown in FIG. 4, the failure indicator is provided with a built-in resistor element 17 having a smaller maximum discharge withstand capacity C than the maximum discharge withstand capacity a of the current limiting element.

The purpose of this is that if the fault indicator l indicates a fault,
This lightning arrester 34 should be inspected or replaced as it has deteriorated, and should be maintained as a lightning arrester device that can always perform its lightning protection function.

In the second embodiment, in FIG. 4, a failure indicator is selected that incorporates a resistive element 17 having a smaller maximum discharge withstand capacity C than the maximum discharge withstand capacity a of the current limiting element.

Therefore, if an electric surge current exceeding the maximum discharge withstand capacity of the current limiting element flows, the resistance element 17
is activated, and the resistance element 17 is destroyed with a thermal shock due to thermal runaway. Then, as in the first embodiment, the pressure release cover 5
separates from the cylindrical body 3, indicating a failure of the lightning arrester 34.

For example, in order to make the resistance element 17 perform this operation by using the resistance element 17 having the same varistor voltage as the current-limiting element, the cross-sectional area of the resistance element 17 can be made smaller than that of the current-limiting element. .

Furthermore, if the maximum discharge withstand capacity of the resistor element 17 is set to be much smaller than the maximum discharge withstand capacity of the current limiting element, a failure will be indicated by the prescribed duty current of the lightning arrester. It is desirable that the difference in maximum discharge capacity of the elements be as small as possible, and even considering manufacturing variations, it is desirable to reduce the difference by about 5%.

[Embodiment 3] Next, the failure indicator 51 of Embodiment 3 will be explained based on FIG. 6. Note that the same parts as in Example 1 will be briefly described.

The case 52 of the fault indicator 51 of this third embodiment is constructed by sealing and fixing each end of a cylindrical body 53 with a cover 54, 55 in the same way as the fault indicator 1 of the first embodiment. Connecting conductive plates 56 and 57 are connected and fixed on both sides, and connecting portions 58 and 59 are formed at each end of the connecting conductive plates 56 and 57 to connect the lightning arrester in series. An opening 62 having a smaller diameter than the inner circumferential surface 61 of the body of the cylinder 53 is provided in the center of the bottom surface 60 of the cylinder 53 .

A flange 63 having a U-shaped cross section is provided on the outer periphery of both ends of the cylinder 53.
．． 64 is formed, and the metal cover 54 has conductivity.
．． The outer edges of the flanges 63 and 64 are bent into a U-shaped cross section to cover and fix the opening. Also cover 5
A pressure relief hole 65 is formed in the center of 5, and this pressure relief hole 65
A pressure relief cover 67 is covered and fixed via a mounting ring 66 fixed to its outer edge. In addition, the pressure release cover 6
A backing 68 is inserted between the case 7 and the cover 55 to ensure the airtightness of the case 52.

In FIG. 6, a dish-shaped spring holder 69 is provided between the resistance element 17 in the opening 62 and the pressure release cover 67.
A spring 70 is interposed between them to press and bias the pressure release cover 67. In addition, a tape-shaped conductive material 71 is attached to the spring 7°.
is wrapped around the spring receiving fitting 69 and the pressure release cover 67 to ensure electrical connection.

A pointed striker 72 is adhesively fixed to the spring receiving metal fitting 69 and is disposed facing the pressure release cover 67 .

The effect when the fault indicator 51 of this third embodiment is attached to a lightning arrester is almost the same as that of the first and second embodiments, but as the resistance element 17 is destroyed due to thermal shock, the striker 72 It breaks through the pressure relief cover 67 and protrudes from the pressure relief cover 67.

The failure is indicated by the appearance of the pressure relief cover 67 that has been pierced. Therefore, in this third embodiment, the failure indicator 5
There can be almost no dangerous falling objects associated with the operation of item 1.

Note that if the striker 72 is made of a white, red, or yellow display that can be seen from a distance and is configured to remain in a protruding state after activation, the striker 72 can also indicate a malfunction.

Further, as shown in the first or second embodiment, the fault indicator 51 of this third embodiment also has a maximum discharge of the current limiter shown in FIG. Resistance element 1 with maximum discharge withstand capacity C or maximum discharge withstand capacity C for withstand capacity a
You can select a failure indicator with built-in 7.

In addition to the above embodiments 1 to 3, the present invention can also be embodied as follows. In addition, for the sake of brevity,
The same parts as in Examples 1 to 3 are given the same reference numerals, and details thereof will be omitted.

(1) The case 2° 52 in Examples 1 to 3 is a cylindrical body 3, 53, but the case and the cover may be formed integrally, or a cylindrical case may be used. Not limited to.

(2) In the case 2 in Embodiments 1 to 3, the pressure relief covers 5 and 67 are biased from inside by springs to facilitate the operation of the pressure relief covers 5 and 67. It is not necessarily necessary to apply a biasing force, and the structure may be such that it is activated by a shock when the resistance element is destroyed.

(3) In the first embodiment, the failure indicator 1 is attached to the mounting adapter 33 of the suspension insulator 29, but the failure indicator may also be connected to the mounting bracket 35 of the suspension insulator 29, or attached to other appropriate parts. It is also possible to attach it.

(4) In the first embodiment, the connecting conductive plates 6 and 7 are made of a flexible plate material, but they are made of a rigid material, and the connecting conductive plates are rotatable downwardly. A section may be provided.

(5) In Examples 1 and 2, an example was shown in which the lightning arrester 26 was installed in parallel with the suspension insulator 29 and the air discharge gap G was provided in series, but the lightning arrester that can be installed is limited to this. It can be widely applied without being affected.

〔Effect of the invention〕

As described in detail above, the invention of claim 1 electrically connects the resistance element that is destroyed by a faulty ground fault current to the connecting part,
Since the pressure release cover is separated or damaged when the resistance element is destroyed, it is possible to provide a lightning arrester insulator failure indicator that is reliable over a long period of time and can reliably indicate failure of the lightning arrester insulator. Moreover, the failure indicator can clearly indicate that the lightning arrester is damaged, and the necessity of replacing the lightning arrester can be recognized.

The invention of claim 2 provides electrical connection between both connecting portions of a resistive element having non-linear voltage-current characteristics and having a maximum discharge withstand capacity smaller than the maximum discharge withstand capacity of a current limiting element built into the lightning arrester. Since the pressure relief cover is separated from the case or damaged when the resistance element is damaged, it is possible to provide a reliable failure indicator for the lightning arrester. Further, by displaying the fault indicator, it is possible to indicate a fault in a deteriorated lightning arrester insulator that requires replacement, thereby making it possible to maintain a healthy power transmission line.

[Brief explanation of the drawing]

1 to 5 show Embodiment 1 of the present invention, FIG. 1 is a sectional view, FIG. 2 is a front view showing the installed lightning arrester, FIG. 3 is an enlarged front view of the installed part, and FIG. FIG. 4 is a graph showing the relationship between the current limiting element and the resistance element, FIG. 5 is a sectional view conceptually showing the state after operation, and FIG. 6 is a partial sectional view showing the third embodiment. 1...Fault indicator, 2...Case, 5,67...
Pressure release cover 8... Connection hole as a connection part, 9...
Connection hole as a connection part, 15... opening, 17...
Resistance element, 34... Lightning arrester

Claims (1)

[Claims] 1. The case (2) is provided with connecting parts (8, 9) that are connected in series between the power transmission line side and the ground side, and the case (2) has voltage-current characteristics. A resistive element (17) which has non-linearity and is damaged by faulty ground fault current is connected to both the connecting parts (8, 9).
The opening (15) provided in the case (2) is covered and fixed with a pressure release cover (5), and when the resistance element (17) is damaged, the pressure release cover (5) ) is separated from the case (2) or damaged. 2. The case (2) is provided with a connection part (8, 9) that connects in series between the power transmission line side and the ground side, and the voltage-current characteristic has non-linearity in the case (2). And lightning insulator (34)
A resistor element (17) having a maximum discharge withstand capacity smaller than the maximum discharge withstand capacity of the current limiting element built in the above-mentioned connecting parts (8, 9)
), and the opening (15) provided in the case (2) is covered and fixed with a pressure release cover (5), and when the resistance element (17) is damaged, the pressure release cover ( 5) is configured to be separated from the case (2) or damaged.