JP2014116157A - Transmission line arrester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission line arrester having high compatibility with conventional products, in which switching surge withstand voltage and economy are enhanced.SOLUTION: In a transmission line arrester attached to a support insulator 2 for supporting a transmission line 4 where one end of a ground side fixing metal fitting 3 is attached to one end of the support insulator 2, a ground side discharge electrode 7 is coupled to the other end of the ground side fixing metal fitting 3 and supported, one end of a charging side fixing metal fitting 5 is attached to the other end of the support insulator 2, and a charging side discharge electrode 10 is coupled to the other end of the charging side fixing metal fitting 5 via a charging side arrester element 8a, a charging side shield electrode is provided, at least partially, around the charging side arrester element 8a.

Description

  Embodiments of the present invention relate to a lightning arrester for power transmission attached to a support insulator.

  In the power transmission system, a support insulator is provided for insulating and holding the power transmission line from a support such as a steel tower. A lightning arrester for power transmission is a device attached to this support insulator, and it is equipped with a lightning protection element that prevents insulation breakdown of the holding part due to lightning and surge due to overvoltage and damage to the holding part due to AC arc discharge current following insulation breakdown. Have.

  The support insulator is configured such that the upper end is attached to the steel tower and the power transmission line is held at the lower end. The lightning protection element is connected and supported by the support insulator, and the support insulator and the lightning protection element are arranged in parallel. In recent years, a lightning arrester for power transmission having a configuration in which a grounding discharge electrode provided to be connected to and supported by a support insulator and a charging discharge electrode provided at an end of the lightning protection element are opposed to each other with a predetermined discharge gap. Equipment is mainstream.

JP 2011-066585 A

  By the way, in a lightning arrester for power transmission, switching surge withstand voltage performance is one of the important factors for determining electrical characteristics and external dimensions. The switching surge withstand voltage performance is a tolerance performance against an abnormal voltage generated when a current is switched. The switching surge withstand voltage performance is obtained by a method such as a lifting method from the presence or absence of flashover when a switching surge voltage is applied to the device to be measured. The switching surge withstand voltage performance is required to be higher in order to ensure that the flashover does not occur due to the system voltage even when the lightning arrester body fails and a high voltage is applied to the discharge electrode.

  In addition, the gap length of the discharge gap that increases the switching surge withstand voltage performance varies depending on the lightning arrester equipment and the voltage applied to the discharge gap. Therefore, in general, the gap length is determined by performing two tests, a preliminary test and a main test. That is, in the preliminary test, the ground side discharge electrode and the charging side discharge electrode of the lightning protection part are simulated, and the switching impulse voltage is instantaneously applied to these electrodes, and the lower limit of the gap length is determined by the response to the voltage. The value is determined. Next, in this test, the entire lightning arrester is simulated and the same test as the preliminary test is performed to determine the gap length that increases the switching surge withstand voltage performance.

  The reason for conducting the preliminary test separately from the main test is that it takes cost and labor to simulate the entire lightning arrester in consideration of the installation environment, etc., so this test is repeated to optimize the gap length. Doing so may affect development efficiency and economic efficiency. On the other hand, since the optimum gap length differs depending on the configuration of the lightning arrester, there is a case where the switching surge withstand voltage performance varies between the preliminary test simulator and the main test simulator. In this case, the preliminary test and the main test are repeated a plurality of times, and the development period becomes longer, which may affect economic efficiency.

  The embodiment of the present invention has been proposed in order to solve the above-described problems of the prior art. The object is to provide a lightning arrester for power transmission with improved switching withstand voltage performance, high compatibility with conventional products, and improved economy.

  A lightning arrester for power transmission according to an embodiment for achieving the object as described above is a lightning arrester for power transmission attached to a support insulator that is attached to a steel tower and supports a transmission line, and is fixed to one end of the support insulator on the ground side One end of the metal fitting is attached, and the ground-side discharge electrode is connected to and supported by the other end of the fixing metal fitting. One end of the power application side fixing metal fitting is attached to the other end of the supporting insulator, and the other end of the fixing metal fitting is charged. In the lightning arrester for power transmission in which the side discharge electrode is connected and supported via the power distribution side lightning protection element, a power transmission side shield electrode is provided on at least a part of the periphery of the power distribution side lightning protection element. .

It is a front view which shows an example of a structure of the lightning arrester for power transmission of 1st Embodiment. It is a front view which shows an example of a structure of the lightning arrester for power transmission of 2nd Embodiment. It is a front view of the shield electrode which shows the modification of embodiment. It is a front view of the shield electrode which shows the modification of embodiment.

[First Embodiment]
[1. Constitution]
A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing an example of a lightning arrester for power transmission according to this embodiment. As shown in FIG. 1, the lightning arrester A for power transmission is a device that is attached to a support insulator 2 that supports a power transmission line. The support insulator 2 is suspended and fixed to a support arm 1 extending from a steel tower of a transmission line provided fixed to the ground. In the following description, the support arm 1 side is expressed as the ground side or the upper side, and the power transmission line 4 side is expressed as the power application side or the lower side.

  At the lower end portion of the support arm 1, the upper end portion of the support insulator 2 extending toward the charging side is suspended and fixed toward the ground by a bolt (not shown). The support insulator 2 is composed of a plurality of suspension insulators, and the power transmission line 4 is insulated and supported at the lower end. Further, the support insulator 2 is attached with a grounding side fixing bracket 3, a power-charging side fixing bracket 5, and a pair of arc horns 6. Specifically, the ground-side fixing metal fitting 3 is a plate-like or bar-like member extending in a direction perpendicular to the axis of the support insulator 2, and one end thereof is attached to the upper end side of the support insulator 2.

  In addition, the charging-side fixing bracket 5 is a plate-like or bar-like member that extends in the same direction and parallel to the ground-side fixing bracket 3, and one end thereof is attached to the lower end side of the support insulator 2. The pair of arc horns 6 are attached to the upper and lower ends of the support insulator 2 so as to face each other with a discharge gap therebetween. The pair of arc horns 6 are extended so as to face the fixtures 3 and 5 with the support insulator 2 interposed therebetween.

  On the lower surface of the other end of the ground side fixing bracket 3, a ground side discharge electrode 7, which is a rod-shaped conductor, is provided perpendicular to the ground side fixing bracket 3. Specifically, the ground-side discharge electrode 7 is fixed by a bolt (not shown) so as to hang from the lower surface of the ground-side fixing bracket 3. That is, the ground-side discharge electrode 7 is connected and supported on the upper end side of the support insulator 2 via the ground-side fixing bracket 3 and is disposed substantially parallel to the axis of the support insulator 2.

  A lightning protection element 8 a is provided on the upper surface of the other end of the power application side fixing metal 5 perpendicularly to the power application side fixing metal 5. The lightning protection element 8a is a cylindrical pressure-resistant insulating cylinder, and a plurality of zinc oxide elements are accommodated therein. Metal flanges 9a and 9b are provided at the upper and lower ends of the lightning protection element 8a. The lightning protection element 8a is provided so that the lower end metal flange 9b is fixed to the charging-side fixing bracket 5 with a bolt (not shown) and rises from the upper surface of the charging-side fixing bracket 5, and is substantially parallel to the axis of the support insulator 2. Is arranged.

  On the metal flange 9a at the upper end of the lightning protection element 8a, a charging-side discharge electrode 10 which is a rod-shaped conductor is provided so as to face the ground-side discharge electrode 7. Specifically, the electricity application side discharge electrode 10 is fixed by a bolt (not shown) so as to rise from the upper surface of the metal flange 9a. That is, the charging-side discharge electrode 10 is connected and supported to the lower end side of the supporting insulator 2 via the metal flanges 9a and 9b, the lightning protection element 8a, and the applying-side fixing metal fitting 5, and is substantially the same as the axis of the supporting insulator 2. They are arranged in parallel.

  The ground-side discharge electrode 7 and the power-applying-side discharge electrode 10 installed as described above are arranged so as to face each other with a predetermined discharge gap g. The discharge gap g is set to a distance that discharges only to lightning and does not discharge with an open / close surge or an AC ground voltage.

  In the above-described configuration, the lightning protection device A is provided with the power application side shield electrode 11a at least at a part around the lightning protection element 8a. The charging-side shield electrode 11a is arranged around the lightning protection element 8a, that is, with a predetermined distance from the lightning protection element 8a. It is preferable that nothing is arranged in the space between the shield electrode 11a and the lightning protection element 8a. It is preferable that the charging-side shield electrode 11a is arranged around at least a part of the surface facing the support insulator 2 in the periphery of the lightning protection element 8a.

  It is preferable that the charging-side shield 11a is disposed around a surface within a range of ± 90 degrees in the circumferential direction from the position closest to the support insulator 2 in the lightning protection element 8a. Specifically, for example, assuming that the support insulator 2 and the lightning protection element 8a are arranged so that their central axes are parallel, the center axis connecting the lightning protection element 8a and the center axis of the support insulator 2 is A straight line a perpendicular to the line can be assumed. In the lightning protection element 8a, when the straight line a is 0 degree, it is preferable that the electric power application side shield electrode 11a is arranged around a surface in the range of ± 90 degrees in the circumferential direction from 0 degree in the lightning protection element 8a. .

  Moreover, it is preferable that the charging-side shield electrode 11a is disposed around the position closest to the support insulator 2 in the surface facing the support insulator 2 in the lightning protection element 8a. Specifically, for example, it is ideal to be arranged on the straight line a, that is, near 0 degrees.

  The power application side shield electrode 11a of the present embodiment is a rod-shaped metal conductor, one end of which is fixed to the metal flange 9b by a bolt (not shown), and the other end extends toward the ground side. The charge-side shield electrode 11a has at least a tip shape that does not have a corner and is a curved surface.

  Further, the power application side shield electrode 11a is a rod-like member having a bent portion at a predetermined position and having a V-shaped cross section. Specifically, the charging-side shield electrode 11 a is configured to extend obliquely upward from the metal flange 9 b toward the support insulator 2, bend in the middle, and extend substantially parallel to the support insulator 2.

  However, the cross-sectional shape of the shield electrode 11a is not limited to the V shape, and may be a linear shape or a curved shape. That is, the shield electrode 11a only needs to be arranged with a predetermined distance from the lightning protection element 8a, and the fixed angle and the cross-sectional shape can be selected as appropriate. Further, the length of the shield electrode 11a is set to such a length that no discharge occurs between the discharge electrodes 7 and 10 and a length that can sufficiently prevent a change in potential distribution described later. .

[2 effects]
(Lightning arrester for power transmission)
Regarding the operation of the present embodiment having the above-described configuration, first, the operation of the lightning arrester A for power transmission will be described below. When a lightning surge voltage caused by a lightning strike or the like enters the power transmission line 4, the voltage applied to the lightning protection element 8a and the charging side discharge electrode 10 rises, and a discharge current flows in the discharge gap g to be discharged. Then, the current is discharged from the steel tower to the ground via the grounding side fixing bracket 3 and the support arm 1.

  Further, the subsequent current generated thereafter is cut off by the voltage-current characteristics of the zinc oxide element in the discharge gap g and the lightning insulator 8a, and is restored to the normal AC voltage waveform. The pair of arc horns 6 are destroyed by discharging at a voltage lower than the discharge voltage of the support insulator 2 in the discharge gap set between the two arc horns, so that a discharge current flows through the support insulator 2. To prevent that.

(Shield electrode)
Next, the effect | action of the shield electrode 11a is demonstrated, contrasting with a prior art example. In a conventional lightning arrester that does not have a shield electrode, the withstand voltage performance is reduced by about 10% in this test even if the discharge gap g is set to increase the switching surge withstand voltage performance in the preliminary test simulating the discharge electrode. There was a thing. The inventor's research has revealed that this decrease in switching surge withstand voltage performance is caused by the presence or absence of a support insulator.

  As a result of analysis, it has been clarified that in the conventional lightning arrester, when there is a support insulator, electrolytic concentration on the discharge electrode is more intense than when only the discharge electrode is arranged. That is, the electric potential of the lightning arrester is entirely pushed down to the power application side due to the influence of the support insulator. As a result, the potential distribution near the discharge electrode becomes dense. Thus, for example, in the preliminary test and the main test, the change in the potential distribution of the lightning arrester due to the presence or absence of the support insulator has affected the switching surge withstand voltage performance. In this case, there is a possibility of discharging at a voltage lower than the predetermined withstand voltage performance necessary for stabilizing the power system.

  On the other hand, in the lightning arrester A for power transmission according to this embodiment, since the shield electrode 11a is provided around the lightning protection element 8a, the change in potential distribution due to the presence or absence of the support insulator 2 is reduced. That is, even if the support insulator 2 is present, the shield electrode 11a can prevent the potential of the lightning arrester from being pushed down to the power application side, and can alleviate the concentration of the potential distribution in the vicinity of the discharge electrodes 7 and 10.

  In addition, since the charging-side shield electrode 11a is disposed around at least a part of the surface of the lightning protection element 8a that faces the support insulator 2, the potential change caused by the presence of the support insulator 2 as described above is prevented. It can suppress more reliably. Moreover, if the charging-side shield electrode 11a is arranged around the nearest position of the surface facing the support insulator 2 in the lightning protection element 8a, the potential change can be suppressed more reliably.

  Furthermore, since the power application side shield electrode 11a is formed in the rod-shaped member, the cost and the processing steps are reduced. Since the charging-side shield electrode 11a has at least a tip shape formed in a curved surface, there is no possibility that electrolytic concentration occurs at the corners and becomes a starting point of discharge as in the case where it is not formed in a curved surface.

[3 effects]
The effects of the present embodiment as described above are as follows.
(1) Since the power application side shield electrode 11a is arranged at least at a part around the lightning protection element 8a, concentration of potential can be alleviated. Therefore, in the lightning arrester A for power transmission having the support insulator 2, changes in the potential distribution can be suppressed and the switching surge withstand voltage performance can be improved.

(2) Further, since the charging-side shield electrode 11a is provided around at least a part of the surface facing the support insulator 2 of the lightning protection element 8a, the shielding function is enhanced and the switching surge withstand voltage performance is improved. Can be made.

(3) Further, in the development stage, after forming a simulation device with only the discharge electrodes 7 and 10 and the shield electrode 11a to set the gap length of the discharge gap g, the entire lightning arrester for power transmission including the support insulator 2 in this test Even when the test is performed in the simulation apparatus, since the potential change due to the difference between the configuration of the preliminary test and the main test can be alleviated by the shield electrode 11a, the number of tests can be reduced and the economy can be improved.

(4) Since the charge-side shield electrode 11a is formed of a rod-shaped member, costs and processing steps can be reduced, and economic efficiency can be improved. In addition, when the tip shape of the power application side shield electrode 11a is processed into a curved surface, if it is a rod-shaped member, the processing becomes relatively easy, and the economy can be improved. Furthermore, since such a rod-shaped power transmission side shield electrode 11a can be applied to an existing lightning arrester for power transmission, compatibility with conventional products can be enhanced.

[Second Embodiment]
[1. Configuration]
The front view of the lightning arrester A for power transmission of 2nd Embodiment is shown in FIG. The second embodiment is a lightning arrester A for power transmission provided with a shield electrode on the ground side. The same parts as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the lightning arrester A of the present embodiment, the lightning protection element 8b is perpendicular to the grounding side fixing bracket 3 on the lower surface of the end of the grounding side fixing bracket 3 opposite to the end attached and fixed to the support insulator 2. Is provided. The lightning protection element 8b is a cylindrical pressure-resistant insulating cylinder, and a plurality of zinc oxide elements are accommodated therein. Metal flanges 9c and 9d are provided at the upper and lower ends of the lightning protection element 8b. The lightning protection element 8b is provided such that the upper end metal flange 9c is fixed to the installation side fixing bracket 3 with a bolt (not shown) and hangs down from the lower surface of the charging side fixing bracket 3, and is substantially parallel to the axis of the support insulator 2. Has been placed.

  On the metal flange 9d at the lower end of the lightning protection element 8b, the installation-side discharge electrode 7 which is a rod-shaped conductor is provided so as to face the charging-side discharge electrode 10. Specifically, the installation-side discharge electrode 7 is fixed by bolts (not shown) so as to hang down from the lower surface of the metal flange 9d. That is, the ground-side discharge electrode 7 is connected and supported to the lower end side of the support insulator 2 through the metal flanges 9c and 9d, the lightning protection element 8b, and the charging-side fixing bracket 3, and is substantially parallel to the axis of the support insulator 2. Is arranged.

  In the above-described configuration, the lightning arrester A is provided with the ground side shield electrode 11b on at least a part of the periphery of the lightning protection element 8b. The arrangement and shape of the ground side shield electrode 11b are the same as those in the first embodiment. The shield electrodes 11a and 11b are preferably arranged so as to face each other at the same central axis at least at the tip portion.

[2. Action and effect]
As a function and effect peculiar to the second embodiment as described above, a change in potential distribution can be further suppressed as compared with the first embodiment. That is, by providing the lightning side shield electrode 11a to the lightning protection element 8a on which the power application side discharge electrode 10 is provided, a change in potential distribution can be suppressed, but a lightning protection element 8b is further provided on the ground side. In this case, by arranging the ground side shield electrode 11b around the lightning protection element 8b, the change in potential distribution can be further alleviated. Further, by arranging the shield electrodes 11a and 11b to face each other with the same central axis at at least the tip portions, the effect of suppressing the change in potential distribution can be further enhanced. As described above, the effect of the first embodiment can be improved.

[Modification of First and Second Embodiments]
[Modification 1]
The configuration of Modification 1 of the embodiment is basically the same as that of the above-described embodiment. However, the extended portion 20 is provided at the tip of the shield electrodes 11a and 11b, which are rod-shaped members. An example of the configuration of the expansion unit will be described with reference to FIG.

  As shown in FIG. 3A, a spherical expansion portion 20a may be provided at the tip of the shield electrodes 11a and 11b. Further, as shown in FIG. 3B, a semicircular annular expansion portion 20b may be provided at the tip of the shield electrodes 11a and 11b, or a quarter circular expansion member may be provided. Also good. That is, the shape of the extended part 20 should just be selected suitably, and is not limited to these. However, it is preferable that the extended portion 20 has at least a tip shape that is a curved shape having no corners.

  In the modified example having the above-described configuration, the operation of the lightning arrester for power transmission is the same as that in the above embodiment. The action of the lightning arrester A for power transmission is the same as that of the above embodiment, but even with the shield electrodes 11a and 11b, which are rod-shaped members, the shielding effect can be exerted in a wider range by having the extended portion 20. Can do. Therefore, the change in potential distribution can be more reliably suppressed, and the effect of the embodiment can be further improved.

[Modification 2]
The configuration of the second modification of the embodiment is basically the same as that of the above embodiment. However, instead of the shield electrodes 11a and 11b which are rod-shaped members, an annular shield electrode 21 is provided. An example of the form of the annular shield electrode 21 will be described with reference to FIG. As shown in FIG. 4, the shield electrode 21 has an annular metal conductor 21a, and the support member 21b supports the annular member 21a. It is preferable that the annular member 21a has at least a tip shape of a curved surface having no corners.

  In the modified example having the above-described configuration, the operation of the lightning arrester for power transmission is the same as that in the above embodiment. Although the operation of the lightning arrester A for power transmission is the same as that of the above embodiment, the shield electrode 21 having an annular member can surround the entire circumference of the lightning arrester 8a with the shield electrode. Therefore, for example, the change in the potential distribution of the lightning arrester A for power transmission including the change in the potential distribution in the range that was not predicted can be most effectively suppressed, and the effect of the embodiment can be further improved. .

[Other Embodiments]
(1) In the above embodiment, the shield electrode is arranged so as to reduce the change in potential distribution caused by the support insulator 2, but the position of the shield electrode is not limited to this range. That is, the shield electrode may be arranged in consideration of the actual configuration and arrangement position of the lightning arrester A for power transmission. That is, when a member other than the support insulator 2 causes a change in the potential distribution, it may be arranged so as to reduce the change.

(2) The vertical / horizontal and arrangement directions of the members in the above embodiment are merely examples for explaining the embodiment, and are not limited to the above contents. That is, the fixtures 3 and 5 do not necessarily have to be extended in the vertical direction from the support insulator. Even when the fixing brackets 3 and 5 are extended in directions other than the vertical direction, the angles of the lightning protection elements 8a and 8b and the discharge electrodes 7 and 10 are changed, and the respective members are arranged substantially parallel to the axis of the support insulator 2. You can also.

  Similarly, the lightning protection elements 8a and 8b and the discharge electrodes 7 and 10 are not necessarily arranged substantially parallel to the axis of the support insulator 2. Even when the lightning protection elements 8a and 8b are arranged so as not to be parallel to the support insulator, the angle of the discharge electrodes 7 and 10 can be changed to be arranged substantially parallel to the axis of the support insulator 2. Further, the discharge electrodes 7 and 10 are not necessarily arranged substantially in parallel with the axis of the support insulator 2 and can be appropriately changed.

  That is, the present invention has a shield electrode as one of the characteristic structures, and can be applied to conventional and future lightning arresters for power transmission regardless of the detailed structure of the lightning arrester for power transmission. Therefore, the shield electrode can be applied to a wide variety of lightning arresters for power transmission by changing the position of the shield electrode in consideration of changes in the potential distribution due to the device configuration and installation environment.

  (3) In the above-described embodiment, an example in which a rod-like shape, a rod-like shape having an extended portion, and an annular shield electrode are described, but a plurality of shield electrodes may be provided. That is, a plurality of rod-shaped shield electrodes may be provided, or a plurality of shield electrodes each having an extended portion obtained by dividing an annular member may be used to form an annular extended portion. Moreover, the combination of each shield electrode is also free. That is, you may provide an expansion part in one part among several bar-shaped shield electrodes.

  (4) Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

A ... Lightning arrester 1 for power transmission ... Support arm 2 ... Support insulator 3 ... Grounding fixture 4 ... Power transmission line 5 ... Electric charging fixture 6 ... Arc horn 7 ... Ground discharge electrodes 8a, 8b ... Lightning protection elements 9a, 9b , 9c, 9d ... Metal flange 10 ... Electric discharge electrode 11a, 11b ... Shield electrode

Claims (8)

It is a lightning arrester for power transmission that is attached to a support insulator that supports the transmission line,
One end of the ground side fixing bracket is attached to one end of the support insulator, and the ground side discharge electrode is connected and supported to the other end of the ground side fixing bracket,
One end of a charging side fixing bracket is attached to the other end of the support insulator, and a lightning arrester for power transmission in which a charging side discharge electrode is connected to and supported by the other end of the charging side fixing bracket via a lighting side lightning protection element. In
A lightning arrester for power transmission, characterized in that a power-sending-side shield electrode is provided on at least a part of the periphery of the power-sending-side lightning protection element. The ground side discharge electrode is connected and supported via a ground side lightning protection element,
The lightning arrester for power transmission according to claim 1, wherein a ground shield electrode is provided on at least a part of the periphery of the ground lightning protection element.   The lightning arrester for power transmission according to claim 1 or 2, wherein the shield electrode is disposed around at least a part of a surface of the lightning protection element facing the support insulator.   The lightning arrester for power transmission according to any one of claims 1 to 3, wherein the shield electrode is a rod-shaped member.   The lightning arrester for power transmission according to any one of claims 1 to 4, wherein an extended portion is provided at a tip of the rod-shaped shield electrode.   The lightning arrester for power transmission according to any one of claims 2 to 5, wherein the power application side shield electrode and the ground side shield electrode are arranged so that center axes thereof coincide with each other.   The lightning arrester for power transmission according to any one of claims 1 to 3, wherein the shield electrode has an annular member surrounding the lightning protection element.   The lightning arrester for power transmission according to any one of claims 1 to 7, wherein the shield electrode is formed with a curved surface at least in a tip shape.

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