JPH0129933Y2 - - Google Patents

Description

[Detailed description of the invention] This invention limits or blocks the follow-on flow of AC caused by lightning flashovers in power transmission and distribution lines using insulated wires, thereby eliminating disconnection and damage to the insulators, protecting the lines and preventing ground faults. This relates to a lightning disconnection prevention unit that restores insulation on its own to prevent power outages.

Conventionally, when an impact overvoltage caused by a lightning surge is applied to a power transmission/distribution line fault using insulated wires, the insulation coating of the wire is penetrated and flashover occurs in the insulator. Damage occurred, including melting and damage to the insulators. In addition, even if the wire did not break, the insulator did not have the ability to restore its insulation on its own, and ground fault relays and equipment at the substation were activated to cut off the following current, resulting in a power outage to the line. Therefore, JP-A-55
-As in the invention described in Publication No. 136412, a current-limiting element containing a current-limiting element made of a material with non-linear voltage-current characteristics is interposed in the energizing-side arcing horn attached to the cap fitting of the clamp-top insulator. It is also known that the insulator device is able to limit or cut off the follow-up current that accompanies lightning flashing, prevent wire breakage and damage to the insulator, and also allow the insulator device to restore its insulation on its own to prevent power outages on the line. However, in this invention, in order to clamp the electric wire and connect it to the arcing horn on the energized side, it is necessary to strip off the insulation coating. Therefore, it is necessary to install an insulating cover, which takes time to install the pole, and if the insulating cover is installed, birds may use their beaks to catch insects and cause ground faults using themselves as a medium. There was a risk of damage from birds and stress corrosion of the core wire due to rainwater entering the inside of the insulating cover. In addition, the current-limiting element attached to the arcing horn on the energized side is large because it has a pleated insulation coating, and it also forms an intervening part close to the insulator body, so snow can freeze in this part in the winter. A large snowpack will adhere to the head of the insulator, and icicles that form on this snowpack will hang down and connect to the ground side arcing horn, inducing a ground fault due to normal overvoltage caused by line switching, and There was also a concern that external force would be applied to the current limiting element due to weight, wind pressure load, etc., accelerating deterioration of the current limiting element. Furthermore, the above-mentioned invention relates to a clamp-top insulator, and in power distribution lines where tight-top insulators that grip electric wires with their insulation coatings are in the majority, when installing the current-limiting element on an existing line, it is necessary to Various problems remained, including a lack of practicality, such as the need to replace the insulator due to a power outage.

Furthermore, in JP-A-50-41088, an air gap is formed between an insulated wire and an intermediate electrode attached to a current limiting unit, and the intermediate electrode is formed in an arc shape to partially cover the creeping surface of the insulator. A gap device with a current limiter is disclosed that is disposed around a current limiter. Although this device is more practical than the case where it is installed on the power supply side as in the previous example, special consideration has not been given to the ability to capture flashovers caused by lightning surges and the simple means of installation to huge existing equipment on power lines. I wasn't there.

The present invention was completed with the aim of providing a lightning disconnection prevention unit that solves the above-mentioned problems, and the present invention will be described in detail below with reference to the illustrated embodiments.

Reference numeral 1 denotes a grounding fitting such as a grounding arm; a tight-tipped insulator body 2 is fastened and fixed to the grounding fitting 1 with a base fitting 6a and a pin fitting 6b which are integrally fixed to the grounding side end of the grounding fitting 1; A wire receiving groove 3a is provided on the circumferential surface of the head 3 of the insulator body 2, and the covered wire 4 is inserted into the wire receiving groove 3a without removing the insulation coating 4b, and the bound wire 5
It is fixedly supported by the head 3 with a . 7 is a conventionally known current limiting element 7a, which is made of a material with non-linear voltage-current characteristics such as silicon carbide or zinc oxide, and has electrode surfaces formed by welding a metal such as aluminum to both end surfaces of the main body. Side electrode 7b and ground side electrode 7
A pleated insulator 7 made of rubber or synthetic resin is sandwiched by c and leaving only the tips of both electrodes.
The current limiting element 7 is made of a material such as aluminum alloy or brass having an inner diameter sufficient to surround the insulator body 2 in an annular shape at a predetermined distance. A substantially C-ring-shaped intermediate electrode 8 made of a highly flexible and thin metal wire is the second
As is clear from the figure, the mounting end 8b is bent into a long U-shape to protrude and is mounted substantially horizontally. The intermediate electrode 8 is formed by bending the tip portions of a pair of arcuate arm portions 8a, 8a continuing from the long U-shaped mounting end portion 8b and forming a circular ring outward in an arcuate shape. The distance between the arm tips 8c, 8c is normally smaller than the diameter of the body of the insulator body 2, but when necessary, the elasticity of the material allows the opening 8d to be expanded to pass through the body of the insulator body 2. Moreover, this intermediate electrode 8 is arranged in parallel with the insulated wire 4 supported by the bind wire 5 so as to cover the grounding fitting 1 with an air gap between the intermediate electrode 8 and the holding plate. 9 and bolts 10, the mounting end 8b is connected and fixed to the power-supplying electrode 7b. On the other hand, the ground side electrode 7c of the current limiting element 7 is a two-split band metal fitting 11 which can be opened and closed and is secured by a bolt 12 while holding the ground side base metal fitting 6a of the insulator body 2 fixed to the grounding metal fitting 1. is fixed to one of the support arms 11b with bolts 13. This band metal fitting 1
Reference numeral 1 has a hinge portion 11a provided in an annular portion so that it can be opened and closed freely, and a pair of support arms 11b, 11b are provided at symmetrical positions. In addition,
As shown in FIG. 2, the intermediate electrode 8 and the base metal fitting 6a are arranged so that their rings are concentric with each other. is held constant.

15 is a mounting bracket 1 provided with a connecting part such as a screw hole
A supporting insulator made of rubber, synthetic resin, or porcelain, etc., with 5a and 15b fixed to both ends, is attached to the other support arm 11b of the band fitting 11 so as to be placed in parallel with the current limiting element 7. The upper mounting bracket 15a has a receiving bracket 16 made of a metal plate having receiving grooves 16a for holding the arm tips 8c, 8c at both ends. The arm ends 8c, 8c of the intermediate electrode 8 are connected and fixed by bolts 17, and the arm ends 8c, 8c of the intermediate electrode 8 are engaged with the receiving groove 16a. The free ends, that is, the arm tip portions 8c, 8c side are supported by a support insulator 15 so that they are always held horizontally.

With this structure, the insulated wire 4 is held by the bind wire 5 with the insulation coating 4b attached to the head 3 of the insulator body 2 attached to the grounding fitting 1 without exposing the core wire 4a. When an impact overvoltage is applied to the line due to a lightning surge, the insulation coating 4b of the wire is broken through and the discharge is emitted from the core wire 4a or the binding wire 5, passes through the air gap, and is captured by the intermediate electrode 8. The electrode 8 is in the shape of a C-ring, and is connected to an insulated wire with an equal distance from the circumferential surface of the insulator body 2, that is, while keeping the horn coordinates constant, surrounding the insulator body 2 almost all the way around. 4
Because it is placed in parallel with the pole, it has a wide range of capture of flash voltage, and can be oriented freely even in irregular pole mounting conditions, such as when the wire is placed at an arbitrary horizontal angle at the gripping point. It can be installed on. In addition, unstable flashover paths due to excessive and steep lightning surges or uneven staining of the insulator surface can be sufficiently covered, and a stable discharge path is formed to provide a reliable trapping function. The lightning surge captured by the intermediate electrode 8 in this way is
It is discharged from the current-loading side electrode 7b of the current-limiting element 7 via the current-limiting element 7a and the grounding-side electrode 7c, but when a high impact voltage is applied to the current-loading side of the current-limiting element 7a, the current limiter is The flow element 7a reduces its resistance value due to the non-linearity of voltage-current characteristics and passes a large current, and after the impact large voltage disappears, it bears the line voltage, but the line voltage recovers its resistance value. The following current discharge is immediately restricted and cut off, and the insulator device quickly recovers its insulation. Therefore, no follow-on arc occurs,
Damage such as wire breakage and insulator damage is reliably prevented, and since the insulator device instantly recovers its insulation after a shock-high voltage discharge, ground fault relays and equipment at substations do not operate, and line power outages are avoided. It will be done. Furthermore, in the present invention, there is no need to attach an insulating cover to prevent electric shock, and the intermediate electrode 8 has a current limiting element 7 and its base is supported by the band fitting 11. Support insulator 1 on metal fitting 11
5 is supported on both sides, compared to conventional systems, there is less adhesion of snowpack on the power supply side, which can easily cause icicles and ground faults during snowfall in the winter. 3 even if snow adheres to and freezes on the electrode 8, current limiting element 7, supporting insulator 15, etc.
Since the electrodes are interconnected and reinforced, they maintain sufficient mechanical strength against snow mass weight and wind pressure load, and maintain the intermediate electrode 8 in a predetermined horizontal state while preventing external forces from concentrating on the current limiting element 7a. It also has the advantage of preventing snow damage, such as preventing deterioration. Furthermore, by attaching the current-limiting element 7 and the intermediate electrode 8 to the base metal fitting 6a on the ground side of the insulator body 2 using the two-piece band metal fitting 11 that can be opened and closed, tight-tipped insulators, which are commonly used in power distribution lines, can be used. Also,
As in the embodiment, the C-ring-shaped intermediate electrode 8 has an opening 8d that can be expanded by utilizing the elasticity of a highly flexible and thin metal wire, and the opening 8d is formed at opposing arcuate ends. In addition, the insulator main body 2 can be surrounded in an annular shape which is desirable in terms of flash catching performance, and the opening 8d is a long U-shaped mounting end. 8
b makes it easier to add elasticity, and to reduce the diameter of the body of the insulator body 2 to the minimum that can more reliably capture the flash, and furthermore,
If the opposing arcuate ends are made so that the opening can pass through smoothly without damaging the insulator body 2,
If you hold the wire and press it against the body of the insulator body 2, the opening will expand, allowing it to pass freely through the cross section and be installed.Furthermore, after passing the wire, it will return to its original shape due to its elasticity, so it will not fit the existing wire. Even for tight insulators, repair work can be carried out in a short time by using the existing equipment without modifying the energized part of the line or causing a power outage.Furthermore, the intermediate electrode 8 limits and blocks follow-on arcs. Since there is almost no melting loss, it is possible to mold wire rods as small as a few millimeters in diameter, so uniform products can be mass-produced at low cost using simple molds, and they are lightweight, easy to handle, and have good elasticity. Therefore, even if the insulator or the surrounding pillar fittings are accidentally hit, the external force can be easily absorbed and the insulator is less likely to be damaged or the connected current limiting element 7 is less likely to be damaged.

As is clear from the explanation of the above embodiments, the present invention is not only highly effective in maintaining the stability of power transmission and distribution lines, but also has great practical value as a lightning disconnection prevention unit that can be easily installed on poles. be.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention, and FIG. 2 is a partially cutaway plan view. 1: Grounding metal fitting, 2: Insulator body, 4: Insulated wire,
7: Current-limiting element, 7b: Voltage-side electrode, 8: Intermediate electrode, 8a: Arm portion, 8b: Mounting end portion, 8c: Arm tip portion, 8d: Opening portion, 11: Band fitting, 11b:
support arm.

Claims (1)

[Scope of utility model registration request] A lightning disconnection prevention unit in which an air gap is formed via an intermediate electrode 8 between an insulated wire 4 supported on an insulator body 2, and a current limiting element 7 with non-linear voltage-current characteristics is provided on a grounding fitting 1. , the intermediate electrode 8 has a long U-shaped mounting end 8b formed of a highly flexible metal wire, a pair of arc-shaped arm parts 8a, 8a, and the tips thereof are bent outward. An opening 8d whose width is smaller than the diameter of the body of the insulator body 2 is formed between the arm tips 8c and 8c.
is provided, and the current limiting element 7 is attached to one of the support arms 11b of the two-piece band fitting 11, which is further provided with a pair of support arms 11b, 11b at left-right symmetrical positions, via the ground side electrode 7c. , the insulating support 15 is attached to the other support arm 11b, the attachment end 8b of the intermediate electrode 8, which is concentric with the insulator body 2 and the band fitting 11, is attached to the energizing side electrode 7b, and the arm tip 8c, 8c is fixed to an insulating support 15.