JPH047594Y2 - - Google Patents

Description

[Detailed description of the invention] A. Purpose of the invention A-1. Field of industrial application The present invention relates to an improvement of a device for preventing disconnection of insulated wires in high-voltage distribution lines, and in particular, to improve the electrical connection of insulated wires. It is related to a structure that allows reliable mechanical operation.

E-RO Prior Art Recent high-voltage distribution lines use insulated wires 2 consisting of a core wire 2b and an insulating sheath 2a surrounding the core wire 2b. The insulated wire 2 is usually as shown in FIG.
The high-voltage pin insulator 3 attached to the cross arm 8 is supported and fixed to the head 5 of the insulator body 4 by a support fitting 6 such as a binding wire or a wrapping grip. This is shown in an electrical equivalent circuit as shown in FIG.

However, 2b is the core wire of the insulated wire 2, 6 is the support metal fitting, E is the ground, _C1 is the capacitance between the core wire 2b and the support metal fitting 6, and _C2 is the ground capacitance of the insulator surface of the high voltage pin insulator 3. Show each.

By the way, in the support device that supports and fixes the insulated wire 2 to the head 5 of the insulator body 4 using the support metal fitting 6, if a lightning surge h enters the line and an abnormal overvoltage is applied, the capacitance C will be reduced. Since the relationship between C ₂ and C ₂ is C ₂ ≫ _{C 1} , most of the overvoltage is applied to C ₂ and flashes between the support metal fitting 6 and the pin 7, and flows outward from both ends of the support metal fitting 6 ( A creeping streamer (g) develops along the left and right electrodes centering on the insulator, and a breakdown of the wire occurs at the weakest point 2a'' somewhere in the insulation coating 2a, and the trailing current is fixed at the point of insulation breakdown. The electric wire 2 is broken and the insulator 4 is damaged by uneven heat due to the arc heat generated by the flow.As mentioned above, once a wire breakage occurs, it takes a long time to discover the faulty section and restore it, which increases the power outage time.
In addition, there is a risk that a broken electric wire may be left in a charged state and cause a public disaster.

Therefore, measures to prevent disconnection of insulated wires due to lightning surges are extremely important issues, and in some high-voltage distribution lines, arcing horns are attached to high-voltage pin insulators, and measures are taken to prevent the occurrence of follow-on arcs. Measures have been taken to eliminate this problem, such as installing a current-limiting horn with a current-limiting element connected in series to the arcing horn, and these measures have been effective to some extent.

However, the above-mentioned arc horn (including current-limiting horn) systems still have major problems.

A-3 Problems to be solved by the present invention In other words, the above-mentioned arc horn system uses an arc horn equipped with one or both of the charging side and the ground side of the high-voltage pin insulator to absorb incoming lightning surges. In this case, the discharge starting voltage of the arcing horn is controlled by the high-voltage pin insulator to which the horn is attached, so that the discharge always occurs first at the horn (side). This is a fatal problem as it is set much lower than the flash fault voltage (discharge starting voltage between the live part of the insulator and the ground) of the (side), and for this reason deterioration of the insulation of the high voltage distribution line is unavoidable. Had to have.

Therefore, the present applicant directly attached a current-limiting element to the insulated wire near the head of the insulator, and connected the live-side electrode in close contact with one end face of the element to the core wire of the insulated wire via a mounting bracket. In addition, the discharging electrode provided on the non-charging side electrode that is in close contact with the other end face of the element is attached to the outer periphery of the insulated wire coating, and the tip of the electrode is attached to the support metal fitting (bind wire) on the head of the insulator. For example, if the
In order to solve the above-mentioned problem of insulation deterioration, we proposed a wire breakage prevention device as shown in Utility Model Application No. 59-154567, which is directly attached to electric wires. However, when installing the above (prevention device), a creeping gap is formed between the discharge electrode and the support fitting, so even if the insulation coating of the insulated wire near the support fitting is damaged, there may be scratches, pinholes, etc. If there is a weak point, an incoming lightning surge will cause dielectric breakdown at this point. In other words, since the incoming lightning surge cannot be reliably captured by the device's discharge electrode, the surge does not pass through the current limiting element and generates a follow-on arc between the insulated wire and the pin (branch arm). In some cases, the same results as not installing a preventive device were obtained. In addition, in the above, when attaching the disconnection prevention device to an insulated wire, the needle-shaped contact part provided on the mounting bracket breaks through the insulation coating of the insulated wire and is electrically connected to the core wire. There is also the problem that rainwater enters through the small hole in the insulation coating formed by this puncture, corroding the core wire of the insulated wire, or even developing stress corrosion, leading to a disconnection accident of the insulated wire. Ta. This proposal concerns a structure for solving these various problems.

B. Structure of the device B-1 Means for solving the problem To this end, in the present proposal, the head 5 of the insulator body 4
An insulated wire 2 consisting of a core wire 2a and an insulating sheath 2b surrounding it is supported and fixed by a support fitting 6 such as a bind wire or a winding grip, and further supported and fixed by a pin 7 fixed to the insulator body 4. A support device 1 for an insulated wire in a distribution line includes a current limiting element 11 having voltage nonlinearity, a charging side electrode 18 that is in close contact with one end surface 11a of the current limiting element 11, and an insulated wire 2 provided on the charging side electrode 18.
A needle-shaped contact portion 24a that can be clamped and attached to the device and protrudes inward, and a tip 24 of the contact portion 24a.
An insulating adhesive compound 2 is arranged around the tip 24a so that only a' protrudes.
6, a non-charging side electrode 15 that is in close contact with the other end surface 11b, and a non-charging side electrode 15 that is provided with a tip 21b on the side (axial direction) of the element 11. An extended rod-shaped discharge electrode 21, these current limiting elements 11, and a mounting bracket 22
The disconnection prevention device 9 is formed by integrally covering and molding the outer peripheral surfaces of the charging side electrode 18 excluding the tip 21b, the discharging side electrode 21 excluding the tip 21b, and the non-charging side electrode 15 with an insulating member 20. A disconnection prevention device for an insulated wire, characterized in that it is attached to and supported on the coated outer periphery 2a' of the insulated wire 2 near the end of the support metal 6, and at the same time directly electrically connects the discharge electrode 21 and the support metal 6. This is what we propose.

B-2 Effect The disconnection prevention device 9 of the present invention is directly attached to the insulated wire 2 which is supported and fixed to the head 5 of the insulator body 4 by a support fitting 6 such as a bind wire. One of the current-limiting elements 11 is mechanically and electrically connected to the insulated wire 2 via the mounting fitting 14, and
The tip 21b of the support fitting 6 is mechanically attached and connected to the support fitting 6 using a band-shaped conductive rubber 26, and at the same time, it is directly electrically connected. In addition, when installing the prevention device to the insulated wire, use the mounting bracket 22.
The needle-shaped contact portion 24a breaks through the insulation sheath 2b of the insulated wire 2 and a small hole is formed in the insulation sheath 2b, but an adhesive insulating compound 26 is disposed around the contact portion 24a. Therefore, the small holes are blocked by the compound 26 and rainwater does not enter. The disconnection prevention device installed in this way does not cause deterioration in the insulation of the line (high-voltage pin insulator), and also prevents flash shorts from occurring on the insulator surface due to abnormal voltages such as lightning surges. Since the lightning surge can be captured accurately, the lightning surge can be quickly released to the ground via the current limiting element of the prevention device without causing a delay in discharge (spark) or variations in the discharge starting voltage. At the same time, follow-on current can be blocked.

RO-3 Embodiment Next, an embodiment of the present invention will be described in detail based on FIGS. 1 to 9.

Reference numeral 1 designates a well-known support device for an insulated wire 2, in which an insulated wire 2 consisting of a core wire 2b and an insulating sheath 2a surrounding the core wire 2 is attached to a head 5 of an insulator body 4 of a high-voltage pin insulator 3 using a binding wire and a winding grip. The insulator body 4 is attached to a grounded cross arm 8 via a pin 7 fixed to the insulator body. Reference numeral 9 indicates a disconnection prevention device of the present invention, which is located at the end of the support fitting 6 and is directly attached to the insulated wire 2. 1
Reference numeral 1 denotes a cylindrical current-limiting element having voltage non-linearity and mainly composed of silicon carbide (Sic) or zinc oxide (ZnO), which constitutes the main part of the current-limiting element unit 10. For example, metal such as aluminum is thermally sprayed onto 11a and 11b. 12
is an approximately funnel-shaped insulating inner cylinder made of synthetic resin such as glass fiber-containing polyester resin, and has a screw hole 12a protruding in the axial direction on one open side, and a slight recess on the inner end surface 12b. A spring seat 12c is formed on the inner wall surface 12d, and guide protrusions 12e that evenly project inward are formed on the inner wall surface 12d. Reference numeral 12f indicates a through-hole for attachment formed in the other open side circumferential surface 12g. For such an insulated inner cylinder 12, a charging side auxiliary electrode 1 is provided with a disc spring 13 as a spring seat 12c and a rotation stopper 14a formed thereon.
4 and the current limiting element 11 are sequentially inserted into the center of the cylinder by the guide protrusion 12e and housed. Reference numeral 15 denotes a non-charging side electrode that is fixed to the outside of the non-charging side auxiliary electrode 16 in close contact with the end surface 11b of the current limiting element 11 so as to press it.
After aligning a with the through holes 12f of the insulating inner cylinder 12, fixing pins 17 made of metal such as stainless steel are inserted into these through holes (holes) and fixed. 1
8 screws one threaded part 18a into the threaded hole 12a of the insulating inner cylinder 12 from the outside, and then screws the threaded part 18a into contact with the disc spring 13 in the insulating inner cylinder 12 with its tip 18b, and then tightens it to a predetermined level. The charging side electrode consists of a stepped bolt tightened to the specified torque, and the same electrode 18
By tightening, each member assembled to the insulating inner cylinder 12 is securely fixed, and at the same time, reliable electrical contact is maintained. Reference numeral 19 indicates a silicone resin filler that is injected into the gap formed between the insulating inner cylinder 12 and each member housed within the cylinder after the charging side electrode 18 is tightened. 20 integrally covers the insulating inner cylinder 12, the outer circumferential surface of the charging side electrode 18 except for the threaded part 18c of the non-charging side electrode, and the same electrode 15 except for the threaded part 15b of the non-charging side electrode after the filler 19 is injected. It is an insulating member made of rubber such as EP to be formed, and during molding, it is located on the charging side electrode 18 side to form a flange-shaped engagement protrusion 20a, and is located on the non-charging side electrode 15 side to form a recess 2 for adhesion.
0b is integrally formed. In addition, when molding the insulating member (EP rubber) ( Vulcanized adhesive (product name: Chemrock 205, 236)
The primary treatment is performed by coating the material, and then the insulating member is coated and molded on top of the primary treatment. 21 connects one threaded portion 21a to the threaded portion 15b of the non-charging side electrode 15 protruding in the axial direction (lateral direction), and extends the other end 21b to the lateral (axial direction) of the current limiting element 11. This is a discharge electrode made of a copper rod, which is covered with an insulating member 20 made of rubber, such as EP, in the shape of a stress cone, except for the tip 21b and the threaded part 21a at the rear end. There is a protrusion 21 for adhesion on the threaded part 21a side.
c is formed, and this convex portion 21c is adhered to the concave portion 20b on the non-charging side electrode 15 side during the above connection. In the above, the insulating inner cylinder 12 and the like and the discharge electrode 21 are each covered with the insulating member 20 and molded separately. There is no problem even if they are connected by screws and then integrally covered and molded with the insulating member 20 in this connected state.

22 is a threaded portion 18 of the charging side electrode that protrudes laterally.
It is a clamp-type mounting fitting attached to a with a nut 23, and has two separable clamping pieces 2 that can be tightened from the outer periphery of the insulated wire 2.
4 and a tightening screw 25, and one of the clamping pieces 24 has a needle-shaped contact portion 24 that protrudes inward.
a, and its contact portion 24a pierces through the insulation coating 2a of the insulated wire to electrically contact the core wire 2b. Reference numeral 26 denotes an adhesive synthetic rubber insulating compound disposed around the contact portion 24a so that the tip 24a' of the contact portion 24a protrudes. When installing the clamping piece 2 to the clamping piece 2 so that it is interposed (in close contact) between the clamping piece 24 and the insulation coating 2a.
4 is provided on the inner surface 24b of the insulation coating 2a, thereby closing the small hole in the insulation coating 2a penetrated by the contact portion 24a to prevent rainwater from entering through the hole. 27 is a rubber plate that prevents the tightening screw 25 from falling; 28 is a discharge electrode 2 that is uncovered;
This is a band-shaped conductive rubber whose tip 21b of the discharge electrode 21 is attached to and supported on the outer periphery 2a' of the insulated wire 2. On the other hand, the rubber, which is electrically connected and is wrapped around the discharge electrode 21 and the insulated wire 2 from the covering outer periphery 2a', has its fixing holes 28a and 28b close to the tip 21b of the discharge electrode 21. It is attached by fitting into the fixing protrusion 20c of the formed insulating member 20. 29 is a synthetic rubber such as EPR or polyethylene that is removably attached to the engagement protrusion 20a of the current limiting element unit 10 and the insulated wire 2 so as to cover the mounting bracket 22 and the threaded portion 18a of the charging side electrode 18. Insulating cover made of resin.

In the original disconnection prevention device configured in this way and attached to the insulated wire, if a lightning surge has now entered and the impact overvoltage is at least greater than the flash voltage of the high voltage pin insulator, the pin 7 on the ground side
A flashover occurs between the arms 8 and the support fittings 6.
Then, the same surge is caused by the core wire 2b of the insulated wire - the mounting bracket 22 - the charging side electrode 18 - the current limiting element 11 - the non-charging side electrode 15 - the discharge electrode 21 - the conductive rubber 28 - the support fitting 6 - the insulator body 4 - the pin 7 or It is quickly discharged to the earth through the discharge path of arm arm 8. At the same time, a current limiting element 1 interposed in series in the above path
1 prevents (cuts off) the follow-on current of the commercial frequency, so it is possible to reliably prevent disconnection accidents of insulated wires caused by follow-on arcs that have conventionally occurred.

C. Effect of the present invention As described above, in the disconnection prevention device of the present invention, the insulated wire 2 consisting of the core wire 2b and the insulation coating 2a covering the core wire 2b is attached to the head 5 of the insulator body 4 using a bind wire or a wrapping grip. A pin 7 is supported and fixed by a support fitting 6 and further fixed to the insulator body 4.
In a support device 1 for an insulated wire in a high-voltage distribution line, which is attached and fixed to a cross arm 8 on the ground side, a current limiting element 11 having voltage nonlinearity and a charging side that is in close contact with one end surface 11a of the element 11 are provided. The electrode 18 and the needle-shaped contact portion 24 that is provided on the charging side electrode 18 and can be clamped onto the insulated wire 2 and that protrudes inward and are arranged in the same manner so that only the tip 24a' of the contact portion 24a protrudes. A clamp-shaped mounting bracket 22 with an adhesive insulating compound 26 disposed around the contact portion 24, and the other end surface 11b.
non-charging side electrode 15 in close contact with non-charging side electrode 1
5, a rod-shaped discharge electrode 21 extending laterally (in the axial direction) of the element 11, these current-limiting elements 11, and the charging side electrode 18 excluding the mounting bracket 22;
The same electrode 21 excluding the tip 21b of the discharge electrode 21,
A disconnection prevention device 9, which is formed by integrally covering the outer peripheral surface of the non-charging side electrode 15 with an insulating member 20, is mechanically and electrically connected to the insulated wire 2 near the end of the support fitting 6 using the mounting fitting 22. The discharge electrode 2 is attached and connected to the discharge electrode 2 and is further uncovered.
The distal end 21b of the insulated wire 2 is attached and supported by the band-shaped conductive rubber 28 to the sheathed outer periphery 2a' of the insulated wire 2, and at the same time, the discharge electrode 21 and the support fitting 6 are electrically connected directly, resulting in a conventional arc horn. It goes without saying that installation does not cause deterioration in the insulation of the power distribution line as in the conventional method, but when installing the disconnection prevention device on insulated wires, the clamp-type mounting bracket and conductive rubber prevent electrical and mechanical damage. Since the installation work can be done at the same time, work efficiency can be further improved. In addition, when installed as described above, since the discharge electrode on the prevention device side and the support fitting on the support device side are electrically connected directly using conductive rubber, it is necessary to temporarily connect the insulation coating of the insulated wire near the support fitting. Even if there are insulating weak points such as scratches or pinholes, the invading lightning surge is accurately captured by the discharge electrode and guided to the current limiting element, which safely and quickly sends it to the ground. Since it is possible to release the current and cut off the follow-on current at the same time, it is possible to reliably prevent disconnection of insulated wires due to lightning surges. In addition, when connecting to an insulated wire, the needle-shaped contact part provided on the clamping piece of the mounting bracket pierces the insulation coating of the insulated wire and a small hole is formed in the coating. Even in such a case, the small hole is blocked by an adhesive insulating compound placed around the contact part, preventing rainwater from entering through the small hole. It has features such as being able to prevent corrosion of the core wire and even wire breakage accidents due to stress corrosion.

[Brief explanation of the drawing]

Figures 1 to 9 show examples of the present invention. Figure 1 is a diagram of the installation state of the wire breakage prevention device, and Figure 2 is a diagram of the wire breakage prevention device when the wire breakage prevention device is partially broken and the insulation cover is removed. Installation state diagram, Fig. 3 is a sectional view taken along line AA in Fig. 2, Fig. 4 is a sectional view taken along line BB in Fig. 2, Fig. 5 is a half sectional view of the current limiting element unit, and Fig. 6 is an insulating section. A cross-sectional view of the current limiting element unit in a state before it is coated with a member, FIG. 7 is a cross-sectional view of the insulating inner cylinder, b is a partially cutaway plan view,
C is a left side view, FIG. 8 is a plan view of the auxiliary electrode on the charging side, FIG. 9 is a plan view of the band-shaped conductive rubber, and FIG. 10 is a well-known support device for insulated wires in high voltage distribution lines. Installation state diagram, Figure 11 is the first
Electrical equivalent circuit of Figure 0. 1... Insulated wire support device, 2... Insulated wire,
2a...Insulation coating, 2a'...Insulation coating outer periphery, 2b
... core wire, 3 ... high voltage pin insulator, 4 ... insulator body,
5... Head, 6... Support metal fittings, 7... Pin, 8...
... Bracelet, 9... Disconnection prevention device, 11... Current limiting element, 11a, 11b... End face, 15... Non-charging side electrode, 18... Charging side electrode, 20... Insulating member,
21... Discharge electrode, 21b... Tip, 22... Mounting bracket, 24... Clamping piece, 24a... Contact portion, 2
4a'... Tip, 28... Conductive rubber.

Claims (1)

[Scope of utility model registration request] An insulated wire 2 consisting of a core wire 2b and an insulating sheath 2a surrounding the core wire 2b is supported and fixed to the head 5 of the insulator body 4 by a support fitting 6 such as a bind wire or a winding grip, and a pin 7 is fixed to the insulator body 4. In a support device 1 for an insulated wire in a high voltage distribution line, which is attached and fixed to a cross arm 8 on the ground side, a current limiting element 11 having voltage non-linearity;
Charging side electrode 18 in close contact with one end surface 11a of
The charging side electrode 18 is provided with a needle-shaped contact portion 24a that can be clamped and attached to the insulated wire 2 and that protrudes inward, and the contact portion is arranged so that only the tip 24a' of the contact portion 24a protrudes. 24, a clamp-shaped mounting bracket 22 with an adhesive insulating compound 26 disposed around the non-charging side electrode 15, and a non-charging side electrode 15 in close contact with the other end surface 11b.
A rod-shaped discharge electrode 21 is provided in the device 11 and extends laterally (in the axial direction) of the element 11,
The outer peripheral surfaces of the charging side electrode 18 excluding the mounting bracket 22, the discharging electrode 21 excluding the tip 21b, and the non-charging side electrode 15 are integrally coated with an insulating member 20 to prevent disconnection. The device 9 is mechanically and electrically connected to the insulated wire 2 near the end of the support fitting 6 using the mounting fitting 22, and the tip 21b of the uncovered discharge electrode 21 is attached to a band-shaped conductive rubber. 28. A breakage prevention device for an insulated wire, characterized in that the wire is attached and supported on the coated outer periphery 2a' of the insulated wire 2, and at the same time, the discharge electrode 21 and the support fitting 6 are directly electrically connected.