JPS645957Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an edge turning device that takes measures to prevent wire breakage due to follow-on arcs.

A conventional power transmission/distribution line edging device is one in which a wire is held to a holding clamp of a tension insulator device that is stretched in the direction of the line by holding a grounding fitting such as a cross arm, and both holding clamps are connected by a jumper wire. If an impact overvoltage such as a lightning surge occurs on the wire, a flash may occur between the jumper wire and the grounding fitting, or the pin of the tension-resistant insulator on the power-carrying side connected to the retaining clamp holding the wire may A flash short circuit occurs between the fitting and the cap fitting of the tension insulator on the grounding side, and the subsequent arc heat from the follow-on arc not only damages the tension insulator, but also causes damage to the tension on the energized side if the energy of the follow-on arc is large. The insulator pin fittings were fused due to the heat generated by the arc, and as a result, the wires were broken and fell to the ground. In addition, if the electric wire and jumper wire are insulated wires, if a flash occurs between the grounding fitting and the jumper wire, the point of generation of a follow-on arc will be fixed at the point where the insulation coating of the wire has penetrated and broken, causing the jumper wire to break. It was hot. Furthermore, if the insulation coating is not stripped off at the point where the wire is held by the retaining clamp, the wire will easily break due to the above-mentioned reason when a follow-on arc occurs. It is necessary to strip the insulation coating of the wire so that it can be connected properly.
Another drawback was that this work was time-consuming.

The present invention was completed with the aim of providing an edge turning device that does not have the above-mentioned drawbacks and takes measures to prevent wire breakage.Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

In the first embodiment shown in FIGS. 1 and 2,
Reference numerals 1 and 1 designate a tension insulator device which is stretched in the track direction with a grounding metal fitting 2 such as a cross arm in between. It consists of tension insulators 5, 5 with 4 attachments, and a retaining clamp 6 for retaining the electric wire 7 to the tension insulator 5 on the power-supplying side. The jumper wire 7a is electrically connected to the jumper wire 7a.
If runout or sag occurs in line a, the jumper wire 7a may be supported with a binding wire on the head of the jumper support insulator that is vertically attached to the grounding fitting 2. There is no difference from the edge mawashi device. Reference numeral 9 denotes a current-limiting element, in which a voltage-supplying terminal 11 and a grounding-side terminal 12 are brought into contact with electrode surfaces at both ends of a current-limiting element 10 made of a material with non-linear voltage-current characteristics such as silicon carbide or zinc oxide. Both terminals are covered with an insulator 13 made of rubber or synthetic resin, except for the tips thereof, and the current limiting element 9 constitutes one tension insulator device 1 so as to be electrically connected to the grounding fitting 2. Ground side tension insulator 5
It is attached to a band fitting 14 that holds a cap fitting. Reference numeral 15 denotes a substantially C-ring-shaped discharge electrode provided so as to substantially concentrically surround at least one, that is, a required tension insulator 5 constituting the tension insulator device 1, and this discharge electrode 15 is connected to the current limiting element. 9
The jumper wire 7a and the grounding metal fitting 2 are connected to the energizing side terminal 11 of the
It forms an air gap smaller than the gap between the two. The material and shape of the discharge electrode 15 are not limited as long as it is made of a conductive material, but as shown in the figure, it can be grounded if it is made of a metal material such as stainless steel, aluminum alloy, or brass. If the tension insulator 5 on the side is made into a C-ring shape with an inner diameter sufficient to surround it from the outside, it will have an excellent trapping function for streamers generated by shock overvoltage such as lightning surges. If the ring-shaped discharge electrode 15 is made of a spring material such as spring stainless steel or phosphor bronze, and its opening is made expandable, the discharge electrode 15 can be attached to the existing tension insulator 5 through the opening. This is preferable because it can be done. Further, as described above, the discharge electrode 15
Making the air gap between the jumper wire 7a and the grounding fitting 2 smaller than the gap between the jumper wire 7a and the grounding fitting 2 is as follows:
The insulation strength of the tension insulator device 1 equipped with this discharge electrode 15 is the insulation strength between the jumper wire 7a and the grounding metal fitting 2, and the insulation strength of the tension insulator device 1 on the side without the discharge electrode.
As shown in FIG.
The -t characteristic curve is made low and does not intersect with the Vt characteristic curve between the jumper wire 7a and the grounding metal fitting 2, and the Vt characteristic curve of the tension insulator device 1 having no discharge electrode. In addition, the jumper wire 7a
When supported by a jumper support insulator (not shown), the tension insulator device 1 equipped with the discharge electrode 15
Of course, the air gap between the discharge electrode 15 and the retaining clamp 6 should be set so that the V-t characteristic of the jumper support insulator is lower than that of the jumper supporting insulator. Therefore, when an impact overvoltage such as a lightning surge occurs in the electric wire 7, a flash will always occur in the tension insulator device 1 equipped with the discharge electrode 15, and a flash will occur in the tension insulator device 1 or the jumper support insulator that does not have a discharge electrode. Although not necessary, in order to further improve reliability, the discharge electrode 15 connected to the current limiting element 9 may be attached to both of the tension insulator devices 1, 1. On the other hand, Figure 3 shows the second example of the present invention.
This shows an example of current limiting element 9 and discharge electrode 1.
Only the mounting condition of No. 5 is different from the first embodiment. That is, in the second embodiment, the current limiting element 9 is directly attached to the grounding fitting 2 with the ground side terminal 12, while the discharge electrode 15 is connected to each of the tension insulators 5 on the ground side of the double tension insulator device 1. Between the discharge electrodes 15, 15, which are attached to the band metal fitting 16 holding the cap metal fitting 4 via an insulating support 18 made of rubber, synthetic resin, porcelain, etc., and insulated from the grounding metal fitting 2, and the retaining clamps 6, 6. forming an air gap smaller than the gap between the jumper wire 7a and the grounding fitting 2;
Further, each discharge electrode 15 is electrically connected to the current-supplying terminal 11 of the current limiting element 9 through a conductive wire 17 made of copper or the like having high electrical conductivity. Even when a plurality of electrodes 15 are used, the number of current limiting elements 9 can be reduced to one, so that simplification of the device can be expected. Further, the electric wire 7 held by the tension insulator device 1 may be either a bare wire or a covered wire, and in the case of a covered wire, the portion held by the holding clamp 6 of the tension insulator device 1 is generally Either the insulation coating of the wire 7 is stripped off and the core wire is gripped by the retention clamp 6, as was done previously, or the insulation coating is not stripped off and the retention clamp 6 is used to grip it from above. Further, in the above embodiment, only one current-limiting element 9 is used, but for example, a plurality of current-limiting elements 9 may be used to increase the capacity to flow an impact current such as a lightning surge, that is, to increase the discharge withstand capacity. Current limiting elements 9 may be connected in parallel, or when used on high voltage lines, multiple current limiting elements 9 may be connected in series as necessary, and the number of current limiting elements 9 may be limited. There isn't.

With this structure, when an impact overvoltage such as a lightning surge occurs in the electric wire 7, an air gap smaller than the gap between the jumper wire 7a and the grounding fitting 2 is formed between the retaining clamp 6 and the jumper wire 7a. Since at least one tension insulator device 1 is provided with the discharge electrode 15, the gap between the retaining clamp 6 of the tension insulator device 1 with the lowest insulation strength and the discharge electrode 15 is provided with the discharge electrode 15. However, since the discharge electrode 15 is electrically connected to the current-loading side terminal of the current-limiting element 9 which is grounded to the grounding fitting 2, the shock current flowing at that time is caused by the discharge electrode 15. Current-limiting element 10 built into current-limiting element 9
It flows through the grounding metal fitting 2 to the armrest. Subsequent current that attempts to flow thereafter is blocked by the non-linearity of the voltage-current characteristics of the current limiting element 10, and a follow-on current arc is not generated, thereby preventing disconnection of the electric wire 7 and damage to the tension insulator 5. As described above, the current that attempts to flow after the flash is blocked by the current limiting element 9, so if the wire 7 is an insulated wire, the wire 7 is held from above the insulation coating with the clamp 6. Even if this is done, there is no risk of wire breakage, and there is also the advantage that the work of stripping off the covering, which was conventionally required, can be omitted. Further, a discharge electrode 1 attached to the tension insulator device 1
5 can be installed with an air gap between it and the retaining clamp 6 under the conditions described above, so even if it is applied to an existing edging device, the existing insulator can be used as is and it can be installed with a live wire. It has the advantage of being able to carry out construction work. Moreover, the discharge electrode 15 is attached to at least one of the tensile insulator devices 1, 1, which are stretched in the line direction with the grounding fitting 2 in between, so that the air gap with the retaining clamp 6 is smaller than the gap between the jumper wire 7a and the grounding fitting 2. It is sufficient to electrically connect the current-limiting element 9 to the energizing side terminal 11 of the current-limiting element 9 which is small in size and connected to the grounding fitting 2 by some means. There is no need to attach an additional discharge electrode, and therefore, the number of current limiting elements 9 to be provided can be reduced to provide a simple and economical edging device.

As is clear from the explanation of the above embodiments, the present invention is not only highly effective in terms of the safety of power transmission and distribution lines and the stable supply of power, but also facilitates the maintenance of the lines, and is therefore more effective than the conventional method. It is of great practical value as it eliminates the drawbacks of edge-wrapping devices for power transmission and distribution lines.

[Brief explanation of the drawing]

FIG. 1 is a front view showing the first embodiment of the present invention;
Fig. 2 is a view taken along arrow A-A in Fig. 1, Fig. 3 is a front view showing the second embodiment of the present invention, and Fig. 4 is a diagram showing the structure between the jumper wire and the grounding fitting, and the structure where the discharge electrode is attached. 1 is a graph showing Vt characteristic curves of a tension-resistant insulator device and a tension-resistant insulator device without a discharge electrode. 1: Tension-resistant insulator device, 2: Grounding fitting, 5: Tension-resistant insulator, 6: Retaining clamp, 7: Electric wire, 7a: Jumper wire, 9: Current-limiting element, 11: Power-supplying side terminal, 1
5: Discharge electrode.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. The edge of a power transmission and distribution line where a wire is held to a holding clamp of a tension insulator device stretched in the direction of the line with a grounding fitting in between, and both holding clamps are connected by a jumper wire. In the turning device, a current-limiting element 9 made of a material with non-linear voltage-current characteristics is connected to the grounding fitting 2, and at least one tension-resistant insulator device 1 is connected to the current-limiting element 9.
A clamp 6 holds the discharge electrode 15 electrically connected to the energizing side terminal 11 of the jumper wire 7a with an air gap smaller than the gap between the jumper wire 7a and the grounding fitting 2.
An edge turning device with measures to prevent wire breakage, characterized in that it is installed between. 2. An edge turning device with measures to prevent disconnection as set forth in claim 1 of the utility model registration claim, in which the discharge electrode 15 is C-ring shaped and is provided so as to surround the tension insulator 5 of the tension insulator device 1.