JPH0134505Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to a lightning-strength device that takes measures to prevent disconnection due to follow-on arcs in power transmission and distribution lines.

Conventional technology Tension devices for power transmission and distribution lines, in which insulated wires are held in place by generally two connected tension insulators stretched in the direction of the line from a grounding metal fitting such as a cross arm, are designed to protect the power lines from shocks such as lightning surges. If an overvoltage occurs, it may flash over from the edge part supported by the jumper wire support insulator to a grounding object such as the base metal fitting of the jumper wire support insulator, or the voltage connected to the retaining clamp holding the wire may flash over. It flashes over to the grounded object through the pin fittings and cap fittings of the tension insulator on the side, and the arc heat of the subsequent arc that occurs not only damages the jumper wire support insulator or the tension insulator, but also causes the energy of the follow arc to be damaged. If the voltage was large, the pin fittings of the tension insulator on the power supply side would melt due to the arc heat generated by the arc, and as a result, the wire would break and fall to the ground. Another disadvantage is that the firing point of the follow-on arc is fixed at a point where the insulation coating of the insulated wire has broken through, causing the wire to break.

For this reason, it is known that a separate lightning arrester with an arcing horn or the like is attached in parallel to the jumper wire support insulator and the tension insulator, and the device faces the discharge point through an air gap. The number of attachments increased, the installation of pillars became complicated, and work on the pillars such as inspection and repair was troublesome.

Purpose of the invention The present invention was made to eliminate the above-mentioned conventional drawbacks, and its purpose is to prevent damage or separation of the jumper wire support insulators and tension-resistant insulators when shock overvoltage such as lightning surge occurs on the power line. It is an object of the present invention to provide a lightning-resistant tension device that can prevent electrical wires from breaking and also prevent electrical wires from breaking.

Structure of the invention In order to achieve the above-mentioned object, the present invention holds the insulated wire in place with an insulator device stretched in the direction of the track by sandwiching the arms, and supports the edging part with a jumper wire support insulator. In a tension device for power transmission and distribution lines, the insulator device is composed of a tension insulator with a capacitance _C1 and a current limiting element unit with a capacitance _C2 with nonlinear voltage-current characteristics such that 2C ₁ <C _2. The insulation level is set to be lower than that of the jumper wire supporting insulator.

Embodiment Hereinafter, an embodiment embodying the present invention will be described with reference to FIG. The hem portion 4a of the insulated wire 4 is tied down. Reference numerals 5 and 6 indicate ground side retaining devices fastened to the arm 2, and reference numerals 7 and 8 indicate insulated wires 4.
9 is a tension-resistant insulator connected between the ground-side retainer 5 and the wire-grip 7 by connecting pins 13, and 11 is the ground side. This is a current limiting element unit connected by a connecting pin 13 between the retainer 5 and the tension insulator 9.

Next, the current limiting element unit 11 will be explained with reference to FIGS. 2 and 3. Reference numeral 14 is an insulating rod made of a material with excellent mechanical strength such as reinforced plastic, and has screws 14a formed at both ends. Terminal fitting 15 on the power supply side having a screw hole 15a on one side
are screwed together, and a ground side terminal fitting 16 having a screw hole 16a is screwed onto the other side. Further, a screw 1 formed on the outer periphery of the tip of both terminal fittings 15 and 16
Cap electrodes 17 and 18 on the energizing side and the grounding side are screwed into the cap electrodes 5b and 16b, respectively, and are connected to the retaining devices 5 and 6 and the tension insulator 9 by the connecting pin 13. .

Reference numeral 19 denotes a cylindrical current-limiting element made of a material with non-linear voltage and current characteristics, such as zinc oxide, which is fitted into the center of the insulating rod 14, and has electrode parts 20 formed by metal spraying on both end faces thereof. It is formed by welding.
Reference numeral 21 denotes an electrode plate on the power supply side interposed between the terminal fitting 15 on the power side and the electrode section 20, and 21 and 22 interposed in series between the terminal fitting 16 on the grounding side and the electrode section 20. It is a conductive elastic body consisting of an electrode plate on the ground side, a disc spring, etc.

By the way, the above-mentioned current limiting element 19 and electrode part 2
0, both electrode plates 21, 22, and conductive elastic body 23
etc. are fitted onto the outer periphery of the insulating rod 14 with a predetermined gap G, and are press-fitted to each other by being tightened and fixed by terminal fittings 15 and 16 on the power supply side and the grounding side. . Each of these members is placed with the cap electrodes 17 and 18 exposed.
It is sealed and enclosed by an elastic insulating material 24 such as EP rubber. During this sealing, notches 15c and 1 are formed on the opposing end surfaces of both terminal fittings 15 and 16.
6c (see FIG. 3), the elastic insulating material 24 is filled into the gap G, and the elastic insulating material 24 is further filled into the gap G through the groove 14b formed in the thread 14a of the insulating rod 14.
4 is the screw hole 15a, 16 of both terminal fittings 15, 16
The remaining air is discharged while filling the void within a to strengthen internal electrical insulation. In the above,
Capacitance _C1 of tension insulator 9 and current limiting element unit 1
1 and capacitance C ₂ are configured so that 2C ₁ <C ₂ . Regarding the jumper wire support insulator 1, a separate lightning arrester may be attached as in the conventional case, but the insulation level of the jumper wire support insulator 1 should be made sufficiently higher than the tension device part to prevent lightning surge voltage. If the tension insulator 9 is used for flashover, there is no need to install a separate lightning arrester.

Next, the operation of the lightning-resistant tension device constructed as described above will be explained.

Now, when an impact overvoltage such as a lightning surge occurs in the insulated wire 4, the voltage is applied to the current limiting element unit 11 by flashing over the tension insulator 9 from the insulated wire 4 or the wire gripper 7, but at this time, The current-limiting element 19 contained in the current-limiting element unit 11 quickly reduces the resistance value due to the non-linearity of the voltage-current characteristics and discharges the large current of the lightning surge, and at the same time discharges the large current of the lightning surge. Since the voltage is low, the resistance value is immediately restored and the insulation is restored, so follow-on discharge is suppressed and interrupted, and the electrical line returns to normal.

Now, in the embodiment of the present invention, the grounding side retaining tool 5
Since the current limiting element unit 11 is connected in series between the tension insulator 9 and the tension insulator 9, even if a flashover occurs in the tension insulator 9, the subsequent current caused by the flashover can be prevented by the current limiting element unit 1.
1 to prevent breakage of the tension insulator 9 and breakage of the insulated wire 4. Furthermore, if the capacitance C ₂ of the current limiting element unit 11 and the capacitance C ₁ of the tension insulator 9 are set in the relationship 2C ₁ <C ₂ , the line voltage can withstand approximately 70% or more of the normal line voltage. Since the insulator 9 is responsible for this, deterioration of the current limiting element 19 is suppressed. Furthermore, even if the current limiting element 19 deteriorates due to long-term use, it will not result in a ground accident because it is insulated and isolated by the tension insulator 9 arranged in series. Furthermore, even if the current limiting element 19 is destroyed by an excessive lightning surge caused by a direct lightning strike, the insulating rod 14 provides tensile strength, so the current limiting element unit 11 itself will be severed and the insulated wire 4 will be disconnected. It is possible to prevent this from occurring.

Note that the present invention can also be embodied in the following embodiments.

(1) Instead of the current limiting element unit 11, a current limiting element unit 11' shown in FIG. 4 may be used.
In this current-limiting element unit, a current-limiting element 19 is fitted onto the outer periphery of an insulating rod 14 via a foamed insulating material 25 or the like, and the outer circumferential surface of the current-limiting element 19 is coated with a high-low resistance layer 26 made of glass or the like. There is. Further, both ends of the current limiting element 19 are connected to cap electrodes 17,1.
It is covered by a cover plate 27 that is fitted into the cover plate 8 , and the inside of the cover plate 27 is filled with an adhesive 28 .

(2) Two or more current-limiting element units 11 are connected in series between the ground side retaining device 5 and the tension insulator 9, depending on the voltage class of the electric line.

Effects of the invention As detailed above, the present invention does not make the installation of the pole complicated by attaching a lightning arrester separately, and when an impact overvoltage such as a lightning surge occurs on the electric wire, the following current can be avoided. This can prevent wire breakage due to follow-on arcs and damage to the tension insulators, etc., and since the tension insulators are always burdened with the line voltage, it is possible to suppress deterioration of the current limiting element, and it is also possible to use it for a long time. It is of high practical value as it can prevent ground faults even if the current limiting element has deteriorated.

[Brief explanation of the drawing]

Fig. 1 is a front view showing the lightning resistance device of the present invention;
Figure 2 is a longitudinal sectional view of only the current limiting element unit;
The figure is a partial perspective view of the terminal fitting, and FIG. 4 is a longitudinal sectional view showing another example of the current limiting element unit. 1... Shyamper wire support insulator, 2... Bracelet, 4
...Insulated wire, 4a...Edge section, 5...Grounding side retaining tool, 7...Wire gripping tool, 9...Tension-resistant insulator, 1
1...Current limiting element unit, 14...Insulating rod, 1
5, 16... Terminal fitting, 19... Current limiting element, 25
...Foam insulation material.

Claims (1)

[Scope of utility model registration request] In a tensioning device for a power transmission and distribution line, in which an insulated wire 4 is held in place by an insulator device stretched in the line direction with a cross arm 2 held therebetween, and the hem 4a is supported by a jumper wire support insulator 1. , the insulator device is connected in series with a tension-resistant insulator 9 having a capacitance C ₁ and a current limiting element unit 11 having a capacitance C ₂ and having a non-linear voltage-current characteristic, setting 2C ₁ <C ₂ . , and its insulation level is set lower than that of the jumper wire support insulator 1.