JPH0229676Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention captures and releases lightning surges that have entered the electrical line, and also blocks the following current to prevent wire breakage and damage to the insulator due to the following arc. This invention relates to an insulated wire protection device for preventing lightning damage.

(Prior Art) An insulated wire protection device for lightning damage prevention uses a current-limiting element unit equipped with a current-limiting element made of a material with non-linear voltage-current characteristics to prevent lightning damage. Although it has already been proposed, in the conventional device of this type, an insulated wire is supported by a metal binding wire on the head of an insulator, a current limiting element unit is attached to a grounding metal fitting, and the current limiting element unit is connected to the energized side. The arcing horn is installed with an air gap between it and the insulated wire, and when a lightning surge enters the wire, the lightning impulse voltage breaks through the insulation wire's sheath and flashes over to the arcing horn. In this case, the dielectric strength of the sheathing changes depending on the grounding conditions of the electrical line and the degree of deterioration or damage due to the operating period, etc., and the fluctuation of the discharge voltage characteristics becomes large and the insulation coordination with other equipment becomes unstable and the transformer This can cause flashover accidents during bushing and cut-outs, and once the sheathing is penetrated and destroyed, the metal binding wire will be charged to approximately the same potential as the power line, causing not only direct danger during track repair work but also accidental electric shocks and bird damage. There were problems, such as the risk of causing harm or accidents.

(Problems to be solved by the invention) The invention solves the above-mentioned problems, stabilizes the discharge voltage characteristics from the insulated wire due to lightning surge, and prevents charging of the metal bound wire, thereby improving the electrical wiring. This was completed in order to provide an insulated wire protection device for lightning damage prevention that can maintain stability and ensure safety.

(Means for Solving the Problems) The present invention supports an insulated wire with a metal binding wire on the head of an insulator, and has voltage-current characteristics at a position of the insulated wire at a required distance from the insulator. A current-limiting element unit consisting of a current-limiting element made of a non-linear material, a discharge electrode, and a charging side electrode covered with a jacket made of an insulating material is placed in parallel with the insulated wire and connected to the charging side electrode. is electrically connected to the insulated wire, and the discharge electrode is opposed to the metal binding wire, and a predetermined discharge is generated between the discharge end of the discharge electrode and the metal binding wire. It is characterized by the formation of an air gap with voltage characteristics.

(Embodiment) Next, the present invention will be described in detail with reference to the illustrated embodiment. Reference numeral 1 denotes a current-limiting element unit, and the current-limiting element unit 1 includes a discharge electrode 1b and a current-side electrode 1c.
A current-limiting element 1a made of a material with non-linear voltage-current characteristics mainly composed of ZnO or SiC is interposed between the casing 1d made of a highly elastic insulating material such as rubber, etc. It consists of a discharge electrode 1b and a voltage-applying side electrode 1c that are encased with their discharge ends exposed. Reference numeral 2 denotes an insulator for supporting an insulated wire, and an insulated wire 4 is supported with a metal binding wire 3 at the head of the insulator 2. The above-described current limiting element unit 1 with a connector 5 is electrically connected to the insulated wire 4 in parallel with the insulated wire 4 at a position separated from the insulator 2 by a required distance. When installed, the discharge end of the discharge electrode 1b of the current limiting element unit 1 is made to face the metal binding wire 3, and the metal binding wire 3 and the discharge electrode 1
An air gap _l1 having a predetermined discharge voltage characteristic sufficiently lower than the penetration breakdown voltage of the insulated wire 4 is formed between the insulated wires 4 and 4b. The electrical connection between the current limiting element unit 1 and the insulated wire 4 is as shown in FIG.
The current limiting element unit 1 is supported and fixed in parallel with the insulated wire 4 by the connector 5 which connects the core wire 4a of
An insulating coating 5a is applied to the connector 5, and the stripped portion of the connector 5 is filled with an insulating sealing material 7 such as silicone rubber, and an insulating tape 8 is wrapped around the connector 5 to prevent electric shock and prevent leakage current from the core wire 4a. prevents it from flowing out. In addition, the jacket 1d covering the discharge electrode 1b of the current limiting element unit 1 opens at the discharge end of the discharge electrode 1b, and suppresses the leakage current flowing from the discharge electrode 1b when it is dirty or wet, and prevents water from running out during rain. The outer shell 1d is designed to suppress leakage current.
A pleated portion 1e is provided at the bottom. An air gap l2 is formed between the metal binding wire 3 and the base metal fitting 2a of the insulator 2 or the arcing horn ₉ , which is a grounding metal fitting.

As shown in FIG. 3, the connector 5 has a tip 5b that penetrates the sheath 4b of the insulated wire 4 and electrically connects with the core wire 4a, and has a jacket 1d integrally with the current limiting element 1a. If the insulated wire 4 is coated, there is no need to strip off the sheath 4b of the insulated wire 4 in order to obtain electrical connection with the core wire 4a, thereby simplifying the work of attaching the current limiting element unit 1 to the insulated wire 4.

(Function) In this structure, an insulated wire 4 is supported with a metal binding wire 3 on the head of an insulator 2.
The current-limiting element unit 1 forms a predetermined air gap _l1 between the discharge electrode 1b and the metal binding wire 3, and electrically connects the current-limiting element 1a to the core wire of the insulated wire 4. Since it is installed so that it can discharge at a sufficiently low voltage with respect to the penetration breakdown voltage, when a lightning surge enters the power line, the air between the discharge electrode 1b of the current limiting element unit 1 and the metal binding wire 3 〓l ₁ and the metal binding wire 3 and the base metal fitting 2a of the insulator 2 or the arcing horn 9
The lightning impulse flashes over along the path of 〓l ₂ between the air and the current, but the follow-on current continues from the current to the voltage-applied side electrode 1.
The voltage and current non-linearity of the current limiting element 1a between the current limiting element 1a and the discharge electrode 1b interrupts the current and prevents the generation of follow-on arcs, thereby preventing wire breakage and insulator destruction due to follow-on arcs. Furthermore, since the current limiting element unit 1 is supported along the insulated wire 4, even if the wire swings, the air gap leading to the metal binding wire 3 hardly changes, and therefore the discharge characteristics are stable. However, since the lightning surge is discharged along the path of the current limiting element unit 1, the metal binding wire 3, the base metal fitting 2a, or the arcing horn 9, the metal binding wire 3 and the core wire 4a of the insulated wire 4 have approximately the same potential. Strictly speaking, in this path, a slight voltage drop occurs in the current-limiting element unit 1 and the air intermediate _l1 during discharge due to the current-limiting element unit 1, but this causes a slight voltage drop between the metal binding wire 3 and the core wire 4a. Since the potential difference is smaller than the voltage at which the sheathing 4b of the insulated wire 4 is destroyed, the voltage burden on the sheathing 4b is substantially reduced. Therefore, the insulated wire 4 does not undergo through-breakage, and the conventional problem in which the lightning impulse flashover voltage fluctuates between when the sheathing 4b is healthy and when through-breakage occurs can be solved. In addition, since the discharge electrode 1b of the current limiting element unit 1 and the metal binding wire ₃ are discharged in the air between the two, once the lightning surge disappears, the metal binding wire 3 is charged to the same potential by the line voltage. Therefore, there is no risk of electric shock or bird damage caused by the metal binding wire 3. Furthermore, in the present invention, the air gap _l1 is formed along the electric line, so even if a sudden lightning surge occurs, there will be no accidental discharge accident to an unspecified grounded object.
The discharge path can be stabilized.

(Effect of the invention) As is clear from the above description, the present invention electrically connects the current limiting element unit to the core wire of the insulated wire, and connects the insulated wire to the discharge electrode of the current limiting element unit and the head of the insulator. Since a predetermined air gap is provided between the metal binding wire and the lightning surge, it has stable discharge characteristics to reliably block the following current from lightning surges, and prevents charging of the metal binding wire. The metal binding wire, which tends to cause dielectric breakdown of the insulated wire when a lightning surge occurs, can be used to protect the insulated wire, so it is highly effective in maintaining the stability and safety of the wire, and the installation structure is simple and can be implemented at low cost. Together with the advantages, the practical value is extremely great.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view showing an embodiment of the present invention, Fig. 2 is a partially cutaway front view of the main part, and Fig.
The figure is a partially cutaway front view of the main part showing another embodiment of the present invention. 1: Current-limiting element unit, 1a: Current-limiting element, 1
b: discharge electrode, 1c: power supply side electrode, 1d: mantle, 2: insulator, 3: metal binding wire, 4: insulated wire, 4a: core wire, 5: connector, 5b: tip,
l ₁ : Ki middle =.

Claims (1)

[Claims for Utility Model Registration] 1. An insulated wire 4 is supported with a metal bind wire 3 on the head of the insulator 2, and a voltage-current characteristic is provided at a position of the insulated wire 4 at a required distance from the insulator 2. A current-limiting element unit 1 consisting of a current-limiting element 1a made of a non-linear material, a discharge electrode 1b, and a voltage-applying side electrode 1c covered with a jacket 1d made of an insulating material is arranged in parallel with the insulated wire 4. hand,
In addition, the discharge electrode 1b is connected to the metal binding wire 3 by attaching it via the connector 5 while electrically connected to the insulated wire 4 with the energizing side electrode 1c.
An insulated wire protection device for preventing lightning damage, characterized in that an air gap _L1 having predetermined discharge voltage characteristics is formed between the discharge end of the discharge electrode 1b and the metal binding wire 3, facing each other. 2. The insulated wire protection device for lightning damage prevention according to claim 1, wherein the connector 5 has a tip 5b that penetrates the sheath of the insulated wire 4 and contacts the core wire 4a.