CN201075576Y - Puncture-type lightning protection fittings for preventing overhead insulated conductors from being disconnected by lightning - Google Patents

Abstract

The utility model relates to a stab-type lightning-protection fitting used for preventing insulated overhead conductor from being broken by lightning. The fitting is directly arranged at the upper end of an insulator and the top cap at the upper part of the fitting is provided with an electrode provided with stab; the electrode directly penetrates the insulation layer of an insulated lead, electrically and closely contacts the conductor in the insulated conductor and leads the electricity to the upper metal electrode of the exposed insulator formed by the top cap of the fitting and a fitting chassis. Under the function of lightning overvoltage, a stab blade closely contacting the conductor leads the lightning overvoltage to the metal electrode at the upper of the insulator to ensure the lightning overvoltage to be directly added between the upper metal electrode and the metal electrode at the lower part of the insulator, thus breaking down the surface of the insulator. Therefore, the structure of the insulated conductor becomes similar exposed conductor which is not easy to be burnt by power-flow current, thereby preventing insulated overhead conductor from being broken by lightning. The fitting is free of maintenance during operation, safe in operation and reliable in performance and is especially applicable to the insulated overhead conductor of 10 KV.

Description

Puncture-type lightning protection fittings for preventing overhead insulated conductors from being disconnected by lightning

technical field

The utility model relates to the field of electric power distribution network, which is used for overhead distribution lines of electric power system, and is mainly used for preventing lightning breakage of overhead insulated wires, and is especially suitable for use on 10kV overhead insulated wires.

technical background

In order to reduce the faults of overhead distribution lines caused by external factors such as trees, birds, and snow accumulation, and improve the reliability of power supply, overhead insulated wires have been widely used at home and abroad in recent decades. Insulated wires do solve the corridor and safety problems that bare wires cannot solve. Compared with cables, it has the advantages of low investment and fast construction, but its lightning disconnection problem is very prominent. It has become a problem in the distribution network system. important issues that urgently need to be addressed.

Economically developed countries have used overhead insulated wires for power transmission and distribution for a long time, accumulated a lot of operating experience, and adopted many preventive measures and methods, as follows.

Overhead lightning protection line: In open areas, erecting overhead lightning protection lines on the same pole to deal with the induced overvoltage of distribution overhead insulated lines is a traditional method with a large investment. However, due to the low insulation level of the distribution line design, it is very easy to cause flashover after lightning strikes the overhead lightning conductor, which will still cause power frequency freewheeling to fuse the insulated conductor. Therefore, this method is rarely used abroad.

Zinc oxide arrester: In recent years, zinc oxide arresters have been widely used in lines to limit lightning overvoltage by taking advantage of their non-linear resistance characteristics and fast blocking power frequency continuous current characteristics. Their protection range is limited, and basically they can only protect the pole equipment. . Japan, the United States, Canada and other countries have invested heavily in the transformation of the line. After installing three (phase) zinc oxide arresters on each base pole, the lightning disconnection rate has been reduced from the original 93.3% to 2.7%, basically no recurrence Lightning strike disconnection accident. However, with this method, a large number of lightning arresters will be used. When the quality of lightning arresters is poor, it may cause more line accidents during operation and affect safe operation.

Clamp insulators: Tokyo Electric Power Company in Japan uses discharge clamp insulators to prevent insulated wires from being disconnected by lightning. That is, peel off the insulation layer at the fixed place of the insulated wire, install a specially designed metal wire clip, and set the arc discharge gap. When lightning flashover triggers power frequency freewheeling, the power frequency freewheeling arcs on the metal clamp until the line trips to extinguish the power frequency freewheeling, thereby avoiding burning insulators and fusing insulated wires.

According to the same principle, the covered line power distribution system (SAX system) developed by Finland's Nokia company uses suspension clamps and other devices as flashover protectors, and the suspension clamps withstand power frequency arcs. But the anti-seismic performance of this device is relatively poor, and when the line is blown and danced by wind, it often breaks down.

Increasing the flashover path: By increasing the flashover path, reducing the power frequency arc establishment rate is another way to prevent lightning strike and disconnection accidents of overhead insulated lines. The Russian State Electric Power Company first proposed the long flashover gap protection method. Install a U-shaped insulation flashover path on the cross arm, so that the impulse discharge voltage between the U-shaped head and the insulated wire is lower than the insulator discharge voltage. When the lightning overvoltage occurs, the gap precedes the breakdown and flashover of the insulator, and develops along the insulation flashover path. The insulation path is designed to be long enough to prevent power frequency freewheeling from building an arc and cut off power frequency freewheeling. However, this method is not mature and has not been widely used.

Improve line insulation level: replace porcelain insulators in power distribution lines with silicon rubber insulating crossarms, improve line insulation level across the line, and power frequency freewheeling caused by lightning cannot establish arcs due to large creepage distances.

In order to reduce the cost of the line, it is possible to use overhead insulated wires to strengthen local insulation, that is, to thicken the insulation where the insulated wires are fixed. This is also an attempted method, and the effect is not very satisfactory.

Line overvoltage protector: In some lightning-damaged countries such as Japan, Australia, the United States and Europe, a large number of line overvoltage protectors have been widely used on overhead insulated lines in recent years, which are actually out-of-band gap arresters. The device uses the outer gap to form an outer discharge gap to the zinc oxide current limiting element. When the line has a lightning overvoltage, the outer gap is first discharged, and the lightning current is released through the zinc oxide current limiting element, while the power frequency freewheeling current is absorbed by the zinc oxide The current limiting element is cut off, so as to prevent the occurrence of lightning breakage accidents of overhead insulated lines. After the protection device is put into operation, the maintenance and repair workload is relatively large.

To sum up, although the above-mentioned methods can effectively prevent wire breakage due to lightning strikes, there are still some problems as follows: some of the current anti-breakage fittings, some insulated wires need to be stripped for a long length before use, and the exposed parts are relatively large. Large, this will have a certain impact on the sealing and insulation of the wires, and will seriously affect the mechanical strength and service life of the wires; some installations are more complicated and not easy to use in practice. However, the use of surge arresters and overvoltage protectors has good protection effects, but there are mainly problems such as difficult operation and maintenance.

Contents of the invention

The purpose of the utility model is to overcome the defects of the prior art and provide a puncture type lightning protection fitting for preventing overhead insulated wires from being broken by lightning.

The utility model's puncture type lightning protection fittings for preventing overhead insulated wires from being struck by lightning and disconnecting include insulators, overhead insulated wires and piercing fittings. The piercing fittings include fittings chassis, fittings top cap and electrodes. Located in the top cap of the fittings and connected with the bolts in the top cap of the fittings, there is a piercing blade on either or both sides of the electrode and the chassis of the fittings, the piercing blade directly penetrates the insulation layer of the insulated wire, and is in close electrical contact with the conductor inside the insulated wire , an insulating sheath is provided outside the puncture fitting.

In the lightning protection fittings of the utility model, the piercing fittings (including fittings top cap and fittings chassis) directly installed on the upper part of the insulator constitute the exposed metal electrodes on the upper part of the insulator. Under the action of lightning overvoltage, the piercing blade that is in close contact with the conductor will lead the lightning overvoltage to the upper metal electrode of the insulator, so that the lightning overvoltage is directly added between the upper metal electrode and the lower metal electrode of the insulator, causing the surface of the insulator to break down . In this way, the insulated wire is changed into a similar bare wire structure, which makes it difficult to be burned out by power frequency freewheeling, thereby protecting the overhead insulated wire from being disconnected during a lightning strike. The fitting is maintenance-free during operation, and is especially suitable for application on 10kV overhead insulated conductors, suitable for copper and aluminum overhead insulated conductors.

In order to protect the porcelain surface of the insulator from arc burning and avoid the insulator from burning out in the event of lightning strike. Electrode A extending to both sides can be set in the radial direction of the fitting chassis; or electrode B extending to both sides can be set at the metal electrode at the lower end of the insulator; or electrodes extending to both sides can be set at the radial direction of the fitting chassis and the metal electrode at the lower end of the insulator . In this case, due to the action of load current or short-circuit current, the arc will be electrodynamically driven to the outside of the extension electrode. In this way, the arc burns in the air gap and does not burn on the surface of the insulator, thereby protecting the surface of the insulator from burning damage.

The lightning protection fitting adopts a torque nut to control the cutting depth of the piercing blade to ensure good electrical contact between the blade and the conductor without damaging the wire.

An insulating cover is installed on the outside of the lightning protection fitting to ensure insulation.

The advantages of the lightning protection fittings of the present utility model are:

(1) Easy to install, no need to strip the insulation layer of the insulated wire, and there is no size requirement for up, down, left, and right during installation;

(2) It has the indication function of lightning short-circuit accident (the bottom of the outer insulating cover has obvious color change after lightning strike and arc burning, from black to white);

(3) Maintenance-free, outstanding burning resistance;

(4) The installation of fittings has nothing to do with the direction of load flow;

(5) The impact on the breakdown voltage of the line insulation is small;

(6) The device has excellent reusability;

(7) Protect the surface of the insulator from arc burn damage;

(8) Free from grounding.

The lightning protection fitting has the advantages of lightning protection against broken wires, no stripping of the wire insulation layer, simple construction, with an insulating cover, safe operation, high reliability, and maintenance-free during operation.

Description of drawings

Fig. 1 is a kind of specific structural schematic diagram of lightning protection fittings of the present invention;

Fig. 2 is a schematic side view of Fig. 1;

Fig. 3 is an axial sectional view of the piercing fitting in the lightning protection fitting of Fig. 1;

Fig. 4 is the puncture schematic diagram between the electrode with puncture and overhead insulated wire;

Fig. 5 is the half-ring ear clip connecting the insulator and the puncture fitting in Fig. 1;

Fig. 6 is a schematic diagram of electrodes extending to both sides at the lower end of the hardware chassis and the insulator in Fig. 1;

Fig. 7 is another specific structural schematic diagram of the lightning protection fitting of the present invention;

Fig. 8 is a schematic side view of Fig. 7;

Fig. 9 is an axial sectional view of the piercing fitting in the lightning protection fitting of Fig. 7;

Fig. 10 is a schematic diagram of the lower ends of the hardware chassis and the insulator in Fig. 7 having electrodes extending to both sides.

Fig. 11 is another schematic diagram of the structure in which the chassis of the metal fittings of the present invention is directly connected with the insulator.

Detailed ways

In order to further illustrate the application of the utility model, the following three typical structures of lightning protection fittings will be taken as examples (in conjunction with the accompanying drawings) to further introduce. Of course, the utility model is not limited to the three structures introduced here, and can be further expanded based on the claims of the utility model.

Application example of typical structure (1)

Referring to Figures 1 to 5, puncture-type lightning protection fittings for preventing overhead insulated conductors from being disconnected by lightning strikes. Half ring ear clip, 4 is silicone rubber insulating sheath, 5 is torque nut, 6 is screw rod, 7 is insulator, 8 is electrode with puncture, 9 is overhead insulated wire, 10 is hexagon bolt, 11 is insulator lower metal electrode.

The installation steps are as follows:

(1) Unscrew the two outer hexagonal bolts 10 on the fitting top cap 2, and remove the fitting top cap 2;

(2) Put the metal fitting chassis 1 into the neck of the insulator 7, so that the U-shaped groove of the metal fitting chassis 1 is completely matched with the U-shaped groove at the top of the insulator 7, and then put the overhead insulated wire 9 into the U-shaped groove of the hardware chassis 1;

(3) Insert the half-ring ear clip 3 into the neck of the insulator 7, snap both ends into the side grooves on both sides of the hardware chassis 1, pull the half-ring ear clip 3 upward with even force with both hands, and then tighten the half-ring ear The nuts at both ends of the clip 3;

(4) Install the hardware top cap 2, and tighten the two hexagon bolts 10 on the top cap;

(5) Use a special torque wrench to tighten the torque nut 5 until it is broken;

(6) Cover the silicone rubber insulating sheath 4 well.

FIG. 6 is a case where the chassis of the lightning protection fittings shown in FIG. 1 has extension electrodes 12 and the bottom metal electrode 11 of the insulator with extension electrodes 13 in the radial direction.

Application examples of typical structures (2)

Referring to Figures 7 to 9, the puncture-type lightning protection fittings for preventing overhead insulated conductors from being disconnected by lightning strikes. Is the hex nut, 4 is the silicone rubber insulating sheath, 5 is the torque nut, 6 is the screw rod, 7 is the insulator, 8 is the electrode with a puncture, 9 is the overhead insulated wire, 10 is the outer hexagonal bolt, 11 is the lower end metal of the insulator electrode.

The installation steps are as follows:

(1) Unscrew an outer hexagonal bolt 10 on the lightning protection fitting first, and separate the two semi-circular metal extension electrodes constituting the fitting chassis 1;

(2) Put the fitting top cap 2 on the top of the insulator 7, and at the same time clamp the two semicircular metal extension electrodes together on the neck of the insulator. Tighten the bolt 10 to fix the piercing hardware and the insulator;

(3) Use a special torque wrench to tighten the torque nut 5 until it is broken;

(4) Screw the hex nut 3 under the torque nut into the top surface of the fitting top cap and flatten it;

(5) Cover the silicone rubber insulating sheath 4 well.

FIG. 10 is a case where the metal electrode 11 at the lower end of the insulator of the lightning protection fitting shown in FIG. 7 has an extended electrode 13 .

Application examples of typical structures (3)

In this example, the chassis of the fittings is integrated with the insulator.

Referring to Figure 11, the puncture type lightning protection fittings for preventing overhead insulated conductors from being disconnected by lightning strikes, in the figure: 1 is the chassis of the fittings (it is directly integrated with the insulator when it is manufactured), 2 is the top cap of the fittings, 3 is the hexagonal nut, 4 is a silicone rubber insulating sheath, 5 is a torque nut, 6 is a screw rod, 7 is an insulator, 8 is an electrode with a puncture, 9 is an overhead insulated wire, 10 is an outer hexagonal bolt, and 11 is a metal electrode at the lower end of the insulator.

The installation steps are as follows:

(1) Put the wire into the U-shaped groove of the hardware chassis 1 connected with the insulator;

(2) Install the fitting top cap 2, and tighten the two outer hexagonal bolts 10 on the fitting top cap 2;

(3) Use a special torque wrench to tighten the torque nut 5 until it is broken;

(4), screw the hex nut 3 under the torque nut into the top surface of the fitting top cap and flatten it;

(5) Cover the silicone rubber insulating sheath 4 well.

In this example, there are extended electrodes 12 in the radial direction of the metal fitting chassis, and extended electrodes 13 are provided on the metal electrodes 11 at the lower end of the insulator.

Claims (4)

1. prevent the penetration type lightning protection gold utensil of suspended insulated guide wire lightning-caused breaking, comprise insulator (7), suspended insulated guide wire (9), it is characterized in that also comprising the puncture gold utensil, the puncture gold utensil comprises gold utensil chassis (1), gold utensil top cap (2) and electrode (8), gold utensil chassis (1) is fastened on the upper end of insulator (7), electrode (8) is arranged in gold utensil top cap (2), link to each other with the bolt (6) in the gold utensil top cap (2), any one party or both sides in electrode (8) and gold utensil chassis (1) are provided with the puncture blade, the puncture blade directly penetrates the insulating barrier of insulated conductor, closely electrically contact with insulated conductor (9) conductor inside, outside the puncture gold utensil, be provided with insulating sleeve (4).

2. the penetration type lightning protection gold utensil that prevents the suspended insulated guide wire lightning-caused breaking according to claim 1, what it is characterized in that gold utensil chassis (1) radially has an electrode (12) that extends to both sides.

3. the penetration type lightning protection gold utensil that prevents the suspended insulated guide wire lightning-caused breaking according to claim 1 is characterized in that the lower end of insulator (7) is provided with the metal electrode (11) that has to both sides extension electrode (13).

4. the penetration type lightning protection gold utensil that prevents the suspended insulated guide wire lightning-caused breaking according to claim 1 is characterized in that radially with the lower end metal electrode (11) of insulator the electrode that extends to both sides being set simultaneously in gold utensil chassis (1).

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