CN201075637Y - Piercing lightning protector for preventing overhead insulated conductors from being disconnected by lightning - Google Patents

Abstract

The utility model discloses a puncture type lightning protector for preventing overhead insulated wires from being broken by lightning. Including insulators, overhead insulated conductors, piercing clamps, piercing extension conductors and arc shield electrodes. Under the action of lightning overvoltage, the piercing blade that is in close contact with the conductor leads the lightning overvoltage to the arc-shaped shielding electrode on the opposite side of the metal electrode at the bottom of the insulator, so that the lightning overvoltage is directly applied to the arc-shaped shielding electrode and the insulator Between the lower metal electrodes, the air gap between the arc-shaped shielding electrode and the lower metal electrode of the insulator is broken down. In this way, after the lightning strike, the power-frequency freewheeling arc will burn in the air gap, thereby protecting the overhead insulated conductor from breaking during the lightning strike. The lightning protection gap is maintenance-free during operation, safe in operation and high in reliability, and is especially suitable for application on 10kV overhead insulated wires.

Description

Piercing lightning protector for preventing overhead insulated conductors from being disconnected by lightning

technical field

The utility model relates to a puncture type lightning protector for preventing overhead insulated wires from being broken by lightning, and belongs to the technical field of power distribution networks.

Background technique

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. But this method is immature and has not been promoted and applied.

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 protector for preventing overhead insulated wires from being broken by lightning.

The puncture-type lightning protector for preventing overhead insulated wires from being struck by lightning and disconnected according to the utility model includes insulators and overhead insulated wires, and is characterized in that a puncture wire clip is installed on the overhead insulated wire, the puncture wire clip is connected with a puncture extension conductor, and the puncture extension conductor The end is provided with an arc-shaped shielding electrode, and an insulating sheath is set on the puncture extension conductor and the arc-shaped shielding electrode. The lower metal electrode of the insulator, the arc-shaped shielding electrode and the lower metal electrode of the insulator form a pair of discharge gaps.

The puncture clamp of the puncture type lightning protector of the utility model directly penetrates the insulation layer of the overhead insulated wire, and is in close electrical contact with the conductor inside the insulated wire, so that the potential of the insulated wire is directly led to the puncture extension conductor and the arc-shaped shielding electrode superior. Under the action of lightning overvoltage, the piercing blade that is in close contact with the conductor leads the lightning overvoltage to the arc-shaped shielding electrode by piercing the extended conductor, so that the lightning overvoltage is directly applied between the arc-shaped shielding electrode and the metal electrode at the bottom of the insulator The discharge gap between them causes breakdown of the air gap between the arc-shaped shielding electrode and the metal electrode at the bottom of the insulator. In this way, after the lightning strike, the power-frequency freewheeling arc will burn in the air gap, thereby protecting the overhead insulated conductor from breaking during the lightning strike.

A further feature of the utility model is that the end of the arc-shaped shielding electrode is slightly convex and flat, and the side is arc-shaped. In this way, the arc-shaped shielding electrode can play a role in making the electric field on the surface of the electrode uniform. The metal electrode at the lower part of the insulator is a cylindrical surface with a larger diameter, and the electric field on its surface is relatively uniform, so that the arc-shaped shielding electrode and the metal electrode at the lower part of the insulator are in a face-to-face state in the horizontal direction, thus forming a pair of relatively uniform electric field gaps. It can make the discharge voltage more reliable and stable.

Usually, the air discharge gap between the arc-shaped shielding electrode and the metal electrode at the bottom of the insulator is between 10 and 20 cm, so as to ensure that the gap can break down before the insulator under the action of lightning overvoltage and play a protective role.

The lightning arrester uses standard piercing clips to pierce overhead insulated wires. An insulating sleeve is installed outside the piercing extension conductor and the arc-shaped shielding electrode to ensure insulation.

The advantage of the lightning arrester of the present utility model is:

(1) Easy to install, no need to strip the insulation layer of the insulated wire;

(2) Maintenance-free, outstanding burning resistance;

(3) The installation of the lightning arrester has nothing to do with the flow direction of the load;

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

(5) No grounding, safe operation, high reliability, especially suitable for application on 10kV overhead insulated wires, suitable for copper and aluminum overhead insulated wires.

Description of drawings

Fig. 1 is a kind of concrete structure schematic diagram of the utility model lightning arrester;

Fig. 2 is a schematic diagram of an arc surface of an arc-shaped shielding electrode.

Detailed ways

Referring to Fig. 1, the puncture type lightning protector for preventing overhead insulated wires from being struck by lightning and disconnected includes insulators 5 and overhead insulated wires 6, and a puncture wire clip 1 is installed on the overhead insulated wires, and the puncture wire clip 1 is connected with a puncture extension conductor 2, The end of the piercing extension conductor 2 is provided with an arc-shaped shielding electrode 3, and an insulating sheath 7 is set on the piercing extension conductor 2 and the arc-shaped shielding electrode 3, wherein the end of the insulating sheath covering the arc-shaped shielding electrode 3 is open The arc surface of the arc-shaped shielding electrode 3 faces the lower metal electrode 4 of the insulator, and the arc-shaped shielding electrode 3 and the lower metal electrode 4 of the insulator form a pair of discharge gaps.

The arc-shaped shielding electrode shown in Fig. 2 has a slightly convex flat surface at the end and an arc-shaped side that shields the electric field uniformly, which can make the electric field gap uniform.

Claims (3)

1. prevent the penetration type lightning protection device of suspended insulated guide wire lightning-caused breaking, comprise insulator (5), suspended insulated guide wire (6), it is characterized in that being equipped with on the suspended insulated guide wire penetrating cable clamp (1), penetrating cable clamp (1) is connected with puncture and extends conductor (2), puncture is extended conductor (2) end and is provided with arc bucking electrode (3), on puncture extension conductor (2) and arc bucking electrode (3), be with insulating sleeve (7), wherein, be enclosed within the insulating sleeve termination openings on the arc bucking electrode (3), the cambered surface of arc bucking electrode (3) is towards insulator lower metal electrode (4), and arc bucking electrode (3) and insulator lower metal electrode (4) constitute a pair of discharging gap.

2. the penetration type lightning protection device that prevents the suspended insulated guide wire lightning-caused breaking according to claim 1, the spacing that it is characterized in that the discharging gap between arc bucking electrode (3) and the insulator lower metal electrode (4) is at 10～20cm.

3. the penetration type lightning protection device that prevents the suspended insulated guide wire lightning-caused breaking according to claim 1 is characterized in that the end of arc bucking electrode (3) is the dimpling flat horizontal surface, and the side has been the evenly arc of shielding of electric field.

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