CN107369508A - A kind of arrester - Google Patents

Abstract

The present invention relates to field of power, discloses a kind of arrester, and the arrester includes the arc extinguishing section and resistive segments coaxially and vertically set, and the upper end of the arc extinguishing section is connected with the lower end of the resistive segments, and the upper end of the resistive segments is connected with extraneous the earth；The arc extinguishing section includes epoxy plug and is spirally coiled in the spiral umbrella disk of the insulation of the epoxy outside plug, and multiple arc extinguishing units are arranged at intervals along the outward flange of the spiral umbrella disk；The resistive segments include the annular umbrella disk of the multiple insulation of the resistor main body and spacer sleeve of column on the outside of the resistor main body.Lightning current of the invention of effectively being released in transmission line of lightning strike, the power frequency continued flow current amplitude after lightning wave effect can be also limited, ensure that circuit is struck by lightning；Even if resistive segments are damaged or failure, it is possibility to have effect ground cut-out power frequency continued flow, ensure the normal table operation of transmission line of electricity.

Description

a lightning arrester

technical field

The invention relates to the technical field of power systems, in particular to a lightning arrester.

Background technique

The phenomenon of lightning strikes widely exists in the power system. The tripping and blackout accidents of transmission lines caused by lightning strikes bring huge economic losses to the power system and also threaten the safe and stable operation of the power grid. The installation of line arresters is currently the main lightning protection method for transmission lines measure.

In the existing metal oxide lightning arrester, when the resistor sheet is damaged, the resistance value of the resistor sheet will decrease, so that the arrester cannot cut off the power-frequency freewheeling current after the lightning wave acts, thereby making the arrester invalid. Although the existing multiple short-gap arresters can cut off large freewheeling currents, single multiple short-gap arresters are prone to high-amplitude power-frequency freewheeling after the lightning wave, which has a great impact on the power grid. Therefore, multiple short-gap arresters must be used in conjunction with the automatic reclosing system. However, when a large number of multiple short-gap arresters are assembled on overhead lines, the insulation level of the lines will inevitably be reduced to a certain extent.

Contents of the invention

(1) Technical problems to be solved

Existing metal oxide arresters are prone to problems such as resistance drop and arrester failure due to the aging and damage of resistors, while single multiple short-gap arresters are prone to high-amplitude power-frequency freewheeling after the action of lightning waves, which is harmful to the power grid. It produces a large impact, so it must be used in conjunction with the automatic reclosing system, which reduces the insulation level of the line to a certain extent.

(2) Technical solution

In order to solve the above technical problems, the present invention provides a lightning arrester, which includes a coaxial and vertical arc extinguishing section and a resistance section, the upper end of the arc extinguishing section is connected to the lower end of the resistance section, and the resistor The upper end of the segment is connected to the outside earth;

The arc extinguishing section includes an epoxy mandrel, and an insulating spiral umbrella disk spirally wound outside the epoxy mandrel, and a plurality of arc extinguishing units are arranged at intervals along the outer edge of the spiral umbrella disk;

The resistor section includes a columnar resistor body and a plurality of insulating ring-shaped umbrella disks spaced outside the resistor body.

As an implementable manner, the arc extinguishing unit includes an electrode connected to the spiral umbrella disk, and a rubber layer covering the outside of the electrode; the electrode has smooth edges, and the adjacent arc extinguishing unit The electrodes of the unit are separated from each other to form an air gap, and two discharge protrusions are arranged symmetrically on the outside of the rubber layer;

In each of the arc extinguishing units, the two discharge protrusions are respectively opposite to and spaced from the discharge protrusions of the arc extinguishing units adjacent on both sides. An arc extinguishing gap is formed between them.

Further, pressure equalizing rings are sheathed on both ends of the arc extinguishing section.

Furthermore, the distance between the electrodes of adjacent arc extinguishing units is greater than or equal to 5 mm and less than or equal to 10 mm; the arc extinguishing gap is greater than or equal to 2.5 mm and less than or equal to 5 mm. mm.

Furthermore, the cross-sectional area of the discharge protrusion gradually decreases from the inside to the outside.

Furthermore, the ends of the discharge protrusions are spherical.

As another practicable manner, the arc extinguishing unit includes an arc extinguishing tube and a gas-generating material layer attached to an inner wall of the arc extinguishing tube, and the gas-generating material layer can release gas when heated.

Further, the resistor body includes an epoxy resin barrel and a plurality of resistor sheets stacked in the inner cavity of the epoxy resin barrel.

Furthermore, the resistor body also includes crimping fittings and two elastic pieces sealed at both ends of the epoxy resin cylinder, and each of the elastic pieces is respectively arranged between each of the crimping fittings and the resistor sheet. between.

Further, the distance between adjacent annular umbrella disks is greater than or equal to 35 mm.

(3) Beneficial effects

In the lightning arrester provided by the present invention, the resistance body of the resistance section has a relatively high resistance value, and the resistance value will decrease when the lightning strikes the transmission line, effectively releasing the lightning current, and the resistance value recovers after the lightning wave attenuates, and the power frequency continues to flow It is maintained at the milliampere level, and a spiral umbrella disk is set outside the epoxy mandrel. The arc extinguishing unit on the outer edge of the spiral umbrella disk can ensure that the arc is reliably extinguished when the power frequency continuous current crosses zero, and it can also be limited by the arc extinguishing section. The amplitude of the power frequency freewheeling current after the action of the lightning wave can further suppress the lightning overvoltage and achieve the purpose of lightning protection for the transmission line.

At the same time, when the resistance value of the resistance section in the arrester is reduced under the action of lightning waves, the breakdown conduction leads to a short circuit, or the resistance value of the resistance section cannot be recovered after the lightning voltage decays, resulting in too high power frequency freewheeling amplitude, the off The arc section can cut off the freewheeling current with an amplitude of up to a thousand amperes, and can also effectively cut off the power frequency freewheeling current before the relay protection action of the power system. The lightning arrester of the invention can better reduce the impact of lightning on the transmission line, improve the stability and reliability of the power system, and ensure the normal operation of the transmission line.

Description of drawings

Fig. 1 is the structural representation of lightning arrester of the present invention;

Fig. 2 is the schematic diagram of the cross section of the arc extinguishing section of the lightning arrester of the present invention;

Fig. 3 is a schematic cross-sectional view of the resistor body of the arrester of the present invention.

Reference signs:

1- pressure equalizing ring; 2- end fittings of lightning arrester; 3- ring umbrella plate;

4-Resistor body;

41-epoxy resin cylinder; 42-resistor sheet; 43-crimping fittings; 44-elastic piece;

5-spiral umbrella disc; 51-spherical electrode; 52-rubber layer;

53-discharge protrusion; 54-arc extinguishing gap;

6- Epoxy mandrel.

detailed description

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

Please refer to FIG. 1 , the present invention proposes a lightning arrester, which includes an arc extinguishing section and a resistance section arranged coaxially, and both the arc extinguishing section and the resistance section are arranged vertically. The upper end of the arc extinguishing section is connected with the lower end of the resistance section, and the upper end of the resistance section is connected with the external earth.

The arc extinguishing section includes an epoxy mandrel 6 and an insulating spiral umbrella disk 5 spirally wound outside the epoxy mandrel 6 , and a plurality of arc extinguishing units are arranged at intervals along the outer edge of the spiral umbrella disk 5 . The resistor section includes a columnar resistor body 4 and a plurality of insulating annular umbrella disks 3 that are spaced outside the resistor body 4 .

That is to say, the upper end of the resistance section is connected to the earth, which is the low-voltage section of the arrester, and the lower end of the arc-extinguishing section can be connected with external wires, which is the high-voltage section of the arrester. Preferably, both the spiral umbrella disk 5 and the annular umbrella disk 3 are made of silica gel, and the arc extinguishing units are distributed on the outer edge of the spiral umbrella disk 5 in a spiral band shape.

In the lightning arrester provided by the present invention, the resistance body of the resistance section has a relatively high resistance value, and the resistance value of the resistance body will decrease when the lightning strikes the power transmission line, effectively releasing the lightning current, and the resistance value of the resistance body after the lightning wave attenuates recovery, power frequency freewheeling is maintained at the order of milliamps, and a spiral umbrella disk is set outside the epoxy mandrel. The arc extinguishing unit on the outer edge of the spiral umbrella disk can ensure that the arc is reliably extinguished when the power frequency freewheeling flow crosses zero, and the The arc-extinguishing section can be used to limit the amplitude of power-frequency freewheeling current after the action of lightning waves, thereby suppressing lightning overvoltage and achieving the purpose of lightning protection for transmission lines.

At the same time, when the resistance section in the arrester fails and the power frequency freewheeling amplitude is too high, the arc extinguishing section can also effectively cut off the power frequency freewheeling flow before the relay protection action of the power system to ensure the normal operation of the transmission line. The invention does not need to be used in conjunction with the automatic reclosing system, and the insulation level of the line will not be reduced.

That is to say, when the resistance value of the resistance section is reduced under the action of lightning waves, the breakdown conduction leads to a short circuit, or the resistance value of the resistance section cannot be recovered after the lightning voltage decays, the arc extinguishing section can cut off the electric current with an amplitude of up to a thousand amperes. Freewheeling current, and then extinguish the power frequency arc before the relay protection action. The lightning arrester of the invention can better reduce the influence of lightning on the power transmission line, and improve the stability and reliability of the power system.

As an implementable mode, please refer to Fig. 2, the arc extinguishing unit includes an electrode 51 connected to the spiral umbrella disc 5, and a rubber layer 52 covering the outside of the electrode 51, the electrode 51 has smooth edges, and the adjacent The electrodes 51 of the arc extinguishing unit are separated from each other to form an air gap, and two discharge protrusions 53 are arranged symmetrically on the outside of the rubber layer 52 .

In each arc extinguishing unit, the two discharge protrusions 53 are opposite to and spaced from the discharge protrusions 53 of the adjacent arc extinguishing units on both sides, and an arc extinguishing gap 54 is formed between the two discharge protrusions 53 facing each other. .

That is to say, in each arc extinguishing unit, the outwardly protruding discharge protrusions 53 are symmetrically arranged on both sides of the center line of the arc extinguishing unit, and the distance between the inner ends of the two discharge protrusions 53 is smaller than the distance between their outer ends, so that the discharge protrusions The ends of the arc extinguishing units 53 respectively extend toward the directions where the arc extinguishing units adjacent on both sides are located, so as to form smaller arc extinguishing gaps 54 with the discharge protrusions 53 of the arc extinguishing units adjacent on both sides.

Preferably, the electrode 51 can be a spherical electrode, an elliptical electrode, a disc electrode, or other electrodes with smooth edges. The air gap between the electrodes 51 exists stably, which ensures the reliability of the arc extinguishing section.

In this embodiment, the electrode 51 is a spherical electrode, and the spherical electrode is partially wrapped in an insulating rubber layer 52. There is an air gap between adjacent spherical electrodes 51, and the air gap passes through the arc-extinguishing gap 54 provided outside the rubber layer 52 and the external Air connection. Under the action of lightning waves, the air gap between the spherical electrodes 51 made of metal is broken down, and an arc occurs. After the lightning wave acts, the air between the air gaps is heated and expanded by the arc, and the arc is pushed out of the air gap, which increases the length of the arc and reduces the temperature, prompting the arc to extinguish.

Further, as shown in FIG. 1 , voltage equalizing rings 1 are sheathed at both ends of the arc extinguishing section, which not only can form an electric field corresponding to each arc extinguishing unit, but also make the discharge more stable.

As an implementable manner, a voltage equalizing ring 1 may also be provided on the upper end of the resistance section to make the discharge more stable.

Furthermore, as shown in Figure 2, the distance between the electrodes 51 of adjacent arc extinguishing units is greater than or equal to 5 millimeters, and less than or equal to 10 millimeters, an air gap is formed between adjacent electrodes 51, due to air The gaps are small, and the number is large, and multiple air gaps make the arc extinguishing section have multiple short gaps. The width of the arc extinguishing gap 54 is small, which is greater than or equal to 2.5 mm and less than or equal to 5 mm. When the arc burns, the heated and expanded air in the air gap blows the arc out from the arc extinguishing gap 54 with a smaller width, so that the arc is extinguished.

Furthermore, the cross-sectional area of the discharge protrusion 53 gradually decreases from the inside to the outside, so as to facilitate the occurrence of discharge.

Furthermore, the ends of the discharge protrusions 53 are spherical to make the discharge more stable.

As another practicable manner, the arc extinguishing unit includes an arc extinguishing tube and a gas-generating material layer attached to the inner wall of the arc extinguishing tube, and the gas-generating material layer can release gas when heated, that is, the arc extinguishing unit can Adopt air flow arc extinguishing unit. When the layer of gas-generating material is subjected to the heat generated by the arc, the gas is released at a rate higher than the rate at which the air expands, so that the gas blows out the arc. The arrangement of the gas-generating material layer capable of releasing gas in the arc extinguishing tube belongs to the prior art, and will not be repeated here. Since the air flow arc extinguishing unit is subjected to the air flow for a long time, the relevant components are prone to material aging, so the structure of multiple short gaps is preferred for the arc extinguishing section.

Further, as shown in FIG. 3 , the resistor body 4 includes an epoxy resin cylinder 41 and a plurality of resistor chips 42 stacked in the inner cavity of the epoxy resin cylinder 41 .

As an implementable manner, the resistor 42 is a metal oxide resistor, and in this embodiment, a zinc oxide resistor is used.

The lightning arrester of the present invention adopts a structure in which a resistance segment with a zinc oxide resistance sheet and an arc extinguishing segment with multiple short gaps are connected in series. Under normal operating conditions of the circuit, the arc extinguishing section bears most of the external processing frequency voltage, that is to say, multiple short gaps bear the grid voltage.

Under the action of lightning waves, multiple short gaps are broken down, and the lightning overvoltage is applied to the zinc oxide resistor, which makes the zinc oxide resistor move, and the resistance value of the resistor 42 decreases. The gap vents down to the ground. That is to say, the arc breaks down along the zinc oxide resistor, the multiple short gaps and the three equalizing rings 1. At this time, the zinc oxide resistor is in a low-resistance state, and the lightning current is discharged to the ground through the above-mentioned breakdown path.

The action time of the lightning wave is very short. When the lightning current on the conductive path decays but the arc is not extinguished, the grid voltage is applied to both ends of the zinc oxide resistor, and the zinc oxide resistor returns to a high resistance state, and the power frequency freewheeling current is only mA level. Due to the recovery of the resistance value of the zinc oxide resistor, the freewheeling current is very small, and the freewheeling arc is quickly cut off, and only the power frequency freewheeling current with an amplitude of mA level flows through the zinc oxide resistor. When the power frequency continuous flow crosses zero, the arc is blown out and extinguished in the arc extinguishing gap in the multiple short gap arc extinguishing section. Compared with the traditional lightning arrester, the lightning arrester proposed by the present invention can limit the amplitude of the power frequency freewheeling current to the milliamp level, which reduces the power frequency short-circuit arc caused by the lightning breakdown gap, thereby avoiding the power frequency freewheeling current The current impacts the power grid.

When the zinc oxide resistor in the arrester is aged or damaged due to long-term operation or external factors, the resistance value of the resistor 42 decreases, and the amplitude of the freewheeling current reaches the kiloampere level, or in the worst case, the resistor is in the lightning strike state Short circuit, or the resistance value is difficult to recover after the lightning wave decays. Due to the strong arc extinguishing performance of multiple short-gap arc extinguishing sections, when the freewheeling current up to the kiloampere level flows through the short gap (that is, the air gap), the air in the air gap will be heated and expanded due to the heat generated by the arc. The continuous current arc leaves from the arc extinguishing gap 54 between the spherical electrodes 51, that is to say, the arc is pushed out of the arc extinguishing gap 54 along the arc extinguishing gap 54, and the arc is elongated when passing through the narrower arc extinguishing gap 54, so that The resistance of the arc increases, and the temperature of the arc decreases, so that the arc is extinguished and the power frequency freewheeling is cut off.

It can be seen from the above that even if the zinc oxide resistor has a short-circuit fault, because the arc-extinguishing section has multiple short-gap structures, it can still extinguish the thousand-ampere-level power-frequency freewheeling arc before the relay protection action, avoiding the occurrence of short-circuit tripping accidents.

Furthermore, the resistor body 4 also includes crimping fittings 43 and two elastic pieces 44 sealed at both ends of the epoxy resin cylinder 41 , and each elastic piece 44 is respectively arranged between each crimping fitting 43 and the resistor sheet 42 .

As shown in FIG. 1 , the crimping fittings 43 are threadedly connected to the end fittings 2 of the arrester to ensure that when lightning waves are applied to both ends of the resistance section, the stacked resistance sheets 42 can realize an effective electrical connection.

In this embodiment, the elastic member 44 is a spring. The upper end of the upper spring abuts against the lower end surface of the upper crimping fitting 43, and its lower end abuts against the upper end surface of the uppermost resistance piece 42; the upper end of the lower spring abuts against the lowermost resistance piece 42 The lower end surface of the lower end of which leans against the upper end surface of the crimping fitting 43 located below.

Further, the distance between adjacent annular umbrella disks 3 is greater than or equal to 35 mm. The distance between the ring-shaped umbrella disks 3 is small, so that the arrester can have a large creepage length.

As can be seen from the above, the lightning arrester of the present invention, when the lightning strikes the power transmission line, the resistance value of the resistance sheet 42 is reduced, and the lightning current is effectively released. The power frequency freewheeling current amplitude ensures that the line is struck by lightning. At the same time, after the lightning overvoltage decays, even if the resistor sheet 42 in the arrester is damaged or fails, resulting in too high power frequency freewheeling amplitude, the power frequency freewheeling current can be effectively cut off before the relay protection action of the power system, ensuring Normal and stable operation of transmission lines.

In the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (10)

1. a kind of arrester, it is characterised in that the arrester includes the arc extinguishing section and resistive segments coaxially and vertically set, described The upper end of arc extinguishing section is connected with the lower end of the resistive segments, and the upper end of the resistive segments is connected with extraneous the earth；

The arc extinguishing section includes epoxy plug and is spirally coiled in the spiral umbrella disk of the insulation of the epoxy outside plug, edge The outward flange of the spiral umbrella disk is arranged at intervals multiple arc extinguishing units；

The resistive segments include the annular of the multiple insulation of the resistor main body and spacer sleeve of column on the outside of the resistor main body Umbrella disk.

2. arrester as claimed in claim 1, it is characterised in that the arc extinguishing unit includes what is be connected with the spiral umbrella disk Electrode and the rubber layer being covered on the outside of the electrode；The electrode has smooth edge, the adjacent arc extinguishing unit The spaced formation the air gap of the electrode, two electric discharge projections are symmetrical arranged on the outside of the rubber layer；

In each arc extinguishing unit, the electric discharge of two electric discharge projections arc extinguishing unit adjacent with both sides respectively Projection is facing each other and spaced, and gap in arcing chamber is formed between two electric discharge projections facing each other.

3. arrester as claimed in claim 2, it is characterised in that be arranged grading ring respectively at the both ends of the arc extinguishing section.

4. arrester as claimed in claim 2 or claim 3, it is characterised in that between the electrode of the adjacent arc extinguishing unit Spacing distance be more than or equal to 5 millimeters, and less than or equal to 10 millimeters；The gap in arcing chamber be more than or equal to 2.5 millimeters, and Less than or equal to 5 millimeters.

5. arrester as claimed in claim 2 or claim 3, it is characterised in that it is described electric discharge projection cross-sectional area from inside to outside by It is tapered small.

6. arrester as claimed in claim 5, it is characterised in that the end of the electric discharge projection is spherical in shape.

7. arrester as claimed in claim 1, it is characterised in that the arc extinguishing unit includes arc-extinguishing tube and is attached to described go out Gas exhausted material layer on the inwall of arc pipe, gas can be discharged when the gas exhausted material layer is heated.

8. arrester as claimed in claim 1, it is characterised in that the resistor main body includes epoxy resin cylinder and is stacked and placed on institute State multiple resistor discs in the inner chamber of epoxy resin cylinder.

9. arrester as claimed in claim 7, it is characterised in that the resistor main body also includes being sealed on the epoxy resin The crimping armor clamp and two elastic components at cylinder both ends, each elastic component are separately positioned on each crimping armor clamp and the resistor disc Between.

10. arrester as claimed in claim 1, it is characterised in that the spacing distance of the adjacent annular umbrella disk be more than or Equal to 35 millimeters.