CN111490459B

CN111490459B - Surge arrester

Info

Publication number: CN111490459B
Application number: CN202010065068.3A
Authority: CN
Inventors: T.迈尔; H.扎格比尔
Original assignee: Phoenix Contact GmbH and Co KG
Current assignee: Phoenix Contact GmbH and Co KG
Priority date: 2019-01-29
Filing date: 2020-01-20
Publication date: 2021-10-15
Anticipated expiration: 2040-01-20
Also published as: CN111490459A; DE102019102192B3

Abstract

A surge arrester for a surge protection device, having a housing, an arc combustion channel formed in the housing, a first electrode and a second electrode, wherein the electrodes are each arranged on an end side of the arc combustion channel, and wherein a spark gap is formed between the first electrode and the second electrode, such that, when the spark gap is ignited, an arc is generated between the two electrodes, and having a first ignition aid for triggering the ignition of the spark gap. The object of providing a surge arrester with a shortened response time is achieved by: the surge arrester has a second ignition aid for triggering the ignition of the spark gap, wherein the first ignition aid is arranged on the first end side of the arc combustion channel and the second ignition aid is arranged on the second end side of the arc combustion channel.

Description

Surge arrester

Technical Field

The invention relates to a surge arrester for a surge protector, having a housing, an arc combustion channel formed in the housing, a first electrode and a second electrode, wherein the electrodes are each arranged on an end side of the arc combustion channel, and wherein a spark gap is formed between the first electrode and the second electrode, such that, when the spark gap is ignited, an arc is generated between the two electrodes, and having a first ignition aid for triggering the ignition of the spark gap.

Background

Surge arresters with spark gaps are known in the prior art in large numbers and are used to protect electrical circuits or devices and lines from overvoltages. In the event of overvoltages above the tolerance limits of the respective nominal voltage, the appliances and lines involved must be short-circuited by means of potential compensation in the shortest possible time.

An essential component of the surge arrester in question is at least one spark gap, which responds to a specific overvoltage (the so-called response voltage). If the spark gap is ignited, an electric arc is generated between the two electrodes of the surge arrester, through which surge current is conducted. This prevents an overvoltage from occurring in the circuit protected by the surge arrester, which overvoltage is greater than the response voltage of the spark gap.

Surge arresters with a spark gap, although having the advantage of a high surge current carrying capacity, nevertheless have the disadvantage of a relatively high and not particularly constant response voltage. For spark gap ignition, therefore, different types of ignition aids have long been used, by means of which the response voltage of the spark gap or of the surge arrester is reduced. The air in the arc chamber or the gas located therein is ionized by means of an ignition aid, so that the spark gap ignites when the ionization is sufficient and thus an arc is formed.

Surge arresters of the type in question are known, for example, from DE10338835 a 1. The surge arrester has two electrodes facing each other and an ignition aid, which is composed of an ignition element and an ignition electrode. The ignition element and the ignition electrode are arranged in the vicinity of one of the two electrodes. In the event of an overvoltage, an initial arc is first formed between the ignition electrode and the electrode located nearby, by means of which initial arc the air in the arc chamber is ionized. Upon sufficient ionization, a spark gap between the two electrodes ignites and an arc forms.

The ignition aid is usually a component of the ignition circuit, in which the components of the voltage switch are also included. In the known surge arrester, it is disadvantageous that the ignition time is maintained until the spark gap is ignited. Although the ignition time is in the range of a few microseconds, the components of the ignition circuit must withstand the rush current until the spark gap ignites.

Disclosure of Invention

The invention is therefore based on the following tasks: a surge arrester is provided which has a reduced response time.

According to the invention, this object is achieved with the surge arrester according to the invention by: the surge arrester has a second ignition aid for triggering the ignition of the spark gap. The first ignition aid is arranged at a first end side of the arc burning passage, and the second ignition aid is arranged at a second end side of the arc burning passage. Thus, an electrode and an ignition aid are disposed at each end side of the arc burning passage.

Since the surge arrester has two ignition aids, the ignition of the spark gap is triggered at two points of the arc combustion path, or ignition plasmas are generated at two points of the arc combustion path, which ignition plasmas spread in the arc combustion path. Since the ignition aid is also arranged on the end face of the arc-burning channel, the ignition plasma generated by impact ionization propagates into the arc-burning channel starting from both end faces. If the two ignition plasmas meet, an arc is generated, from which the impact current to be conducted away is conducted away. According to the invention, faster spark gap ignition and the derivation of the inrush current by the arc are achieved by: two ignition plasmas are generated at the end sides of the arc combustion channel, which diffuse kinematically toward one another and meet one another.

Given that two ignition plasmas are generated simultaneously and diffuse at the same rate, the surge arrester according to the invention only needs half the time for a structurally identical surge arrester, for example, with only one ignition aid, to respond.

The ignition aid is realized according to the ways and methods known from the prior art. For example, the ignition aid can be realized by an impedance-type ignition element (as is known from DE 102014102065B 4). The resistive ignition element can thus have, for example, an insulating layer with at least two electrically conductive, low current-carrying regions arranged in the insulating layer. At least two electrically conductive, low current-carrying capacity regions extend between the upper side and the lower side of the insulating layer, respectively, so that at least two electrically conductive connections exist between the upper side and the lower side of the insulating layer. A "burnout" of the electrically conductive connection occurs if a discharge current flows through at least one of the electrically conductive, low current-carrying capacity regions of the insulating layer. The ignition element must be arranged in the arc chamber in such a way that it is ionized by burning out air present in the arc chamber or gases present in the arc chamber.

Likewise, the ignition aid can have an ignition element (in particular an impedance ignition element) and an ignition electrode, as is known from DE10338835 a1 mentioned at the outset. Since the ignition aid with the ignition element and the ignition electrode and the electrode are arranged according to the invention at the end side of the arc chamber, an initial arc is formed between the ignition electrode and the electrode when an overvoltage occurs, so that an ionization of the air present in the arc chamber or of the gas present in the arc chamber occurs. The plasma spreads here in the direction from one end side to the other end side.

Particularly preferably, the ignition aid is part of an ignition circuit, wherein the ignition circuit has a voltage switching element in addition to the ignition aid (i.e. the resistive ignition element or the ignition element and the ignition electrode). The voltage switching element can be realized, for example, by a varistor or a gas-filled surge arrester, or by a series connection of a varistor and a gas-filled surge arrester.

In one embodiment of the surge arrester according to the invention, each of the two ignition aids has a respective ignition circuit. However, a configuration of the surge arrester according to the invention is particularly advantageous, in which the first ignition aid and the second ignition aid have a common ignition circuit and are electrically connected in series. This ensures that both ignition aids ignite simultaneously. This again achieves that ignition plasmas are generated simultaneously at the two ignition aids, which ignition plasmas diffuse into the arc combustion channels in each case.

It was previously implemented that the ignition aid is arranged at the end side of the arc-burning channel. There are various possibilities regarding the arrangement of the ignition aid relative to the electrodes. In a preferred variant, it is provided that the ignition aid is arranged in each case laterally to the electrode, i.e. next to the electrode.

In a further variant, the ignition aid is arranged in the center of the electrode. Preferably, the electrodes each have a central recess in which the ignition aid is arranged. Also, the following arrangements are included: in this arrangement, the ignition aid is not arranged directly in the center, but rather is arranged essentially centrally in the electrode. I.e. it means that the electrode surrounds the ignition aid.

In an alternative variant, the ignition aid surrounds the electrode. The ignition aid can completely surround or partially surround the electrode, i.e., for example, be arranged in a semi-annular manner around the electrode.

In various embodiments of the surge arrester according to the invention, the arc combustion path is embodied differently in the housing of the surge arrester. In a first embodiment according to the invention, the arc combustion channel is straight. The first electrode and the second electrode are opposed to each other, and the first ignition aid and the second ignition aid are also opposed to each other. Particularly preferably, the two electrodes are arranged along a common electrode axis, wherein the ignition aid is arranged parallel to the electrode axis.

In a further embodiment of the surge arrester according to the invention, the arc combustion channel is formed at an angle. The configuration of a right-angled arc-burning channel is particularly advantageous. Due to the shape of the arc combustion channel, the electrodes are not placed along a common electrode axis, i.e. are not directly opposite, unlike the previous configuration. Accordingly, the ignition aid is not directly opposite.

In a further alternative embodiment, the arc combustion channel is U-shaped. The electrode is then arranged at the U-shaped end of the arc burning channel. The end sides of the arc combustion channel thus correspond to the starting and the terminating side of the U-shaped arc combustion channel at the end of the U. Since the electrodes are arranged at the U-shaped ends, the surface normals of the end faces of the electrodes are parallel to each other. The end face of the electrode is the face adjoining the arc combustion channel. An ignition aid is also disposed at the end of the U-shape. With this configuration, the ignition plasma generated at the ignition aid, after being generated, first spreads towards the same spatial direction. When referring to "U-shaped", it does not necessarily mean a circular arc burning path. Conversely, a U-shaped arc-burning channel can also be realized by: a partition wall parallel to the two opposing side walls is introduced into the space in a rectangular or square configuration, wherein the length of the partition wall is shorter than the length of the side walls, and wherein the partition wall adjoins the third wall.

In a particularly preferred embodiment of the surge arrester according to the invention, the arc combustion channel has an outflow opening. When the ignition plasma diffuses in the arc combustion channel, the cold, non-ionized gas flows outward through the outflow openings, which leads to a targeted diffusion of the ignition plasma.

With this preferred configuration, the ignition plasma fronts no longer meet recoiling, thereby further reducing the time to arcing.

A further advantage is obtained not only because cold gas can escape through the outflow opening before the formation of the arc, but also in particular because ionized gas can escape through the outflow opening after the formation of the arc, so that the extinguishing of the arc can be simplified in an advantageous manner after the discharge operation. Thereby, the power supply freewheel occurring after the overvoltage event can be better extinguished.

In a particularly advantageous manner, the outflow opening is arranged between the ignition aids at the same distance from the first ignition aid and from the second ignition aid. This makes it possible to influence the diffusion of the two ignition plasmas in the same way. In particular, the two ignition plasmas meet in the region of the outflow opening.

In a further advantageous embodiment, the arc combustion channel is at least partially surrounded by an electrically insulating material. In one embodiment, the housing itself can be made at least partially of an electrically insulating material. In an alternative embodiment, the arc combustion channel can be coated with an electrically insulating layer. Preferably, the entire arc combustion channel is lined with an electrically insulating material. When the ignition aid is realized by the ignition element and the ignition electrode, the electrical insulating material can prevent, for example, a base point of the initial arc that forms from spreading along the arc combustion path.

In another configuration, the arc burning passage is at least partially surrounded by the gassing material. Here, too, a housing made of gassing material can be realized, or the arc combustion channel can also be coated with gassing material. When the outgassing material is heated, it releases gas. This makes it possible to accelerate the ignition of the spark gap in a particularly elegant manner. Particularly preferably, the gassing material is arranged in the region of the electrodes, i.e. the arc combustion channel is lined with the gassing material in the region of the electrodes.

Drawings

In detail, there are now a number of possibilities for configuring and expanding the surge arrester according to the invention. For this reason, reference is made to the following description of the preferred embodiments taken in conjunction with the accompanying drawings. Shown in the drawings are:

in a first configuration of the surge arrester of figure 1,

figure 2 shows a second configuration of the surge arrester,

figure 3 shows a third configuration of the surge arrester,

figure 4 a first arrangement of electrodes and ignition aid,

FIG. 5 second arrangement of electrodes and ignition aid, an

Fig. 6 a third arrangement of electrodes and ignition aid.

Detailed Description

Fig. 1 shows a surge arrester 1 for an overvoltage protection device, not shown. The surge arrester 1 has a housing 2 in which an arc combustion channel 3 is formed. Furthermore, the surge arrester 1 has a first electrode 4 and a second electrode 5. Two

electrodes

4, 5 are formed on the end sides 6, 7 of the arc-burning channel 3. A spark gap 8 is formed between the two

electrodes

4, 5, so that an arc is generated between the

electrodes

4, 5 when the spark gap 8 is ignited.

In order to initiate the ignition of the spark gap 8, the surge arrester 1 has a first ignition aid 9 and a second ignition aid 10. The two ignition aids 9, 10 each have an ignition element 11 of the resistive type and an ignition electrode 12. The first ignition aid 9 is arranged next to the first electrode 4 at the first end side 6 of the arc-burning channel 3. A second ignition aid 10 is arranged next to the second electrode 5 at the second end side 7 of the arc-burning channel 3. An ignition plasma is generated at each of the two ignition aids 9, 10, which spreads out from the

respective end side

6, 7 of the arc combustion channel 3. The diffusion directions of the two ignition plasmas are shown by arrows in fig. 1. The two ignition plasmas meet in the arc combustion channel 3, so that the entire arc combustion channel 3 is sufficiently filled with ionized gas and an arc can be generated between the

electrodes

4, 5. The surge current is conducted through the arc. Since an ignition plasma is generated at each

end side

6, 7 of the arc combustion channel 3, which ignition plasma diffuses into the arc combustion channel 3, the time to formation of an arc and thus to derivation of a rush current can be significantly reduced.

In the case of the surge arrester 1 from fig. 1, the first ignition aid 9 and the second ignition aid 10 have a common ignition circuit 13 and are electrically connected in series. This ensures that the two ignition aids 9, 10 respond simultaneously and that ignition plasmas are generated simultaneously on both

end sides

6, 7 of the arc combustion channel 3. In addition to the ignition aids 9, 10, the ignition circuit 13 also comprises components of a voltage switch, namely a surge arrester 14, which is currently gas-filled. In the event of an overvoltage, the first gas-filled surge arrester 14 is switched on, so that the

ignition aid

9, 10 then responds.

In the case of the embodiment shown in fig. 1, the arc combustion channel 3 is of straight design, so that the first and

second electrodes

4, 5 and the first and second ignition aids 9, 10 are directly opposite one another. Furthermore, the arc combustion channel 3 has an outflow opening 15, which is formed in the housing 2 between the two ignition aids 9, 10 at the same distance from the two ignition aids 9, 10. During the diffusion of the ignition plasma, cold gas can escape from the arc combustion channel 3 through the outflow openings 15, so that the diffusion of the ignition plasma can be regulated. The outflow openings 15 also result in that the ignition plasma fronts no longer meet back-flushly as in the arc combustion channel 3 without the outflow openings 15. Thereby enabling a further reduction in the time to arc formation. The outflow opening 15 also effects an outflow of ionized gas after the inrush current has been conducted away, so that occurring power freewheeling can be better extinguished.

Fig. 2 shows a second configuration of the surge arrester 1. The surge arrester 1 shown here differs from the surge arrester 1 shown in fig. 1 in that the arc combustion duct 3 is formed at right angles. The

electrodes

4, 5 and the ignition aids 9, 10 are again arranged at the end sides 6, 7 of the arc combustion channel 3. By means of this form of the arc combustion channel 3 and the illustrated arrangement of the outflow openings 15, the discharge of cold gas during the diffusion of the ignition plasma and the discharge of hot gas after the formation of the arc are simplified. The ignition circuit 13 is not shown in fig. 2.

Fig. 3 shows a third configuration of the surge arrester 1. The surge arrester 1 shown in fig. 3 has a U-shaped arc combustion channel 3. The U-shape is currently achieved by: a partition wall 16 is introduced into the space, which is itself of a right-angled construction, said partition wall being arranged parallel to the two opposite side walls 17 and meeting the third side wall 19. The partition wall 16 is shorter than the two side walls 17, so that a U-shape of the arc burning channel 3 is created. The two

end sides

6, 7 of the arc-extinguishing channel 3 are arranged side by side in one plane at the U-shaped end 18 in the illustrated embodiment and are formed at the third side wall 19. The surface normals 24 on the end faces of the

electrodes

4, 5 are parallel to one another. The outflow opening 15 is formed in a fourth side wall 20 of the housing 2 and is opposite the partition wall 16. The spark gap 8 can be realized in an extremely compact space by the illustrated configuration. In addition, the arc extinction is further simplified in the illustrated embodiment, since the ionized gas diffuses directly in the direction of the outflow opening 15.

Fig. 3 shows an ignition circuit 13 in its present configuration. In contrast to ignition circuit 13 from fig. 1, ignition circuit 13 shown here has a varistor 21 in addition to gas-filled surge arrester 14, wherein gas-filled surge arrester 14 and varistor 21 are electrically connected in series.

In the case of the configuration according to fig. 2, the arc combustion channel 3 is lined, in particular currently coated, with an electrically insulating material 22. This prevents the base point of the initial arc formed between the starting electrode 12 and the

electrodes

4, 5 from spreading along the arc combustion channel 3, so that an electrically conductive connection between the first electrode 4 and the second electrode 5 is not possible via the housing 2.

In the case of the configuration according to fig. 3, the arc combustion channel 3 is lined with gassing material 23 in the region of the

electrodes

4, 5. As the outgassing material 23 is heated, it releases gases. This makes it possible to accelerate the ignition of the spark gap 8 in a particularly elegant manner.

Different arrangements of the first electrode 4 and the first ignition aid 9 relative to each other are schematically shown in fig. 4, 5 and 6. A plan view of the first end side 6 of the arc combustion channel 3 is shown.

In the illustration according to fig. 4, the ignition aid 9 is arranged in a recess in the electrode 4. The electrode 4 completely surrounds the ignition aid 9. In the illustration according to fig. 5, the ignition aid 9 and the electrode 4 are arranged side by side, whereas in the illustration according to fig. 6, the electrode 4 is arranged in the center of the ignition aid 9, i.e. the ignition aid 9 completely surrounds the electrode 4.

Reference numerals

1 Surge arrester

2 casing

3 arc combustion channel

4 first electrode

5 second electrode

6 first end side

7 second end side

8 spark gap

9 first ignition aid

10 second ignition aid

11 impedance type ignition element

12 ignition electrode

13 ignition circuit

14 gas-filled surge arrester

15 outflow opening

16 partition wall

17 side wall

18U-shaped end

19 side wall

20 side wall

21 pressure sensitive resistor

22 electrically insulating coating

23 outgassing materials

24 end faces of the electrodes.

Claims

1. A surge arrester (1) for a surge protection device, having a housing (2), an arc combustion channel (3) formed in the housing (2), a first electrode (4) and a second electrode (5), wherein the electrodes (4, 5) are each arranged on an end face (6, 7) of the arc combustion channel (3), and wherein a spark gap (8) is formed between the first electrode (4) and the second electrode (5) such that, when the spark gap (8) is ignited, an arc is generated between the two electrodes (4, 5), and having a first ignition aid (9) for triggering the ignition of the spark gap (8),

it is characterized in that the preparation method is characterized in that,

the surge arrester (1) has a second ignition aid (10) for triggering the ignition of the spark gap (8), wherein the first ignition aid (9) is arranged on a first end side (6) of the arc combustion channel (3) and the second ignition aid (10) is arranged on a second end side (7) of the arc combustion channel (3).

2. The surge arrester (1) as claimed in claim 1, characterized in that the first ignition aid (9) and the second ignition aid (10) have a common ignition circuit (13) and are electrically connected in series.

3. The overvoltage protection arrester (1) according to claim 1, characterized in that the ignition aid (9, 10) is arranged on the side of the electrode (4, 5), in the center of the electrode (4, 5) or surrounding the electrode (4, 5).

4. The surge arrester (1) according to claim 1, characterized in that the arc combustion channel (3) is of straight construction, the first electrode (4) and the second electrode (5) are opposite one another, and the first ignition aid (9) and the second ignition aid (10) are opposite one another.

5. The surge arrester (1) as claimed in claim 1, characterized in that the arc combustion channel (3) is configured at an angle.

6. The surge arrester (1) as claimed in claim 1, characterized in that the arc combustion channel (3) is designed at right angles.

7. The surge arrester (1) according to claim 1, characterized in that the arc combustion channel (3) is U-shaped and the electrodes (4, 5) are arranged at the U-shaped ends (18) such that the first electrode (4) and the second electrode (5) are arranged parallel to one another.

8. The surge arrester (1) according to claim 1, characterized in that the arc combustion channel (3) has an outflow opening (15).

9. The surge arrester (1) as claimed in claim 8, characterized in that the outflow opening (15) is arranged between the ignition aid (9, 10) at the same distance from the first ignition aid (9) and from the second ignition aid (10).

10. The surge arrester (1) according to claim 1, characterized in that the arc combustion channel (3) is at least partially surrounded by an electrically insulating material (22).

11. The surge arrester (1) according to claim 1, characterized in that the arc combustion channel (3) is at least partially surrounded by a gassing material (23).

12. The surge arrester (1) according to claim 1, characterized in that the arc combustion channel (3) is surrounded by a gassing material (23) in the region of the electrodes (4, 5).