WO2013014167A1

WO2013014167A1 - Electric three-electrode surge arrester

Info

Publication number: WO2013014167A1
Application number: PCT/EP2012/064521
Authority: WO
Inventors: Winfried VÖLKNER; Gero Zimmermann
Original assignee: Epcos Ag
Priority date: 2011-07-28
Filing date: 2012-07-24
Publication date: 2013-01-31
Also published as: DE102011108858A1

Abstract

An electric gas-filled three-electrode surge arrester comprises a first outer electrode (2), a second outer electrode (3) and a center electrode (4). The first outer electrode (2) and the center electrode (4) delimit a first cavity (7). The second outer electrode (3) and the center electrode (4) delimit a second cavity (8). The first cavity (7) and the second cavity (8) are arranged on either side of the center electrode (4). A first spark gap (d1) between the first outer electrode (2) and the center electrode (4) is shorter than a second spark gap (d2) between the second outer electrode (3) and the center electrode (4).

Description

description

Electric three-electrode surge arrester The invention relates to a three-electrode surge arrester.

From the document DE 4330178 B4 a surge ^¬ Abieiter is known.

In the interior of the surge arrester occurs in about ^¬ exceed a certain threshold voltage, the ignition voltage, an arc-over between two or three electrodes. The threshold voltage is increased under static or static load with a rise in the voltage of

100 V / s as Ansprechgleichspannung Uag and under dynamic load with a rise in the voltage of 1 kV / ys referred to as Ansprechstoßspannung Uas. The arc is maintained by the feeding current as long as the electrical conditions for the arc are met.

A problem to be solved is to provide an improved concept for Kon ^¬ a three-electrode surge arrester.

This object is achieved by the subject matter of the independent An ^¬ entitlement. Embodiments and developments are the subject of the dependent claims. An electric gas-filled three-electrode

Surge arresters has a first outer electrode, a second external electrode and a center electrode ^¬ jointly define a first and a second cavity ge, which are arranged on both sides of the center electrode. The first and the second outer electrode are in this case arranged with unsymmetri ^¬ rule intervals with respect to the center electrode. Since ^¬ by arise differently long distances between the outer electrode and the center electrode, leading to different lengths in the ignition spark gaps ^¬ case. This will for example be achieved in that the respective static ignition voltage between the first outer electrode and the center electrode and between the second outer electrode and the center electrode are different or have the Ab ^¬ stands according unbalanced distribution. As ^¬ by a low ignition delay between the sections can be achieved. According to an embodiment of the surge arrester be ^¬ adjoin the first outer electrode and the center electrode ei ^¬ NEN first cavity while the second outer electrode and the center electrode define a second cavity. The first cavity and the second cavity are disposed on both sides of the center electrode. A first spark gap Zvi ^¬ rule of the first outer electrode and the center electrode is shorter than a second spark gap between the second Au ^¬ ßenelektrode and the center electrode. It can thereby be achieved that an ignition voltage for the first spark gap is smaller than the corresponding ignition voltage of the second

Radio link. The ratio between the lengths of the two spark gaps and the ratio between the resulting ignition voltages has a non-linear dependence ^{voneinan ¬} on.

For example, the first spark gap is at least a factor of 2, in particular at least a factor of 5, shorter than the second spark gap. In various embodiments a length of the first spark gap is a maximum of 1 mm. Ge ^¬ Mäss further embodiments, a length of the second spark gap is at least 5 mm. In various embodiments, the first spark gap and the second spark gap are so dimensioned di ^¬ with respect to their length that an ignition voltage between the Außenelekt ^¬ rode and the center electrode is smaller, and in particular we ^¬ nigstens is smaller by a factor of 5, than the firing voltage between the second Outer electrode and the center electrode. The ignition voltages are in particular static Zündspannun ^¬ conditions.

In an exemplary embodiment, the length of the first spark gap can be adjusted so that a static ignition voltage of 300 V between the first outer electrode and the center electrode results, while the second spark gap is dimensioned so that a static Zünd ^¬ voltage between the second outer electrode and the center electrode is 1500V. With such a dimensioning, a voltage in the Wertebe results as ignition voltage between the first outer electrode and the second external electrode ^¬ range between 1300 V and 2000 V. The very different distances between the electrodes or length of the spark gaps, for example, by an asymmetrical configuration, in particular a hochunsymmetrische embodiment the center electrode he ^¬ reaches.

Accordingly, the center electrode in an exporting ^¬ approximate shape to the side of the first outer electrode in the form of a Pot electrode on. As a result, for example, a distance to the first outer electrode can be reduced.

According to a further embodiment, the center electrode to the side of the second outer electrode in the form of a flat electrode. As a result, a high distance to the second outer electrode can be achieved.

Thus, advantageously, in various embodiments, the center electrode to the side of the first outer electrode has a greater expression than to the side of the second Au ^¬ ßenelektrode.

In further embodiments, the first outer electrode alternatively or additionally on the shape of a pot electrode. This further supports the formation of a first spark gap of short length, in particular in conjunction with egg ^¬ ner corresponding shaping of the center electrode also as a pot electrode.

According to further embodiments, the second Außenelekt ^¬ rode on the shape of a flat electrode. This allows as ^¬ derum a greater distance from the center electrode upright sustainer ^¬ th to maintain a suitably long second spark gap to be expected.

The electrodes may have a waffled surface in various embodiments. For example, we have ^¬ nigstens one of the outer electrodes or at least one side of the center electrode in such a surface of embossed.

In particular, an electrode activation compound can be applied to the electrodes in the area of the waffled surface be. In particular, the surfaces may be pasted with an activating compound.

The interior of the surge arrester is gas-tight against the environment. Inside the surge arrester there is a gas. This results in the parameter of the surge arrester, in particular in loading ^¬ train to the ignition voltage advantageous in a reproducible manner. The surge arrester, in various embodiments, has a common gas space formed by the first cavity and the second cavity. Accordingly, there is a gas-permeable connection between the first and second cavities. The first cavity and the second cavity are ^{beispielswei ¬} se limited by a respective cylindrical ceramic body. In various embodiments, several ignition strips are integrally ^¬ arranged on the inside of such a ceramic body. This measure supports the build-up of a discharge when the surge arrester responds. The ignition strips are either electrically connected to one of the side electrodes and extend into the discharge rear space behind the center electrode, but not deep into the ^rear space of the respective other side electrode. As a result, wall discharges are avoided. Alternatively, the ignition strips are not connected to any of the electrodes. In a further embodiment, both alternatives of the Zündstrichanordnung are advantageously used. The activation mass has a positive effect on a discharge build-up and its reproducibility.

In various embodiments, the second cavity is in particular characterized by a cylindrical ceramic body. borders, which comprises two composite, in particular soldered, cylindrical Teilkeramikkörper. Thus, the larger electrode distance between the Mittelelekt ^¬ rode and the second external electrode can be achieved advantageous ^¬ way. In addition, two similar cylindrical ceramic body can be used, so that can be dispensed with the production of a separate ceramic body with a larger cylinder height. Since ^¬ through can be kept low production costs. The outer electrodes and the center electrode have electrical connection contacts in various embodiments. Via the connection contacts a contact to a board can be made. Preferably, the distance of the terminals between the first outer electrode and the center electrode is smaller than the distance between the on ^¬ connection contacts between the second outer electrode and the center electrode.

The surge arrester is explained in more detail below with reference to exemplary embodiments and the associated figures.

The drawings described below are not to be construed as measured ^¬ rod to scale. Rather, for a better representation, individual dimensions can be enlarged, reduced or distorted.

Like elements or elements having the same functions are denoted by the same reference numerals. Show it:

FIG. 1 shows a sketch of an embodiment of a surge arrester in partial cross-section with side electrodes and a center electrode,

Figure 2 is a perspective view of an embodiment of a surge arrester, Figure 3 is a side view of an embodiment of a

Surge arrester, and

Figure 4 is another side view of an embodiment of a surge arrester.

FIG. 1 shows an embodiment of a three-electrode surge arrester 1 in a sectional view. The surge arrester 1 has a first outer electrode 2, a second outer electrode 3 and a center electrode 4. Between the first outer electrode 2 and the center electrode 4, a first cylindrical insulating body 5 is provided, which is designed in particular as a ceramic body. Similarly, between the second outer electrode 3 and the center electrode 4 on the opposite side, a second cylindrical insulating body 6 is arranged, which is also designed as a ceramic body. In particular, the second ceramic body 6 is composed of two cylindrical partial ceramic bodies 16, 16 '. The ceramic bodies 5, 6 form respective cavities 7, 8. The ceramic bodies 5, 6, 16, 16 'and the electrodes 2, 3, 4 are fixedly connected to each other, in particular by soldering, so that in the interior of the cylindrical ceramic body 5, 6 a common Gas space is formed. The thus formed interior or gas space 7.8 of the Surge arrester 1 is sealed gas-tight and ent ^¬ holding a gas having a hydrogen content of between 5% and 30%, but in particular has a proportion of about 20%. At the electrodes 2, 3, 4 respective terminal contacts 12, 13, 14 are attached. Due to the common gas space 7, 8 results in a low ignition delay between the individual spark gaps dl, d2.

The electrodes 2, 3, 4 are preferably formed from copper or have a copper content. The first outer electrode 2 has the shape of a pot electrode, the pot shape being directed in the direction of the center electrode 4. The center ^¬ electrode 4 has on the side facing the first Außenelektro ^¬ de, also a shape of a pot electrode, while the second outer electrode 3 facing Sei te ^{¬ formed} as a flat electrode. The second Außenelekt ^¬ rode 3 is also designed as a flat electrode itself.

In the cavities 7, 8 between the electrodes 2, 3, 4 are on the inside of the ceramic body 5, 6 ignition strips 11, 11 'are provided. Through the ignition strips 11, 11 'of the structure of a Ent ^¬ charge is supported in the response of the surge arrester. 1 Due to the shape of the electrodes 2, 3, 4 results in a highly asymmetric structure of the surge arrester 1, in particular ^¬ special with respect to the respective distances between the outer electrodes 2, 3 and the center electrode 4. In particular, the center electrode 4 is constructed clearly asymmetric. Presently results from the two-sided cup-shaped Gestal ^¬ tion of the first outer electrode of the corresponding side of the center electrode 4, a small electrode spacing relationship ^¬ a small first spark gap dl. Between the two Th outer electrode 3 and the corresponding side facing the center electrode 4 results in a larger Elektrodenab ^¬ stand or a larger second spark gap d2. For example, a length of the first spark gap is at most 1 mm, while a length of the second spark gap is at least 5 mm. Due to the common gas space 7, 8 results in a low ignition delay between the individual spark gaps dl, d2. In the present case a length of 0.4 mm is selected, for example, for the first spark gap dl, while the second Funkenstre ^¬ blocks d2 has a length of 9.5 mm. This results in a static ignition voltage of about 300 V for the first spark gap dl, while the static ignition voltage for the second spark gap d2 is 1500 V. The size of the ignition ^¬ voltages depends on the spacing of the electrodes or the length of the spark gap, said ^¬ together menhang has a non-linear course. Between the first outer electrode 2 and the second outer electrode 3 there is a static ignition voltage of about 1300 V to

2000 V. Due to the asymmetrical arrangement, an ignition voltage ratio between the first and the second spark gap of approximately 1: 5 is achieved. The surfaces 9, 9 'are designed honeycombed in the present execution ^¬ form in particular, wherein in the Vertie ^¬ levies of the weapon Lung an electrode activation mass is pre see ^¬ which supports a discharge assembly and ensures re ^¬ producible static ignition voltage as well as a stable Zündspannungspegel. Various versions ^¬ approximately forms the center electrode 4 is bepastet on one or both sides. Figure 2 shows a perspective view of an embodiment ^¬ form of a three-electrode surge arrester 1, which is formed in ^¬ example, according to the embodiment shown in Figure 1. Here, the structure of the surge arresters conductor 1 to the external electrodes 2, 3 and the central electric ^¬ en 4 and the interposed ceramic bodies 5, 6 can be seen. The ceramic body 6 is in turn composed of two partial ceramic bodies 16, 16 ', wherein the connection of the partial ceramic body 16, 16' is made by a soldering. The electrodes 2, 3, 4 each have an outwardly guided metallic ring, which are electrically connected to the electrode surfaces not visible here. Attached to the rings of the electrodes 2, 3, 4 are pin-shaped connection contacts 12, 13, 14, which are respectively bent at the end, which is fastened to the electrodes 2, 3, 4. The connection contacts 12, 13, 14 are soldered or welded, for example, to the rings of the electrodes 2, 3, 4. With the connection contacts 12, 13, 14 of the surge arrester 1 can be mounted for example on a circuit board.

FIG. 3 shows a side view of an embodiment of the surge arrester 1 in accordance with one of the previously ^illustrated embodiments. Here again, the composite structure of the surge arrester 1 of the Außenelektro- 2, 3, center electrode 4 and ceramic bodies 5, 6 to erken ^¬ NEN.

FIG. 4 shows a plan view of an embodiment of a surge arrester 1 along the cylinder axis of the ceramic body of the surge arrester. In this view, in particular the first outer electrode 2 and the ring of the center electrode 4 can be seen. In addition, the curved Closing contact 12 can be seen, which is attached to the first outer electrode 2.

It is advantageous to use copper for the electrodes in the interior of the surge arrester and to provide the outer connections of an iron-nickel alloy. Particularly advantageous is the iron-nickel alloy, for. B. Fe ₅₈ Ni ₄ 2, copper-plated. This optimal self ^¬ properties can be achieved in the interior and in the Verschlusslötung of the surge arrester.

Particularly advantageous is an embodiment in which the gas-tight and filled with a gas interior 7, 8 of the surge arrester 1 contains an addition of hydrogen. The proportion of hydrogen may be between 5% and 30%; however, about 20% hydrogen is typical. As a result, the buildup time for a discharge when the surge arrester 1 responds is shortened, and the Ansprechstoßspannung decreases.

For example, the surge arrester 1 is formed cylindrically with an outer diameter of less than 8 mm. In a preferred embodiment, the surge arrester has an outer diameter of at most 5 mm. The particularly small design and the excellent electrical values result in a variety of possible applications, in particular for the protection of small electronic devices.

The surge arrester 1 is preferred munikationseinrichtung in a telecom, for example, used a Telecommunicati ^¬ onsnetzwerk; but is not limited to Telecommunicati ^¬ onsnetzwerke and can be used in any other electrical circuit in which high voltages gene must be removed by means of a surge arrester. In particular, the surge arrester 1 is suitable for lightning protection applications in which the surge arrester is or can be at least temporarily at symmetrical voltages relative to ground.

The use of an unbalanced three-electrode surge arrester allows the interpretation of a trigger ^¬ circle so that failures of a high-impedance and little current transformer under load can be avoided.

Claims

claims

An electric gas-filled three-electrode surge arrester comprising a first outer electrode (2), a second outer electrode (3) and a center electrode (4), wherein

the first outer electrode (2) and the center electrode (4) define a first cavity (7),

the second outer electrode (3) and the center electrode (4) define a second cavity (8),

the first (7) and the second (8) cavity on both Be ^¬ th of the center electrode (4) are arranged, and

a first spark gap (dl) is shorter between the first outer electrode ^¬ (2) and the center electrode (4) as a second spark gap (d2) between the second outer electrode (3) and the center electrode (4).

2. surge arrester according to claim 1, wherein the first spark gap (dl) at least by a factor of 2, in particular at least by a factor of 5, is shorter than the second Fun ^¬ kenstrecke (d2).

3. surge arrester according to one of the preceding claims, wherein the first spark gap (dl) and the second spark gap (d2) are dimensioned with respect to their length so that an ignition voltage between the first outer electrode (2) and the center electrode (4) smaller is smaller, in particular by a factor of five, than the ignition voltage between the second outer electrode (3) and the center electrode (4).

4. surge arrester according to one of the preceding claims, in which the center electrode (4) to the side of ers ^¬ th outer electrode (2) has the shape of a pot electrode.

5. surge arrester according to one of the preceding claims, wherein the center electrode (4) to the side of the second outer electrode (3) has the shape of a flat electrode.

6. surge arrester according to one of the preceding claims, wherein the first outer electrode (2) has the shape of a pot electrode.

7. surge arrester according to one of the preceding claims, wherein the second outer electrode (3) has the shape of a

Flat electrode has.

8. surge arrester according to one of the preceding claims, wherein the center electrode (4) to the side of the first outer electrode (2) has a greater expression than to the side of the second outer electrode (3).

9. surge arrester according to one of the preceding claims, wherein a length of the first spark gap (dl) is at most 1 mm.

10. surge arrester according to any preceding claim, wherein a length of the second spark gap (d2) is min ^¬ least 5 mm.

11. surge arrester according to one of the preceding claims, wherein at least one of the outer electrodes (2, 3) or at least one side of the central electrode (4) has a waffled surface (9, 9 ').

12. surge arrester according to the preceding claim, in which in the area of checkered surface (9, 9 ') a Elect ^¬ roden activating compound (10) is applied.

13. surge arrester according to one of the preceding claims, comprising a common gas space formed by the first cavity (7) and the second cavity (8).

14. surge arrester according to one of the preceding claims, in which the first cavity (7) and / or the second cavity (8) by a respective cylindrical ceramic body (5, 6) is limited, at the inside of several ignition strips (11, 11 ') are arranged.

15. surge arrester according to one of the preceding claims, wherein the second cavity (8) is bounded by a cylindrical ceramic body (6), the two ^{zusammenge ¬} sat, in particular soldered, cylindrical part ceramic body (16, 16 ').