DE2321726A1 - SPARK GAP ARRANGEMENT - Google Patents

Description

Westinghouse

Electric Corporation OR apd

Pittsburgh * - ° - APR.

My reference: VPA 72/8344 Et / Sho

Spark gap arrangement

For this registration, the priority is the corresponding USA filing Serial Wo. 250,000 claimed on May 3, 1972. "

To protect electrical circuits and devices against overvoltages Spark gap arrangements are often used. This is mostly done in a series circuit with non-linear resistors. Such arrangements are called surge arresters known. When a predetermined overvoltage occurs, the spark gaps respond and conduct the Surge wave to earth, whereby the non-linear resistances the follow-up current following the surge wave limit and reduce so that the spark gaps can interrupt this current.

To ensure reliable protection of the circuits or devices it is essential that the response voltage of the Spark gap is precisely determined and changes during the service life of the surge arrester not changed. However, the conventional spark gap arrangements like them are subject to are used for surge arresters and other protective purposes, external influences that change the electrical field in the area of the spark gaps. Because of this, are So far, relatively large and complicated control rings have been used in high voltage arresters to the electrical Control the field and achieve the desired stress distribution. A change in the electric field in the The spark gap arrangements can also be rich in foreign layers on the outer surface of the housing, in which the effective components of the surge arrester are housed.

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So far, no satisfactory means have been available to achieve an effective stabilization of the operation of spark gap arrangements.

The invention is concerned with one particularly for surge arresters provided spark gap arrangement with at least two electrodes held by spacers. The invention is based on the object of determining the response voltage and other modes of operation of the spark gap arrangements to make it as independent as possible of external influences. According to the invention achieves this in that the electrodes, including their spacing means, from a metallic, are enclosed by an intermediate space interrupted envelope which is in electrically conductive contact with at least one of the electrodes. This covering also forms a shield for the spark gap and a noteworthy capacitance, which is connected in parallel to the electrodes. In this way, the response of the spark gap arrangement completely stabilized and made independent of any external influences.

The spark gap arrangement can be a simple spark gap with two electrodes or a multiple spark gap with a plurality of electrodes connected in series be. In both cases, the invention improves the response stabilized. ~

The enclosure of the spark gap arrangement can be formed, for example, by shielding members that are connected to the electrodes are in contact and face each other with a space in between. It is advisable here to dimension the space in such a way that the spark gap always comes first when the voltage rises responds and does not break through the space between the shielding members. In this embodiment, the shielding members can be bowl-shaped or bowl-shaped be designed.

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The same effect, i.e. the stabilization of the response behavior of the spark gap arrangement, can also be achieved by a Another embodiment of the envelope can be achieved in which only a shield member is provided, which extends from one end of the Spark gap arrangement extends to its other end and is in conductive connection with one of the electrodes. The difference from the first-mentioned embodiment is essentially that the gap is a has an unbalanced position.

The invention is explained in more detail below with the aid of two exemplary embodiments.

Fig. 1 shows a section through a simple spark gap arrangement, while in Fig. 2 a multiple spark gap is shown partially in view and partially in section.

The spark gap according to FIG. 1 consists of two plate-shaped electrodes 1 and 2 made of brass or another suitable conductive material. The electrodes have opposing flat central portions between which the actual spark gap 3 is present. The electrodes 1 and 2 are kept at a distance from each other by an im essential cylindrical spacer ring 4, which is made of an insulating material, such as. B. porcelain, or from a resistance material can exist to control the voltage distribution via a series connection of spark gaps. The edges of the Electrodes 1 and 2 touch the ends of the spacer ring 4 and are sealed against this in a suitable manner so that an encapsulated spark gap is created. If desired, a tube can be provided in one of the electrodes for the purpose be the spark gap arrangement with a suitable gas, ζ. B. nitrogen or a mixture of nitrogen and - " Hydrogen with an addition of tritium, whereupon the Tube 5 squeezed off and the spark gap arrangement is thereby sealed. The purpose of adding tritium is to obtain a low and constant response voltage.

VPA 72/8344

The spark gap arrangement according to FIG. 1 is in In accordance with the present invention with a Envelope provided, which consists of shielding members 6 and 7. These are made of sheet metal or some other suitable conductive material Material made and are shaped like a bowl. Each the Äbschirmglieder 6 and 7 is at one end of the spark gap arrangement in electrical contact with the edge extending toward the opposite end of the spark gap arrangement extends. Between the edges of the Shield members 6 and 7, there is an interspace 8 so that the conductive sheath formed by the shield members is interrupted between the ends of the spark gap arrangement. The edges "of the shielding members 6 and 7 can as indicated at 9, be rolled up. The length of the gap 8 is not critical, but dimensioned such that the Gap 8 is not broken down in front of the spark gap 3 in the event of overvoltages. . ;

The gap 8 between the two shielding members 6 and 7 causes a considerable capacitance to be created parallel to the spark gap arrangement which, together with the shielding effect of the metallic casing, makes the spark gap almost completely independent of external influences. The voltage between the electrodes 1 and 2 is given by the size of the spark gap 3 and the characteristic of the envelope, so that the spark gap arrangement of the surrounding '' shows "^ independent electric field response after assembly of a constant and changes.

In Fig. 2 the invention is in its application to a multiple spark gap which may, for example, be of the type described in US Pat. No. 3,534,221. This spark gap arrangement consists of a number of Electrodes 10 which are joined together between metallic end plates 11 in the form of a stack. Preferably is a coil 12 for generating a magnetic field at

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Occurrence of an overvoltage wave intended to move the Msht »arcs in & §n spark gaps so that their is facilitated *

2 is stranded with shield members 15 and 14, which are shaped like a bowl similar to those in Pig 1 and are in contact with the metal end plates gap: 15 are separated from each other in turn ,, is selected so large "that is no way for a punch before the response üe ^ Sm series-connected spark Streeken exists. As already described, the shielding members 125 and 14 form a substantial capacitance connected in parallel with the Fujgfceöstreckemanordnuiig. Similarly to, in the manner described, the bands of the Abschiriaglieder _r rolled at 16 to 15 and 14 to promote the effectiveness of the Absehirmglieier in a certain way.

The spark gap arrangements described are particularly for use in surge arresters; suitable, although their suitability is not limited to this and they can accordingly also be used for other ijberspannungsschutzz.wec; ke * The shielded and gas-filled spark gap according to FIG n type described 3,534,221 and 3,611,044. the multiple spark gap according to FIG. Z is as Hauptfunken- * route in Hochspannungsableitern this type, however, both types can also be used in other type arresters, spark gaps.

In the invention, modifications may be made. For example, in some cases the metallic covering of the spark gap arrangement can also be formed by just one shielding element that extends from one end of the spark gap arrangement to the opposite end.

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extends the end, whereby "also an interrupted Sheath is formed with the effect described. as well the shape of the shield members can be modified; as

conductivea material come in addition to the preferred sheet metal too perforated or latticed materials into consideration.

The unchangeability of the characteristics of the spark gap arrangement brings significant advantages. In some cases, the previously required control rings are not needed more or these rings may T ^ eI Höchspannungsableitern be significantly reduced. Furthermore, the influence of the foreign layers on the conductor housings on the functioning of the spark path arrangement has been largely eliminated.

5 claims

2 figures. =,

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Claims (5)

VPA 72/8344 Claims M.) Spark gap arrangement with at least two by spacing medium held electrodes, especially for surge arresters, characterized in that the electrodes (1, 2) including their spacing means (4) are made of a metallic, are enclosed by an intermediate space (8) interrupted envelope which is in electrically conductive contact with at least one of the electrodes (1, 2) is standing. 2. Spark gap arrangement according to claim 1, characterized in that that the envelope is formed by Absehirmglieder (6, 7) that are in contact with the electrodes (1, 2) and face each other with a gap (8). 3. spark gap arrangement according to claim 1, characterized by e, ine dimensioning of the gap (8) such that the When the voltage rises, the gap (8) is not in front of the spark gap (3) is pierced. 4. spark gap arrangement according to claim 1, characterized in that that the Absehirmglieder (6, 7) are designed in the shape of a bowl or bowl. 5. spark gap arrangement according to claim 1, characterized in that that the envelope comprises only one shield member extending from one end of the spark gap to the other End extends and is in conductive contact with one of the electrodes. 30 9 8 4670488 Blank page