DE1911074A1 - Surge arresters - Google Patents

Description

Aktiengesellschaft Brown, Boveri & Cie., Baden (Switzerland)

Surge arresters

The invention relates to a surge arrester, the active part of which consists of at least one column-shaped stack, which is made up of spark gaps and resistors and which is located in a closed housing which is provided with a pressure relief device at least at one point, using ring-shaped resistance bodies. In Ueberlastüng of the active part of a surge arrester, the arrester according to heavily loaded of the arc in Ableiterinnern thermally and mechanically, which may trouble to explosive decomposition can result in {of the housing. It is known to create a relief path for the pressure wave through a break point provided for this purpose, e.g. in the form of a safety membrane, and to protect the housing by a heat-insulating separating layer in the form of a protective cylinder made of inorganic insulating material arranged in front of the housing inner wall (Switzerland. Pat. 289 179) Despite the relief point, there is still a sudden, brief pressure

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stress, so that the housing insulator and / or the. Protective cylinders have to be dimensioned correspondingly large / 'whereby' the arrester is very taxable, which has a strong effect on the price, especially in the Mrt'teTspan'-voltage range. Further, it is "known ^ the arc by means of fuse-like Verbindungsreltüngeri to ^r relief in a centrally disposed of the arrester elements" to ignite suppressing fixed tube (Switzerland. Pat. 391,859) * Here, "" are "the fuse elements in series with the Ableiterelemeriteri. But that If damage to the active parts is effectively avoided, the η-speaking limit of the fusible conductor must be significantly below the power speed of the active parts of the arrester, which means that the latter are poorly utilized Part of 'the' resistors parallel spark gaps a part of the resistance body is formed in a ring shape and the parallel spark gaps are housed for mutual illumination inside the annular resistors'. The purpose of this arrangement is "to let beirr occurrence of an overvoltage carried out the response of the Funkenstrecften nächeinander, wherein the resistors' their V / ert'tiäcn are particularly staggered (DRP 696 097) · The configuration." Lsi ^so: getr'of - fen that the annular resistance body with 'the parallel'; ■ Spark gaps are housed in a special insulating cylinder, while additional solid resistance disks with "between! Il'ge ⁼ n- '■ the spacers are located directly in the actual housing of the arrester, so that a consistent explosion protection is not provided here. -. _v ... ..,

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The invention is based on the object of a simple and cheaper Solution for an explosion-proof surge arrester indicate where the thermal and mechanical stresses in the event of overloads can be controlled. According to the invention it is proposed that the also ring-shaped spark gaps and = the opposing body are clamped together in such a way that the stack has a continuous, has approximately centrally located canal and that in the immediate vicinity The pressure relief device is arranged near the end of the channel.

Based on the drawing, which "shows an embodiment according to the invention reproduces, this is explained in more detail.

The figure shows in section a surge arrester for medium Voltage at which an insulating housing4, e.g. made of ceramic, has flanges ^ cemented on on both sides. These Flanges are screwed to covers 3 with gaskets in between 4, creating a closed housing. The lids 3 are not solid throughout, but have openings in the middle, which are closed by rupture membranes 5. Inside the insulating housing 1, a stack is housed, which consists of the resistor bodies 6 and consists of the spark gaps 7, the resistance and spark gap elements are designed and ring-shaped clamped together so that on the one hand they lie close to one another and on the other hand form a channel 8, which the stack in the middle

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te interspersed. The channel 8 ends on both sides in rooms 9, which are immediately are located in front of the membranes 5. With this structure it is essential that the channel 8 has practically no connection with the gap 10 between the insulating housing 1 and the stack, so that any internal pressure stress in the event of arcing faults from the insulating housing 1 is kept. The end faces of the resistor body 6 are metallized. When not completely flat end faces, it is advisable not to place the disk-shaped resistance body 6 directly, but with an intermediate layer To stack soft metallic rings, not shown in detail, on top of one another, so that a tight seal between the resistance bodies is achieved. Furthermore, it is expedient to have the resistance body 6 on one or both sides with conical countersinks 6a to be provided, whereby the thickness of the resistance body in the region of the channel-forming bore 8 is smallest, so that any Breakdowns of the resistance body as a result of thermal overload form in the vicinity of the channel 8 and the resulting ionized gases definitely get into the channel 8 and not into the gap 10. The configuration of the spark gaps 7 is like this taken that the insulating washers 7a each have a spark chamber 7t> leave blank, in which the electrodes 7c on both sides of the central bore are housed. The insulating washers 7a have am Edge 7d a labyrinth-like shape for sealing. The electrodes 7c of the spark gaps are correspondingly connected from floor to floor by connections 7e, so that a Multiple spark gap results. From the first and last electrode

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Similar connections ¹ each lead to the metal disks 7f, which establish the connection to the neighboring resistor bodies 6. Given that if the arrester is overloaded, arcing faults and the associated pressure increases only develop in the duct 6 with this design and the excess pressure is reduced by breaking the membranes 5 without the housing insulator being stressed, resulting in a perfect control of overloads and the resulting in Related thermal and mechanical loads.

The invention can also be applied to arresters in which several columnar stacks of catfish, known per se, can be found in a housing insulator. Each stack then has a channel which ends at corresponding pressure relief devices. In certain cases it can be advantageous to design the pressure relief device as a pressure relief valve.

Corporation

BROWN, BOVER! & CIi.

BADEN [Switzerland)

909885/0998

Claims (1)

? a t e r. t a η :: ρ backward: 'WC. rrr; r r.rur. "-. ^v lri; er, dr-asen active part consists of at least one column-shaped stack, egg of spark gaps and V.'iI .rctändcn -". is built and which is in a closed go ;. .Cu is located, which is provided with a Lruckeri'tlastun-Seinrichtung at least at one point, using ring-shaped V.'iderctandskorper, characterized in that the also ring-shaped spark gaps (77) and aie V / resistor body (6) together in such a way. that the stack has a continuous, approximately centrally located channel (3) and that the pressure relief device (5) is arranged in the immediate vicinity of the channel end (9). "Jebe.'o ^ line arrester according to claim 1, a ^ characterized by, that the thickness of the resistance body (6) in the area around the channel-forming hole (8) is smallest and increases on all sides in the radial direction. Surge arrester according to claims 1 and 2, thereby characterized in that the resistance body (6) on the end face lying next to one another via metallic intermediate rings arranged close to the hand, the intermediate ring being the electrical Contact is used and at the same time forms an approximately tight seal between the resistance bodies (6). 4. Surge arrester according to claim 1, characterized in that that the pressure relief device is designed as a pressure relief valve. 909885/0998 ' .:, * j, i - .. ».- ■■ BAD ORJGIMAt , -. _v . . "- 7 - 78/68 5. "Jebercpannungsableiter according to claim 1, characterized in that öuijc c.ic pressure relief device is designed as a 3ruchniöiribrane (5). Joint stock company BRO «A, BOVSRI & CIE. 909885/09 9 8 Blank page