EP2162961B1 - Device and module for protecting against lightning and overvoltages - Google Patents

Abstract

A device for protecting against lightning and overvoltages includes two electrodes closing off, in a gas tight manner, both end faces of a cylinder made of insulating material, and defining a discharge chamber in the interior of the chamber thus formed. At least one step is provided in the chamber in the contact area of at least one of the electrodes and the cylinder such that the chamber extends outwards past the internal wall of the cylinder.

Description

The invention relates to a device for protection against lightning and overvoltage with two electrodes, the gas-tightly seal both end faces of a cylinder of insulating material and define a discharge space inside the chamber thus formed, and a module with these devices.

Such devices are, inter alia, as lightning and / or overvoltage protection in the main power supply system of structural systems, in which the outer conductors are connected via a respective lightning arrester with the neutral conductor provided. Such a device is also referred to as a spark gap arrangement or arrester arrangement. In the JP 2006024423 such a device will be described. Such devices are also in the FR 1105065 . FR 990361 . CH 345061 . DE 29810937 and the EP 1353422 described and may have multiple electrode plates.

A surge arrester serves to avoid dangers to living beings, plant and equipment damage as well as fires. The purpose of lightning and overvoltage protection is to reduce overvoltages to a protection level of 1.5 kV and dissipate strong pulse currents up to 50 kA. In this case, jet flames and pressure waves are to be avoided in order to allow installation in typical installations without taking into account special safety distances and passive fire protection measures. The extinguishing capacity and the limitation of the line frequency secondary current must be such that: Do not trigger house connection fuses. Finally, compatibility with standardized mounting systems and insensitivity to climatic influences and contamination is required.

Typical characteristics of such lightning and overvoltage protection devices are: a DC response voltage U _ag > 600 V, a Ansprechstoßspannung u _as ≤ 1.5 kV at a voltage increase of 5 kV / μs, a nominal surge current i _SN of 50 kA at standard surge currents of 8 / 20 μs and 10/350 μs and each 15-fold load, as well as a line-frequency secondary current ≤ 50 kA.

When a arrester responds, an arc is produced which generates combustion products which can be deposited as conductive vapor deposition on the inner cylinder of the ceramic or of the insulating material and cause an insulation fault.

To fulfill the protective function, a low dynamic response voltage is required. For the entire component, the required value is 1500 V when a ramp voltage of 5 kV / μs is applied. For a single arrester, this level of protection and the other characteristics mean that ignition aids must be used. One way to improve ignition performance is to introduce a primer, e.g. graphite, which provides primary charge carriers, distorts the electric field, and improves dynamic detonation behavior via a sliding discharge along the ceramic surface of the inner wall of the cylinder.

The invention is based on the object to provide a device of the type mentioned above, with the required characteristics can be achieved or exceeded.

The invention solves this problem with the features of the independent patent claims. Embodiments of the invention are characterized in the subclaims.

The device for protection against lightning and overvoltages provides two electrodes which seal both faces of the cylinder made of insulating material, in particular of alumina ceramic, gas-tight and define a discharge space in the interior of the chamber thus formed. Within the chamber, at least one step is provided in the contact region of at least one of the electrodes and the cylinder such that the chamber extends beyond the inner wall of the cylinder.

The electrodes are preferably made of copper or copper alloys. The chamber is the entire gas-filled interior that results after soldering or closing the cylinder to the electrodes. The discharge space is basically the chamber area, but a high-energy discharge to protect against lightning and overvoltages in a discharge gap, which is formed between each other with a small distance facing electrode surfaces, in particular in the central region of the device. The area of contact of the area of the end face of the cylinder is referred to, on which in principle the cylinder can be connected or soldered to the electrode. The contact region thus extends at least over the thickness of the inner wall of the cylinder.

Due to the gradation, the insulation distance to the respective electrode extends at least by the length and height of the gradation. As a result, even with repeated shock and Continuous current loads achieved a high level of insulation of the device or the arrester during the entire life.

It is envisaged that the gradation is arranged in the front-side inner wall of the cylinder. Alternatively or additionally, the gradation is arranged in at least one of the electrodes.

Ignition aids, in particular, such as graphite ignition strips, which are applied to the inner wall of the cylinder and extend the view according to the inventive embodiment to the front-side inner wall of the cylinder, improve the ignition and the load capacity of the device or the arrester. The ignition aid improves the dynamic ignition behavior of the arrester, in particular by providing primary charge carriers, distorting the electric field and improving a sliding discharge along the surface of the ceramic cylinder.

Alternatively or additionally, it is provided on ignition aids that the electrodes are pasted with an activating compound which likewise improves the ignition behavior.

The ignition properties of the device can be further improved if the ignition aids according to the invention extend on the inner wall of the cylinder except for the gradation in the front-side inner wall of the cylinder. As a result, the distance between the end of the ignition strips to the metallic electrodes (residual insulation) set and keep so low that the function of the ignition fuse is optimized. In particular, it is provided in one embodiment that the ignition aids are widened in the transition region from the inner wall to the front-side inner wall of the cylinder. Further variations of the igniter geometry are designed to further enhance the dynamic detonation behavior of the arrester.

In one embodiment, the ignition strips thus formed are distributed at intervals of 45 ° over the inner circumference of the cylinder.

The device is designed to be stackable for stacking a plurality of similar devices. As a result, it is easy to build modules with multiple devices that are individually interchangeable and can have different threshold voltages.

In one embodiment, at least one of the electrodes has both a cup-shaped region and a bead-like region, which extend in the longitudinal axis direction of the device in each case on both sides of the plane of the contact surface of the cylinder and the electrode. This allows a particularly efficient stacking, because the middle electrode of two arresters must be present only once, but is available as an electrode for both arresters.

In one embodiment, the arrester is formed so that the electrodes are mirrored at the transverse axis of the device. This allows efficient stacking with small dimensions of the module thus formed.

In one module several devices or arresters are connected in series. It is particularly space-saving when two devices connected in series have a central common Electrode formed as one of the two electrodes of each of the two devices.

The characteristics of a module of series-connected arresters can be optimized if a varistor is connected in parallel to at least part of the devices connected in series. If necessary, several varistors can be connected in parallel to combinations of arresters.

In one embodiment of the module, a plurality of arresters with different response voltages are connected in series.

The use of one or more arresters with a hermetically sealed gas-filled housing makes it possible to avoid flashes or pressure waves.

A series connection of several arresters of different characteristics in one module allows the mastering of the required DC response voltage, the Ansprechstoßspannung and the power-frequency follow current. An additional wiring of several elements of the series connection with a varistor arranged in parallel favors the behavior under load with the required DC response voltage and the Ansprechstoßspannung. The high arc voltage of the individual conductors limits the mains frequency follow current.

Due to the high heat capacity of the arrangement, in particular when using copper electrodes, and the good thermal conductivity of the filling gas, the arc is cooled efficiently and the extinguishing behavior is improved.

In a practical embodiment, a module comprises a holding device with two electrically conductive holders arranged on both sides of the module, which are connected by spacer insulators and clamp the module. The possible low height of a surge arrester and also a series circuit of arresters in a module, which is clamped between contact elements as needed, simplifies the assembly of the device.

The design of a surge arrester and the possibility of a modular construction of several arresters makes it possible to optimize the device. The use and design of ignition strips supports the defined response of the device.

The combination of arresters with varistors an improved protection of the system to be protected.

The objects described above will be explained in more detail with reference to the following figures and embodiments.

Figur 1a

zeigt einen Ableiter mit einer Abstufung in dem Zylinder aus isolierendem Material,

Figur 1b

zeigt einen Ableiter mit einer Abstufung in jeder der beiden Elektroden,

Figur 1c

zeigt einen isolierenden Zylinder mit einer Abstufung und Zündstrichen auf der Innenwand und der Abstufung,

Figur 1d

zeigt den Zylinder gemäß Figur 1c in perspektivischer Darstellung,

Figur 2

zeigt ein erstes Modul mit einer Reihenschaltung gestapelter Ableiter,

Figur 3

zeigt ein zweites Modul mit einer Reihenschaltung gestapelter Ableiter,

Figur 4a-c

zeigt Ersatzschaltbilder von Modulen mit Varistoren, die parallel zu Ableitern liegen und

Figur 5

zeigt ein drittes Modul mit einem Varistor in einer Klemmhalterung.

The drawings described below are not to be considered as true to scale. Rather, for better representation, individual dimensions can be enlarged, reduced or distorted. Elements that are equal to each other or that perform the same functions are denoted by the same reference numerals.

FIG. 1a

shows a trap with a gradation in the cylinder of insulating material,

FIG. 1b

shows an arrester with a graduation in each of the two electrodes,

Figure 1c

shows an insulating cylinder with a graduation and ignition marks on the inner wall and the gradation,

Figure 1d

shows the cylinder according to Figure 1c in perspective,

FIG. 2

shows a first module with a series connection of stacked arresters,

FIG. 3

shows a second module with a series connection of stacked arresters,

Figure 4a-c

shows equivalent circuits of modules with varistors, which are parallel to arresters and

FIG. 5

shows a third module with a varistor in a clamp holder.

An arrester according to FIG. 1a contains a housing which is formed of a cylinder 1 of insulating material, for example a ceramic of Al ₂ 0 ₃ , and two electrodes 2, 3, in particular with advantageous flow properties and high thermal conductivity, for example of copper. The electrodes are in particular symmetrical. Inside the chamber 7 formed by the housing is the discharge space. By grading 4 in the ceramic, a sufficiently high level of insulation of the arrester over its entire lifetime is ensured even with repeated shock and residual current loads. The gradation lengthens the wall-side insulation gap between the electrodes.

According to FIG. 1b contains as another embodiment of a diverter a housing which is formed of a cylinder 11 of insulating material, for example a ceramic of Al ₂ 0 ₃ , and two electrodes 21, 31, in particular with advantageous flow properties and high thermal conductivity, for example of copper. The electrodes are in particular symmetrical. Inside the chamber 71 formed by the housing is the discharge space. In each case a gradation 41 in the electrodes ensures a sufficiently high level of insulation of the arrester over its entire life, even with repeated shock and residual current loads. The gradation lengthens the wall-side insulation gap between the electrodes.

According to FIGS. 1a and 1b an arrester has an outer diameter D of eg 30 mm and a height H of eg 3 mm or 4 mm.

Stage 4 in the ceramic or 41 in the electrodes prevents a continuous vapor deposition layer in the case of an arc discharge in the arrester and thus insulation problems of the arrester, which can lead to a reduced or unusable function.

By using ignition strips 5 and 51 on the inner surface of the housing and a paste of the electrodes with an activation mass, the ignition behavior and the load capacity of the arrester can be further optimized.

For the function of the device or the Zündstriches each arrester the distance of the Zündstrichs to the metallic electrodes of the arrester is important. In one embodiment according to FIG. 1a is preferably a shape the Zündstrichs into the stage in the ceramic advantageous because it improves the connection of the ignition strips. The way from the ignition end to the electrodes can be optimized thereby.

Figure 1c shows the ignition strips 52 on the inner wall of the cylinder and the gradation 4 in detail and in perspective, Figure 1d , In the edge region between the inner wall of the cylinder and the gradation 4, the ignition strips are widened. Other igniter geometries are of course provided. A metallization 6 is applied to a portion of the end face of the cylinder for the Verschlusslötung with one of the electrodes.

After the Verschlusslötung, in which advantageously a gas mixture of high thermal conductivity and pressure-dependent easily adjustable dielectric strength, eg Ar / H ₂ - / Ne mixtures) is used, there is a hermetically sealed gas-filled arrester with defined static and dynamic ignition properties and a high arc voltage ,

To obtain protection against higher voltages and lightning, it is preferred to use several of the according to FIG. 1a or FIG. 1b trained arrester connected in series and form a module. To optimize the volume and the manufacturing process further embodiments are according to FIG. 2 or FIG. 3 provided in which the insulating ceramics 12, 14, 16 and 18 with respect to the electrodes 22, 32 and the electrodes 23a, 23b relative to the insulating ceramics 13, 15 and 17 are stepped.

According to FIG. 2 and FIG. 3 For example, at least one of the electrodes has both a cup-shaped region 25, 35 or 27, 28 and a bead-shaped region 24, 34 and 26, which extend in the longitudinal axis direction of the device respectively on both sides of the plane of the contact surface of the cylinder and the electrode. This allows a particularly efficient stacking because the middle electrode 25 or 28 of two arresters must be present only once, but is available as an electrode to both associated arresters.

The arresters are designed so that the electrodes are mirrored on the transverse axis of the device. This allows efficient stacking with small dimensions of the module thus formed.

For the modules according to FIG. 2 respectively. FIG. 3 Several devices or arresters are connected in series. It is particularly space-saving when two devices connected in series have a central common electrode, which is formed as one of the two electrodes of each of the two devices.

The overall arrangement is according to FIG. 4 from a series connection of individual arresters FS200 and FS600 with the same (FS200) or different characteristics, eg with response DC voltages of 200V or 600V. An external wiring of different sections is advantageous. This wiring is preferably done with varistors V1, V2, V3. However, it can also be realized in another way with the aim of achieving a rapid increase in potential at one or more individual conductors under dynamic load.

A preferred embodiment of 6 elements FS200 with U _ag = 200 V and an element FS600 with U _ag = 600 V in combination with two varistors V1 with 250V and V2 with 420V shows FIG. 4a. FIG. 4b shows the same arrester arrangement as FIG. 4a , but with two 200V varistors V3, each connected in series with three series-connected arresters FS200 and with each other in series. Figure 4c shows the same arrester arrangement as FIG. 4a but with a varistor V2 with 420V, which is connected in parallel to the six arresters FS200.

The series circuit of individual arresters FS200 and FS600, which is preferably realized by clamping in an electrically conductive, tong-shaped holder 61, 62, 63, taking into account the mounting ability in standardized rail systems, shows FIG. 5 , The holders 61 and 63 are insulated from each other by spacers. Parallel to the arresters FS 200, a varistor V is connected.

The clamping allows easy adaptation of the electrical properties to the application, by individual arresters can be varied or replaced and an external wiring of different sections can be made. This wiring is preferably carried out with varistors, but can also be realized in another way with the aim to achieve a rapid increase in potential at one or more Einzelableiter under dynamic load.

Claims (12)

1. Apparatus for protection against lightning and overvoltages having two electrodes (2, 3; 21, 31; 22, 32) which close both end faces of a cylinder (1; 11; 12) composed of an insulating material in a gastight manner and define a discharge area (7; 71) in the interior of the chamber formed in this way, with at least one step (4; 41; 42) being provided within the chamber, in the contact area of at least one of the electrodes and the cylinder, such that the chamber extends beyond the inner wall of the cylinder, and such that the inner wall of the cylinder has ignition aids (5; 51), characterized in that these ignition aids extend to the end-face inner wall of the cylinder.
2. Apparatus according to Claim 1, in which the step is arranged in the end-face inner wall of the cylinder and/or in at least one of the electrodes.
3. Apparatus according to Claim 1 or 2, in which the ignition aids (51, 52) are in the form of lines and extend as far as the step in the end-face inner wall of the cylinder.
4. Apparatus according to Claim 1, 2 or 3, in which the ignition aids are broadened in the junction area from the inner wall to the end-face inner wall of the cylinder.
5. Apparatus according to one of Claims 1 to 4, which can be stacked in order to stack the plurality of apparatuses of the same type.
6. Apparatus according to Claim 5, in which at least one of the electrodes has both an area (25, 35) in the form of a pan and an area (24, 34) in the form of a bead, which each extend in the longitudinal direction of the apparatus, on both sides of the plane of the contact surface between the cylinder and the electrode.
7. Apparatus according to one of Claims 1 to 6, in which the electrodes are mirrored on the lateral axis of the apparatus.
8. Module, comprising a plurality of series-connected apparatuses (FS200, FS600) according to one of Claims 1 to 7.
9. Module according to Claim 8, in which two series-connected apparatuses have a central common electrode (32, 35, 36; 28), which is in the form of one of the two electrodes of each of the two apparatuses.
10. Module according to Claim 8 or 9, comprising a holding apparatus having two electrically conductive holders (61, 62), which are arranged on both sides of the module, are connected by spacing isolators (63) and clamp the module.
11. Module according to one of Claims 8 to 10, in which a varistor (V; V1, V2; V3) is connected in parallel with at least some of the series-connected apparatuses.
12. Module according to one of Claims 8 to 11, in which a plurality of apparatuses with a different response voltage are connected in series.

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