DE29707618U1 - Arrangement for protecting electrical systems or devices against overvoltages and overcurrents - Google Patents

Description

European Patent Attorney Fax: 49 (0911) 599842 (Qr. II + III 24 hours)

Company DEHN + Söhne GmbH + Co. KG 23.04.1997

Rennweg 11 - 15, 90489 Nuremberg R/vo

"Order for the protection of electrical installations or equipment against overvoltages and overcurrents"

The invention relates to an arrangement for protecting electrical systems or devices against overvoltages and overcurrents, wherein the arrangement is provided with one or more overvoltage protection devices and one or more overcurrent protection devices (preamble of claim 1). The overvoltage protection devices can be overvoltage arresters, but also lightning current arresters. So-called N-H fuses, for example, but also other fuse and current limiting devices such as other fuses or mechanical switching devices with a comparable characteristic can be considered as overcurrent protection devices.

For example, it is known to use surge arresters in the form of lightning arresters as part of building lightning protection for so-called "internal lightning protection". In addition, current fuses can be provided. The aforementioned protective devices are spatially separated from one another and are connected to one another and to the other current-carrying components of such an installation by means of wiring.

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From DE 296 17 778 Ul, an electrical house installation is known in which main fuses are provided for the power supply of a building and further devices for the discharge and limitation of overvoltages. The aforementioned protective devices are spatially closer to each other than in the previously mentioned protective devices of a building lightning protection system. However, they are spatially separate, spaced apart from each other and connected to each other by

^q Components connected to wiring, which are housed together with this and other wiring, as well as with the incoming and outgoing connections in a first connection compartment and a second connection compartment of a house connection box. The surge arresters and the fuses must

, _c mounted inside the house connection box and with

the corresponding wiring.

The two prior art embodiments explained above correspond to the preamble of claim 1.

They each have the disadvantage that the protective organs have to clear-20

are more or less far apart, with the electrical connections between the overvoltage protection devices and the overcurrent protection devices being made by wiring. The installation work is relatively

complex, since the protective devices are mounted individually and 25

the wiring must also be provided. Furthermore, there is a risk of improper installation, since the placement and wiring of the important protective devices must be carried out on site, i.e. on the construction site.

In contrast, the task and problem of the

The invention consists in combining an arrangement according to the preamble of claim 1 into a compact, space-saving assembly unit which requires very little assembly work on site.
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To solve this task or problem, based on the generic term of claim 1, an assembly unit is provided in which the overvoltage protection devices and the overcurrent protection devices are mounted on a common carrier and are located close to one another. This provides a prefabricated partial installation of the components required for overvoltage and overcurrent protection, which is held together by the common carrier. Such an arrangement can be manufactured in the factory and is provided with the necessary connections between the aforementioned protective devices and with defined connection points for the installer. A partial installation or assembly unit prefabricated in this way can therefore be prefabricated in the factory as a factory-type-tested, in particular lightning current-tested, network connection group. The line or cable connections between the overvoltage protection devices and the overcurrent protection devices that occur in the state of the art are no longer necessary. This is particularly advantageous if relatively long cable connections were previously required for the respective application, which not only entailed corresponding costs, but also caused an additional voltage drop when discharging the lightning current, which can significantly impair the protective properties (protection level) of the surge protection devices. By manufacturing the assembly unit at the factory, such possible errors on the construction site due to improper placement and faulty electrical connections of surge protection devices and/or overcurrent protection devices are avoided. Since only the assembly unit has to be attached to the relevant location, the assembly work on site is significantly reduced. This saves working time and assembly costs. Very short connection paths between the aforementioned protective devices are possible or can be achieved by

gc the assembly unit is specified. This allows the very large forces involved in the discharge of a lightning impulse current to be safely controlled. This advantage is even more

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This is reinforced by the fact that, due to the immediate proximity of the overvoltage protection devices to the overcurrent protection devices, the necessary connections between these protection devices can be made using a mechanically very strong connection bracket (see claim 5). Such a connection can carry lightning currents. The voltage drops explained in the prior art are avoided. Overall, an assembly unit is created which, with the aforementioned advantages, realizes both overcurrent and overvoltage protection, and in an optimal connection. The assembly unit according to the invention can have unchanged external dimensions even when different protection devices are attached and can therefore also be subsequently replaced either with defective assembly units or with other protective devices. If necessary, the assembly unit can alternatively be integrated into a separate additional housing to which the supply and discharge lines are connected. The aforementioned short cross connections between the overvoltage protection devices and the overcurrent protection devices also advantageously result in a low protection level.

In a preferred embodiment of the invention, according to claim 2, the common carrier is designed in the form of a platform-like support and mounting part with mounting surfaces for attaching the overvoltage protection devices and the overcurrent protection devices. It is preferably made of a conductive material such as a metal sheet (claim 7), so that it can simultaneously serve as an electrical connection between the mass (earth) and the associated connections of the aforementioned protection devices.

Further features of the invention and the advantages that can be achieved with the invention can be found in the further subclaims, as well as the following description and the associated drawings of embodiments according to the invention. The drawing shows:

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Fig. 1: in section along the line I-I in Fig. 2 a

first embodiment of the invention,

Fig. 2: the top view of Fig. 1, including a possible variant according to Fig. 3,

Fig. 3: a section along the line III-III in Fig. 2,

Fig. 4, 4a: electrical circuit diagrams of the versions according to

Fig. 1 - 3.

Fig. 1 shows the assembly unit 1 with the platform-like

Supporting and assembly part 2, which according to this sectional view 15

has roughly the shape of a "U". The web 3 of the "U" merges into legs 4 that are angled away from it. The free ends 5 of the legs 4, located at the bottom in the drawing, are angled outwards and are used to support or mount the unit 1 on a base plate, a switchboard or the like.

The web 3 forms a support surface 3' for the fuse base 6 of an N-H fuse 7 indicated by a dot-dash line, which serves here as an overcurrent protection device and in a known

way into slotted holders 8 of the fuse base 6 and held there in a clamped manner.

The leg 4 shown on the right in Fig. 1 carries on the corresponding, externally located connection surface ⁴¹ a surge current-carrying arrester 9 as an overvoltage protection device, which is preferably detachably connected to the leg 4, here by a screw connection 10. The fuse base 6 is also preferably detachably connected to the web 3. A connection bracket 11 serves for the electrical connection of one of the connections 12 of the fuse base 6 with the corresponding, preferably directly below it

connection 13 of the surge arrester. This makes it possible to make the bracket 11 very short. Furthermore, another connection 12 is provided on the opposite side, on the left in the drawing, of the fuse base. Both connections 12 are used to attach supply and discharge lines 14. From Fig. 1 it can be seen that the current is carried from the left connection 12 via the fuse 7 to the right connection 12. The surge arrester, e.g. spark gap 9, is connected to the fuse 7 via the bracket 11 in a very short way. The spark gap in turn is connected and attached to the support part 2. This support part can have ground potential or any intermediate potential.

It is clear that the support and assembly part 2 together with the overvoltage and overcurrent protection devices 9 and 6, 7 form an assembly unit that is held together and, where necessary, electrically connected. This assembly unit only needs to be connected to the supply and discharge lines 14 on site.

The support and mounting part 2 can be bent into the shape shown from a flat sheet of metal or flat strip of plastic. The use of a sheet of metal or another electrically conductive material has the advantage that it can be used electrically as a ground or connected to the respective electrical earthing (ground), for which purpose it has corresponding connection options for the earthing connection of the respective overvoltage protection devices.

Fig. 2 shows a top view of a three-phase arrangement with three fuse bases 6 and associated fuses 7. Furthermore, three overvoltage protection devices 9 and connection brackets 11 assigned to the fuse bases are provided.

Furthermore, Fig. 2 shows that at the height of the legs 4 corresponding side walls 15 are provided on the supporting and mounting part 1

are provided, whereby these walls 15 together with the legs 4 and the web 3 of the "U" form an interior space 16. When the assembly unit is placed on a base or when the assembly unit is attached to a wall, the space 16 is then preferably closed on all sides. This enables the design of the surge arrester 9 as a blowing-out spark gap, the blow-out opening 17 of which opens into the space 16. This allows the blown-out gases 18 to spread out in the space 16 and cool down. When using

With low or no discharge arresters, an open design of room 16 is also possible.

Instead of a blow-out spark gap, another one, for example one that is closed on all sides or capped, can also be used.

A rare spark gap must be provided. In all cases, it is essential that the spark gap can withstand the surge currents that occur, especially surge currents caused by a lightning strike. The previously explained spark gap with blow-out opening or a spark gap without blow-out opening

² ^ is advantageously designed so that its electrodes have the same central longitudinal axis. Each of the electrodes is designed as a screw connection. This can be either an outwardly projecting threaded connector or an inwardly directed threaded hole. The embodiments show spark gaps with outwardly projecting threaded connectors.

It is within the scope of the invention to give the support and assembly part 2 a different shape than that shown in the embodiment of Fig. 1-3. It is important that this provides support and bearing surfaces according to numbers 3', 4' (Fig. 1) for attaching and holding the protective elements explained. A support or assembly part with a modified shape can also be designed and used according to the invention, for example like a pot with side walls and an interior space 16 formed by them.

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The right-hand area of Fig. 2 and Fig. 3 shows a further embodiment of the invention. A connecting rail 21 and 22 are each attached to supports 19 and 20. The aforementioned connecting rails have connection openings 23 (see also Fig. 2). The support 19 is electrically insulating and the support 20 is electrically conductive. This provides predefined connection points for all active conductors and the protective conductor ^ for the connection, e.g. of a low-voltage supply line introduced into a building, whereby various connection options are possible depending on the different network form (Fig. 4, 4a). The connecting rails 21, 22 can be "PE" (or "PEN") and "N". As Fig. 3 shows, the heights h and h' of the supports 19 and 20 are different, with h ¹ being slightly

¹ ^ is greater than h. After loosening the locking screw 19' or 20', the two rails 21, 22 can be pushed over one another so that their respective openings 23 are aligned. For example, a PEN connection for the network system can be made by moving the right rail 22 in Fig. 3 by one hole pattern R to the left and thereby aligning its left-hand connection opening 23 with the connection opening 23 on the right in the drawing of the left rail 21. The screw 20' must then be tightened again and an electrically conductive screw connection of the openings 23 must be made.

It would also be possible to connect an N-PE arrester circuit as required by the network system, as is used as a so-called 3+1 circuit in a TT network. For this purpose, a necessary N-PE spark gap 9' is mounted on the rail 21 as shown in Fig. 3. In this case, the platform-like support and mounting part 2 is at N conductor potential1.

All network systems encountered in practice can therefore be connected. The associated busbars and any spark gap 9' are included in the assembly unit

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integrated. This meets one of the preferred areas of application of the assembly unit according to the invention, namely installation in a so-called house connection box, whereby an exchange with fuse modules already present there is possible. Alternatively, the assembly unit according to the invention can also replace external installations (see the state of the art explained at the beginning). A retrofit unit is therefore also created here.

Fig. 4 and 4a show the electrical circuit diagram of the described circuit variants.

The variant in Fig. 4 shows the arrangement with a so-called NPE spark gap 9'. The further circuit variant in Fig. 4a shows the electrical connection of the two rails 21, 22. In this case, a further insulating support can be provided at the location of the spark gap 9 ¹ shown in Fig. 4. 20

- Expectations -

Claims (13)

1. Arrangement for protecting electrical systems or devices against overvoltages and overcurrents, the arrangement being provided with one or more overvoltage protection devices and one or more overcurrent protection devices, characterized by a mounting unit (1) in which the overvoltage protection devices (9, 9 ¹ ) and the overcurrent protection devices (6, 7) are mounted on a common carrier (2) and are located spatially close to one another. 2. Arrangement according to claim 1, characterized in that the common carrier (1) is designed as a pedestal-like support or mounting part with mounting surfaces (3', 4 ^' ) for attaching the overvoltage protection devices and the overcurrent protection devices. Arrangement according to claim 2, characterized in that the support and mounting part (2) is approximately "U"-shaped in cross section with a flat web (3) having a support surface (3 ¹ ) for the overcurrent protection device(s), and with a leg (4) which preferably has the support or mounting surface (4') for the overvoltage protection device(s) on the outside. 4. Arrangement according to claim 2 or 3, characterized in that on the support surface (3') there is a corresponding number of securing bases (6) for receiving preferably detachable from associated NH fuses (7)
is attached. 5. Arrangement according to claim 3 or 4, characterized in that one of the connections (12) of the associated Fuse base (6) by means of a connecting bracket (11) is electrically connected to the associated overvoltage protection device (9), which is connected to its connection
(13) is located directly below the aforementioned connection (12) of the fuse base. 6. Arrangement according to one or more of claims 3 to 5, characterized in that the free ends of the legs (4) facing away from the web (3) of the "U" are angled outwards towards mounting or standing surfaces (5). 7. Arrangement according to one or more of claims 1 to 6, characterized in that the common carrier (2) consists of an electrically conductive material, preferably a metal, and serves as an electrical ground connection for „c the relevant overvoltage protection devices (9) and overcurrent protection devices (7) serves or is designed. 8. Arrangement according to one or more of claims 2 to 7, characterized in that the supporting and mounting part (2) with the webs (4) and the side walls connecting them
(15) forms an interior space (16). 9. Arrangement according to claim 8, characterized in that in the case of the use of a blow-out spark gap whose outlet opening (17) opens into the interior (16), 35 Preferably, a spark gap capable of carrying surge currents is used. 10. Arrangement according to one or more of claims 1 to 9, characterized by the use of spark gaps whose electrodes have the same central longitudinal axis and at their ends as a screw connection for connection 5 with conductor rails and other connections. 11. Arrangement according to one or more of claims 1 to 10, characterized in that the common carrier in addition to the overvoltage protection devices and overcurrent protection devices (19, 20) has connecting rails (21, 22) for electrically connecting the assembly unit to differently constructed and switched three-phase networks, one of these supports being electrically insulated from the one opposite the carrier and the other of these supports being electrically connected to the carrier. 12. Arrangement according to claim 11, characterized in that the connecting rails run parallel to the fuse bases and thus to the current direction of the phases. 13. Arrangement according to claim 11 or 12, characterized in that the heights (h, h ¹ ) of the supports (19, 20) are so different from one another that after loosening a locking screw (20') the connecting rails (21, 22) can be brought one above the other and electrically connected by longitudinal displacement of one of these rails with their connection openings (23).