EP4309197A2

EP4309197A2 - Low voltage shielding element, low voltage current transformer, low voltage current transformer arrangement and low voltage electrical arrangement

Info

Publication number: EP4309197A2
Application number: EP22718050.2A
Authority: EP
Inventors: Norbert Koch
Original assignee: Redur & Co Kg GmbH
Current assignee: Redur & Co Kg GmbH
Priority date: 2021-03-19
Filing date: 2022-03-17
Publication date: 2024-01-24
Also published as: WO2022194328A2; DE112022001632A5; WO2022194328A3

Abstract

Separating the functionalities of shielding on the one hand and fastening on the other makes it possible to devise a low voltage current transformer that can be used flexibly and with the greatest possible measuring accuracy. In order to put this basic concept into practice, in particular a low voltage shielding element can have a geometrically simple and/or functionally optimised shielding body or have an appropriate fastening and/or a low voltage current transformer can have a mounting appropriate for a low voltage shielding element or be appropriately fastened.

Description

Low-voltage shielding body, low-voltage current transformer, low-voltage current transformer arrangement or low-voltage electrical arrangement

[01] The invention relates to low-voltage electrical arrangements and corresponding ones

Shielding bodies, current transformers and current transformer arrangements, in particular according to the preambles of the independent claims.

[02] Shields in the field of low-voltage electrical systems are, for example, from

EP 0011 590 A1, EP 1 241 926 A2, EP 2 700953 A2, GB 2 073 499 A, DE 17 66774 A1 or DE 101 55450 A1.

[03] WO 1991/019305 A1 in particular discloses a low-voltage shielding body which, when attached to a low-voltage current transformer, is intended to improve the measurement accuracy, with this arrangement being designed in particular for low-voltage currents of more than 1 kA.

It is the object of the present invention to provide a low-voltage current transformer that can be flexibly replaced and is as accurate as possible. [05] The object of the invention is achieved by low-voltage shielding bodies, low-voltage current transformers, low-voltage current transformer arrangements or low-voltage electrical arrangements having the features of the independent claims. Further advantageous configurations, which may also be independent of this, can be found in the subclaims and the following description. The invention is based on the basic knowledge that by separating the functionalities of the shielding on the one hand and the attachment on the other hand, in particular also in contrast to WO 1991/019305 A1, a low-voltage current transformer that can be used flexibly and is as accurate as possible can be provided. To implement this basic idea, a low-voltage shielding body can in particular have a shielding body that is geometrically simple and/or optimized for its function or a suitable fastening and/or a low-voltage current transformer can have a suitable holder for a low-voltage shielding body or be suitably fastened. Thus, a low-voltage current transformer comprising a housing and a transformer core held by the housing and surrounding a low-voltage busbar opening can be characterized in that the housing has a shielding body mount for holding a low-voltage shielding body. A shielding body designed to match the shielding body mount can then be held by the shielding body mount in the appropriate position in relation to the converter core. Due to the shielding body, such an arrangement enables a correspondingly increased measurement accuracy if this appears necessary under the given installation conditions, while the shielding body can be dispensed with in a flexible manner if corresponding shielding is not absolutely necessary.

[08] Accordingly, it is particularly advantageous if the low-voltage shielding body can be inserted into or removed from the shielding body holder independently of the transformer core. This enables easy conversion if this appears necessary. [09] In the present context, any construction group of the housing of a low-voltage current transformer which is suitable and intended for holding a shielding body can be used as a shielding body mount. In this case, a corresponding shielding body mount can be attached or provided in several pieces to the housing. In particular, it is also conceivable that a corresponding shielding body mount can be formed in one piece with the corresponding housing.

[10] Advantageously, the shielding body holder comprises at least one holding web, so that a free area is arranged in the housing, which connects a shielding body provided for the low-voltage area to the rest of the interior of the housing. In this way, a free area can be created in which the low-voltage shielding body can be inserted into the low-voltage current transformer as simply as possible and at the same time can be held by the holding web. The holding web can hold the low-voltage shielding body from any side and, in cooperation with the walls of the housing, for example, ensure the appropriate hold of the low-voltage shielding body. [11] The shielding body mount preferably comprises two holding webs, since the

The interaction of two holding webs alone holds the low-voltage shielding body as simply and securely as possible and at the same time a free area can be created in which the low-voltage shielding body can be used as simply as possible. [12] Around the low voltage shielding body adequate but with minimal

Effort to hold, it is advantageous if the holding web extends from a housing wall going perpendicularly to this housing wall and forms an overhang for holding the low-voltage shielding body. In this way, the overhang of the holding webs ensures that the low-voltage shielding body is held appropriately without covering a large part of the surface of the low-voltage shielding body. Instead, the holding webs can hold the low-voltage shielding body with a minimal coverage area of the latter.

[13] It is conceivable that the holding web or the holding webs are arranged on any side of the low-voltage shielding body. In an advantageous embodiment, the holding webs or the holding web extend from the housing wall perpendicularly to this housing wall and thus form a corresponding overhang, so that the low-voltage shielding body is held laterally by overhangs.

[14] However, it is also conceivable that the holding web extends from a housing wall, starting perpendicularly to this housing wall, but is arranged, for example, below or above the low-voltage shielding body. Various configurations are conceivable here, which can entail different structural configurations depending on the configuration of the low-voltage current transformer.

[15] In particular, the holding webs may also have other functions, such as latching functions or safety functions, with which the housing halves are connected to one another or are secured against lateral slippage. [16] In the present context, a “free area” is understood to mean in particular an area within which no other objects or any other material are arranged that protrude into this area, so that the area is free for the use of an object. A free area can thus represent, for example, an area that is available to a low-voltage shielding body and thus includes at least the volume of the low-voltage shielding body. Also, a vacant area can be regarded as an empty space. [17] A “retaining web” can preferably be understood to mean a plate-like or sheet-like accumulation of a material which, for example, protrudes from the housing or is arranged on it and correspondingly due to its shape and its positioning, in particular in relation to the housing and the Low-voltage shielding body can achieve a corresponding holding of the low-voltage shielding body. In this case, the holding web can in particular be formed in one piece with the housing.

[18] In the present context, “housing wall” is preferably understood to mean any wall of the housing. For example, a housing can be formed from several housing walls. [19] In the present context, a “housing” is understood to mean, in particular, a solid shell for the low-voltage current transformer, which protectively surrounds the transformer core and is preferably not electrically conductive at room temperature or under operating conditions. The housing is also preferably not made of metal, for example made of plastic. A housing can be designed as a divided housing, in which case the housing can consist of several, in particular two, housing parts.

[20] Here, the housing is preferably a good thermal conductor in order to dissipate any heat generated in the transducer cores or in the pickup coils.

[21] Here, it is also conceivable in particular that the housing is cast, possibly even cast around the converter core and the other assemblies to be arranged inside the housing.

[22] In particular, the housing can include a transformer core holder, by means of which the transformer core of the low-voltage current transformer is held in the housing. Depending on the specific configuration, the converter core holder can also be designed as a fastening, so that the converter core is not only held but is firmly connected to the housing under normal operating conditions.

[23] In the present context, the term "converter core", often colloquially also called armature, refers to an assembly that is designed to conduct magnetic flux. Here, the magnetic flux density is a physical quantity of electrodynamics. It is the areal density of the magnetic flux that passes perpendicularly through a specific surface element, in particular through a surface element of the transformer core. [24] A transducer core can preferably consist of a soft magnetic material with the highest possible magnetic saturation flux density, with the most linear characteristic possible and the highest possible magnetic permeability. As a result, the magnetic flux, which is induced by a primary current in the converter core, can be bundled or guided with low losses. This ensures that the primary current generates a course of the secondary current that is as linear as possible and that the required load power is essentially guaranteed.

[25] Furthermore, a transformer core can be produced by pressing a suitable ferromagnetic powder in a tool. In this case, the pressed so-called green compacts are generally solidified in subsequent temperature treatments and, in the case of ferrite materials, optionally sintered at high temperature to form a ceramic.

[26] A transformer core can in particular also be made up of several layers of a corresponding material, e.g. made of current transformer or transformer sheet metal. Depending on the specific configuration, the strip material is preferably equipped with a thin insulation layer to reduce eddy current losses. A large number of possibilities are known per se for such insulating layers, such as targeted oxidation or a coating with a fack and the like. In certain situations, for example with a corresponding material, the material jump caused between the layers on the respective surfaces lying on top of one another can possibly already be sufficient to minimize the formation of current turbulence. [27] Advantageously, a transducer core has a low hysteresis behavior in the

Reversal of the magnetizing current, in particular the primary current, whereby a small phase shift angle between the primary current and the secondary current and low heat development in the converter core can be achieved.

[28] In particular, the transformer core can be ring-shaped and have a central opening, which in the present context is referred to as a low-voltage busbar opening. Depending on the specific configuration, the transformer core can then be wound in particular as a toroidal tape core in the form of a strip material, with the low-voltage busbar opening then being able to be provided in a structurally simple manner by the winding core on which the strip material is wound. [29] In a specific embodiment, the transformer core can be divided and have two or more transformer core parts, in the case of an annular transformer core in a not purely radial, so not in a low-voltage busbar opening representing or this parallel plane, running main axis plane is divided. In particular, a transformer core divided in this way can make it possible for a conductor for the primary current, called the low-voltage busbar in the present context, not to be threaded through the low-voltage busbar opening in the transformer core, but for the divided transformer core to be fitted around the low-voltage busbar in the open state can. With such an embodiment, it goes without saying that the associated housing can or should also have a corresponding division.

[30] In the case of a converter core designed as a toroidal strip core, this can be designed as a cut strip core, in which case it is then preferably cut open, sawed through or otherwise severed transversely to the direction of flow in order to provide the converter core parts. Here, the cut surface can be polished after cutting, whereby the magnetic flux property through the cut surfaces can be improved.

[31] In the present context, a "low-voltage current transformer" is understood to mean a current transformer that is specially tailored to the requirements of

Applications in the low-voltage range is adapted. The low-voltage range extends up to a voltage of 1,000 V, preferably up to a voltage of just 750 V or 720 V. In the constant effort to test the limits, there are also certain devices for the low-voltage range defined in this way that can go up to Voltage up to 1,200 V or slightly above can be operated. Depending on the type of construction, however, such equipment is also not referred to as medium-voltage equipment, although it can still be operated in the lower limit range of the medium-voltage range to the low-voltage range.

[32] In general, a current transformer in the present context is preferably an electrical or electronic device which generates a primary current in the present

Correlation called according to low-voltage current, converts into a secondary current according to a fixed relationship. The secondary current can, in particular, be an electrical signal adapted for measurement electronics, so that a current transformer can enable or simplify the measurement of the primary current or the low-voltage current.

[33] Low-voltage current transformers are suitable for low-voltage currents up to 1,000 A (1 kA) and in the present cases for low-voltage currents over 2 kA, in particular over 2.5 kA, or up to 10 kA and above can be used. It goes without saying that ultimately the low-voltage current transformer can also be operated at lower currents or voltages, although it is designed for correspondingly high currents or voltages. However, it has been shown that, particularly in the case of currents of more than 1 kA, low-voltage current transformers are subject to structural requirements which clearly distinguish such low-voltage current transformers from low-voltage current transformers intended for lower currents.

[34] It should be expressly pointed out that the above values for the voltage and the current intensity should not be understood as sharp limits, but rather should be able to be exceeded or fallen below on an engineering scale without departing from the described aspect of the invention . In simple terms, the values should provide an indication of the size of the voltages and currents specified here.

[35] In case of doubt, however, this does not apply to the 1 kA limit mentioned above, which is manifested in design and construction measures so that the corresponding low-voltage current transformers can also be operated reliably with low-voltage currents above 1 kA.

[36] Corresponding low-voltage currents are conducted in low-voltage busbars, which can then be arranged in the low-voltage busbar opening of the respective transformer core, so that these low-voltage busbars transport the primary current or the low-voltage current, by which the associated low-voltage current transformer is excited and which is then converted by this in a corresponding manner will.

[37] In this case, the low-voltage busbar opening accordingly defines a transformer core plane in which or parallel to which the magnetic flux runs through the transformer core when a primary current flows in the low-voltage busbar.

[38] It is understood that the housing of the low-voltage current transformer, depending on the specific design, can also have a low-voltage busbar opening, so that the low-voltage busbar can be positioned in a suitable manner in relation to the transformer core.

[39] Accordingly, it is advantageous if the housing encloses the transformer core, and this in particular also on the side of the transformer core which faces the low-voltage power rail opening. [40] With a suitable configuration, the housing side of the housing, which faces the low-voltage busbar opening, can in particular also serve as a converter core holder, through which the converter core can be held by the housing.

[41] Depending on the specific configuration, the transducer core holder, for example in connection with a housing cover, can be designed in such a way that the transducer core is fastened in the housing by the transducer core holder, so that this can be defined as a fastening.

[42] Accordingly, it goes without saying that the shielding body holder, through which a shielding body can be held by the housing, for example by using a housing cover or by additional measures such as screws, clamps, straps or the like, can be designed in this way can be that a shielding body can be attached to the housing through them, so that the shielding body mount can also be used or referred to as a shielding body attachment.

[43] Depending on the specific configuration, the transformer core holder or also the shielding body holder can be designed in one piece with the housing. This can also be done in particular by casting. If the housing is cast around the transformer core and the shielding body, the transformer core holders and/or the shielding body holder can also be cast in. In this case in particular, they are then considered lost and preferably consist of the housing material, so that as little disruption as possible can be expected as a result. [44] In addition to the transformer core, the low-voltage current transformer often has at least one coil, which is designed as a wound conductor. In the present context, a coil is in particular an electrical component which has a wound conductor and is set up to generate an electromagnetic field or to be inductively excited by it. Most coils consist of at least one winding of a conductor made of wire, enameled copper or aluminum wire, silver-plated copper wire, high-frequency stranded wire or ribbon, with the conductor usually being wound on a coil carrier. In the present context, the transformer core itself can optionally serve as a coil carrier. The winding arrangement and shape, the wire diameter, the winding and the material of the transformer core determine the value of the inductance and other properties of the coil. [45] Very generally, in the present context, a “coil carrier” is understood to mean, in particular, a rectangular, cylindrical or otherwise extending, shaped body with or without lateral flanges, on which a coil can be wound or is wound, which is then carried by the bobbin. Such a coil carrier can in particular stabilize the coil itself, which can ultimately simplify the winding process, for example.

[46] A secondary signal, which corresponds to the magnetic flux in the transformer core, can then be provided via the coil, which is then preferably available as a secondary current for metrological purposes.

[47] It goes without saying that regardless of the combination of features explained above, that the housing has a shielding body mount, which can be designed as a fastener if necessary, the presence of a housing fastener by means of which a low-voltage shielding body can be fastened to the housing of a low-voltage current transformer or can be attached or is attached, can be correspondingly advantageous.

[48] As used herein, the term "enclosure attachment" describes any means by which a low voltage shielding body can be attached to an enclosure. This can in particular be adhesive, for example. This can, for example, only be applied shortly before the fastening process, with a two-component adhesive having proven to be advantageous in particular with such a procedure in terms of durability. It is also conceivable, for example, to provide a double-sided adhesive tape, which can be pre-installed on the housing or on a low-voltage shielding body, so that a corresponding attachment can be made quickly and quickly beforehand. The housing can also be fastened with retaining clips, retaining rails, Velcro strips, cable ties, separately and specially manufactured plastic snap-in devices or the like. include. In particular, the shielding body mount already mentioned above can also be designed as a housing mount. Likewise, screw connections or mounting rails can be used to fasten the housing. [49] In this respect, independently of the other features, cumulatively or alternatively, a low-voltage current transformer that can be used flexibly and is as accurate as possible can be provided if a low-voltage current transformer arrangement, comprising a low-voltage current transformer comprising a housing and a low-voltage current transformer held by the housing and surrounding a low-voltage busbar opening, as well as a low-voltage Shielding body comprising a shielding body, characterized in that the low-voltage shielding body is attached to the housing of the low-voltage current transformer by means of a housing attachment. By loosening the attachment or by attaching it Even then it is possible to configure the associated low-voltage current transformer flexibly and to use it accordingly in order - depending on the requirements - to ensure appropriate shielding via the low-voltage shielding body.

[50] In delimitation in particular from WO 1991/019305 A1, this can, depending on the specific design, in particular also be carried out subsequently or as required, since the

The low-voltage shielding body is attached to the housing itself - and not to the transformer core.

[51] Depending on the specific configuration, the attachment can be done by plugging it on or by inserting it. It can often be sufficient if the attachment is captive with regard to the respective installation situation. It goes without saying that--depending on the specific implementation--a non-detachable connection, ie a connection that cannot be detachable without destroying it, can also be used as a fastening, as can be realized, for example, with adhesive, but also with cable ties. Velcro strips, retaining clips, clip-on caps, etc. On the other hand, they can ensure captive but not inseparable attachment, with further measures such as gluing a housing, additional gluing or sealing and the like possibly being provided in order to implement inseparable attachment.

[52] Accordingly, a low-voltage shielding body that has a housing attachment by means of which the low-voltage shielding body can be fastened to a housing of a low-voltage current transformer can, with a suitable configuration, serve to provide a low-voltage current transformer that can be used flexibly and is as accurate as possible. By fastening the housing, the corresponding low-voltage shielding body can be attached to the housing of the low-voltage current transformer as required, if this appears necessary. On the other hand, it is also possible to loosen the attachment if necessary, given a suitable configuration of the same, if a low-voltage shielding body does not appear necessary.

[53] In this context, it should already be mentioned that - depending on the requirements - a low-voltage shielding body that is to be used effectively as a shield can weigh several 100 grams or even several kilograms, which then requires a corresponding structural design of the housing attachment if this additional weight then loads the housing and the fastening of the low-voltage current transformer. This then also causes a considerable additional weight, which in terms of the stability of the associated low-voltage current transformer and its attachment by means of a transformer attachment to a low-voltage busbar or to a housing of a corresponding low-voltage electrical system must be taken into account.

[54] In this context, it should be mentioned that any attachment device that is suitable and intended for this is to be understood as a converter attachment

Fasten the low-voltage current transformer to a sufficient extent in relation to a low-voltage busbar so that it can fulfill its current-transforming function or its measuring function in the intended manner. In particular, the fastening options already mentioned above come into consideration as fastening options.

[55] In view of the possibly very considerable weight of the low-voltage shielding body, an approach to additional costs for such a low-voltage shielding body must also be taken into account, so that a correspondingly flexible use is promoted by the housing attachment explained above and the possibility of not providing the low-voltage shielding body can.

[56] Especially in view of the considerable weight, it can be cumulatively or alternatively useful to attach the low-voltage shielding body directly to a busbar, preferably directly to the busbar belonging to the low-voltage current transformer, for which purpose a corresponding busbar fastening can then be provided. Flierbei it is understood that such a busbar attachment can also be used cumulatively for a housing attachment, so that the assemblies of low-voltage shielding bodies and low-voltage current transformers can be stabilized in relation to the low-voltage busbar.

[57] Regardless of such a busbar attachment, it goes without saying that an attachment of the low-voltage shielding body to a housing of the entire

Low-voltage electrical arrangement, such as, for example, can be provided on a transformer housing or on a switch cabinet housing or on corresponding support rails of this housing.

[58] Accordingly, cumulatively or as an alternative to the combinations of features explained above, a low-voltage Current transformers are provided when a low-voltage shielding body has a power rail attachment, by means of which the low-voltage shielding body can be fastened to a low-voltage busbar.

[59] It goes without saying that the housing attachment or the busbar attachment, as explained above, can advantageously be provided at least partially on the low-voltage shielding body or can be components of the same.

[60] On the other hand, as already explained above, the housing attachment can also be provided at least partially as part of the housing of the low-voltage current transformer or as a separate or supplementary assembly, as will be explained in detail below.

[61] Accordingly, it can also be advantageous to provide the busbar attachment as a separate assembly so that, cumulatively or as an alternative to the combinations of features explained above, a low-voltage current transformer that can be used flexibly and is as accurate as possible can be provided if a low-voltage electrical system consists of at least one low-voltage busbar and a low-voltage current transformer arrangement comprising a low-voltage current transformer comprising a housing and a transformer core held by the housing and surrounding a low-voltage busbar opening, wherein the low-voltage busbar extends through the low-voltage busbar opening and the low-voltage current transformer comprises a transformer attachment for attachment to the low-voltage busbar, characterized in that a Low-voltage shielding body by means of a busbar attachment to the low-voltage busbar and/or to the rivet the voltage-to-current converter is attached or attachable. As already explained above, by attaching it to the low-voltage current transformer via the busbar attachment, a compact low-voltage current transformer arrangement can be provided overall, which can be used flexibly and is measurement-accurate as desired.

[62] Depending on the specific configuration, the housing attachment or the busbar attachment can include a component on the side of the shielding body, which is permanently attached to the low-voltage shielding body. Such a component on the side of the shielding body can be a corresponding adhesive, for example. Likewise, this can - of course - be another assembly, such as an eyelet, a threaded hole or the like, which is permanently installed in the low-voltage shielding body or connected to it. [63] It goes without saying that, depending on the specific configuration, the housing attachment can have a housing-side component which is non-detachably attached to the housing. Here, too, a one-piece design with the housing can be implemented, such as in the case of a shielding body mount or also if adhesive or attached eyelets, threads or the like are present.

[64] It has already been explained above that the low-voltage shielding body certainly entails an additional weight that must be taken into account with regard to a secure attachment of the low-voltage shielding body. This applies in particular when the low-voltage shielding body is to be attached to the low-voltage current transformer, since the transformer attachment then has to carry this additional weight accordingly. In this regard, it can then appear sensible in such an embodiment to upgrade the converter attachment in a suitable manner, if necessary. The latter can be done in particular by the converter attachment comprising a spacer plate which comes to rest on the housing and/or on the low-voltage busbar. Such a spacer plate can, in particular in contrast to other spacers that may be conceivable, ensure a large contact surface with the housing or with the low-voltage busbar, as a result of which the converter attachment is then more stable. This increased stability may be sufficient to ensure a sufficiently stable attachment of the low-voltage current transformer to the low-voltage busbar per se, so that the low-voltage current transformer can then also carry the low-voltage shielding body. It goes without saying that additional attachments, such as the busbar attachment explained above or attachment to the overall housing of the low-voltage electrical system, can be provided in order to ensure even more stability here.

[65] Such a spacer plate may not only increase the stability of the transformer attachment but also allow the low-voltage current transformer to be positioned more precisely in relation to the low-voltage busbar, which then correspondingly increases the measuring accuracy, for example by centrically or can be positioned in another predetermined form in relation to the low-voltage busbar. [66] In addition, it can be advantageous if, in addition to the converter attachment, an additional attachment is provided by means of which the low-voltage current transformer is attached or can be attached to the low-voltage busbar. Such a Additional attachment can then be provided as required if the converter attachment, for whatever reason, cannot carry sufficient weight. In particular, this advantage can also be used independently of the use of a spacer plate or a busbar attachment. [67] In particular, the additional attachment can include the types of attachment already explained in general terms above. The additional attachment can be realized in particular by clamping jaws, with the above-mentioned spacer plate possibly being able to serve as one of the clamping jaws.

[68] Accordingly, there is also a low-voltage electrical arrangement made up of at least one low-voltage busbar and a low-voltage current transformer arrangement, comprising a low-current transformer comprising a housing and a transformer core held by the housing and surrounding a low-voltage busbar opening, the low-voltage busbar extending through the low-voltage busbar opening and the low-voltage current transformer having a transformer attachment for attachment of the low-voltage busbar, cumulatively or alternatively to the above-mentioned combinations of features, advantageously suitable for providing a flexibly replaceable low-voltage current transformer that is as accurate as possible when the converter attachment includes a spacer plate that comes into contact with the housing and/or on the low-voltage busbar, or the low-voltage current transformer supplements the Transformer attachment by means of an additional attachment to the low-voltage conductor rail attached or attachable.

[69] In this case, the additional fastening can comprise a busbar clip and/or a spacer plate which comes into contact with the housing and/or with the low-voltage busbar, as has already been explained above. [70] In this case, the spacer plate can in particular have one or more projections, through which positioning of the spacer plate in relation to the low-voltage current transformer can be facilitated. If the spacer plate is then arranged below the low-voltage current transformer, it can also support it.

[71] The spacer plate preferably has an extension which corresponds approximately to the width of the low-voltage busbar or the low-voltage busbar opening on which the spacer plate is to come into contact. The supernatant then preferably projects beyond the width of the low-voltage busbar opening, so that then a corresponding installation of the supernatant on the housing of the low-voltage current transformer or on the transformer core can take place.

[72] In the present context, the width of the low voltage busbar opening is preferably measured in the transformer core plane. In particular, the width can be measured parallel to the low-voltage busbar, which is often rectangular and flat, so that the width can be measured along the flat side of the low-voltage busbar.

[73] Particularly preferably, the respective overhangs each extend in the plane of the plate, so that the respective spacer plate still has an essentially plate-like shape. This enables a particularly versatile use, with the directions of rotation and installation directions in particular not being so important.

[74] In particular, it has proven to be advantageous if the low-voltage current transformer is supported on the busbar clamp of the additional attachment, which can be implemented in a structurally particularly simple manner. [75] In practice, it has been found that low-voltage busbars, especially when they are already permanently installed, are intended to conduct increasingly high currents. On the other hand, it is evident that the structural density with which such low-voltage busbars are laid is increasing more and more. This means that low-voltage current transformers that are already in use are subject to more and more interference fields, which is particularly problematic if not only two low-voltage current busbars run close together and a low-voltage current transformer is arranged on one of the two low-voltage current transformers, but on both. It is particularly often the case that several such low-voltage current transformers can be found next to one another at the same height around parallel low-voltage busbars, so that their transformer core levels essentially match. On the other hand, even with low-voltage current transformers that are offset from one another, in which case the transformer core levels can be found at different heights, this can occur in a remarkable way. As already explained above, even with a single low-voltage current transformer that is arranged too close to other low-voltage busbars or even to an angled area of the busbar it encloses, interference fields can already occur to a significant extent be listed. Measurement inaccuracies can be observed above certain current intensities, particularly in the case of such configurations.

[76] Accordingly, it is advantageous if, in the case of a low-voltage electrical arrangement with at least two low-voltage busbars spaced apart from one another, a low-voltage current transformer surrounds a first of the two low-voltage busbars and the low-voltage shielding body is arranged between the second of the two low-voltage busbars and the low-voltage current transformer.

[77] In particular, of course, the low-voltage shielding body can be arranged between two low-voltage current transformers, which are each arranged on the two low-voltage busbars. In this way, the low-voltage shielding body can then shield both low-voltage current transformers from one another or from the other low-voltage busbar.

[78] It can also happen that the low-voltage busbar surrounded by the low-voltage current transformer has a kink. Then, if necessary, one leg of the kinked low-voltage busbar can be defined as being surrounded by the low-voltage current transformer, so that the crease then also has a leg that is kinked to this leg. In this context, the term "kink" refers to a change in direction of the low-voltage busbar with a radius of curvature that is less than twice, preferably than once, the extension of the low-voltage current transformer perpendicular to its converter plane, in particular less than twice, preferably than once, the extension of the corresponding transformer core is perpendicular to its transducer plane. Depending on the specific implementation, the kink can be 90° or 45°, for example. It goes without saying that other angles can also occur. If the low-voltage current transformer is arranged in the vicinity of the kink, the low-voltage shielding body can be arranged between the bent leg and the low-voltage current transformer in order to reduce any interference fields caused by the bent leg. In this context, the aforementioned "proximity to the bend" is given when there is a risk of interference fields from the bent leg in expected operating situations.

[79] As a rule, a low-voltage shielding body can be assigned a shielding level in which it has a particularly effective shielding effect. The presence of a correspondingly designed body, for example a body with a sufficiently large permeability number m _G greater than 5,000, can already have a shielding effect, even if the orientation with respect to a shielding plane is not taken into account. It goes without saying, however, that it makes sense to pay attention to the alignment of the shielding plane in order to ensure appropriate shielding that is as effective as possible or uses as little material as possible. [80] Preferably, the low-voltage shielding body when it is a

Has defined shielding, aligned such that the shielding is perpendicular to one or all transducer core planes and is preferably aligned perpendicular to a distance of the shielding body or a shielding body of the shielding body.

[81] In particular if the low-voltage busbar has a kink, it can alternatively be advantageous to arrange the shielding plane parallel to the transformer core plane or parallel to the bent leg of the low-voltage busbar in order to ensure suitable shielding.

[82] It will be appreciated that when there are two low voltage busbars or two low voltage current transformers, a corresponding low voltage shielding body may be attached to both low voltage busbars or low voltage current transformers in the manners described above. In this way, the load, which is caused by the low-voltage shielding body, is distributed, so that the associated fastenings can be designed accordingly for lighter weight and therefore also correspondingly more cost-effectively. [83] Irrespective of the other combinations of features explained above, a low-voltage shielding body can be characterized in that the low-voltage shielding body comprises a shielding body that is made of current transformer or transformer sheet metal in order to provide a low-voltage current transformer that can be used flexibly and is as accurate as possible. [84] Current transformer laminations or transformer laminations are well known on the market and are used in a variety of forms in current transformers or transformers. In this respect, a shielding body made of sheet metal of this type can be provided relatively inexpensively.

[85] In this context it should be emphasized that, depending on the specific embodiment, a corresponding low-voltage shielding body can only consist of the shielding body if, for example, the corresponding low-voltage shielding body is in a Housing bracket used or to be attached to a housing by simple housing fasteners, such as Velcro straps or cable ties.

[86] As a rule, however, in addition to a shielding body, such a low-voltage shielding body will also have other components, such as a housing surrounding the shielding body or a coating, for example in the form of a cast body, which, among other things, protects the shielding body against external influences , such as weather influences or corrosive influences of the environment can protect. Such other assemblies are usually chosen so that they have a relative permeability m _G close to 1, so that the effects on the magnetic flux are relatively small.

[87] On the other hand, all material components that can be used in a low-voltage shielding body can be considered as a shielding body, in which shielding properties can be found that have a permeability number p _r significantly above 1. [88] In concrete terms, corresponding shielding effects can also be sufficient

Represent effectiveness can already be found with permeability numbers p _r over 10 or over 50.

[89] In particular, however, it is advantageous if the shielding body is made of a shielding material with a permeability number p _r greater than 300, for example iron. Although permeability numbers p _r of this order of magnitude are to be regarded as relatively low, materials with permeability numbers p _r of this order of magnitude can already require certain shielding, which may be sufficient. As a rule, however, the use of such materials will very probably not be cost-effective with regard to the shielding effects that can be achieved.

[90] In this regard, shielding materials with a permeability number p _r greater than 5,000 or in particular greater than 10,000 or even greater have proven to be particularly advantageous and effective

40,000. The latter values can be achieved in particular with appropriately alloyed iron, with specially designed ferrites and with mu-metals. Even higher permeability numbers p _r are then found with amorphous metals, suitably designed mu-metals or with nanocrystalline metals that are optimized in this respect. [91] Accordingly, it turns out to be independent of those already explained above

Combinations of features also a low-voltage shielding as advantageous to a to provide a low-voltage current transformer that can be used flexibly and is as accurate as possible if this is characterized in that the low-voltage shielding body comprises a shielding body made of a shielding material with a permeability number m _G greater than 5,000, in particular greater than 10,000 or greater than 40,000. [92] A particularly simple structure and therefore a correspondingly simple way of providing a low-voltage current transformer that can be used flexibly and is as accurate as possible results if a low-voltage shielding body is characterized independently of the above-mentioned combinations of features in that the low-voltage shielding body is a flat shielding body includes. Such planar shielding bodies, which are therefore essentially plate-like, can be used easily in a prepared holder. Also, once properly positioned, they can be attached to appropriate objects, such as a housing of a low-voltage current transformer or even a low-voltage busbar, via simple attachments such as adhesive layers or retaining straps, Velcro strips or cable ties. They can also be used very flexibly.

[93] In particular, when designing a flat shielding body, complex bending processes can be omitted, which would possibly endanger or damage the integrity of the shielding body. This applies in particular when relatively small bending radii are required, for example to enclose a housing perpendicular to the plane of the transformer core. It is true that small bending radii could also be achieved by winding processes. However, problems would then have to be expected with regard to the individual layers cracking open and with regard to the physical integrity of the associated shielding body. When using archetypal shielding materials for the shielding body, the planar design allows for a simple construction of the corresponding shape.

[94] In particular, it is advantageous if the low-voltage shielding body or the shielding body is designed to be flat and simply connected, ie without any openings or loops. In this way, the formation of eddy currents and similar side effects can be effectively reduced to a minimum, so that the shielding of the associated shielding body, which should preferably be correspondingly flat and simply coherent, can be optimized. Also arises at With such a configuration, the low-voltage shielding body or the shielding body can be manufactured in a relatively simple manner.

[95] Irrespective of the other combinations of features mentioned above, a low-voltage current transformer that can be used flexibly and is as accurate as possible can be provided if a low-voltage shielding body is characterized in that it comprises a shielding body with a thickness of more than 1 mm and/or less than 60 mm .

[96] Here, the thickness of the shielding body is preferably defined perpendicular to a shielding plane if such a shielding plane can be assigned to the associated shielding body or if its material, material composition or configuration allows such a definition. Alternatively or in addition to this, the thickness of the shielding body can also be measured, for example, parallel to the smallest dimension of the shielding body. In the end, this can easily be determined, particularly in the case of a flat shielding body. If the shielding body is curved or designed with a three-dimensional structure, the thickness of the shielding body can usually be defined along the narrowest extension from one surface to the other surface, with the thickness being measured perpendicular to these surfaces in each case .

[97] It turned out that with a shielding body with a thickness of less than 1.5 mm, the shielding performance is significantly reduced, even if by others

Measures such as a shielding material with a high relative permeability m _G are counteracted here. In particular, it is advantageous if the shielding body is at least 1.8 mm thick in order to ensure adequate shielding. A corresponding minimum thickness can also ensure a certain inherent stability of the shielding body, so that handling when attaching, detaching, assembling and similar activities does not turn out to be too complex.

[98] In addition, it has been found that a shielding body that is more than 60 mm thick is ultimately unsuitable in terms of its handling and weight and, in particular, makes retrofitting more difficult if a corresponding low-voltage current transformer is then to be arranged between two low-voltage busbars or between two low-voltage current transformers . Here, too, countermeasures may have to be taken in a suitable manner, for example by using a shielding material with high permeability number m _G or other measures to increase the shielding performance. In particular, it is advantageous if the shielding body has a thickness of less than 50 mm, preferably less than 45 mm.

[99] Here, the thickness of the shielding body can also be selected depending on the associated transducer core, which is to be shielded accordingly. Accordingly, regardless of the other combinations of features mentioned above, a low-voltage current transformer arrangement comprising a low-voltage current transformer comprising a housing and a transformer core held by the housing and surrounding a low-voltage busbar opening, as well as a low-voltage shielding body comprising a shielding body, is advantageous if it is characterized in that the Strength of the shielding body is chosen such that a magnetic reluctance is at least 0.01 times and/or no more than 1 times the magnetic reluctance of the transformer core in order to provide a low-voltage current transformer that can be used flexibly and is as accurate as possible. Here, too, it applies that exceeding 1 times leads to a relatively low shielding performance, which makes the use of a low-voltage shielding body appear questionable. On the other hand, falling below 0.01 times means that the risk of other disruptive influences increases and, in particular, the costs for the associated low-voltage shielding body reach questionable levels. [100] In particular, it is advantageous if the strength of the shielding body is chosen such that its magnetic reluctance is at least 0.03 times, in particular 0.05 times, the magnetic reluctance of the transducer core in order to achieve a sufficiently high level of shielding at reasonable costs and an operationally safe avoidance of disturbing side influences. [101] It is also particularly advantageous if the thickness of the shielding body is chosen such that its magnetic resistance is no more than 6 times, preferably no more than 5.5 times, the magnetic resistance of the transducer core to be in a safe area in terms of shielding performance.

[102] It goes without saying that the thickness of the shielding body is limited by the exact spacing of these assemblies, particularly in the case of low-voltage current transformers arranged close together or very close to a low-voltage current rail or very close to a kinked area of a low-voltage current rail is, since the corresponding shielding body or the corresponding low-voltage shielding body usually has to be arranged in between. Accordingly, the shielding performance, ie the magnetic resistance, can be influenced not only by the strength of the shielding body but also, for example, by its choice of material or by other measures.

[103] As already explained above, under certain circumstances a shielding level, ie a level in which the shielding takes place particularly effectively, can be assigned to a low-voltage shielding body or a shielding body. This also applies in particular when the shielding body is formed in layers, as will be explained in detail below, in which case the shielding plane can then generally be defined parallel to these layers.

For the most effective shielding possible, the low-voltage shielding body can then be arranged in relation to the low-voltage current transformer in such a way that the shielding plane is perpendicular to the transformer core plane of the low-voltage current transformer, at least with a significant component. This then requires correspondingly effective shielding.

[105] It is particularly advantageous here if the shielding plane is aligned perpendicular to a distance between the low-voltage current transformer and an adjacent low-voltage current transformer or an adjacent low-voltage busbar against which the shielding is intended to act.

[106] Alternatively, particularly when there is a bent low-voltage busbar, the shielding plane can also be aligned parallel to the bent area or parallel to the plane of the transformer core.

[107] Irrespective of the other combinations of features explained above, a low-voltage current transformer arrangement, comprising a low-voltage current transformer comprising a housing and a transformer core held by the housing and surrounded by a low-voltage busbar opening, and a low-voltage shielding body comprising a shielding body, can be characterized in that the transformer core spans a transformer core plane and the shielding body extends more than 5% beyond the transformer core perpendicular to the plane of the transformer core, in order to provide a low-voltage current transformer that can be used flexibly and is as accurate as possible. [108] Cumulatively or alternatively to this, a low-voltage current transformer arrangement, comprising a low-voltage current transformer comprising a housing and a transformer core held by the housing and surrounded by a low-voltage busbar opening, as well as a low-voltage shielding body comprising a shielding body, can be characterized in that the transformer core spans a transformer core plane and parallel to the transducer core plane and perpendicular to a distance between the shielding body and the transducer core, the shielding body extends by more than 5% beyond the transducer core in order to provide a low-voltage current transformer that can be used flexibly and is as accurate as possible. [109] Alternatively or cumulatively, if the shielding body or the

Low-voltage shielding body can be assigned a shielding plane or if the shielding body is layered, the shielding body extends more than 5% parallel to the shielding plane or parallel to the layers via a vertical projection of the transformer core onto the shielding plane or onto one of the layers extend beyond the parallel plane in order to have a low-voltage current transformer that can be used flexibly and is as accurate as possible.

[110] Due to this 5% greater extension, which is ultimately found in the shielding level or which results either in the transformer core plane or perpendicularly thereto beyond the transformer core, the shielding of the respective low-voltage shielding body can be increased, since it the magnetic flux is made more difficult to reach the low-voltage shielding body around the low-voltage current transformer. It goes without saying that the associated overhang can also be selected to be larger, for example so that the extent extends by more than 20% or more than 50% beyond the converter core. In particular, the extension can also be selected to be more than 100% larger beyond the transducer core. It goes without saying that there may also be a slight underlap. If this is 50% in relation to the extension of the converter core, the shielding performance becomes questionable. However, minor underlaps, such as when the span is only 85% or 88% of the span of the transducer core, may appear acceptable. [111] Depending on the specific configuration, it is also conceivable that the extension is selected to be larger than the housing not only in relation to the transducer core but also in particular in relation to the housing, which in this respect also has a positive effect on the shielding. [112] Naturally, however, there are also limits to such an overhang, which can be found, for example, in weight, in the practicability of handling and also in the size of the respective low-voltage shielding body itself.

[113] As already indicated above, the low-voltage shielding body or the shielding body can be formed in layers.

[114] In this respect, regardless of the feature combinations explained above, a low-voltage shielding body can be characterized in that the low-voltage shielding body comprises a layered shielding body body in order to provide a low-voltage current transformer that can be used flexibly and is as accurate as possible.

[115] Such layers can be produced, for example, by winding appropriate foils or metal sheets, which are then severed in a suitable manner. Current transformer laminations or transformer laminations, in particular, can preferably be used for this purpose. Depending on the specific configuration, the individual layers can each be coated or otherwise isolated from one another in order to reduce any jumps and the formation of eddy currents to a minimum. However, in special embodiments, the surface transitions between the layers may already be sufficient for such effects.

[116] Accordingly, independently of the combinations of features explained above, a low-voltage current transformer arrangement, which comprises a low-voltage current transformer comprising a housing and a transformer core held by the housing and surrounding a low-voltage busbar opening, and a low-voltage shielding body comprising a shielding body, can be characterized in that the shielding body is layered is formed and the layer is arranged perpendicular to the core plane of the converter in order to provide a low-voltage current converter that can be used flexibly and is as accurate as possible.

[117] By arranging the layers in this regard perpendicularly to the plane of the converter core or parallel to an alignment of converter core laminations from which the converter core is wound, the highest possible permeability number m _G can be ensured. On the other hand, depending on the orientation of the respective low-voltage busbars that can be found in the vicinity of a low-voltage current transformer, a different arrangement of the layers, for example parallel to the transformer core plane, can also be advantageous. [118] The layers of the shielding body preferably have a layer thickness

0.08mm. If the layer thickness is below this, this can lead to packing density problems during layering, which increase the magnetic resistance of the shielding body and which ultimately is actually not desirable. [119] In particular, it is advantageous if the layer thickness is even more than 0.1 mm, since this enables the respective layer to be easily handled when packing the layers.

[120] On the other hand, it is advantageous if the layers of the shielding body have a layer thickness of less than 1.8 mm, in particular less than 1.5 mm. In this way, any eddy currents that can form in the layers can be reduced to a minimum, which is correspondingly useful with regard to a high permeability number m _G . In particular, layer thicknesses of less than 1.0 mm or even less than 0.5 mm can prove to be advantageous. Particularly in the case of very large low-voltage shielding bodies or shielding bodies, larger layer thicknesses, that is to say just over 0.5 mm, can be sufficient, with this certainly also depending on other material parameters, such as the permeability number m _G .

[121] Depending on the alignment of the layers, it can be advantageous if the layers are aligned parallel to the course of the field lines to be shielded; this corresponds to the preferred alignment of the shielding plane, which has already been explained above. [122] In particular, it is advantageous if the layers are aligned parallel to the course of the field lines to be shielded and perpendicular to the plane in which the field lines to be shielded lie, which accordingly results in particularly effective shielding. As a rule, the layers will then be aligned perpendicular to a distance between the low-voltage current transformer and neighboring low-voltage current transformers or from neighboring low-voltage busbars.

[123] In particular, the shielding body can comprise at least 3, preferably at least 5 or at least 10 layers, with clear effects in terms of improved shielding already being observed from 3 layers onwards, which increase with the increase in the number of layers. In particular, more than 20 layers have proven advantageous in this regard. Depending on the specific requirements and in particular also on the layer thickness of the individual layers, however, 600 layers and more are also conceivable, as long as sufficient packing densities can be guaranteed. Here it is understood that Ultimately, a compromise must be found between the number of layers and the weight or volume of the shielding body, in which case—as already explained above—the layer thickness cannot be arbitrarily reduced in order to be able to increase the number of layers even further. In this respect, a maximum number of layers of 300 or 200 layers, in particular 150 layers, proves to be advantageous. In particular, among these

Prerequisites a number of layers between 3 and 100 turns out to be a very good compromise. Here, too, it goes without saying that the other material parameters, such as permeability number m _G , weight, layer thickness, thickness and type of insulation between the layers, etc., can have an influence on the number of layers. [124] As already explained at the outset, the combinations of features explained above are particularly suitable for arrangements that are designed for currents of more than 1 kA, in particular more than 1.2 kA or even more than 2 kA. Packing densities are now occurring, especially with these current strengths, in which such low-voltage shielding bodies can advantageously be used in order to use low-voltage current transformers as flexibly and accurately as possible.

[125] It is understood that the low-voltage shielding body is for shielding a magnetic field and just not related to shielding an electric field.

[126] It goes without saying that the features of the solutions described above or in the claims can also be combined, if necessary, in order to be able to cumulatively implement the advantages accordingly.

[127] Further advantages, goals and properties of the present invention are explained using the following description of exemplary embodiments, which are also shown in particular in the attached drawing. Show in the drawing:

FIG. 1 shows a first low-voltage electrical arrangement in a perspective schematic view obliquely from above;

FIG. 2 shows a second low-voltage electrical system in a perspective schematic view corresponding to FIG. 1;

FIG. 3 shows the low-voltage electrical arrangement according to FIG. 2 in a partially exploded view corresponding to FIG. 2;

Fig. 4 shows the low-voltage electrical arrangement according to Figs. 2 and 3 in a partially exploded view obliquely from below; Fig. 5 shows the low-voltage electrical arrangement according to Figs. Figures 2 to 4 are a partially exploded top side view; FIG. 6 shows a schematic partial section through a low-voltage current transformer and a low-voltage shielding body of the arrangement according to FIG. 1 perpendicular to the plane of the transformer core;

FIG. 7 shows a schematic partial section corresponding to the section according to FIG. 6 through an alternative low-voltage shielding body;

8 shows a busbar clamp designed as a spacer plate, corresponding to one of the busbar clamps according to FIGS. 2 to 5; 9 shows another busbar clamp designed as a spacer plate, corresponding to one of the busbar clamps according to FIGS. 2 to 5; 1 and 2; 11 shows a fourth low-voltage current transformer arrangement in a perspective and partially exploded view;

FIG. 12 shows the arrangement according to FIG. 11 in the assembled state; 13 shows a fifth low-voltage current transformer arrangement in a perspective and partially exploded view;

FIG. 14 shows the arrangement according to FIG. 13 in the assembled state; 15 shows a sixth low-voltage current transformer arrangement in a perspective and partially exploded view;

FIG. 16 shows the arrangement according to FIG. 15 in the assembled state; 17 shows a seventh low-voltage current transformer arrangement in a perspective and partially exploded view; FIG. 18 shows the arrangement according to FIG. 17 in the assembled state; 19 shows another low-voltage shielding body in an exploded view; FIG. 20 shows the low-voltage shielding body according to FIG. 19 in an eighth low-voltage current transformer arrangement;

FIG. 21 shows the low-voltage shielding body according to FIG. 19 in the ready-to-assemble state; 22 shows the arrangement according to FIG. 20 in the assembled state; FIG. 23 shows a ninth low-voltage current transformer arrangement, partially open; 24 shows a tenth low-voltage current transformer arrangement; FIG. 25 shows the low-voltage current transformer arrangement according to FIG. 24 partially opened; 26 shows a further low-voltage current transformer arrangement in a perspective view; 27 shows a schematic cross section through a low-voltage busbar and shielding bodies arranged in relation to it;

28 shows a schematic plan view of a low-voltage busbar and shielding bodies arranged in relation to it; 29 shows a further low-voltage current transformer arrangement, partially opened; and FIG. 30 shows the low-voltage current transformer arrangement according to FIG. 29 without the transformer core and collector coil used.

[128] The low-voltage electrical system 1 shown in FIG. 1 comprises three

Low-voltage busbars 11, which are each surrounded by a low-voltage current transformer 2 and form three low-voltage current transformer arrangements 10 accordingly.

[129] The low-voltage current transformers 2 are each fastened to the low-voltage busbars 11 via transformer fasteners 27, the transformer fasteners 27 each comprising a fastening plate 271 and fastening screws 272, and the fastening plate 271 is permanently fastened to a housing 23 of the respective low-voltage current transformer 2. In alternative embodiments, a detachable connection, for example via a dovetail connection, can also be provided here, but this does not change the basic structure.

[130] As can be seen immediately, the low-voltage current transformers 2 are arranged at the same level, so that they are accordingly arranged in a common transformer core plane 211, which is spanned by the associated transformer cores 21. In this case, the converter cores 21 are each located in the associated housings 23 and each surround a low-voltage busbar opening 24, as shown by way of example in FIGS. 23 and 25 and then also explained with reference to these figures. It goes without saying that--depending on the specific circumstances--the low-voltage current transformers 2 can also be arranged at different heights.

[131] Between the low-voltage current transformers 2, low-voltage shielding bodies 3 are arranged, which are fastened to the housings 23 of the low-voltage current transformers 2 via housing fasteners 32.

[132] In this exemplary embodiment, the housing attachment 32 has projections of the low-voltage shielding body 3, which serve as components 321 of the housing attachment 32 on the shielding body side. In addition, the housing attachment includes 32 mounting screws 323 in threaded openings of the supernatants or the Shielding body side component 321 are provided so that the low-voltage shielding body 3 can be attached to the housing 23 of the low-voltage current transformer 2.

[133] The embodiment shown in Figures 2 to 5 corresponds essentially to the embodiment of Figure 1, so that matching approaches are not described twice here.

[134] In addition to the configuration according to FIG. 1, the arrangement according to FIG can be supported on the additional attachment 4, which is implemented in each case by busbar clamps 41.

[135] In order to enable appropriate support, the busbar clamps 41 have suitable overhangs 421. [136] In addition, the arrangement according to FIGS. 2 to 5 also has busbar fastenings 33, by means of which the low-voltage shielding body 3 can be fastened directly to the respective low-voltage busbars 11. These busbar fasteners 33 each have fastening screws 331 for fastening brackets 332, by means of which the busbar fastener 33 can be clamped to the respective low-voltage busbars 11. In turn, the fastening clamps 332 are then fastened to the low-voltage shielding bodies 3 via the fastening screws 323 of the housing fastening 32 .

[137] In this way, even relatively heavy low-voltage shielding bodies 3 can be used. [138] The low-voltage shielding body 3 of the exemplary embodiments according to FIGS

5 each have, as shown in particular in FIG. 6, a shielding body 31 which is cast into a base body which, in this exemplary embodiment, consists of plastic. This base body also forms the overhangs 421 for the component 321 of the housing attachment 32 on the side of the shielding body, in which the already explained threaded openings may be embedded. [139] As can be seen in particular from FIG. 6, the low-voltage shielding body 3 and therefore also the respective shielding body 31 can be positioned in relation to the housing 23 of the low-voltage current transformer 2 in this way. This positioning takes place in particular in relation to the converter core 21 and its converter core plane 211 spanned by it.

[140] A distance 212 of the shielding body 31 from the converter core 21 can then also be defined by the corresponding arrangement - namely as the shortest distance between the converter core 21 and the shielding body 31.

[141] The shielding body 31 is made up of several layers 311, so that the shielding body 31 can also be easily assigned a shielding plane 34. It goes without saying that the number of layers 311 in the figures is only an example and—depending on requirements—can vary. The layer thicknesses can be less than 0.1 mm. Cumulatively or as an alternative to this, in particular more than 6 layers 311 and possibly more than 50 or more than 100 or even more than 600 layers can be used. The number of layers is particularly preferably at least more than 3 or between 10 and 100. In the present exemplary embodiment, 20 layers 311 are used. The number of layers 311 can depend in particular on the type of specific application, on the material selected, on the layer thickness and on other parameters.

In addition, a thickness 312 of the shielding body 31 can be defined perpendicularly to the shielding plane 34 or also along the narrowest extension of the shielding body 31 .

[143] As can be seen immediately, in the present exemplary embodiments, the shielding plane 34 is perpendicular to the distance 212 of the shielding body 31 from the transformer core 21 or perpendicular to the transformer core plane 211. [144] The alternative low-voltage shielding body 3 shown in Figure 7 essentially corresponds to the low-voltage shielding body FIG. 6, the shielding body 31 being constructed higher along the shielding plane 34, so that a corresponding extent over the converter core 21, which is also present in the exemplary embodiment according to FIG. 6, is increased. [145] As can be seen directly from FIGS. 1 to 5, the low-voltage shielding body 3 and therefore also the associated shielding body 31 also protrude in the transducer plane 21 itself beyond the transducer core 21 or beyond the housing 23.

[146] As already explained at the beginning, the latter measures enable better shielding.

[147] The busbar clamps 41 used in the exemplary embodiment according to FIGS. 2 to 5 can alternatively also be designed in the form of plates, as shown in FIGS. 8 and 9 as an example.

[148] Then these busbar clamps 41 can also serve as spacer plates 42, whereby their surface, depending on the specific arrangement, is attached to the housing 23 of the

Low-voltage current transformer 2 or a low-voltage busbar 11 can be applied. Likewise, if several such spacer plates 42 are used as a stack, the spacer plates 42 can lie flat against one another.

In this way, the busbar clamps 41 or corresponding spacer plates 42 can be used to position the low-voltage current transformer 2 or the low-voltage shielding body 3 in relation to the respective low-voltage busbar 11, regardless of whether this is used as an additional attachment 4 or just as a spacer plate 42 can be used without an additional fastening function. The use of such spacer plates 42 has the particular advantage that the friction and thus the fastening strength can be correspondingly increased by the surface contact. A suitable arrangement of the spacer plates 42 and a suitable choice of their strength can also enable the best possible centering of the low-voltage current transformer 11 in relation to the low-voltage busbar 11 .

[150] The low-voltage electrical arrangement 1 shown in FIG. 10 essentially corresponds to the arrangements according to FIGS. 1 to 5 and also uses the busbar clamps 41 as a spacer plate 42.

In the exemplary embodiment according to FIG. 10, a low-voltage current transformer 2 is also part of the low-voltage electrical system 1, which is arranged around a low-voltage busbar 11 and in this way provides a low-voltage current transformer arrangement 10. The low-voltage current transformer 2 itself is attached to the low-voltage busbar 11 in a conventional manner via a transformer attachment 27, which is not visible here but is described with reference to the above exemplary embodiments, with the corresponding attachment plate 271 and attachment screws 272. [153] In addition, low-voltage shielding bodies 3 are provided on both sides of the low-voltage current transformer 2, which essentially only consist of a flat shielding body 31, which corresponds to the shielding body according to FIGS.

[154] Depending on the specific design, the shielding body 31 according to FIG. 10 can be blank. However, it is also conceivable that an anti-corrosion agent or some other thin coating protects the shielding body 31 of the exemplary embodiment according to FIG.

[155] In the exemplary embodiment illustrated in Figure 10, the shielding body 31 is accommodated in a fastening body 324, which is fastened to the low-voltage busbar 11 via a busbar clamp 41 with fastening screws 411 and rear spacer plates 42, which also serve as busbar clamps 41. The fastening takes place here via recesses and legs of the fastening body 324, which is also designed like a shell in this exemplary embodiment. Alternatively, however, other configurations can also be provided here.

The spacer plates 42 also act here between the low-voltage busbar 11 and the housing 23, so that in this way positioning of the low-voltage current transformer 2 in relation to the low-voltage busbar 11 can be improved. A good busbar fastening 33 can also be realized in this way.

[157] The low-voltage current transformer arrangement 10 shown in FIGS. 11 and 12 comprises a low-voltage current transformer 2 with a low-voltage busbar opening 24, in which ultimately a low-voltage busbar 11 can in turn be arranged.

[158] On two sides, similar to the embodiment according to FIG. Finally, the low-voltage shielding body 3 of the embodiment shown in FIG. 10 can also be used in this embodiment come, which can be formed, for example, with a layer structure or with and without a coating.

[160] The fastening bodies 324 each have latching lugs 325, by means of which the fastening caps 324 can be snapped onto the housing 23 of the low-voltage current transformer.

[161] In addition, the fastening bodies 324 are formed from a non-conductive plastic.

[162] As illustrated in this embodiment, the low voltage busbar opening 24 has a width 241 which can be measured in the transducer core plane 211. FIG. The width 241 of the low-voltage busbar opening 24 is preferably measured according to the arrangement of the low-voltage busbar 11 or perpendicular to the shielding plane 34 of the respective shielding bodies 31 .

[163] The embodiment shown in Figures 13 and 14 corresponds essentially to the embodiment of Figures 11 and 12, wherein the housing attachment 32, however, in addition to the locking lugs 325 or Velcro straps 326 includes, which

Secure fastening body 324 to the housing 23 of the low-voltage current transformer 2 .

[164] In a different implementation, the locking lugs 325 can also be omitted if necessary.

The exemplary embodiment according to FIGS. 15 and 16 also uses Velcro strips 326 as part of the housing attachment 32, but here the two low-voltage shielding bodies 3 are secured directly to one another via Velcro strips 326, while the fastening bodies 324 were merely slipped over protectively.

The arrangement according to FIGS. 17 and 18 essentially corresponds to the arrangement according to FIGS. 15 and 16, but the housing attachment 32 has components 321 on the shielding body in the form of tabs, which are captively connected to the low-voltage shielding body 3 and by means of which cable ties 327 can be performed, by means of which the two low-voltage shielding body 3 can be attached to the housing 23. Here, too, the fastening caps 324 only serve as a cover. The embodiment shown in Figures 19 to 22 is based on a ring-like low-voltage shielding body 3, which is composed of two shielding body parts 35, which in turn, as shown in Figures 19 and 20, consist of a ring-like shielding body 31, which also consists of two body parts 36 is provided. [168] Cover layers 351 are also provided, one of which has a slight overhang to facilitate positioning. Otherwise, these cover layers 351 only serve to protect the shielding body 31.

[169] The cover layers 351 are captively connected to the respective body part 36, in which case an adhesive connection or casting of these components can preferably also take place here.

The low-voltage shielding body 3 can then be assembled and fixed from its shielding body parts 35 on the one hand and fastened to the housing 23 of the low-voltage current transformer 2 on the other hand via a housing fastening 32, which comprises a fastening plate 328 and fastening screws 323. [171] In this exemplary embodiment, the fastening screws 323 are screwed into the housing 23, which is cast so that a tight fit can be ensured. It goes without saying that other types of connection, such as more complex clamping systems or adhesive connections, can also be used as an alternative.

[172] The low-voltage current transformer arrangement 10 shown in Figure 23 essentially comprises a low-voltage current transformer 2, in which the side of the housing 23 facing the low-voltage busbar opening 24 also serves as a transformer core holder 26, in that the pickup coils 22 of the transformer core 21 are supported on this side of the housing 23 .

[173] Low-voltage shielding bodies 3 can then be inserted into a remaining gap between the transformer core 21 or its pick-up coils 22 and the side of the housing 23 opposite the low-voltage busbar opening 24, so that this wall or side of the housing 23 interacts with the Transducer core 21 or the respective pickup coil 22 provides a shielding body mount 25 . A converter attachment can then be realized by casting or by closing the housing 23 . [174] The other low-voltage current transformers 2 presented here are also provided with a transformer core 21 and pick-up coils 22 in their interior, whereby with regard to the exact design of the respective transformer cores 21 and the pick-up coils 22 and their arrangements, there are deviations that are already sufficiently known from the status quo known in the art are possible. In particular, a circumferential and essentially continuous pick-up coil 22 can be provided, for example. It is also conceivable that only one or very small or short pick-up coils 22 are provided. Depending on the specific implementation, the housing 23 can also be cast.

The exemplary embodiment illustrated in FIGS. 24 and 25 also shows a similar construction, but here a separate shielding body holder is provided in the housing 23

25 is formed, in each of which low-voltage shielding bodies 3 can be inserted and which can therefore be referred to as the housing-side component 322 of the housing attachment 32 of the low-voltage shielding body 3 on the housing 23 .

[176] It goes without saying that in the case of the exemplary embodiments illustrated in FIGS. 23 to 25, low-voltage shielding bodies 3 can be inserted or removed, depending on the requirements, insofar as the housing is not yet permanently closed. In this way, a low-voltage current transformer 2 that can be used flexibly and is as accurate as possible can be provided.

[177] Also in the latter exemplary embodiments, the low-voltage shielding body 3 is preferably formed essentially from the shielding body 31, which—as already explained in detail above—can be varied in many respects or adapted to the actual circumstances.

If necessary, a low-voltage shielding body 3 can also be arranged in the area of a bend 110 of the low-voltage busbar 11, as shown by way of example in FIG. Here, interference fields can occur in a low-voltage current transformer 2 due to a bent leg 112 if the low-voltage current transformer 2 surrounds the other leg 111 of the bend 110 in the vicinity of the bend 110 . It can then be advantageous to arrange a low-voltage shielding body 3 between the bent leg 112 and the low-voltage current transformer 2 . [179] In particular, the low-voltage current transformer 2 with the layers of its shielding body or with its shielding plane 34 parallel to the transformer core plane of the corresponding low-voltage current transformer 2 or parallel to the bent leg 112 may be arranged.

[180] Depending on the specific configuration, it can be attached to the low-voltage busbar 11 or to the housing of the low-voltage current transformer 2 in the manner already explained above.

[181] Figures 27 and 28 show an example of the arrangement of shielding bodies 31 in relation to a low-voltage busbar 11 through which a low-voltage current 5 flows.

[182] The low-voltage current 5 generates field lines 50 in a manner known per se, which run around the low-voltage busbar 11 in a field line plane 51 .

[183] Shielding bodies 31 can be arranged shielding in different ways in relation to the field line level 51 or in relation to the course of the field lines 50 .

[184] Thus, as explained by way of example using the shielding body 313 and using the shielding body 314, the shielding body 31 or the associated low-voltage shielding body 3 can be aligned in such a way that its layers 311 and therefore its shielding plane 34 are tangential to the course of the field lines in the field line plane 51 and are aligned perpendicularly to the field line plane 51 .

[185] Here, the arrangement of the shielding body 313 corresponds, for example, to the corresponding arrangement of the low-voltage shielding body 3 in FIGS. 1 to 7 and 10 to

18. The low-voltage shielding body 3 according to FIGS. 19 to 22 also has corresponding partial areas. Likewise, individual low-voltage shielding bodies 3 of the arrangements shown in FIGS. 23 to 25 are aligned accordingly.

[186] The arrangement of the shielding body 314, however, corresponds to the low-voltage shielding body 3 of FIG

Figure 26 of the arrangement according to Figure 26.

Depending on the specific requirements, the shielding body 31 can also have layers 311 that are not tangential to the course of the field lines in the field line plane 51, but can have layers 311 that are oriented perpendicularly to the field line plane 51, as shown by way of example in Figure 27 by the shielding body 315. Such arrangements are found, for example, in individual Low-voltage shielding bodies 3 of the arrangements shown in Figures 23 to 25 and in partial areas of the low-voltage shielding body 3 according to Figures 19 to 22.

[188] Depending on the specific requirements, the shielding body 31 can be arranged in such a way that its layers 311 are aligned tangentially to the course of the field lines in the field line plane 51 and not at right angles to the field line plane 51, as shown by way of example using the shielding body 316 in Figure 28.

The embodiment shown in FIGS. 29 and 30 also shows a structure similar to that shown in the embodiment according to FIGS. As a result, a free area 29 is arranged in the housing 23 . This connects an area 39, which is provided for the low-voltage shielding body 3, with the rest of the interior 231 of the housing 23.

[190] The holding webs 28 extend, starting from a housing wall 232, perpendicular to this housing wall 232 and form an overhang, as a result of which the low-voltage shielding body 3 is held.

The holding webs 28 thus each have a free area 29 ready, in which the low-voltage shielding body 3 can be inserted in the simplest possible way and held by the overhang of the holding webs 28 . Here, the holding webs 28 only hold the low-voltage shielding body 3 in a small outer area, so that most of the low-voltage shielding body 3 is exposed to the area 39 or to the rest of the interior of the housing 23 or is not covered by a shielding body holder 25, for example. The low-voltage shielding body 3 is thus held sufficiently in the present exemplary embodiment according to FIGS. 29 and 30 by the retaining webs 28, but with a minimum of structural and material effort required, with a simple installation of the low-voltage shielding body 3 in the low-voltage current transformer 2 being possible.

[192] In the present exemplary embodiment, the low-voltage shielding body 3 can be fixed by two-sided pressure, on the one hand by the retaining bar 28 and on the other side by the housing wall 232, so that the low-voltage shielding body 3 is clamped between the retaining bar 28 and the housing wall 232. In this way, a holding web 28 does not necessarily have to be formed on both sides of the low-voltage shielding body 3 in order to be able to grip or hold it accordingly, but an additional holding web or several additional holding webs can be saved in that instead, the area 29 between the holding web 28 and the housing wall 232 is used to hold the low-voltage shielding body 3 .

[193] In the present exemplary embodiment, the retaining webs 28 are formed like plates in order to be able to provide a sufficiently strong mounting of the low-voltage shielding body 3 with as little structural effort and use of materials as possible. However, it is also conceivable that any other structures can be used as holding webs, as long as they can provide holding of the low-voltage shielding body 3 .

[194] In addition, the retaining webs 28 extend perpendicularly to the housing wall 232. The two retaining webs 28, which together form the shielding body mount 25, extend from two different opposite housing walls 232. The free area 29 is thus between the retaining webs 28 and a housing wall 232 is formed, from which the holding webs 28 do not extend or which lies between the two housing walls 232, from which the holding webs 28 extend perpendicularly.

[195] It goes without saying that the holding webs 28 also extend, for example, from a common housing wall 232 and thus between the holding webs 28 and the common housing wall 232, from which the two holding webs 28 extend, a free area 29 for holding a low-voltage shielding body 3 can form.

[196] Both in an arrangement of the holding webs 28 according to the present exemplary embodiment and in alternative arrangements of the holding webs 28, such as extending out of a common housing wall 232, the holding webs 28 can laterally hold the low-voltage shielding body 3 or, for example, at least one of the holding webs 28 may also be arranged underneath the low-voltage shielding body 3 for holding the same. The side describes in particular the type of holder in which, as in the present exemplary embodiment, the holding webs 28 extend from housing walls 232 that lie opposite one another and are preferably parallel to one another. Reference sign list :

1 low voltage electrical assembly 3 low voltage shielding body

10 low-voltage current transformers on 31 shielding body order 311 layer of shielding body 31

11 Low-voltage busbar (numbered as an example)

110 kink of the low-voltage current 40 312 thickness of the shielding body 31 rail 11 313 shielding body with tangential to

111 of the low-voltage current field line course in the field line converter surrounded leg of the plane 51 and perpendicular to the Feldli Knicks 110 plane 51 aligned layer

112 bent leg 45 th 311

314 shielding body with tangential to

2 low-voltage current transformers Field line course in the field lines

21 transducer core level 51 and perpendicular to the Feldli

211 layer aligned by the transducer core 21

212 Distance of the shielding body 31 from 315 shielding body with the transducer core 21 not tangential to the course of the field lines in the Feldli

22 pick-up coil niebene 51 and perpendicular to the

23 housing field line level 51 aligned

231 interior of the case 23 55 layers 311

232 housing wall 316 shielding body with tangential to

24 Low-voltage busbars Course of the field lines in the field line opening level 51 and not at right angles to

241 width of the low-voltage current of the field line level 51 aligned- rail opening 24 60 th layers 311

25 shield body mount 32 case mount

26 Transducer core mount 321 Shield body side component

27 Transducer mount housing mount 32

271 mounting plate 322 housing-side component of the

272 fastening screw (example 65 housing fastening 32 numbered) 323 fastening screw (example

28 footbridge numbered)

29 free area 324 fastener body

325 detent 326 Velcro 39 area for low voltage

327 cable tie shield body 3

328 mounting plate 15

33 Busbar fastening 4 Additional fastening 331 fastening screw (numbered 41 busbar clamp as an example) 411 fastening screw (example

332 fastening clamp (numbered as an example) numbered) 20 42 spacer plate

34 shielding plane 421 overhang 35 shielding body part 351 cover layer 5 low-voltage current 36 body part 50 field line

25 51 field line level

Claims

Patent claims :

1. Low-voltage shielding body (3), characterized in that the low-voltage shielding body (3) comprises a shielding body (31) formed flat and layered and made of current transformer sheet metal and/or a shielding material with a permeability number m _G greater than 5,000.

2. Low-voltage shielding body (3) according to claim 1, characterized in that the low-voltage shielding body (3) comprises a shielding body (31) formed with a thickness (312) of more than 1 mm and/or less than 60 mm.

3. Low-voltage shielding body (3) according to claim 1 or 2, characterized in that the low-voltage shielding body (3) has a housing attachment (32), by means of which the low-voltage shielding body (3) can be fastened to a housing (23) of a low-voltage current transformer (2), and/ or a busbar attachment (33) by means of which the low-voltage shielding body (3) can be fastened to a low-voltage busbar (11). 4. Low-voltage shielding body (3) according to claim 3, characterized in that the housing attachment (32) and/or the busbar attachment (33) comprises a component (321) on the shielding body side, which is permanently attached to the low-voltage shielding body (3).

5. Low-voltage shielding body (3) according to one of Claims 1 to 4, characterized in that the shielding body (31) is flat and simply coherent and/or that the layers (311) of the shielding body (31) have a layer thickness of more than 0.08 mm and/or less than 1.8 mm and/or that the field lines (50) to be shielded lie in a field line plane (51) and the layers (311) are tangential to the course of the field lines in the field line plane (51) and/or perpendicular to the field line plane (51 ) are aligned and/or that the shielding body (31) comprises at least 3, preferably at least 5 or at least 10 layers (311) and/or less than 300, in particular less than 100 layers (311). 6. Low-voltage current transformer (20) comprising a housing (23) and a transformer core (21) held by the housing (23) and surrounding a low-voltage busbar opening (24), characterized in that the housing (23) has a shielding body holder (25) for Holder for a low-voltage shielding body (3), in particular according to one of Claims 1 to 5.

7. Low-voltage current transformer (20) according to claim 6, characterized in that the low-voltage shielding body (3) can be inserted into or removed from the shielding body holder (25) independently of the transformer core (21).

8. Low-voltage current transformer (20) according to claim 6 or 7, characterized in that the shielding body holder (25) has at least one, preferably two, holding webs

(28) so that a free area (29) is arranged in the housing (23) which connects an area (39) provided for the low-voltage shielding body (3) to the rest of the interior (231) of the housing (23).

9. Low-voltage current transformer (20) according to claim 8, characterized in that the holding web (28) extends from a housing wall (232) perpendicularly to this housing wall (232) and forms a projection for holding the low-voltage shielding body (3).

10. Low-voltage current transformer arrangement (10), comprising a low-voltage current transformer (2) comprising a housing (23) and a transformer core (21) held by the housing (23) and surrounding a low-voltage busbar opening (24), preferably according to one of claims 6 to 7 , and a low-voltage shielding body (3) comprising a shielding body (31), preferably according to one of Claims 1 to 5, characterized in that

(i) that the low-voltage shielding body (3) is attached to the housing (23) of the low-voltage current transformer (2) by means of a housing attachment (32); and or

(ii) that the transducer core (21) spans a transducer core plane (211) and that (a) is perpendicular to the transducer core plane (211) and/or parallel to the transducer core plane (211) and perpendicular to a distance (212) of the shielding body (31 ) of the transducer core (21) the shielding body (31) extends by more than 5% beyond the transducer core (21) and/or (b) the shielding body (31) is layered and the layers (311) are arranged perpendicular to the transducer core plane (211). are; and/or (iii) that the shielding body (31) is assigned a shielding plane and/or the

The shielding body (31) is layered and the shielding body (31) extends parallel to the shielding plane or parallel to the layers (311) by more than 5% via a vertical projection of the transducer core (21) onto the shielding plane or onto one of the layers (311) extends beyond parallel plane; and/or (iv) that the thickness (312) of the shielding body (31) is chosen such that its magnetic reluctance is at least 0.01 times and/or not more than 1 times the magnetic reluctance of the transducer core (21) amounts to.

11. Low-voltage current transformer arrangement (10) according to Claim 10, characterized in that the housing fastening (32) comprises a component (321) on the shielding body which is undetachably fastened to the low-voltage shielding body (3) and/or a component (322) on the housing which is attached to the housing (23) is permanently attached, and/or that the shielding body (31) extends more than 20%, in particular more than 50%, beyond the converter core (21), preferably beyond the housing (23), and /or that the shielding body (31) comprises at least 4, preferably at least 5 or at least 6 layers (311) and/or that the thickness (312) of the shielding body (31) is selected such that its magnetic resistance is at least 0, 03 times and/or no more than 6 times the magnetic reluctance of the converter core (21).

12. Low-voltage electrical arrangement (1) comprising at least one low-voltage busbar (11) and a low-voltage current transformer arrangement (10), preferably according to claim 10 or 11, comprising a housing (23) and a housing (23) held and surrounding a low-voltage busbar opening (24). Low-voltage current transformer (2) comprising a transformer core (21), preferably according to one of claims 6 to 9, wherein the low-voltage current busbar (11) extends through the low-voltage current busbar opening (24) and the low-voltage current transformer (2) has a transformer attachment (27) for Attachment to the low-voltage busbar (11), characterized in that

(i) that, preferably the low-voltage shielding body (3) according to one of Claims 1 to 5, is or can be fastened to the low-voltage busbar (11) and/or to the low-voltage current transformer (2) by means of a busbar fastening (33).

13. Low-voltage electrical arrangement according to Claim 12, characterized in that the additional attachment (4) is a busbar clip (41) on which the low-voltage current transformer (2) is preferably supported, and/or one or which is or are attached to the housing (23) and/or to the Low-voltage busbar (11) coming into contact with spacer plate (42).

14. Low-voltage electrical arrangement (1) according to Claim 12 or 13, characterized by at least two low-voltage busbars (11) spaced apart from one another by a distance, the low-voltage current transformer (2) surrounding a first of the two low-voltage busbars (11) and the low-voltage shielding body (3) between the second of the two low-voltage busbars (11) and the low-voltage current transformer (2), preferably between the low-voltage current transformer (2) and a further low-voltage current transformer (2) arranged on the second of the two low-voltage busbars (11). 15. Low-voltage electrical arrangement (1) according to one of Claims 12 to 14, characterized in that the low-voltage busbar (11) surrounded by the low-voltage current transformer (2) has a kink (110) with a leg (111) surrounded by the low-voltage current transformer (2) and has a limb (112) which is bent towards this limb (111) and the low-voltage current transformer (2) is arranged in the vicinity of the fold (110) and that the low-voltage shielding body (3) is located between the bent limb (112) and the low-voltage current transformer (2 ) is arranged.

16. Low-voltage shielding body (3), low-voltage current transformer (20), low-voltage current transformer arrangement (10) or low-voltage electrical arrangement (1) according to one of the preceding claims, characterized by a design for current intensities of more than 1 kA, in particular more than 1.2 kA.