Method for tapping a voltage for a current transformer

Abstract

The invention relates to a device (100) for securing a current transformer (200) to a busbar (300). The device (100) comprises a contact surface (122) in order to rest against the current transformer (200). A contact pin (112) is capable of transmitting a clamping force between the contact surface (122) and the at least one contact pin (112) to the busbar (300), in order to secure the current transformer (200) to the busbar (300), and contacting the busbar (300) in an electrically conductive manner. A signal output (118) can output a voltage signal, which indicates the electric voltage of the busbar (300), on the basis of the electric contact of the at least one contact pin (112).

Description

[0001] Voltage tapping technology for a current transformer

[0002] The invention relates to a technique for fastening a current transformer. In particular, a device for fastening a current transformer to a busbar, a system comprising a current transformer and a corresponding fastening device, and a measuring method using a corresponding device are disclosed.

[0003] Current transformers are frequently used in industry to non-contact convert large currents in busbars into a current signal that can be used by a measuring device connected to the current transformer. For reproducible, not necessarily calibrated, measurements, the current transformer must be fixed in place relative to the busbar. In the current state of the art, the current transformers are sometimes mounted on a wall behind the

[0004] They are screwed to the busbar or fixed to the busbar with cable ties.

[0005] Utility model CN ​​213 935 858 describes a theft-proof double-coil current transformer for monitoring the distribution of electrical energy, comprising a transformer body and a fixed plate, one end of the transformer body being fixedly connected to a mounting plate and the back of the mounting plate being provided with a contact alarm and a connecting rod.

[0006] Patent application CN 111 009403 describes an inductive DC transformer with a transformer body and a screw for attaching a busbar. The transformer body is formed by an upper and a lower inductive body. Between them is an opening for inserting the busbar. A wedge projects from the upper main body. After the busbar is guided through the opening, the head of the fastening screw is positioned in a groove of the wedge, and the shaft is brought into contact with the busbar. This mounts the DC transformer to the busbar.

[0007] However, such conventional devices only allow for the installation of the current transformer. A voltage measurement would be desirable, especially for power measurement. However, this requires the complex installation of a system consisting of a current measuring point and a voltage measuring point.

[0008] In addition, there is often no space available for an additional terminal point on the busbar for voltage measurement directly at the current transformer's mounting location, or it can only be accessed with additional modifications. Furthermore, spatial separation of the current measuring point and the voltage measuring point makes the circuit layout confusing, leads to additional wiring, and can result in inconsistent and inaccurate power measurements, for example, due to a voltage drop between the measuring points or crosstalk in the wiring.

[0009] The invention is therefore based on the object of specifying a technique for fastening a current transformer which eliminates the need to install a voltage measuring point.

[0010] The object is achieved by the features of the independent claims. Expedient embodiments and advantageous further developments of the invention are specified in the dependent claims.

[0011] Embodiments of the invention are described below with partial reference to the figures.

[0012] One aspect of the device relates to a device for fastening a current transformer to a busbar. The device comprises a contact surface designed to bear against the current transformer. The device further comprises at least one contact pin designed to transmit a clamping force between the contact surface and the at least one contact pin to the busbar for fastening the current transformer to the busbar and to make electrically conductive contact with the busbar. Furthermore, the device comprises a signal output designed to output a voltage signal based on the electrical contact of the contact pin, which signal indicates an electrical voltage of the busbar.

[0013] Due to the clamping force, embodiments of the device, supported by the contact surface on the current transformer (for example, on an inner surface of a through-hole for the busbar), can fasten (i.e., mount) the current transformer on the busbar (or circumferentially around the busbar). By using the same contact pin with the same clamping force for both mechanical fastening and electrical contact, embodiments realize a compact design of a system that fastens the current transformer and provides the voltage signal at the signal output. These or other embodiments of the device can realize a voltage tap that goes beyond the conventional mechanical function of a mounting aid for the current transformer and / or is integrated into the conventionally purely mechanical fastening device.

[0014] Embodiments of the device can measure the power and / or energy flowing through the busbar based on the output voltage signal for voltage measurement with simultaneous current measurement by means of the attached current transformer. Furthermore, these or other embodiments can measure the power locally transmitted through the busbar through spatial and / or temporal coincidence of current measurement and voltage measurement, for example, without distortion due to a voltage drop or crosstalk in the wiring. For example, in branched power grids, subgroups of generators and consumers connected to such a busbar can be monitored.

[0015] Since the device for fastening (e.g. for mounting) the

[0016] Since the device is designed to electrically contact the current transformer, the device can be referred to as a fastening device or mounting device. Since the device is also designed to electrically contact the busbar, the device can also be referred to as a contact device or fastening device with voltage tap.

[0017] When attached to the busbar by means of the device, the current transformer can be designed to inductively detect the current (for example an alternating current component) in the busbar.

[0018] The contact pin can be designed to directly (e.g. galvanically) contact an electrically conductive (e.g. metallic) surface of the busbar, for example by plastic deformation of the surface of the busbar when the contact pin is pressed in.

[0019] The contact pin and the signal output can be directly electrically connected to one another. The voltage signal of the device's signal output can be at the same potential as the contact pin. Thus, when mounted, the signal output can be at the same potential as the busbar. Alternatively or additionally, the device can further comprise a voltage converter (for example, using a reference potential, in particular a ground connection or a neutral conductor). An input of the voltage converter can be connected to the contact pin (and, for example, the reference potential). An output of the voltage converter can be connected to the (for example, single-pole) signal output (and, for example, the reference potential).

[0020] The current transformer can be an analog current transformer. For example, the current transformer can be configured to output an analog current signal indicating the detected current. The current signal can be a current measurement signal having any analog or digital signal form indicating the current detected by the current transformer. Alternatively or additionally, the current transformer can have a magnetic core that surrounds the busbar when attached. The device can be configured as a fastening device for the current transformer with an integrated voltage tap. In particular, the contact pin and / or the signal output can be referred to as a voltage tap (integrated into the fastening device).

[0021] The device can comprise two or more contact pins. The contact surface can be arranged in a longitudinal direction of the busbar between the at least two contact pins. The force flow of the clamping force can be distributed (e.g., symmetrically) from the contact surface to the two contact pins. Because the contact surface lies completely between the (contact points on the busbar of the) two contact pins in the longitudinal direction, the device rests on the busbar in a tilt-resistant manner.

[0022] The contact surface of the fastening device can be directed in a first transverse direction (e.g., upwards). The at least one contact pin can be directed in a second transverse direction (e.g., downwards). The second transverse direction can be opposite to the first transverse direction. The direction (i.e., the "direction") of a surface can be related to the surface normal of the respective surface. The first transverse direction can correspond to a normal to the contact surface (as the surface of the fastening device).

[0023] For example, the first transverse direction and the second transverse direction may be parallel to each other (i.e., opposite and parallel, which may also be referred to as antiparallel). In other words, the contact pin may be oriented perpendicular to the contact surface.

[0024] The contact pin (or at least one of the contact pins) can intersect the contact surface in an (imaginary) linear extension along the first or second transverse direction. This allows the contact pin (for example as a central electrical tap in a circular plane of a magnetic core of the current transformer) to transfer the clamping force to the current transformer via the contact surface without a tilting moment. For example, a housing of the current transformer has a through-hole for receiving the busbar. In the first transverse direction, an inner side of the through-hole can be flattened and have a first contact surface of the current transformer that is complementary to the contact surface of the fastening device. In the fastened state, the contact surface of the fastening device can bear against the first contact surface of the current transformer.

[0025] The first contact surface of the current transformer can be directed in the second transverse direction. The current transformer can have a second contact surface opposite this first contact surface, i.e., in the second transverse direction (e.g., "bottom") (e.g., as part of the inner surface of the through-hole). When mounted, the busbar can rest against the second contact surface of the current transformer.

[0026] The contact pin can be the tip of a spindle screw. Alternatively or additionally, the clamping force of the at least one contact pin can be adjusted using a spindle screw. Optionally, the clamping force of the at least one contact pin can be adjusted using a spindle screw.

[0027] The device may comprise a spindle screw and an internally threaded sleeve for each contact pin. The contact pin and / or the spindle screw may extend parallel to the first and / or second transverse direction.

[0028] Each spindle screw engages the internal thread of an internally threaded sleeve and can be rotated within it. The rotation of the spindle screw causes a (at least also) translational (linear) movement of the contact pin. To fasten the busbar, the contact pin can be moved against the busbar by turning (screwing in) the spindle screw. For removal, it can be lifted off the busbar by turning the spindle screw in the opposite direction (unscrewing). The spindle screw can be rotated using a hexagon socket or a knurled ring. The hexagon socket or the knurled ring can be arranged on a head of the spindle screw, for example as an integral one-piece head of the spindle screw or attached in a rotationally fixed manner.

[0029] The current transformer can be fastened or can be fastened to the busbar using a friction fit via the device. The clamping force can create the friction fit (for example, as contact pressure). Alternatively or additionally, the current transformer can be fastened to the contact surface in a form-fitting manner, for example by three sides of the device (for example, the contact surface and two further side surfaces facing in the longitudinal direction) resting on the current transformer. This means that displacement of the contact surface of the device relative to the current transformer along the longitudinal direction is blocked when fastened. For example, two of the internally threaded sleeves can limit the contact surface in the longitudinal direction (for example, by means of the outer sides of the internally threaded sleeves acting as the side surfaces).

[0030] The clamping force can be generated by preloading the spindle screw when adjusting the spindle screw and / or by elasticity in the housing of the device. A web (for example, connecting the guide sleeves) can enclose the contact surface. The web can be flexible.

[0031] The hexagon socket can be arranged in a socket of the signal output. For example, the signal output can have a recess as a socket for accommodating a plug contact (for example, in the second transverse direction). A head of the spindle screw and / or the hexagon socket can be arranged at the base of the recess.

[0032] The signal output can be designed as a socket and / or for accommodating a standard laboratory plug (banana plug) or a clamping sleeve, for example, to contact a signal line of the voltage signal (possibly with a wire end ferrule). The signal output can comprise a socket, a terminal, or a free conductor end. The signal output, for example, the socket, can be located in the spindle screw or a housing of the device.

[0033] For example, the contact pin (e.g., the spindle screw) and the socket (or the hexagon socket) can be electrically conductively and non-rotatably connected via a press fit. Alternatively or additionally, the socket can be a cylindrical recess in the spindle screw, for example, perpendicular or parallel to the spindle screw axis. The signal output can have a socket coaxial with the spindle screw.

[0034] The electrically conductive (e.g., metallic) spindle screw (e.g., one or each of the at least one spindle screw for the at least one contact pin) can be rotatably arranged in an electrically conductive (e.g., metallic) internally threaded sleeve of the device. The internally threaded sleeve can be electrically connected to the signal output (e.g., directly or via the voltage converter). For the electrically conductive connection, a signal line of the voltage signal can be clamped or soldered to the internally threaded sleeve.

[0035] Alternatively or additionally, the or at least one or each rotatable spindle screw can be electrically connected to the signal output (for example to the signal line) via sliding contacts.

[0036] The signal line or the free conductor end (as the signal output) can be electrically connected to the internally threaded sleeve or the sliding contact. An electrical contact point between the signal line and the internally threaded sleeve can be molded into an insulating housing of the device. The housing can accommodate at least the internally threaded sleeve.

[0037] The device can comprise at least two contact pins (for example the two mentioned above on either side of the contact surface) which are designed to make electrically conductive contact with the busbar at various points when fastened. Thus, a voltage drop (i.e. a voltage difference, for example but not necessarily proportional to the current in the busbar) can be present between the at least two contact pins. The voltage drop can feed an evaluation unit of the current transformer and / or an evaluation unit of the fastening device (for example the voltage transformer). For example, a small amount of power can be drawn from the busbar for operating the current transformer and / or the device without the need for a separate voltage supply for the current transformer and / or the device.Alternatively or additionally, a DC component in the busbar can be detected due to the voltage drop (which, for example, cannot be measured by the current transformer or supplements an AC component in the busbar that is inductively detected by the current transformer). The DC component can be output at another signal output of the device (for example, as a voltage signal).

[0038] Alternatively or additionally, the voltage drop can monitor a contact resistance between the at least two contact pins and the busbar. The contact resistance (i.e. the transition resistance or contact transition resistance) can comprise the electrical resistance between the contact surface of one of the contact pins and the surface of the busbar. The contact resistance can be composed of a constriction resistance and / or a pollution layer resistance. The constriction resistance can arise from microscopic unevenness of a contact surface. An evaluation unit (e.g. of the current transformer or the fastening device) can output the contact resistance as an indicator for insufficient clamping force (e.g. as a warning during assembly). If the clamping force is too low, the effective contact surface is smaller due to the roughness and the current flow is restricted. Alternatively or additionally, the pollution layer resistance can be caused by corrosion (e.g.Oxidation) on the busbar and / or contact pin can increase the contact resistance. An evaluation unit (e.g., of the current transformer or the mounting device) can output the contact resistance as an indicator of corrosion (e.g., as a warning during measurement).

[0039] One system aspect relates to a system with a current transformer and a device according to the device aspect. The system comprises the device according to the device aspect and a current transformer attached to a busbar by means of the device for detecting a current through the busbar. The system further comprises an evaluation unit configured to detect a current signal from the current transformer indicating the current and the voltage signal from the device, and to output a power signal indicating a power and / or a phase position.

[0040] The phase angle can be a phase angle between the current (according to the current signal) and the voltage (according to the voltage signal) of the busbar.

[0041] The evaluation unit can be the aforementioned evaluation unit of the current transformer and / or the device. The evaluation unit can be arranged above the current transformer in the second transverse direction, for example, on an end face of the current transformer opposite the first contact surface of the current transformer, outside the through-hole of the current transformer.

[0042] The device's signal output for the voltage signal can comprise an interface between the device and the evaluation unit. Alternatively or additionally, the signal output for the voltage signal can comprise a socket located in a housing of the evaluation unit.

[0043] An interface (for example, the aforementioned interface for transmitting the voltage signal to the evaluation unit) can be arranged between the device and the evaluation unit in the contact surface of the device. The interface can be designed for the electrical and / or mechanical connection between the device and the current transformer when the contact surface of the device and the first contact surface of the current transformer are brought into contact. For example, the contact surface can have a plug contact for the electrical connection.

[0044] One method aspect relates to a method for measuring electrical power provided by a busbar. The method comprises the step of attaching a current transformer to a busbar that extends through a through-hole in the current transformer. The at least one contact pin of the device according to the device aspect electrically contacts a first side of the busbar and transmits a clamping force. The contact surface of the device bears against a first contact surface on the inside of the through-hole of the current transformer. A second side of the busbar bears against a second contact surface, opposite the first contact surface, on the inside of the through-hole of the current transformer.The method further comprises the step of detecting a current of the busbar by means of the current transformer and a voltage of the busbar by means of the at least one contact pin for measuring the electrical power provided by the busbar.

[0045] The invention is explained in more detail below with reference to the drawings using preferred embodiments.

[0046] They show:

[0047] Fig. 1 is a side view and a plan view of a schematic reference example of a conventional fixing device for fixing a current transformer to a busbar;

[0048] Fig. 2 is a side view and a top view of a schematic first

[0049] Embodiment of the device for fastening a current transformer to a busbar with a coaxial socket as a signal output;

[0050] Fig. 3 is a schematic side view of a use of the first embodiment of the device;

[0051] Fig. 4 shows a side view and a top view of a schematic second embodiment of the device for fastening a current transformer to a busbar with a free conductor end as a signal output;

[0052] Fig. 5 is a side view and a top view of a schematic third embodiment of the device for fastening a current transformer to a busbar with a signal output in a housing of the device;

[0053] Fig. 6A - 6C a perspective view and two side views of a schematic embodiment of a current transformer with evaluation unit, which can be used in each embodiment of the device;

[0054] Fig. 7 is a perspective view of a schematic embodiment of a current transformer with a busbar through it, which can be combined with any embodiment of the device;

[0055] Fig. 8 is a perspective view of a schematic system with a current transformer mounted on a busbar by means of the first embodiment of the device; and

[0056] Fig. 9 is a perspective view of a schematic system with a fourth embodiment of the device, which can be connected to an embodiment of the current transformer via an interface or is designed in one piece.

[0057] Fig. 1 shows a side view and a top view of a schematic reference example of a device 10 for attaching a current transformer to a busbar from the prior art. For example, PHOENIX CONTACT offers such a device 10 as a mounting aid for its current transformers, PACT-FAST-MNT-W1 3-L65.

[0058] The device 10 is inserted into the through-hole of the current transformer together with a busbar. Two metal spindle screws are longitudinally movable via a knurled nut 12 to press the spindle screws against a busbar and thus attach the current transformer to the busbar for measurement.

[0059] Fig. 2 shows a side view and a top view of a schematic first embodiment of the device 100 for fastening a current transformer to a busbar with a coaxial socket 118 as a signal output.

[0060] The device 100 for fastening a current transformer to a busbar comprises a contact surface 122 designed to bear against the current transformer. At least one contact pin 112 of the device 100, for example the pair of two contact pins 112 shown in Fig. 2, is designed to transmit a clamping force between the contact surface 122 and the at least one contact pin 112 to the busbar for fastening the current transformer to the busbar and to make electrically conductive contact with the busbar. A signal output of the device 100, generally designated by reference numeral 118, is designed to output a voltage signal based on the electrical contact of the at least one contact pin 112, which indicates an electrical voltage of the busbar. In a first variant of the first exemplary embodiment, a hexagon socket 116 is connected to the spindle screw 110 at the base of the socket 118 in a torque-resistant manner. As shown in Fig.As shown in Figure 3, the spindle screw 110 can be rotated using an Allen key inserted into the socket 118. In a second variant of the first embodiment (which can be combined with the first variant), the spindle screw 110 can be rotated using a knurled ring 117.

[0061] The rotation of the spindle screw 110 with an external thread 114 that meshes with an internal thread 124 of the device 100 is converted into a longitudinal movement in a transverse direction transverse (preferably perpendicular) to the longitudinal direction of the busbar, for example in a first transverse direction toward the busbar or a second transverse direction away from the busbar.

[0062] The device 110 can comprise a housing 120, preferably made of an insulating material. The housing can rotatably enclose or support each of the spindle screws 114. For example, the housing 120 can have the internal thread 124. The housing sections, each of which encloses or supports a spindle screw 114, are connected to one another via a web having the contact surface 122. The housing can comprise the housing sections and the web, optionally in one piece, for example, by injection molding.

[0063] The spindle screw 110 includes a contact pin 112 which is designed to contact the surface of the busbar.

[0064] The spindle screw 110 can be integrally formed with the contact pin 112. Alternatively or additionally, the spindle screw 110 and / or the contact pin 112 can be made of an electrically conductive, optionally metallic, material. Alternatively, the contact pin 112 can be made of an electrically conductive, optionally metallic, material, and the spindle screw 114 can be made of an insulating material. The spindle screw 110 (or its contact pin 112) can be integrally formed with the socket 118 (or its hexagon socket 116) or can be connected in a rotationally and electrically conductive manner via a press fit 115.

[0065] Fig. 3 shows a schematic side view of a use of the first embodiment of the device with a hexagon key which is inserted into the base of the socket as a signal output 118 for rotating the spindle screw 110 during assembly or disassembly of the device 100 on a busbar.

[0066] Furthermore, Fig. 3 shows a banana plug inserted into the socket as signal output 118 for tapping the voltage signal of the device 100.

[0067] Fig. 4 shows a side view and a top view of a schematic second embodiment of the device 100 for fastening a current transformer to a busbar with a free conductor end (ie a signal line) as signal output 118.

[0068] In a first variant of the second embodiment, the spindle screw 110 (or at least the plug contact 112) is electrically conductive and the device 100 comprises a sliding contact which transmits the electrical potential of the rotatable spindle screw 110 (or the plug contact 112) to the (non-rotating) signal output 118.

[0069] In a second variant of the second embodiment, the internal thread 124 of the device 100 is electrically conductive (for example, a metallic internal thread sleeve). The electrical potential of the rotatable spindle screw 110 (or the plug contact 112) is transmitted to the (non-rotating) signal output 118 via the electrically conductive internal thread 124. In each variant of each embodiment, the internal thread sleeve of the device 100 can be exposed or molded into the housing 120 of the device 100.

[0070] Fig. 5 schematically shows a side view and a top view of a third embodiment of the device 100 for fastening a current transformer to a busbar with a signal output 118 in a housing 120 of the device 100. For reliable contacting or to reduce contact resistance, in each variant of each embodiment, the signal output 118 can be electrically conductively connected to several (for example, all) contact pins 112, for example via sliding contacts (as shown in Fig. 5) or via the aforementioned electrically conductive internal thread sleeve with the internal thread 124.

[0071] Fig. 6A shows a perspective view and Fig. 6B and 6C each show a side view rotated by 90° relative to each other of a schematic embodiment of a current transformer 200 with evaluation unit 202, which can be used in any embodiment of the device 100.

[0072] Such a plug-in current transformer 200 is used to inductively convert a high primary current in the busbar into a lower secondary current. The primary current flows through the busbar, which extends through a through-hole 210 in the housing of the current transformer 200.

[0073] The secondary current is provided at a separate output of the current transformer 200, for example at an evaluation unit 202.

[0074] The through-hole 210 has a first contact surface 212 on the inside, against which the contact surface 122 of the device 100 can rest. Optionally, locking edges are provided on the first contact surface 212 of the current transformer 200 to mechanically connect the contact surface 122 of the device 100 to the current transformer 200. In the attached state, the busbar can rest against a second contact surface 214 on the inside of the through-hole 210 (for example, one of several stepped contact surfaces selectable depending on the cross-section of the busbar).

[0075] The conversion of the primary current into the secondary current occurs through the principle of magnetic induction. The current transformer 200 has a ring-shaped iron core in its housing, which encloses the through-hole 210 and is toroidally wound with a coil. The ends of the coil are each electrically connected to a pole of the output of the current transformer 200. When the primary current flows through the busbar, it is surrounded by a closed magnetic field, which, due to the permeability of the iron core, largely runs within it. This magnetic field, which changes with the primary current, then induces a voltage in the secondary coil that is proportional to the primary current.

[0076] The current transformer 200 shown in Figures 6A-6C can be fastened to the busbar by means of an embodiment of the device 100 as a mounting mechanism, ie can be arranged along the busbar at a selectable location enclosing the busbar.

[0077] However, for power measurement using a current transformer, a conventional measuring device lacks not only the current but also the voltage. This would traditionally have to be tapped from an additionally installed terminal, which is no longer necessary with device 100.

[0078] Fig. 7 schematically shows a perspective view of an embodiment of a current transformer 200 with a busbar 300 passing through the through-hole 210, which can be combined with any embodiment of the device 100. Fig. 8 schematically shows a perspective view of a system with a current transformer 200 that is attached to a busbar 300 by means of the first embodiment of the device 100.

[0079] Fig. 9 shows schematically a perspective view of a system with a fourth embodiment of the device, which can be connected to an embodiment of the current transformer via an interface or is designed in one piece.

[0080] The signal output 118 for the voltage tap is integrated as a built-in socket in a housing of an evaluation unit 202 (e.g., a measuring housing for power measurement) of the current transformer 200. The voltage signal is routed from the device 100 to the current transformer 200 via an electrical interface 119.

[0081] In a variant of the fourth embodiment, the electrical interface 119 functions as a signal output 118 of the device 100. Optionally, the evaluation unit 202 outputs the voltage signal provided via the interface 119 together with the measured current as a power signal at a panel socket, which indicates the power and / or the phase position.

[0082] In each variant of each embodiment, the interface 119 may further comprise the locking edges 212 shown in Figs. 6A - 6C for mechanically connecting the device 100 and the current transformer 200.

[0083] Each embodiment of the device 100 can be implemented as a further development of an existing mounting device 10, for example, the PACT-FAST-MNT-W13-L65 mounting material mentioned above, for an electrically conductive connection for tapping the voltage for a power meter. This allows the voltage to be tapped directly at the location where the current is also measured. Numerous embodiments and variants of the technical solution are shown above. For example, an existing and electrically conductive screw connection (for example, of the PACT-FAST-MNT-W13-L65) can be supplemented by an internal hexagon socket screw, optionally as a replacement for an existing knurled nut. In addition, a signal output 118, for example, a coaxial socket for laboratory cables, can be provided (for example, attached) at the end of a spindle screw as a connection for the voltage tap.

[0084] Furthermore, in a second embodiment, a connecting cable as signal output 118 is injected directly into the housing 120.

[0085] Although the invention has been described with reference to exemplary embodiments, it will be apparent to those skilled in the art that various changes may be made and equivalents may be substituted. Furthermore, many modifications may be made to adapt a particular installation situation or material to the teachings of the invention. Consequently, the invention is not limited to the disclosed embodiments, but encompasses all embodiments falling within the scope of the appended claims.

[0086] List of reference symbols

[0087] 100 device

[0088] 110 spindle screw of the device

[0089] 112 Contact pin of the spindle screw

[0090] 114 External thread of the spindle screw

[0091] 115 press fit

[0092] 116 hexagon socket

[0093] 117 Knurled ring of the spindle screw

[0094] 118 Signal output, e.g. socket or signal cable

[0095] 119 Electrical and / or mechanical interface between the device and the current transformer

[0096] 120 Housing of the device

[0097] 122 Contact surface of the device

[0098] 124 Internal thread of the device

[0099] 200 current transformers

[0100] 202 Current transformer evaluation unit

[0101] 210 Through-hole of the current transformer

[0102] 212 First contact surface of the current transformer, optionally with locking edges

[0103] 214 Second contact surface of the current transformer

Claims

Patent claims 1 . Device (100) for fastening a current transformer (200) to a busbar (300), comprising: a contact surface (122) which is designed to bear against the current transformer (200); at least one contact pin (112) which is designed to transmit a clamping force between the contact surface (122) and the at least one contact pin (112) to the busbar (300) for fastening the current transformer (200) to the busbar (300) and to make electrically conductive contact with the busbar (300); and a signal output (118) which is designed to output a voltage signal which indicates an electrical voltage of the busbar (300) due to the electrical contact of the at least one contact pin (112).

2. Device (100) according to claim 1, wherein the device (100) comprises at least two contact pins (112), and wherein the contact surface (122) is arranged in a longitudinal direction of the busbar (300) between the at least two contact pins (112).

3. Device (100) according to claim 1 or 2, wherein the contact surface (122) is directed in a first transverse direction, and wherein the at least one contact pin (112) is directed in a second transverse direction which is opposite to the first transverse direction, optionally wherein the contact pin (112) or at least one of the contact pins (112) intersects the contact surface (122) in an extension of the first transverse direction.

4. Device (100) according to one of claims 1 to 3, wherein the signal output (118) comprises a socket or a terminal or a free conductor end.

5. Device (100) according to one of claims 1 to 4, wherein the clamping force of the at least one contact pin (112) is adjustable by means of a spindle screw (110), optionally wherein the or each spindle screw (110) is rotatable by means of a hexagon socket (116) or a knurled ring (117).

6. Device (100) according to claim 5, wherein the signal output (118), optionally a socket, is arranged in the or each spindle screw (110) of the device (100), and / or wherein the signal output (118) has a socket coaxial with the spindle screw (110), optionally wherein the hexagon socket (116) is arranged in a socket of the signal output (118).

7. Device (100) according to claim 5 or 6, wherein the or each spindle screw (110) is rotatably arranged in an electrically conductive internally threaded sleeve, and wherein the internally threaded sleeve is electrically conductively connected to the signal output (118).

8. Device (100) according to one of claims 5 to 7, wherein the or each rotatable spindle screw (110) is electrically connected to the signal output (118) via a sliding contact.

9. Device (100) according to claim 7 or 8, wherein a signal line as the signal output (118) is electrically conductively connected to the internally threaded sleeve or the sliding contact, optionally wherein an electrical contact point between the signal line and the internally threaded sleeve is injected into an insulating housing (120) of the device (100).

10. Device (100) according to one of claims 5 to 9, wherein the spindle screw (110) and the hexagon socket (116) or the spindle screw (110) and the socket (118) are electrically conductively and non-rotatably connected to one another via a press fit (115).

11. Device (100) according to one of claims 1 to 10, wherein the device (100) comprises at least two contact pins (112) which are arranged to make electrically conductive contact with the busbar (300) at different points, and wherein a voltage drop between the at least two contact pins (112): feeds an evaluation unit (202) of the current transformer (200); and / or feeds an evaluation unit of the voltage transformer; and / or detects a direct current component in the busbar (300), optionally in addition to an alternating current component in the busbar (300) detected by the current transformer (200); and / or monitors a contact resistance between the at least two contact pins (112) and the busbar (300).

12. System (100, 200) comprising: a device (100) according to one of claims 1 to 11; and a current transformer (200) fastened to a busbar (300) by means of the device (100) for detecting a current through the busbar (300), an evaluation unit (202) which is designed to detect a current signal from the current transformer (200) indicating the current and the voltage signal from the device (100) and to output a power signal which indicates a power and / or a phase position.

13. System (100, 200) according to claim 12, wherein the signal output (118) of the device (100) for the voltage signal comprises an interface between the device (100) and the evaluation unit (202) and / or wherein the signal output (118) for the voltage signal comprises a socket arranged in a housing of the evaluation unit (202).

14. A method for measuring electrical power provided by a busbar (300), comprising: Fastening a current transformer (200) to a busbar (300) extending through a through-hole (210) of the current transformer (200), wherein the at least one contact pin (112) of the device (100) according to one of claims 1 to 11 electrically conductively contacts a first side of the busbar (300) and transmits a clamping force, the contact surface (122) of the device (100) bears against a first contact surface (212) on the inside of the through-hole (210) of the current transformer (200), and a second side of the busbar (300) bears against a second contact surface (214) opposite the first contact surface (212) on the inside of the through-hole (210) of the current transformer (200); and Detecting a current of the busbar (300) by means of the current transformer (200) and a voltage of the busbar (300) by means of the at least one Contact pin (112) for measuring the electrical power provided by the busbar (300).

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