Measuring device for use in an electrical switching device

Abstract

Measuring device with a sensor arrangement (5) and with an insulating carrier (7) for use in an electrical switching device (1), wherein the sensor arrangement has at least one sensor (6, 8) for measuring at least one of the parameters current and voltage of an electric current flowing through a current path (2), wherein the insulating carrier (7) has a sleeve (3) made of electrically insulating material, and wherein the sleeve encloses a space suitable for receiving the current path (2) and wherein the sensor arrangement (5) is arranged on an outside of the sleeve, characterized in that a voltmeter (8) is provided as a sensor for measuring the voltage, wherein the voltmeter is arranged on a circuit board (4) surrounding the sleeve (3).

Description

[0001] The invention relates to a measuring device with a sensor arrangement and with an insulating carrier for use in an electrical switching device, wherein the sensor arrangement has at least one sensor for measuring at least one of the parameters current and voltage of an electric current flowing through a current path, and an electrical switching device with at least one current path, wherein a measuring device is provided for each current path.

[0002] To measure energy flow in electrical circuits, currents and voltages in the load circuit are measured. In switching devices, current transformer measuring systems are primarily used to measure currents. To measure voltage, it is tapped from a current path, such as a phase conductor, primary conductor, or switch pole, and routed, for example, via a resistor network to a trip unit for further processing. One method for integrating a voltage tap into a circuit breaker is known from publication EP 2 590 198 A1. This relates to a circuit breaker with a switch housing, an electronic module, and at least one contact for tapping a voltage from a primary conductor. The tapped voltage is reduced using voltage dividers.To avoid unnecessarily routing the high-voltage signal to the electronic module via conductor tracks, wires, adapters, and contacts, which can lead to contamination, high temperatures, potential creepage distances, and interference with the electronics through electrical or electromagnetic effects, it is proposed that an adapter for reducing the tapped voltage of the primary conductor be provided inside the switch housing, with the adapter being located outside the electronic module.

[0003] German publication DE 203 04 461 U1 discloses an electronic measuring device with an integrated current transformer, which has a two-part housing. Each of the two housing parts has a feedthrough that is aligned with each other when assembled. The feedthrough is completely surrounded by continuous inner housing sections. When assembled, these inner housing sections, which are surrounded by guides, support a wound measuring coil and a power supply and control board with a mains transformer and control electronics.

[0004] One object of the invention is to provide a measuring device for use in an electrical switching device in which a current and / or voltage measurement is designed such that both secondary measuring signals are isolated from the primary input signal of the outer conductor.

[0005] The problem is solved by a measuring device according to claim 1, or by an electrical switching device according to claim 11. Preferred embodiments and advantageous further developments are specified in the dependent claims.

[0006] The measuring device according to the invention is intended for use in an electrical switching device and comprises a sensor arrangement, wherein the sensor arrangement includes at least one sensor for measuring at least one of the parameters current and voltage of an electric current flowing through a current path. Preferably, the sensor arrangement includes at least one sensor for measuring each of the parameters current and voltage for each current path of the switching device.

[0007] According to the invention, the measuring device comprises an insulating carrier with a sleeve made of an electrically insulating material, the sleeve enclosing a space suitable for receiving the current path. The sensor arrangement is arranged on the outer surface of the sleeve. The sleeve, in particular, has a shape that can also be described as a pipe section or hollow cylinder, whereby non-circular or non-round cross-sections are conceivable, for example, a rectangular cross-section. The enclosed space extends along a longitudinal direction of the sleeve. To accommodate the current path, the sleeve is open at both ends arranged longitudinally. The sensor arrangement is arranged outside the enclosed space and separated from the current path by the sleeve wall.

[0008] An advantage of the measuring device according to the invention is that the insulating carrier serves both as insulation of the current path from a secondary circuit of the sensor arrangement and as a receptacle for the sensor arrangement. Designing the insulating carrier as a sleeve that accommodates the current path allows for advantageous positioning of the sensor arrangement, both at a short distance from the current path and within a housing of the switching device.

[0009] According to a preferred embodiment, the insulating carrier has a partition made of electrically insulating material, the partition extending radially outwards from the sleeve. In particular, the partition extends in a plane essentially orthogonal to the longitudinal direction of the sleeve. The partition creates two electrically isolated compartments for the sensor arrangement, which advantageously prevent mutual interference between different sensors. This allows, particularly advantageously, a sensor for measuring the voltage in the current path to be positioned on one side of the partition and a sensor for measuring the current on the other side. Furthermore, it is preferred that more than one partition made of electrically insulating material be provided, arranged essentially parallel to each other and spaced apart along the longitudinal direction of the sleeve, in order to create more than two electrically isolated compartments.

[0010] According to the invention, a voltmeter is provided as a sensor for measuring the voltage, wherein the voltmeter is arranged on a circuit board surrounding the sleeve. The circuit board is preferably arranged parallel to the partition. The sensor for measuring the voltage of a current flowing through the current path can thus be designed to be particularly space-saving.

[0011] An advantageous embodiment is achieved by attaching the circuit board to the partition. It is particularly preferred that at least one recess be provided in the circuit board to receive a projection of the partition. This makes attaching the circuit board particularly easy. After the projection of the partition protrudes through the recess in the circuit board, it can be deformed on the side of the circuit board facing away from the partition to achieve a permanent attachment. It is further preferred that a space between the circuit board and the partition is filled with an electrically insulating potting compound. Attaching the circuit board to the partition has the further advantage that, when the potting compound is poured, the pressure of the potting compound prevents the circuit board from shifting away from the partition. It is also particularly preferred that the insulating carrier has a housing, wherein the housing at least partially encloses the sensor assembly.The housing consists, in particular, of an outer housing wall made of an electrically insulating material, wherein the outer housing wall is, for example, radially spaced and arranged parallel to the sleeve. In the case of a cylindrical sleeve, the housing is thus formed, for example, by a coaxially arranged, also cylindrical, outer housing wall with a larger diameter. The partition preferably extends from the sleeve to the housing and most preferably joins them integrally.

[0012] According to a further preferred embodiment, the voltmeter has at least one contact pin arranged on the circuit board for tapping the voltage from the current path. The contact pin preferably includes a spring element. Particularly preferably, the spring element is designed to press a telescopic pin against the current path by means of spring-mechanical preload. Furthermore preferably, the voltmeter has a voltage divider arranged on the circuit board for reducing the voltage tapped from the current path.

[0013] According to a further preferred embodiment, a measuring coil is provided as a sensor for measuring the current, wherein the measuring coil surrounds the sleeve.

[0014] In principle, the measuring device according to the invention can be configured to measure either the current or the voltage. It is further preferred that the sensor arrangement includes both a sensor for measuring the current and a sensor for measuring the voltage of an electric current flowing through the current path. Particularly preferred is the current sensor, in particular a coil, separated from the voltage sensor, especially on the circuit board, by a partition.

[0015] A further aspect of the invention, which solves the problem formulated at the outset, relates to an electrical switching device with at least one current path, wherein, according to the invention, a measuring device as described above is provided for each current path. Preferably, each current path is guided through the sleeve of the insulating carrier of the respective measuring device.

[0016] The invention is explained in more detail below with reference to exemplary embodiments and the accompanying drawings. These descriptions are exemplary and do not limit the general concept of the invention.

[0017] They show Fig. 1a and Fig. 1b two electrical switching devices according to the state of the art; Fig. 2 a view of the opened switching device according to Fig. 1a; Fig. 3 an embodiment of an electrical switching device according to the invention in a partial view, with an embodiment of a measuring device according to the invention, partially in an exploded view; Fig. 4 another view of the measuring device according to the invention Fig. 3; Fig. 5 a detail of the measuring device according to the invention Fig. 3; Fig. 6 an embodiment of a sensor arrangement of the measuring device according to Fig. 3; Fig. 7 the sensor arrangement according to Fig. 6 in another view; Fig. 8 a detail of the sensor arrangement according to Fig. 6; Fig. 9 another embodiment of the sensor arrangement of the measuring device according to Fig. 3; Fig. 10 an insulating support of the measuring device according to Fig. 3 in detail; Fig. 11 a partition wall of an insulating support of the measuring device according to Fig. 3 in detail; Fig. 12 the measuring devices according to the invention Fig. 3 in a sectional view; and Fig. 13 one of the measuring devices according to the invention Fig. 12 in detail in a sectional view.

[0018] The Fig. 1a and Fig. Figure 1b shows two known embodiments of electrical switching devices 1, namely Fig. 1a a three-pole switching device 1 and Fig. 1b a four-pole switching device 1. The features according to the invention are not recognizable in the representation of the switching devices 1.

[0019] The Fig. Figure 2 shows a view of the opened electrical switching device 1 according to Fig. 1a. This representation serves, as the Fig. 1a and Fig. Figure 1b is for illustrative purposes only and does not show an embodiment of the invention. Within the switching device 1, in addition to other components not discussed here, a magnetic release 18 and a converter housing 16 are arranged.

[0020] The Fig. Figure 3 shows an embodiment of an electrical switching device 1 according to the invention, wherein, for the sake of clarity, only the converter housing 16 and a schematic release mechanism 17 of the switching device 1 are shown here. Fig. 1a, Fig. 1b and Fig. Figure 2 serves to illustrate the arrangement of the converter housing 16 in the switching device. The converter housing 16 is shown without a housing cover and accommodates an embodiment of a measuring device according to the invention, which is described in detail below. The electrical switching device 1 according to Fig. The 3 is four-pole, meaning it has four current paths 2, each of which is assigned a measuring device according to the invention. The current path 2 has a cylindrical conductor section 22 and a connection terminal 21 in the form of an L-shaped angled sheet metal attached to its end. The position of the cylindrical conductor section 22 defines a longitudinal direction X. One of the four measuring devices is shown in an exploded view along the longitudinal axis X. The following descriptions refer to this one measuring device but apply equally to the others.

[0021] The measuring device according to the invention comprises a sensor arrangement 5 and an insulating carrier 7. In the illustrated embodiment, the sensor arrangement 5 includes a sensor 6 for measuring a current and a sensor 8 for measuring a voltage of an electric current flowing through the current path 2. According to the invention, the insulating carrier 7 has a sleeve 3 made of electrically insulating material, wherein the sleeve 3 encloses a space suitable for receiving the current path 2. In the illustrated embodiment, the sleeve 3 is designed as a hollow cylinder, since the current path 2 has the cylindrical conductor 22 in the relevant section. According to the invention, the sensor arrangement 5 is arranged on an outer surface of the sleeve 3 and is thus electrically isolated from the current path 2.

[0022] The insulating carrier 7 preferably has a partition 10, also made of electrically insulating material. The partition 10 extends radially outwards from the sleeve 3. The current sensor 6 is electrically isolated from the voltage sensor 8 by the partition 10. A voltmeter 8 is provided as the voltage sensor 8, which is arranged on a circuit board 4 surrounding the sleeve 3. Furthermore, a voltage divider (not shown here) is arranged on the circuit board 4 to reduce the voltage tapped from the current path 2 to a level suitable for evaluation electronics. The voltage divider on the circuit board 4 will be discussed later in connection with Fig. 6 still described. These are embodiments of the magnetic release 18 (see. Fig. 2) known, which have an internal voltage divider. In this case, for example, the circuit board 4 is omitted and the voltage tap is made, for example, at another suitable location. A space between the circuit board 4 and the partition 10 is filled with an electrically insulating potting compound 15. A measuring coil 6 or so-called Rogowski coil 6 is provided as a sensor 6 for measuring the current, wherein the measuring coil 6 surrounds the sleeve 3. Furthermore, as in the illustrated embodiment, a harvester coil 25 can be arranged on the sleeve 3, wherein an insulating washer 26 is arranged between the measuring coil 6 and the harvester coil 25. The insulating carrier 7 has a housing 14 that at least partially encloses the sensor arrangement 5. Details of the measuring device according to the invention are explained below with reference to the further figures.

[0023] In the Fig. 4 is another view of the measuring device according to the invention. Fig. 3 shown here. Fig. Figure 3 shows an exploded view of the measuring device in a fully assembled state, with the exception of the potting compound 15. A contact spring arrangement 20 of the transducer housing 16, which is in Fig. 3, which is not shown for the sake of clarity, is, for example, screwed onto the converter housing 16 and serves to receive measurement signals from the measuring devices.

[0024] In the Fig. 5 is a detail of the measuring device according to the invention. Fig. Figure 3 shows the partition 10 arranged on the sleeve 3 and the circuit board 4 of the voltage meter 8, which is not yet mounted. The circuit board 4 has a connecting lead 19, via which a measurement signal is transmitted to a contact of the contact spring assembly 20. Preferably, the circuit board 4 is attached to the partition 10. For this purpose, two recesses 12 are provided in the circuit board 4, each of which receives a projection 11 of the partition 10. By deforming the projections 11, the circuit board 4 is permanently fixed in position on the partition 10 and can thus be advantageously secured, for example, during the filling of the potting compound 15 ( Fig. 4) not be moved.

[0025] The Fig. Figure 6 shows the circuit board 4 alone and thus one embodiment of the sensor arrangement 5 of the measuring device, since the measuring device according to the invention can also have a sensor arrangement 5 with only one sensor 8, here the voltmeter 8, which is explained in more detail below. The voltmeter 8 has a voltage divider 9 arranged on the circuit board 4 for reducing a tapped voltage of the current path 2 (see Figure 6). Fig. 3) The reduced voltage is transmitted via the connecting line 19 as a measuring signal to a contact of the contact spring arrangement 20.

[0026] In the Fig. 7 is the sensor arrangement 5 according to Fig. 6 in a further view showing the circuit board 4 from the side which, in the installed state, corresponds to the connection terminal 21 of the current path 2 (cf. Fig. 3) is facing. The voltmeter 8 has a contact pin 23 arranged on the circuit board 4 for tapping the voltage on the current path 2, which is subsequently described with reference to Fig. Section 8 is explained.

[0027] The Fig. Figure 8 shows a detail of the sensor arrangement 5 according to Fig. 7 the contact pin 23 for tapping the voltage on the current track 2, with a non-visible spring element which presses a telescopic pin 24 against the current track 2 by spring-mechanical preload, more precisely, against the section of the L-shaped angled connection terminal 21 of the current track 2 arranged perpendicular to the longitudinal axis X, as well as in connection with the Fig. 12 and Fig. This will be explained in more detail below.

[0028] The Fig. Figure 9 shows another embodiment of the sensor arrangement 5 of the measuring device, which consists of only one sensor 6, here a Rogowski coil 6 for measuring the current flowing through the current path 2. The measuring coil 6 surrounds the current path 2. Advantageously, the measuring coil 6 is arranged on the sleeve 3. Furthermore, the harvester coil 25 is arranged on the sleeve 3, with the insulating washer 26 positioned between the measuring coil 6 and the harvester coil 25. The harvester coil 25 serves to supply power, for example, to the measuring electronics of the switching device 1. The measuring coil 6 and the harvester coil 25 have connecting leads (not shown) which are connected to respective contacts of the contact spring arrangement 20 (see Figure 9). Fig. 4) be connected.

[0029] In the Fig. 10 is the insulating carrier 7 of the measuring device according to the invention. Fig. 3 shown in detail, where the Fig. 10 the insulating carrier 7 with the unmounted sensor assembly 5 according to Fig. Figure 9 shows the insulating support 7 having the sleeve 3 and a housing 14. The partition 10, which is subsequently referred to in relation to Fig. As explained in section 11, this will only be done after the measuring coil 6 and the harvester coil 25 have been installed (see section 11). Fig. 9) used.

[0030] The Fig. Figure 11 shows the partition 10 of the insulating support 7 of the measuring device according to Fig. 3 in detail. A hub 27 of the partition 10 serves to position it on the sleeve 3 of the insulating carrier 7. The partition 10 shown in the exemplary embodiment also has parts 14' of the outer housing 14. Solder pins 28 serve to connect the sensor assembly 5 to the contact spring assembly 20.

[0031] In the Fig. 12 are the four measuring devices of the switching device 1 according to Fig. 3 shown fully assembled in a sectional view. Fig. Figure 13 shows one of the measuring devices according to the invention. Fig. Figure 12 shows the details, also in a sectional view. The current path 2 consists of the cylindrical conductor section 22 and the connection terminal 21 arranged at its end. The sleeve 3 of the insulating carrier 7 surrounds the cylindrical conductor section 22. Outside the insulating carrier 7 is the sensor assembly 5, consisting of the measuring coil 6 for current measurement and the voltmeter 8. The voltmeter 8 has the circuit board 4 with the contact pin 23 for tapping the voltage on the leg of the connection terminal 21 arranged perpendicular to the longitudinal axis X. The circuit board 4 is attached to the partition 10, which electrically isolates the voltmeter 8 from the measuring coil 6 and the harvester coil 25. The circuit board 4 is additionally insulated and fixed with potting compound 15. Reference symbol list 1 Electrical switching device 2. Power line 3 Sleeve 4 circuit boards 5 Sensor arrangement 6 sensors for measuring current, coil, Rogowski coil 7 insulating beams 8. Voltage sensor, voltmeter 9 voltage dividers 10 Partition wall 11 lead 12 Exclusion 14, 14' Housing of the insulating support 15 potting compound 16 converter housings 17 Trigger mechanism 18 magnetic triggers 19 Connection line 20 Contact spring arrangement 21 Connection terminal 22 Cylindrical conductor section 23 Contact pin 24 telescopic pen 25 Harvester spool 26 insulating discs 27 hub 28 solder pins X Longitudinal axis

Claims

[1] Measuring device with a sensor arrangement (5) and with an insulating carrier (7) for use in an electrical switching device (1), wherein the sensor arrangement has at least one sensor (6, 8) for measuring at least one of the parameters current and voltage of an electric current flowing through a current path (2), wherein the insulating carrier (7) has a sleeve (3) made of electrically insulating material, and wherein the sleeve encloses a space suitable for receiving the current path (2) and wherein the sensor arrangement (5) is arranged on an outside of the sleeve, characterized by , that a voltage meter (8) is provided as a sensor for measuring the voltage, wherein the voltage meter is arranged on a circuit board (4) surrounding the sleeve (3). [2] Measuring device according to claim 1, characterized by, that the insulating carrier (7) has a partition (10) made of electrically insulating material, the partition extending radially outwards from the sleeve (3). [3] Measuring device according to claim 2, characterized by , that the circuit board (4) is attached to the partition (10). [4] Measuring device according to claim 3, characterized by , that at least one recess (12) in the circuit board (4) is provided to accommodate a projection (11) of the partition (10). [5] Measuring device according to one of the preceding claims 3 or 4, characterized by , that a space between the circuit board (4) and the partition (10) is filled with an electrically insulating potting compound (15). [6] Measuring device according to any one of the preceding claims 1 to 5, characterized by , that the voltage meter (8) has at least one contact pin (23) arranged on the circuit board (4) for tapping the voltage on the current path (2). [7] Measuring device according to any one of the preceding claims 1 to 6, characterized by , that the voltage meter (8) has a voltage divider (9) arranged on the circuit board (4) for reducing a tapped voltage of the current path (2). [8] Measuring device according to one of the preceding claims, characterized by , that a measuring coil (6) is provided as a sensor for measuring the current strength, wherein the measuring coil surrounds the sleeve (3). [9] Measuring device according to any one of the preceding claims 2 to 8, characterized by , that the sensor arrangement comprises a sensor (6) for measuring the current and a sensor (8) for measuring the voltage of an electric current flowing through the current path (2), wherein the sensor (6) for measuring the current is separated from the sensor (8) for measuring the voltage by the partition (10). [10] Measuring device according to any one of the preceding claims, characterized by, that the insulating carrier (7) has a housing (14) wherein the housing at least partially encloses the sensor arrangement. [11] Electrical switching device (1) with at least one current path (2), characterized by that a measuring device according to one of the preceding claims is provided for each current path. [12] Electrical switching device according to claim 11, characterized by , that each current path (2) is guided through the sleeve (3) of the insulating carrier (7) of the respective measuring device.

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