Electric protection device comprising a measuring module

Abstract

The invention relates to an electric protection device (10), in particular in the form of a fuse strip, comprising at least one receiving chamber (12) for a fuse (13) which has at least one fuse blade (14a, 14b), in particular two fuse blades, for electrically contacting at least one electric contact (15a, 15b) of the electric protection device (10), said at least one electric contact being installed in a fixed manner. Each fuse (13) has a window-like opening (17a) which can be closed by means of a closure element (17b), wherein the opening (17a) is arranged such that one of the fuse blades (14a) can be electrically contacted through the opening. The invention is characterized in that a measuring module (18) can be inserted and / or plugged into the opening (17a).

Description

[0001] Electrical protective device with measuring module

[0002] The present invention relates to an electrical protective device, in particular in the form of a fuse strip, with at least one receiving space for a fuse, which has at least one, in particular two, fuse blades for electrically contacting at least one permanently installed contact of the electrical protective device, wherein each fuse is assigned a cover and the cover has a window-like opening which can be closed in particular by means of a closure element, wherein the opening is arranged such that one of the fuse blades can be electrically contacted through it.

[0003] Current measurements in the energy supply sector are usually carried out using current sensors, which are electrical components with which the current strength in cables and busbars is usually measured in a galvanically isolated (non-contact) manner based on the magnetic flux density caused by electrical currents.

[0004] A distinction is made between sensors that can only detect alternating currents and those that can detect both direct and alternating currents.

[0005] AC current sensors are referred to as current transformers in the narrower sense. They usually consist of a toroidal core and are designed like a transformer. The alternating magnetic field of a conductor through which the alternating current to be measured flows induces an alternating current in the measuring coil, which is proportional to the measuring current via the reciprocal ratio of the number of turns. DC current sensors can also detect alternating currents and transient phenomena.

[0006] In particular, the current transformers described above are built accordingly large and are generally difficult to retrofit without removing covers or housing parts of the respective electrical device. For example, such electrical devices, especially in the form of fuse strips in cable distribution cabinets, cannot usually be retrofitted with corresponding current measuring devices during operation.

[0007] Figures 1a and 1b show electrical (current) measuring devices 5 for low-voltage fuse strips 1, previously known from DE 10 2017 011 374, which have electrical fuses for each electrical phase, each of which is arranged behind covers 2. In the embodiment shown in Figure 1a, the electrical measuring device 5 is arranged in a separate housing 6 next to the fuse strip 1, which is connected via electrical lines (not shown) which are brought into contact with the electrical conductors of the fuse strip. In the embodiment shown in Figure 1b, the electrical measuring device 5 is arranged in the housing 4a of the fuse strip 1. A disadvantage of these embodiments is that the fuse strip must first be de-energized before the measuring device can be mounted and connected.

[0008] A protective device of the type mentioned is known, for example, from the European patent application EP 1 058 283 A2 and the German laid-open specification DE 199 13 017 A1.

[0009] Newly constructed low-voltage switchgear systems, whether within electrical power systems or industrial plants, are increasingly being equipped not only with protective devices but also with appropriate measuring technology for recording electrical quantities. These systems are low-voltage switchgear systems equipped with, for example, NH fuse-switch strips or NH fuse-switch disconnectors for selective line protection. These fuses use the so-called low-voltage high-performance (NH) type according to DIN 43620 / 1 (also called "square body fuses"). These fuses have a rectangular cross-section, from which a solid, flat blade contact protrudes on opposite sides. Each blade contact can be inserted into a corresponding receptacle in the base body of the protective device. These fuses are therefore also referred to as fuse links.

[0010] In such systems, there are increasing attempts to integrate measuring technology as a component of the basic unit of a generic protective device. For example, DE 199 13 017 A1 discloses the integration of measuring devices or similar systems in or on the pivoting flaps of such protective devices, each of which carries a fuse link. By pivoting a flap, the fuse link is inserted with its blade contacts into the corresponding receptacles in the base body. The flap thus covers the space in which the NH fuse is located.

[0011] The following section discusses the current state of the art in the recording of electrical quantities within low-voltage switchgear. Typically, the current in the low-voltage outgoing circuits, the voltage on the busbar, or the voltage on the outgoing circuit of the protective devices are recorded. Other quantities (power, energy, etc.) can be derived from these quantities. Furthermore, temperature sensors can be integrated to record the temperature inside a low-voltage switchgear.

[0012] For current measurement, for example, it is known to attach a module to the output terminals of an NH fuse switch-disconnector. This module integrates current transformers and can be connected to the output cables. Such measuring modules are described in European patent application EP 2 259 284 A2 for NH fuse switch-disconnectors and in German patent application DE 10 2011 052 499 A1 for NH fuse switch-disconnectors.

[0013] In addition, there are so-called transformer-operated fuse-switch disconnectors for NH strip-type fuse-switch disconnectors. A transformer-operated fuse-switch disconnector differs from typical NH strip-type fuse-switch disconnectors in that it incorporates a current transformer. For example, DE 10 2007 051 419 A1 discloses a NH strip-type fuse-switch disconnector in which a current transformer surrounds a connecting element that is attached to the base of the strip on the rear side and connects the blade contact receptacle to the busbar.

[0014] In another variant, current transformers are already integrated during production of the strip, by designing the strip in such a way that a current transformer can be plugged around the blade contact receptacles, as described in the application EP 2 546 856 A1.

[0015] There are also special NH fuse links whose body, which includes the fusible element, has a lower overall height than the NH fuse links designed according to DIN 43620 / 1. Due to this lower overall height of the body, there is sufficient space in the lower part of the NH fuse switch to mount a special current transformer, adapted for this application, onto the blade contact of the fuse. This current transformer itself has a grip tab and thus forms a current transformer fuse combination with the dimensions of DIN 43620 / 1. This is disclosed, for example, in DE 199 13 017 A1.

[0016] For voltage measurement, for example, it is known to use voltage taps on the blade contact receptacles. Patent application EP 1 058 283 A2 offers a solution for detecting and monitoring voltage within low-voltage switchgear. This involves both a voltage measurement and a differential voltage measurement via the NH fuse links within an NH fuse switch-disconnector in such a way that the voltage taps within the strip are made directly at the receptacles (contact tongues) for the blade contacts of the fuses.

[0017] The measuring cables are then routed through the lower section of the strip (base body) to a monitoring system, which is mounted directly on the strip. Temperature measurement can also be carried out by simply integrating temperature sensors within the housing of the low-voltage switchgear. By distributing various temperature sensors, the temperature of individual areas can also be recorded in a differentiated manner. In addition to the sensors (current transformers, temperature sensors, voltage taps), another element of measuring electronics within a low-voltage distribution system is the measured value conversion and processing. Currently, this is usually carried out by a central device outside the protective device, with all connections from the sensors to the external central device being realized by appropriately long cables.In the European patent application EP 1 058 283 A2, the measuring lines are connected to a monitoring unit that is mounted above an NH fuse switch-disconnector.

[0018] In detail, all of the solutions presented offer adequate approaches for measuring the respective physical quantity, while already taking into account a small footprint and reduced wiring requirements. However, none of the solutions offers a simple and cost-effective retrofit option or the optional option of incorporating a measuring device into corresponding fuse blocks.

[0019] Furthermore, fuse strips are previously known, as shown by way of example in Figure 2, in which the covers 17 of the fuses 13 each have openings 17a, which can each be opened and closed by means of a closure means 17b, usually in the form of a lid slidably mounted on the cover, and which are often referred to as "construction site power openings." These openings 17b serve to insert contact terminals (not shown) into the open openings 17b, which are electrically connected to the blades of the fuses 13 located below the respective opening 17b. The contact terminals are electrically connected to electrical cables, thus enabling power to be tapped off during operation of the fuse strip.The fuses 13 each have fuse blades 14a, 14b, which contact electrical contacts 15a, 15b fixedly arranged in the fuse strip 10 as soon as the fuse 13 is inserted into the fuse strip 10 by means of the pivotably mounted covers 17. The fuses 13 are arranged one behind the other in the longitudinal direction of the fuse strip 10 and are connected to the outputs and busbars of the fuse strip 10 via the electrical contacts 15a, 15b. The object of the present invention is to provide a simple way of retrofitting or equipping an electrical protective device according to the invention, in particular in the form of a described fuse strip, with a current measuring device.

[0020] This object is achieved according to the invention with an electrical protective device according to claim 1 and by means of an electrical measuring module according to claim 6. Advantageous embodiments of both the electrical protective device and the electrical measuring module are disclosed in the respective dependent claims.

[0021] The invention is based on the idea of ​​using the so-called "construction site current opening" or other existing openings in the cover to determine at least one physical quantity through them using a measuring module. The measuring module according to the invention can also be pushed onto an exposed fuse blade. As a rule, the measuring module according to the invention will at least be designed to determine the electrical current flowing through the associated fuse. This can be done using a Hall sensor or a current transformer, which is a component of the measuring module.

[0022] The measuring module is advantageously designed in such a way that no separate fastening devices are required to attach it to the electrical protective device. It is therefore particularly advantageous if the measuring module is secured to the protective device after installation, for example, by means of a snap-in connection or form-fitting.

[0023] The measuring module is advantageously small and compact, so that it fits into the installation space of the electrical protective device itself, so that no further modifications to the protective device are required.

[0024] The measuring module can comprise a wide variety of sensors for detecting multiple physical variables. For example, a Hall sensor, current transformer, position sensor, temperature sensor, acceleration sensor, humidity sensor, and / or pressure sensor can be provided as sensors. Advantageously, the measuring module according to the invention measures or determines at least the current I flowing through the fuse blade and / or the temperature T in the fuse housing or in the area of ​​the fuse blade.

[0025] As a rule, one measuring module should be provided for each electrical phase.

[0026] It is also possible for the measuring modules to be electrically connected to one another and / or to communicate with one another and / or to communicate with one another in or on the electrical protective device or in a control cabinet in which the electrical protective device is located, or to send their data to this device and / or to be electrically connected to this device. If they are electrically connected to one another, a common power tap can also be made via the phases of the electrical protective device, thus supplying the measuring modules with power. The measuring modules can also have energy storage devices, which enable them to function even when no current is flowing through the protective device. The energy storage devices can also be of a rechargeable type.

[0027] The measuring module according to the invention advantageously comprises a data processing unit that processes the signal from the at least one sensor. Optionally, the measuring module can also comprise a memory, which can be arranged in particular in the data processing unit, for storing the acquired measurement data.

[0028] Furthermore, it is advantageous if the measuring module has a communication interface, in particular in the form of a radio module, via which the measuring module communicates with a further data processing unit arranged remotely from the measuring module or transmits the determined data to this unit.

[0029] This additional data processing unit can be arranged or integrated on or in the electrical protective device or in a control cabinet in which the electrical protective device is arranged.

[0030] Advantageously, the measuring module can have means, in particular an electrical contact, for tapping power from the fuse blade. For example, two phases of a three-phase network can be used for a voltage tap for the power supply. In this case, an electrical connection would have to be provided between at least two measuring modules. If the measuring module is designed as a current transformer, it does not require a galvanic contact for tapping power.

[0031] The measuring module advantageously has a housing which is designed in such a way that it closes the opening in the mounted state alone or together with the closure element, so that the necessary protection against contact and contamination is provided.

[0032] The measuring module according to the invention can have at least one leg extending in the direction of the fuse blade, which is attached to or in the housing of the measuring module. A Hall sensor, for example, can be arranged on this leg, which is located in the immediate vicinity of or next to the fuse blade when the measuring module is inserted or installed.

[0033] The at least one leg can be formed from one or more parts, in particular two parts, with one leg part being pivotably attached to the other, for example. However, it is also possible for the leg(s) to be formed from a spring-elastic material and / or pivotably mounted on the housing of the measuring module.

[0034] It is advantageous if the legs of the measuring module are designed according to the sensor used, and their material selection is also adapted to the measurement method used. In particular, insulation and / or spacing between the leg(s) and the fuse blade may be provided if necessary. In particular, the leg can also be made of an electrically and / or magnetically conductive material, which can optionally also be coated with a plastic, at least in some areas. In addition, electrical connecting lines can be provided along one leg, with which the sensor(s) are connected to the data processing unit of the measuring module.

[0035] The measuring module according to the invention can also be designed such that its legs extend along both sides of the fuse blade and encompass it, in particular touching / contacting each other with their free ends and forming a closed loop around the fuse blade, so that the measuring module can form a current transformer.

[0036] The measuring module can also have at least one interface, particularly in the form of a connector, for electrical connection to at least one other measuring module or evaluation electronics. This allows the individual measuring modules to be easily wired together. Of course, it is also possible for each measuring module to be equipped with a connecting cable, with which it can be connected to the other measuring modules and / or an external data processing device.

[0037] If the measuring module has a position sensor, this can also be used to advantageously monitor the switching state of the fuse, since when the fuse is covered, the measuring module also changes its position in the room.

[0038] The invention is explained in more detail below with reference to drawings.

[0039] They show:

[0040] Fig. la: First embodiment of an electrical protective device according to the prior art;

[0041] Fig. 1b: second embodiment of an electrical protective device according to the prior art;

[0042] Fig. 2: third embodiment of an electrical protective device according to the prior art with "construction site current openings" for each fuse;

[0043] Fig. 3: a detail view of Figure 3 without cover but with measuring module according to the invention, which is designed as a current transformer;

[0044] Fig. 4: first possible embodiment of a measuring module according to the invention;

[0045] Fig. 5: a detail of Figure 3 with cover and with the measuring module according to the invention mounted according to Figure 4; Fig. 6: a detail of Figure 3 with cover and with the measuring module according to the invention mounted, which has a Hall sensor for current measurement as a sensor;

[0046] Fig. 7a: Measuring module with Hall sensor for current measurement and electrical contacting of the fuse blade;

[0047] Fig. 7b: Measuring module with Hall sensor and another sensor for measuring another physical quantity.

[0048] Figure 3 shows a detail of Figure 3 without cover 17 but with the measuring module 18 according to the invention, which is designed as a current transformer. The measuring module 18 is shown only as a block module and can actually have a completely different shape and contour. The measuring module 18 has a housing 18a in which, as shown in Figure 4, a data processing unit 23, optionally also with a memory 24, is arranged. Below the housing 18a, the legs 18s extend in the direction of the fuse blade 14b and encompass it with their free ends 18sf, which are connected to one another after the measuring module has been inserted from above into the opening 17a of the cover 17.The legs 18s are pushed apart by the fuse blade 14b and then spring back toward each other so that their free ends touch and the legs 18s together form a loop around the fuse blade 14b, which is necessary to create a current transformer. The measuring module 18 can transmit either the pure measurement signal or already evaluated or converted data to a remotely located data processing and evaluation unit. For this purpose, the measuring module can have a communication unit, in particular, also transmit the data via radio signal.

[0049] It is also possible for the individual measuring modules 18 to be connected to one another and / or to externally arranged evaluation electronics by means of electrical cables, in particular data cables. Figure 5 shows the above-described embodiment with cover 17 and with the mounted measuring module 18 according to the invention as shown in Figure 4, wherein the opening 17a is exposed by the displaced cover 17b.

[0050] Figure 6 shows a further possible embodiment in which the measuring module according to the invention has a Hall sensor as a sensor for current measurement. In principle, only one leg 18s is necessary for this, through which the Hall sensor 20 can be placed in the immediate vicinity of the fuse blade 14b. In contrast to the current transformer variant according to Figure 4, the leg 18s can be shorter. A measuring module 18 with a Hall sensor 20 for current measurement and electrical contacting of the fuse blade 14a is shown in Figure 7a. The Hall sensor is mounted on the left leg 18s.

[0051] 20, whereby the Hall sensor 20 does not come into contact with the fuse blade 14b. This can also be achieved by a plastic coating of the leg (not shown). The second leg 18s', however, is in electrical contact with the fuse blade 14a, so that the measuring module 18 can be supplied with power via this contact.

[0052] Figure 7b shows a measuring module 18 with a Hall sensor 20, which is arranged on the left leg 18s. On the opposite second leg 18s', another sensor 21 is arranged for measuring another physical quantity, such as temperature. The two sensors 20,

[0053] 21 are connected to the data processing unit 23 of the measuring module via the electrical lines 24.

Claims

Patent claims 1. Electrical protective device (10), in particular in the form of a fuse strip, with at least one receiving space (12) for a fuse (13), which has at least one, in particular two, fuse blades (14a, 14b) for electrical contacting at least one permanently installed electrical contact (15a, 15b) of the electrical protective device (10), wherein each fuse (13) is assigned a cover (17) and the cover (17) has a window-like opening (17a), which can be closed, in particular by means of a closing element (17b), wherein the opening (17a) is arranged such that one of the fuse blades (14a) can be electrically contacted through it, characterized in that a measuring module (18) can be inserted and / or plugged into the opening (17a).

2. Electrical protective device (10) according to claim 1, characterized in that a cover (17) is provided in each case, which is in particular designed to be pivotable or slidable.

3. Electrical protective device (10) according to claim 1 or 2, characterized in that the measuring module (18) serves to measure the current (I) flowing through the fuse meter (14a) and / or the temperature (T) in the receiving chamber (12) or of the fuse meter (14a).

4. Electrical protective device (10) according to claim 1, 2 or 3, characterized in that the measuring module (18) is attached or can be attached to the cover (17) by means of a snap-fit ​​connection and / or a positive locking mechanism.

5. Electrical protective device (10) according to one of claims 1 to 4, characterized in that a measuring module (18) is provided for each electrical phase.

6. Electrical protective device (10) according to claim 5, characterized in that the measuring modules (18) are electrically connected to each other are and / or communicate with each other and / or communicate with or send their data to an electrical protective device (10) in or on the electrical protective device (10) or in a control cabinet in which the electrical protective device (10) is arranged and / or are in electrical contact with it. Measuring module (18) for installation, insertion, or placement into the opening (17a) of a cover (17) of the electrical protective device (10) according to one of claims 1 to 6 or for mounting on a fuse tester (14a, 14b) of a fuse (17), characterized in that the measuring module (18) has at least one sensor (20) which serves to measure a physical quantity. Measuring module (18) according to claim 7, characterized in that the sensor (20) serves to determine the magnetic field generated by the current (I) to be measured.A measuring module (18) according to claim 7 or 8, characterized in that the sensor (20) is a Hall sensor, current transformer, temperature sensor, accelerometer, position sensor, humidity sensor, and / or pressure sensor. A measuring module (18) according to any one of claims 7 to 9, characterized in that the measuring module (18) has a data processing unit (23) that processes the signals of the at least one sensor (20). A measuring module (18) according to any one of claims 7 to 10, characterized in that the measuring module (18) has a memory (24), which is arranged in particular in the data processing unit (23), for storing acquired measurement data. A measuring module (18) according to any one of claims 7 to 11, characterized in that the measuring module (18) has a communication interface, in particular in the form of a radio module, via which the measuring module (18) communicates with a further data processing unit (DPU) arranged remotely from the measuring module (18).

13. Measuring module (18) according to claim 12, characterized in that the further data processing unit (DPU) is arranged or integrated on or in the electrical protective device (10) or in a control cabinet in which the electrical protective device (10) is arranged.

14. Measuring module (18) according to one of claims 7 to 13, characterized in that the measuring module (18) has means (21), in particular an electrical contact, for tapping energy from the safety meter (14a).

15. Measuring module (18) according to one of claims 7 to 14, characterized in that the measuring module (18) has an energy storage device (22), in particular in the form of a battery or a rechargeable accumulator.

16. Measuring module (18) according to one of claims 7 to 15, characterized in that the measuring module (18) has a housing (18a) which is designed such that it closes the opening (17a) in the assembled state alone or together with the closing element (17b).

17. Measuring module (18) according to one of claims 7 to 16, characterized in that the measuring module (18) has at least one leg (18s) extending towards the safety knife (14a), which is attached to or in the housing (18a).

18. Measuring module (18) according to claim 17, characterized in that the at least one leg (18s) is formed in one or two parts, is made of a spring-elastic material and / or is pivotably mounted.

19. Measuring module (18) according to claim 17 or 18, characterized in that at least one sensor (20), in particular a Hall sensor, is arranged on at least one leg (18s).

0. Measuring module (18) according to any one of claims 17 to 19, characterized in that an electrical The conductor (24) is arranged or the leg (18s) is made of an electrically conductive material and / or ferromagnetic material and / or the legs have a plastic sheathing.

21. Measuring module (18) according to one of claims 17 to 20, characterized in that the legs (18s) encompass the safety knife (14a) on both sides and touch each other with their free ends (18sf) and form a closed loop around the safety knife (14a).

22. Measuring module (18) according to one of claims 5 to 21, characterized in that a measuring module (18) has at least one interface, in particular in the form of a plug, for electrical connection with at least one further measuring module (18).

23. Measuring module (18) according to one of claims 5 to 22, characterized in that the measuring module (18) can be slid onto the fuse meter (14, 14b) transversely to the current direction, in particular also during operation.

24. Measuring module (18) according to one of claims 5 to 23, characterized in that the measuring module (18) has a housing (18a) which, in the installed or plugged-in state, extends into the opening (17a) and / or which, at least with a part of its housing, lies within the cover (17) or the electrical protective device (10).

25. Measuring module (18) according to one of claims 5 to 23, characterized in that the electrical measuring components and / or the at least one sensor (20) are arranged in the housing (18a).

26. Measuring module (18) according to one of claims 5 to 25, characterized in that the housing of the measuring module (18) seals the opening (17a), wherein at least one seal is arranged between the housing of the measuring module and the cover (17).

27. Measuring module (18) according to one of claims 17 to 26, characterized in that the at least one leg (18s) within the The housing (18a) or part thereof, wherein the sensor (20) is arranged within or in the housing wall of the housing (18a). The measuring module (18) according to one of claims 17 to 27 is characterized in that a circuit board extends into a leg (18s) of the housing (18a), in particular is cast into the housing (18a).

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