EP4297055A1 - Measuring module for a switchgear - Google Patents

Abstract

Measuring module (1) for a switching device, in particular for a load disconnector (2), wherein the measuring module (1) has at least one contact piece (3), preferably several contact pieces (3), particularly preferably three contact pieces (3), for at least thermal contacting of at least a switch terminal (4, 5) of the switching device (2), the measuring module (1) further comprising at least one temperature sensor (6) for determining the temperature of the at least one contact piece (3), the measuring module (1) being set up to do this Monitor the temperature of the at least one contact piece (3) and issue an error message if a temperature increase of the at least one contact piece (3) is detected that is greater than or equal to an increase limit or shows a predefined behavior.

Description

FIELD OF THE INVENTION

The present invention relates to a measuring module for a switching device, in particular for a load disconnector.

STATE OF THE ART

Complications always arise with electrical terminal connections, such as those found primarily in switching devices or load disconnectors, especially in low-voltage distributors or switch boxes of low-voltage networks. The main causes are incorrect assembly, such as a screw terminal with incorrect torque or plug-in terminals that are inserted too little, accidents on the device and the resulting damage to the connection, or signs of aging such as corrosion, which can weaken the respective terminal. This can lead to higher contact resistances between the conductor and the terminal, which result in an increase in the temperature at the respective transition, which can even lead to the ignition of the insulating material of the conductor or the terminal. Easily flammable components located nearby are also not excluded. The risk of fire with such faulty connections is very high because they are usually not detected by protective devices such as fuses or circuit breakers.

In preventive maintenance, infrared thermography is used to detect danger spots in electrical connections. With their help, irregularities and problems are identified early before major damage occurs. Thermography is used in switchgear in power plants, in the detection of damaged cable ducts and in the inspection of transformers and control cabinets. A major disadvantage of this method is the accessibility of the clamp connections to be checked. If these are installed in machines or buildings where they are inaccessible, they cannot be recorded using this method. Furthermore, an image from a thermography camera is only a snapshot and only reflects the current stress condition. If, at the time of the test, too little current flows across said increased contact resistance, it will not heat up and be recorded by the camera.

Another measure can be to regularly inspect the clamp connection and also the surrounding area. During these periodic inspections of the electrical systems, gradual increases in resistance can sometimes be detected at an early stage. Discoloration of plastic parts such as insulation material or even deformation can often be seen. However, such visual inspections are complex and therefore expensive and also do not represent ongoing or continuous monitoring.

Said warming can also be perceived through the sense of smell or the visual perception of smoke, but only if it is already sufficiently large. This means that early detection is hardly possible.

OBJECT OF THE INVENTION

The object of the present invention is to provide means which, in order to avoid fires, allow the ongoing control of terminal connections in switching devices or switch-disconnectors and avoid the disadvantages mentioned above.

PRESENTATION OF THE INVENTION

The core of the present invention to solve the stated task is to provide a measuring module for switching devices, in particular switch disconnectors, which continuously monitors the temperature in the area of the terminal connections and can thus detect and report faulty contacts. Specifically, according to the invention, a measuring module is provided for a switching device, in particular for a switch-disconnector, wherein the measuring module has at least one contact piece, preferably several contact pieces, particularly preferably three contact pieces, for at least thermal contacting of at least one switch terminal of the switching device, the measuring module further comprising at least one Temperature sensor for determining the temperature of the at least one contact piece, wherein the measuring module is set up to monitor the temperature of the at least one contact piece and to output an error message if a temperature increase of the at least one contact piece is detected that is greater than or equal to a rise limit value or a shows predefined behavior.

Typically, when contacting the respective contact piece with the respective switch terminal, not only a thermal contact in the sense of a thermally conductive connection is made, but also an electrical contact in the sense of an electrically conductive connection between the contact piece and the switch terminal.

The contacting or at least thermal contacting of the respective switch terminal by the respective contact piece can be done by mechanical contacting, i.e. arranging the respective contact piece on the respective switch terminal. For this purpose, it can be provided, for example, that the respective contact piece is clamped in the respective switch terminal, in particular together with a conductor, which can be, for example, an outer conductor or a further line.

The choice of material for the respective contact piece is such that there is good thermal conductivity and typically also good electrical conductivity. In particular, the respective contact piece can be made of metal, for example copper or a copper alloy.

Preferably, at least one, particularly preferably exactly one, temperature sensor is assigned to each contact piece. Particularly cost-effective embodiment variants would also be conceivable, in which a temperature sensor is assigned to several contact pieces, so that a temperature increase in one or more or all contact pieces can still be reliably detected, but without a clear assignment to a specific contact piece being possible.

The exact arrangement of the respective temperature sensor can vary, although there is clearly an adequate thermal connection to the respective contact piece.

By determining and monitoring the temperature of the respective contact piece using the at least one temperature sensor, the temperature of the respective switch terminal can be determined and monitored if this switch terminal is at least thermally contacted by the respective contact piece.

If a sufficiently large increase in temperature is detected, this is an indication that the quality of the clamping in the respective switch terminal is no longer sufficient. Typically this is due to a loosening of the clamping, e.g. if one or more clamping screws have too little tightening torque, which increases the electrical contact resistance (between a clamped cable and the switch terminal) in the switch clamp. As mentioned at the beginning, signs of aging such as corrosion can of course also be responsible for weakening the clamping or clamping quality.

Specifically, a corresponding error message is issued if the detected temperature increase is greater than a rise limit value. Of course, this increase limit value can be predetermined and, in particular, adjustable by the user.

The increase limit can depend on the type of switching device and/or the currents occurring. For example, in tests with a switch disconnector designed for a rated current of 63 A, it was found that a rise limit in the range of 45°C to 60°C, in particular approximately 50°C, was a reliable indicator of inadequate clamping quality or for a clamping that is too loose. At higher currents above the rated current, higher temperature increases (than with the rated current) occurred with the same inadequate quality of the clamping, so that the clamping that was too loose could also be reliably determined in this case using the increase limit value mentioned.

Testing whether the rise limit value has been exceeded is simple, inexpensive to implement and reliable. Of course it is also possible, not just not to take a simple value of the temperature change or increase in temperature into account, but rather to evaluate the temperature progression over time using a wide variety of algorithms. In particular, it is possible to classify a specific temperature curve over time, which is accompanied by a specific temporal progression or a specific behavior of the temperature increase, as critical or dangerous. For example, applications would be conceivable in which the time course of the temperature increase follows a certain curve or is discontinuous or can even be negative for a short time and then be positive again. In this way, insufficient clamping can be detected particularly reliably at an early stage, depending on the application. Accordingly, algorithms can be stored in the measurement module, which, for example, functionally evaluate, derive, integrate or compare the course of the temperature increase with stored curve shapes.

The error message can be output in a variety of ways. For example, the error message can be displayed by means of an optical functional indicator on the measuring module or on a module housing of the measuring module, with light-emitting diodes, particularly preferably multi-color switchable light-emitting diodes, being suitable for such functional indicators. Alternatively or additionally, it is also possible to provide an acoustic error message, for which appropriate signal generating means, in particular at least one loudspeaker, must then be provided. Furthermore, it is alternatively or additionally possible to transmit the error message via a communication interface to a communication module and by means of the communication module - or alternatively directly - to a user's end device, such as a computer or a mobile phone, so that the user is not in front of it Place needs to be in order to notice the error message.

In principle, of course, it cannot be ruled out that an increase in the ambient temperature occurs, which in turn also results in an increase in the temperature of the at least one contact piece or the respective switch terminal. For example, such a temperature increase can be caused by direct sunlight on a control cabinet or a distribution box, with the switching device and the associated measuring module being arranged in the control cabinet or distribution box. In order to exclude false alarms in such a situation, it is provided in a preferred embodiment of the measuring module according to the invention that the measuring module is set up to determine the temperature increase of the at least one contact piece compared to an ambient temperature and to only output the error message if the temperature increase compared to the ambient temperature is greater than or equal to the increase limit or exhibits a predefined behavior.

It makes sense to determine the ambient temperature in the vicinity of the measuring module or not too far away from the measuring module, otherwise it may happen that the temperature in the area surrounding the measuring module is not actually determined, but in a place where completely different Temperature conditions prevail. In the above-mentioned example of the control cabinet or distribution box that is affected by solar radiation, it would be advisable, for example, to determine the ambient temperature in the control cabinet or in the immediate vicinity of the control cabinet in order to reduce the temperature increase caused by the solar radiation at least to a certain extent at the ambient temperature degree to capture.

In the example mentioned above of increasing the temperature in the control cabinet or distribution box due to solar radiation, all contact pieces or switch terminals in the control cabinet or distribution box are typically larger or less affected by the temperature increase to the same extent. For a particularly simple and cost-effective implementation of a reference or relative measurement to an ambient temperature, the comparison of the temperature increase of one of the contact pieces with the temperature increase of another of the contact pieces of the same measuring module can be used. Accordingly, in a particularly preferred embodiment of the measuring module according to the invention, it is provided that several contact pieces are provided, that several temperature sensors are provided for determining the respective temperature of the contact pieces and that the measuring module is set up to determine the temperature increase of one of the contact pieces compared to the ambient temperature Temperature of at least one other of the contact pieces to be used as the ambient temperature.

In order to be able to record the ambient temperature particularly reliably and thus to make the relative measurement to the ambient temperature particularly safe, it is provided in a particularly preferred embodiment of the measuring module according to the invention that the measuring module comprises a communication interface in order to receive temperature data from outside the measuring module and use it as the ambient temperature can. Ie the ambient temperature is measured at at least one point outside the measurement module in a manner known per se, in particular by means of at least one thermometer and/or by means of at least one temperature sensor, with the at least one measurement result being transmitted to the measurement module by means of the communication interface. This can be a wireless and/or wired data transmission or is the communication interface correspondingly for wireless and/or wired communication in a manner known per se (for example via LAN, WLAN, radio or WPAN or Bluetooth) set up. The measurement module then evaluates the at least one measurement result received as the ambient temperature.

It is also conceivable to carry out several ambient temperature measurements at different local positions, whereby the measurement results can be evaluated by the measuring module, for example in a suitable statistical manner, for example by averaging. This can increase the reliability of the ambient temperature determination. Again, it makes sense that the local positions are not too far away from the measuring module, so that the temperature is actually determined in the area surrounding the measuring module - and not in a completely different location where, for example, completely different solar radiation conditions prevail.

In principle, a wide variety of embodiments of temperature sensors are conceivable. In a preferred embodiment of the measurement module according to the invention, it is provided that the at least one temperature sensor is formed by at least one thermistor, in particular an NTC thermistor. This means that the temperature sensor has an electrical resistance that changes reproducibly depending on the temperature, so that there is generally a high level of reliability.

NTC thermistors have a negative temperature coefficient, meaning they conduct electricity better at high temperatures than at low temperatures. The design of the at least one temperature sensor by at least one NTC thermistor is particularly advantageous in that the function of the temperature sensor is particularly reliable at high or elevated temperatures, so that an error message can then be output particularly reliably in order to reliably indicate an impending danger in a timely manner .

In order to ensure that the at least one temperature sensor functions as undisturbed as possible and that the measurement data thereof is evaluated as accurately as possible, it is advantageous to keep the at least one temperature sensor electrically independent or isolated from the at least one contact piece or from the at least one switch terminal. In a preferred embodiment of the measuring module according to the invention, it is therefore provided that the at least one temperature sensor is in thermal contact with the at least one contact piece and is electrically insulated from the at least one contact piece. Thermal contact is also to be understood here in the sense of a thermally conductive connection, so that a temperature or temperature change of the contact piece can be determined with sufficient accuracy.

In order to realize said electrical insulation on the one hand and said thermal connection on the other hand as space-savingly and economically as possible in terms of production technology, in a particularly preferred embodiment of the measuring module according to the invention it is provided that the at least one temperature sensor is embedded at least in sections in a heat-conducting and electrically insulating material, in particular in a resin or silicone. For production, the material, in particular resin or silicone, can be cast in a liquid state, with the at least one temperature sensor being or will be placed accordingly in the casting compound in order to subsequently be embedded at least in sections in the hardened casting compound.

Materials suitable for this, in particular resins or silicones, are commercially available. For example, corresponding epoxy resins and silicones are available under the Electrolube label (registered trademark).

In order to increase the functionality of the measuring module, it is provided in a preferred embodiment of the measuring module according to the invention that the at least one contact piece is set up for electrically contacting the at least one switch terminal of the switching device and that the measuring module has at least one measuring sensor for detecting at least one of the respective contact pieces and/or the corresponding switch terminal has a measured variable, wherein the at least one measured variable is preferably selected from the group comprising: electrical current, electrical voltage, electrical power, ohmic resistance, energy consumption, power factor, effective factor.

In AC electrical engineering, the power factor λ (lambda), which is also known as the active power factor, is the ratio of the amount of active power P to the apparent power S. The power factor λ can be between 0 and 1. The effective factor can only be defined for sinusoidal alternating variables from the ratio of the active power to the apparent power. The effect factor is equal to the cosine of the phase shift angle ϕ (phi).

Corresponding measuring sensors are known per se and can be easily integrated into the measuring module. At least one measuring sensor can be provided for several contact pieces, in particular for all contact pieces of the measuring module.

The electrical contact not only allows the determination of one or more electrical measured variables, but can also be used to power the measuring module - via at least one switch terminal.

By determining one or more measured variables that can be attributed to the respective contact piece and thus to the respective or corresponding switch terminal, measured variables can ultimately be determined that are relevant to the switching device or the lines that are connected to the switching device on an input side or an output side by clamping in the switch terminals are to be assigned, for example the electrical voltage applied to such a line. Another example of a measurement variable that can be attributed to a switch terminal and thus to a line electrically connected to the switch terminal would be the size of the current that flows through the respective line, whereby the magnetic field generated by the current can be measured without contact to determine the current strength .

In a preferred embodiment of the measuring module according to the invention, it is provided that for the electrical connection of the at least one contact piece to electronic components on a circuit board of the measuring module, at least one spring contact is provided, which contacts the respective contact piece, wherein the at least one spring contact is preferably designed as a surface-mounted component. The electronic components are known components such as integrated circuits, coils, capacitors, ohmic resistors, diodes, transistors and the like. Surface-mounted components are also known under the abbreviation SMD (surface-mounted devices) and, among other things, allow a particularly space-saving design.

This structure can be used in particular to power and operate the at least one temperature sensor and to evaluate the data generated by the at least one temperature sensor.

In addition, the operation of the above-mentioned measuring sensors or the evaluation of measurement data that were generated with these measuring sensors can also be realized using such a structure with electronic components.

Finally, the at least one spring contact can also serve or contribute to the thermal connection between the at least one temperature sensor and the at least one contact piece.

For example, it can be provided that not only the at least one temperature sensor, but also the at least one spring contact is embedded at least in sections in the heat-conducting and electrically insulating material. In this case, heat conduction is possible from the respective contact piece via the respective spring contact and the heat-conducting, electrically insulating material to the respective temperature sensor. As already mentioned, it can be provided that when using the measuring module, the at least one contact piece is also clamped in at least one switch terminal of the switching device with one or more conductors, for the clamping of which the respective switch terminal is provided. Accordingly, in a preferred embodiment of the measuring module according to the invention, it is provided that the at least one contact piece is geometrically designed so that it can be clamped in the at least one switch terminal of the switching device. This means that the contact piece or pieces can be geometrically matched to the switch terminals of the switching device. By clamping the contact pieces, a detachable mechanical connection can also be established between the measuring module and the switching device.

As already mentioned, a communication module can be provided for data transmission between the measurement module and a terminal and vice versa. It is also conceivable that several measurement modules can communicate via the same communication module or via several communication modules. Accordingly, according to the invention, a measuring device is provided, the measuring device comprising at least one measuring module according to the invention and at least one communication module, which uses signaling technology by at least a, in particular wireless, communication channel can be coupled to the at least one measurement module in order to be able to exchange data mutually, the at least one communication module preferably having a communication interface for communication with a network and / or a user's terminal.

As mentioned, the data to be exchanged can in particular be the measurement data of the respective measurement module. On the other hand, setting data can also be transmitted to the respective measuring module, for example to change or specify the increase limit value or to change or specify the predefined behavior of the temperature increase.

The network can be, for example, a LAN or WLAN or a mobile network or telephone network, in which case a connection to the Internet can in particular be provided. Accordingly, a user can communicate remotely with the respective measurement module via the communication module. Furthermore, it is of course conceivable that at least one further or higher-level system, for example an automation system, is addressed via the network and, for example, starts predefined processes (such as evaluation algorithms and/or power shutdowns and/or notification of certain locations or people) automatically when it Data, measurement results or at least an error message can be communicated via the network.

As already described, a relative measurement to the ambient temperature can be provided in order to exclude false error messages. In a preferred embodiment of the measuring device according to the invention, it is correspondingly provided that the at least one communication module has at least one temperature sensor for determining an ambient temperature and in addition is set up to transmit the ambient temperature to the at least one measuring module, and that the respective measuring module is set up to determine the temperature increase of the at least one contact piece compared to the ambient temperature and to only output the error message if the temperature increase compared to the ambient temperature is greater than or equal to the increase limit or shows a predefined behavior. By determining the ambient temperature outside the respective measuring module, a high level of reliability can be achieved.

Furthermore, as already mentioned, it is conceivable that several measurement modules communicate with the same communication module. In this case, a cost-effective determination of the ambient temperature for all of these measuring modules can be carried out by providing the communication module once.

Analogous to what was said above, a system is provided according to the invention, the system comprising at least one measuring module according to the invention or a measuring device according to the invention and at least one switching device, wherein preferably the at least one measuring module can be detachably connected to the at least one switching device.

The switching device can in particular be designed as a load disconnector.

Furthermore, it is conceivable that the at least one measuring module or at least essential parts of the at least one measuring module can also be integrated in the switching device, such as measuring sensors and evaluation and communication electronics. Likewise, contact pieces in the sense of means for thermally contacting the at least one switch terminal can also be provided in the switching device.

The switching device or the switch-disconnector typically comprises a switch housing and at least one input-side switch terminal (hereinafter also referred to as “input side”) and at least one output-side switch terminal (hereinafter also referred to as “output side”), the switching device being set up to provide an electrical connection between the at least one input-side switch terminal and the at least one output-side switch terminal can be switched on or off.

The at least one input-side switch terminal can be provided, for example, for establishing an electrical connection with at least one outer conductor, so that in this case the respective input-side switch terminal could also be referred to as a phase terminal, the term phase being used colloquially for external conductors. The at least one output-side switch terminal can be provided, for example, to establish an electrical connection with at least one further electrical line.

In order to realize a compact arrangement in particular, analogous to what was said above, in a preferred embodiment of the system according to the invention it is provided that for the detachable connection the at least one contact piece of the at least one measuring module is in at least one input-side switch terminal of the at least one switching device and/or in at least one The output-side switch terminal of the at least one switching device is also clamped and contacts it both thermally and electrically.

This means that cases are conceivable where both a measuring module is arranged or clamped on the switch terminals on the input side and a measuring module on the switch terminals on the output side. As already described above, the electrical contacting can serve to supply power to the respective measuring module, but possibly also to determine the measured variables to be assigned to the switch terminals. The Thermal contacting allows the temperature in the area of the contact pieces and thus the clamping quality to be controlled both on the input side and on the output side.

In order to maximize the compactness of the arrangement, in a preferred embodiment of the system according to the invention it is provided that the respective measuring module has a module housing which is geometrically designed in such a way that the module housing of the respective measuring module connects essentially flush to a housing of the respective switching device, if the respective measuring module is detachably connected to the respective switching device. Particularly when arranged in distribution boxes, such as those used in low-voltage networks, such a design is advantageous in terms of making good use of the relatively limited space. In addition, the flush connection increases safety for the user, as they can no longer touch the contact pieces that may be under voltage. Ultimately, the flush connection results in an elegant, high-quality, uniform appearance, which, among other things, increases user acceptance.

BRIEF DESCRIPTION OF THE FIGURES

The invention will now be explained in more detail using an exemplary embodiment. The drawings are exemplary and are intended to explain the idea of the invention, but are in no way intended to restrict or even exhaustively represent it.

Fig. 1

ein erfindungsgemäßes System mit einer erfindungsgemäßen Messeinrichtung, die ein erfindungsgemäßes Messmodul umfasst, und einem Lasttrennschalter in einer schematischen Darstellung

Fig. 2

das Messmodul aus Fig. 1 in geöffneter Anordnung ohne Abdeckungsdeckel in einer axonometrischen Darstellung, wobei aus Klarheitsgründen Kontaktstücke nicht dargestellt sind

Fig. 3

eine Darstellung wie Fig. 2, wobei die Kontaktstücke dargestellt sind

This shows:

Fig. 1

a system according to the invention with a measuring device according to the invention, which includes a measuring module according to the invention, and a load disconnector in a schematic representation

Fig. 2

the measuring module Fig. 1 in an open arrangement without a cover lid in an axonometric representation, with contact pieces not being shown for reasons of clarity

Fig. 3

a representation like Fig. 2 , with the contact pieces shown

WAYS OF CARRYING OUT THE INVENTION

Fig. 1 shows a schematic representation of an embodiment of a system 200 according to the invention comprising a measuring device 100 according to the invention (in Fig. 1 indicated by the dashed rectangle) and a switching device in the form of a switch-disconnector 2. In the exemplary embodiment shown, the measuring device 100 consists of a measuring module 1 according to the invention and a communication module 8, which transmit signals by means of a wireless communication channel 9 (in Fig. 1 indicated by the dotted double arrow) and corresponding communication interfaces (not shown) for the communication channel 9 are coupled in order to be able to exchange data mutually, the communication module 8 further having a communication interface (not shown) for communication with a network and / or a user's terminal having.

In the exemplary embodiment shown, the switch disconnector 2 has a switch disconnector housing 11 as well as three switch terminals 4 on the input side and three switch terminals 5 on the output side, the switch disconnector being set up to selectively switch on or off an electrical connection between the switch terminals 4 on the input side and the switch terminals 5 on the output side.

In the exemplary embodiment shown, the measuring module 1 has a module housing 10 as well as three contact pieces 3 made of metal and three optical functional indicators 13 arranged in the module housing 10, which are assigned to the contact pieces 3, the functional indicators 13 preferably being formed by light-emitting diodes. The contact pieces 3 are geometrically designed so that they can be clamped both in the switch terminals 4 on the input side and in the switch terminals 5 on the output side. In Fig. 1 In this context, the insertion of the contact pieces 3 into the switch terminals 5 on the output side is indicated by the arrow pointing from the measuring module 1 to the switch disconnector 2. By clamping the contact pieces 3 in the output-side switch terminals 5, a detachable connection is established between the measuring module 1 and the switch-disconnector 2, with the contact pieces 3 making both thermal and electrical contact with the output-side switch terminals 5. The module housing 10 and the switch disconnector housing 11 are geometrically designed so that the module housing 10 is essentially flush with the switch disconnector housing 11 when the module housing 10 and the switch disconnector housing 11 are detachably connected to one another, with the contact pieces 3 correspondingly far into the switch terminals 5 on the output side - or alternatively in the switch terminals 4 on the input side - are inserted or inserted. This results in a very compact arrangement of measuring module 1 and switch disconnector 2.

The measuring module 1 is in an open arrangement without a cover lid in an axonometric view with a view of an underside or the side on which the contact pieces 3 are arranged Fig. 2 and Fig. 3 shown. In the operating state of the measuring module 1, the module housing 10 is closed with the cover lid (not shown).

In Fig. 2 For reasons of clarity, the contact pieces 3 are not shown, so that here three temperature sensors, which are formed by three thermistors 6, can be seen particularly well for determining the temperature of the respective contact piece 3. That is, in the exemplary embodiment shown, each contact piece 3 is assigned its own temperature sensor or thermistor 6, and the temperature of each contact piece 3 can therefore be measured individually.

In the exemplary embodiment shown, the thermistors 6 are NTC thermistors, i.e. thermistors with a negative temperature coefficient.

The measuring module 1 is set up to monitor the temperature of the respective contact piece 3 and to output an error message if a temperature increase of the respective contact piece 3 is detected that is greater than or equal to an increase limit value or shows a predefined behavior.

The error message indicates an insufficient clamping quality in the respective switch terminal 4, 5 contacted by the respective contact piece 3, with the in Fig. 1 illustrated arrangement of the measuring module 1 on the input side or on the input-side switch terminals 4, a lack of clamping quality is detected in the respective input-side switch terminal 4. In the exemplary embodiment shown, both the input-side switch terminals 4 and the output-side switch terminals 5 are actuated via screws 18. Accordingly, insufficient clamping quality is typically caused by too low a tightening torque of the screw 18 of the respective switch terminals 4, 5. This in turn has an increased contact resistance in the respective switch terminal 4, 5 between this and a line 19 clamped therein (for reasons of clarity only for one of the Switch terminals 4, 5 indicated by a dash-dotted line), which results in a corresponding heating when current flows and thus to the measured temperature increase of the contact piece 3 clamped in the relevant switch terminal 4, 5.

The application of a wide variety of algorithms to the measured temperature or temperature increase data to check whether the temperature increase shows a predefined behavior is of course also possible in principle in the exemplary embodiment shown, but in the exemplary embodiment shown, due to the simplicity, the said comparison with the increase limit value is primarily made. The rise limit is predefined as 50°C, although the rise limit can also be changed by the user and adjusted as required. The adaptation can be carried out conveniently for the user via a terminal device, in particular via a mobile phone or a computer of the user, for example using an app or web browser-based application, in that the terminal device communicates with the measurement module 1, for example via the Internet and the communication module 8 .can exchange data.

In the exemplary embodiment shown, the error message is output on the one hand via the functional indicator 13 that is assigned to the respective contact piece 3. This means that the functional indicator 13 that is assigned to the contact piece 3, in which the excessive temperature increase was detected, gives an optical signal. Accordingly, a user can see at a glance where an error has occurred. Furthermore, in the exemplary embodiment shown, the corresponding error message is forwarded to the communication module 8 via the communication channel 9 and sent to the user's terminal device via the communication module 8, so that the user does not need to be on site to be informed about the error.

In order to exclude a false alarm due to heating that is due to an increase in the ambient temperature - for example due to particularly strong local solar radiation - a reference measurement is provided in the exemplary embodiment shown, the measuring module 1 being set up to measure the temperature increase of the respective contact piece 3 compared to the Determine the ambient temperature and only output the error message if the temperature increase compared to the ambient temperature is greater than or equal to the increase limit or shows a predefined behavior. The reference measurement or ambient temperature measurement takes place outside the measurement module 1 by means of the communication module 8. For example, the measurement module 1 can be arranged together with the switch disconnector 2 in a distribution box (not shown), and the communication module 8 can also be in the distribution box or outside the distribution box in its Be arranged close in order to actually be able to determine the temperature in the immediate vicinity of the measuring module 1 as the ambient temperature.

In the exemplary embodiment shown, the communication module 8 accordingly has a temperature sensor for measuring the ambient temperature (not shown). These measurement data can be sent from the communication module 8 to the measurement module 1 and received by it, via the communication channel 9 or the associated communication interfaces.

If measurement data from outside the measurement module 1 for the ambient temperature - be it via the communication module 8 or via at least another separate ambient temperature sensor - are not available, the measurement module 1 of the exemplary embodiment shown is set up to determine the temperature increase of one of the contact pieces 3 compared to the ambient temperature Temperature of at least one other of the contact pieces 3 to be used as the ambient temperature. Ie the reference measurement in this case is carried out by comparing the temperatures of at least two different contact pieces 3.

In the exemplary embodiment shown, the thermistors 6 are in thermal, but not electrical, contact with the associated contact pieces 3 in order to ensure trouble-free measurement of the temperature of the contact pieces 3. For this purpose, the thermistors 6 are each embedded or cast in a heat-conducting and electrically insulating epoxy resin 15, cf. Fig. 2 .

In principle, it would be conceivable that the epoxy resin 15 is contacted by the respective contact piece 3 at least in sections. Specifically, the contact pieces 3 are designed with an L-shaped cross section, cf. Fig. 3 . Accordingly, it would be conceivable for an L-shaped leg to rest flat on the epoxy resin 15 at least in sections. In any case, the other leg is intended for arrangement in the respective switch terminal 4, 5.

In the exemplary embodiment shown, the contact pieces 3 are designed not only for thermal contacting, but also for electrical contacting of the switch terminals 4, 5. As a result, the power supply of the measuring module 1, in particular an evaluation electronics of the measuring module 1 with electronic components 17 arranged on a circuit board 16, can be guaranteed via the switch terminals 4, 5. In order to provide the necessary electrical connection between the contact pieces 3 and the electronic components 17, spring contacts 12 which make contact with the contact pieces 3 are provided, cf. Fig. 2 , which in turn are electrically connected to the circuit board 16 or via this to the electronic components 17. Each contact piece 3 is assigned exactly one spring contact 12, with the spring contacts 12 as surface-mounted components are carried out on the circuit board 16.

Furthermore, in the exemplary embodiment shown, the spring contacts 12 are also embedded or cast in sections in the heat-conducting, electrically insulating material, ie in the epoxy resin 15, cf. Fig. 2 . As a result, the thermal contact between the temperature sensors or thermistors 6 and the contact pieces 3 is closed, ie the thermal connection exists via the spring contacts 12 contacted by the contact pieces 3 and the epoxy resin 15, without the contact pieces 3 making contact with the epoxy resin 15 at least in sections.

Furthermore, in the exemplary embodiment shown, the measuring module 1 has three current sensors 7, which are assigned to the three contact pieces 3. By means of the respective current sensor 7, the measured variable current strength to be attributed to the respective contact piece 3 or the respective switch terminal 4, 5 can be determined, the current passing through the line 19 clamped in the respective switch terminal 4, 5 (for reasons of clarity, only such a line is through one indicated by a dash-dotted line) - and thus also flows via the respective switch terminal 4, 5. The current measurement is carried out without contact, with the respective line 19 being guided through the corresponding current sensor 7 and the current sensor 7 measuring the magnetic field generated by the current in a manner known per se, preferably by means of at least one Hall sensor (not shown), from which the current strength in turn results.

The measurement results can be transmitted via the communication module 8 to the user's terminal and/or via the network, for example to a higher-level automation system. Furthermore, it is conceivable that the functional indicators 13 provide an optical signal, for example a specific color. display if the measured current value is below or above a user-configurable threshold value stored in measuring module 1. The parameterization can in turn be carried out by the user using his terminal device via the communication module 8 in the measuring module 1.

REFERENCE SYMBOL LIST

1

Measuring module

2

Switch disconnector

3

contact piece

4

Input side switch terminal

5

Output side switch terminal

6

thermistor

7

Current sensor

8th

Communication module

9

Communication channel

10

Module housing

11

Switch disconnector housing

12

Spring contact

13

Function indicator

15

Epoxy resin

16

Circuit board

17

Electronic component

18

screw

19

Line

100

Measuring device

200

system

Claims (15)

Measuring module (1) for a switching device, in particular for a load disconnector (2), wherein the measuring module (1) has at least one contact piece (3), preferably several contact pieces (3), particularly preferably three contact pieces (3), for at least thermal contacting of at least a switch terminal (4, 5) of the switching device (2), the measuring module (1) further comprising at least one temperature sensor (6) for determining the temperature of the at least one contact piece (3), the measuring module (1) being set up to: Monitor the temperature of the at least one contact piece (3) and issue an error message if a temperature increase of the at least one contact piece (3) is detected that is greater than or equal to an increase limit or shows a predefined behavior. Measuring module (1) according to claim 1, characterized in that the measuring module (1) is set up to determine the temperature increase of the at least one contact piece (3) compared to an ambient temperature and to output the error message only if the temperature increase compared to the ambient temperature is greater or is greater than or equal to the increase limit or shows a predefined behavior. Measuring module (1) according to claim 2, characterized in that a plurality of contact pieces (3) are provided, that a plurality of temperature sensors (6) are provided for determining the respective temperature of the contact pieces (3) and that the measuring module (1) is set up to Determination of the temperature increase of one of the contact pieces (3) compared to the ambient temperature, the temperature of to use at least one other of the contact pieces (3) as the ambient temperature. Measuring module (1) according to one of claims 2 to 3, characterized in that the measuring module (1) comprises a communication interface in order to be able to receive temperature data from outside the measuring module (1) and use it as ambient temperature. Measuring module according to one of claims 1 to 4, characterized in that the at least one temperature sensor is formed by at least one thermistor (6), in particular an NTC thermistor. Measuring module according to one of claims 1 to 5, characterized in that the at least one temperature sensor (6) is in thermal contact with the at least one contact piece (3) and is electrically insulated from the at least one contact piece (3). Measuring module (1) according to claim 6, characterized in that the at least one temperature sensor (6) is embedded at least in sections in a heat-conducting and electrically insulating material (15), in particular in a resin or silicone. Measuring module (1) according to one of claims 1 to 7, characterized in that the at least one contact piece (3) is set up for electrically contacting the at least one switch terminal (4, 5) of the switching device (2) and that the measuring module (1) at least a measuring sensor (7) for detecting at least one measured variable to be assigned to the respective contact piece (3) and/or the corresponding switch terminal (4, 5), the at least one measured variable being preferably selected from the group comprising: electrical current intensity, electrical voltage, electrical power, ohmic resistance, energy consumption, power factor, effective factor. Measuring module (1) according to one of claims 1 to 8, characterized in that at least one spring contact (12) is provided for the electrical connection of the at least one contact piece (3) to electronic components (17) on a circuit board (16) of the measuring module (1). is which contacts the respective contact piece (3), the at least one spring contact (12) preferably being designed as a surface-mounted component. Measuring module (1) according to one of claims 1 to 9, characterized in that the at least one contact piece (3) is geometrically designed so that it can be clamped in the at least one switch terminal (4, 5) of the switching device (2). Measuring device (100) comprising at least one measuring module (1) according to one of claims 1 to 10 and at least one communication module (8), which can be coupled to the at least one measuring module (1) in terms of signaling by means of at least one, in particular wireless, communication channel (9), in order to be able to exchange data mutually, the at least one communication module (8) preferably having a communication interface for communication with a network and/or a user's terminal. Measuring device (100) according to claim 11, characterized in that the at least one communication module (8) has at least one temperature sensor for determining an ambient temperature and is set up to transmit the ambient temperature to the at least one measuring module (1), and that the respective measuring module (1) is designed to increase the temperature of the at least one contact piece (3) compared to the Determine the ambient temperature and only output the error message if the temperature increase compared to the ambient temperature is greater than or equal to the increase limit or shows a predefined behavior. System (200) comprising at least one measuring module (1) according to one of claims 1 to 10 or a measuring device (100) according to one of claims 11 to 12 and at least one switching device (2), preferably the at least one measuring module (1) with the at least one switching device (2) can be detachably connected. System (200) according to claim 13, characterized in that for the detachable connection, the at least one contact piece (3) of the at least one measuring module (1) is in at least one input-side switch terminal (4) of the at least one switching device (2) and/or in at least one The output-side switch terminal (5) of the at least one switching device (2) is also clamped and this is contacted both thermally and electrically. System (200) according to one of claims 13 to 14, characterized in that the respective measuring module (1) has a module housing (10) which is geometrically designed such that the module housing (10) of the respective measuring module (1) is essentially flush connects to a housing (11) of the respective switching device (2) when the respective measuring module (1) is detachably connected to the respective switching device (2).

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