Method for monitoring the switch-on characteristic of a switching device

Abstract

The present invention relates to a method for monitoring the switch-on characteristic of an electrical switching device, having at least the method steps of: i) switching on the switching device; ii) monitoring the supply voltage when the switching device is switched on; and iii) monitoring the switching voltage when the switching device is switched on; wherein, iv) the supply voltage and the switching voltage are monitored with regard to their voltage values and the voltage values are compared with setpoint values or setpoint ranges that can be preset.

Description

[0001] Description

[0002] Method for monitoring the switching characteristics of a switching device

[0003] The present invention relates to a method for monitoring the switching-on characteristic of an electrical switching device. The present invention further relates to a computer program product for carrying out this method, a data processing device for carrying out such a method, and an electrical switching device which has a control unit for carrying out this method.

[0004] The proper functioning of a switching device depends significantly on the quality of the supply or switching voltage. Particularly at the moment of switch-on, the dynamic switch-on characteristic of the switching device typically associated with this can cause the supply or switching voltage to drop below the required minimum voltage if the voltage source is undersized. This can lead to malfunctions and faults. These problems may be noticed by the user during commissioning. However, such effects often go unnoticed at first and only become apparent during later operation.

[0005] Any device failure during commissioning can be discovered during troubleshooting. For example, an oscilloscope can be used to determine the power-on characteristics. If the fault occurs later in operation, long-term recordings of numerous power-on cycles would be required to detect this type of fault.

[0006] State-of-the-art solutions still have potential for improvement. In particular, such solutions offer potential for improvement with regard to safe and reliable monitoring of the switching characteristics of switching devices.

[0007] The object of the present invention is therefore to at least partially overcome the disadvantages known from the prior art. In particular, the object of the present invention is to provide a solution that allows for safe and reliable monitoring of the switching characteristics of switching elements.

[0008] The object is achieved according to the invention at least in part by a method having the features of claim 1. The object is further achieved according to the invention at least in part by a computer program product having the features of claim 7, by a device for data processing having the features of claim 8 and by an electrical switching device having the features of claim 9. Preferred embodiments of the invention are described in the subclaims, in the description or in the figure, wherein further features described or shown in the subclaims or in the description or in the figure can represent an object of the invention individually or in any combination, unless the context clearly indicates the opposite.

[0009] A method is described for monitoring the switch-on characteristic of an electrical switching device, at least comprising the method steps: i) switching on the switching device; ii) monitoring the supply voltage during the switch-on process of the switching device; and iii) monitoring the switching voltage during the switch-on process of the switching device, wherein iv) the supply voltage and the switching voltage are monitored with regard to their voltage values ​​and the voltage values ​​are compared with predefinable target values ​​or target ranges. Such a method allows safe and reliable monitoring of the switch-on characteristic of switching elements.

[0010] The method described here is therefore used to monitor the switching characteristics of an electrical switching device. An electrical switching device can be understood in particular as a circuit breaker or, preferably, a power contactor. For example, the electrical switching device can be part of a medium-voltage switchgear or a high-voltage switchgear.

[0011] A switching characteristic is the behavior of the switching device when it is switched on, i.e. when the contacts of the switching device are brought together.

[0012] In this regard, it is known that when the switching device is switched on, the supply or switching voltage can drop below the required minimum voltage. This can happen, for example, if the voltage source is undersized or incorrectly configured. This can trigger malfunctions, which, however, can be prevented or at least significantly reduced with the invention.

[0013] For this purpose, the procedure comprises the following procedural steps, whereby the numbering does not necessarily indicate the order in which the procedural steps are carried out.

[0014] According to process step i), the switching device is switched on. The switching device contacts are closed accordingly. In this regard, it is known that a fixed contact and a moving contact are present. By axially displacing the moving contact onto the fixed contact, the contacts can be brought toward each other, which switches the switching device on.

[0015] According to process step ii), the supply voltage is monitored during the switch-on process of the switching device, and according to process step iii), the switching voltage is monitored during the switch-on process of the switching device. This can be done in a conventional manner by measuring the voltage at the contactor.

[0016] The voltage measurement is preferably performed using an analog-to-digital converter, which is implemented either as a discrete component in the control electronics or, if a microcontroller is used, preferably as an integrated component in the controller. This is known per se to those skilled in the art.

[0017] In particular, monitoring can mean monitoring the temporal progression of the supply voltage and the switching voltage, whereby the voltage can be recorded over the temporal progression. For example, monitoring of the temporal progression of the supply voltage and the switching voltage can be carried out in such a way that monitoring of these voltages starts before the switching device is switched on or immediately upon switching on the switching device and ends after the termination of high-current activities of the control device, such as switching off the drive current.

[0018] With regard to monitoring the switching voltage and the supply voltage, method step iv) further provides for their voltage values ​​to be monitored and the voltage values ​​to be compared with predefined target values ​​or target ranges. In other words, it is to be checked whether and to what extent the switching voltage and the supply voltage during the switch-on process are within a predefined voltage level, i.e., voltage range or specific voltage value, or whether there is a deviation that is greater than a predefined limit.

[0019] Accordingly, the method described here can be used to determine whether, for example, a voltage drop occurs during power-up. A voltage drop, in particular, can lead to a malfunction during operation, which must be prevented.

[0020] Accordingly, in the method described here, it may be advantageous that in method step iv) it is monitored whether at least one of the supply voltage and the switching voltage falls below a predeterminable minimum value.

[0021] According to the invention, such a fault can be detected in a particularly simple and reliable manner. A possible device failure during commissioning can be easily detected by evaluating the measured voltage values ​​in relation to the corresponding target values. This is achieved in a particularly simple and reliable manner. Complex and extensive troubleshooting is not necessary.

[0022] Furthermore, a potential error can be detected in advance, particularly by recording the measured voltage values ​​or their deviation from the target value. For example, in the case of a gradually increasing error, a gradual decrease in the voltage values ​​can be detected even before a fault has occurred, so that a fault can not only be detected but possibly even prevented through any service work.

[0023] Accordingly, it may be particularly advantageous to record the time course of the supply and switching voltage in process step iv).

[0024] It may further be preferred that a warning is output if at least one of the switching voltage and the supply voltage deviates from the setpoint values ​​or setpoint ranges by a predeterminable margin. In this embodiment, a fault can thus be taken into account particularly reliably. This is because, if the voltage values ​​deviate from a setpoint value or setpoint range by more than a predeterminable margin, a user can be immediately informed of the fault, enabling appropriate countermeasures, such as switching off the switching device or configuring the voltage source.

[0025] The corresponding countermeasures can, for example, be initiated manually by a user in response to the warning.

[0026] In principle, corresponding countermeasures can also be carried out automatically by a control unit of the switching device, whereby this is basically possible regardless of whether a warning has been issued or not.

[0027] Particularly preferably, method step iv) can be carried out using an analog-to-digital converter. In this embodiment, monitoring and, if necessary, recording and evaluation of the switching voltage and the supply voltage can be easily achieved, particularly with a microcontroller. In particular, a control unit can be equipped with appropriate software to carry out the described method. Alternatively, an additional diagnostic device could be provided in the switching device, which can assume this functionality.

[0028] When using an analog-digital converter or a microcontroller, it may be preferable for the converter to be initialized before the switching device is switched on. In other words, the switching device is only switched on once the converter or the microcontroller has been initialized. This embodiment makes it possible to react to the fact that, when the switching voltage and supply voltage are identical, the microprocessor and its AD converter require an initialization time immediately after the supply voltage is switched on, during which time the system cannot measure the supply voltage. This phase cannot therefore be monitored. Since the switching process represents a particularly critical load for the voltage source to be monitored, the switching device can be set in this embodiment such that the switching command is always executed after the initialization phase.This design can, for example, be specifically selected for commissioning tests.

[0029] In principle, it can be advantageous for the initialization phase to be as short as possible, for example by using the most efficient firmware possible.

[0030] If the supply voltage and the switching voltage are separate, the process is simplified. In this case, the switching device is switched on with largely low power. Immediately after the supply voltage is switched on, the microprocessor and its AD converter also require an initialization time during which the system cannot measure the supply voltage. However, no switching command, which represents a particular load for the voltage source to be monitored, is executed during this initialization phase. This embodiment may therefore be preferred.

[0031] With regard to further advantages and technical features of the method, reference is hereby made to the description of the computer program product, the data processing device, the electrical switching device, the figure and the description of the figure.

[0032] Also described is a computer program product comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method as described above.

[0033] Such a computer program can, for example, be loaded onto a control unit of the switching device and include control commands that initialize the steps of the method described here. The advantage of such a computer program product can be seen in the fact that, as is also relevant for the method, it enables automatic detection of defects in the power supply of switching devices, particularly medium-voltage switching devices. This results in frequent and reliable detection of incorrect installations, configurations, and device defects, particularly in the switching device and / or voltage source.

[0034] With regard to further advantages and technical features of the computer program product, reference is hereby made to the description of the method, the device for data processing, the electrical switching device, the figure and the description of the figure.

[0035] Also described is a data processing device comprising a processor configured to carry out the method as described above.

[0036] For example, the device can be a control unit of the switching device. If the switching device, such as the medium-voltage switching device, already has appropriate electronics for controlling the switching device, the described functionality can be easily implemented cost-effectively using appropriate firmware. If this is not the case, this function can be implemented in the form of an additional diagnostic device in the switching device.

[0037] In particular, a previously described computer program product can be loaded onto the control system in order to carry out the described method.

[0038] In summary, the advantage of such a device is that it enables automatic detection of defects in the power supply of switchgear, particularly medium-voltage switchgear. This results in frequent and reliable detection of incorrect installations, configurations, and device defects, particularly in the switchgear and / or power source.

[0039] With regard to further advantages and technical features of the data processing device, reference is hereby made to the description of the method, the computer program product, the electrical switching device, the figure and the description of the figure.

[0040] Also described is an electrical switching device comprising a control unit, wherein the control unit comprises a device for data processing as described above.

[0041] Such a switching device can, for example, be a circuit breaker or, preferably, a power contactor and be part of a medium-voltage switchgear or a high-voltage switchgear. A medium-voltage switchgear is understood to be a switchgear that can switch voltages from approximately 1 kV up to 60 kV. Furthermore, a high-voltage switchgear can be understood to be a switchgear that can switch voltages above 60 kV. Furthermore, the switchgear can be, for example, a gas-insulated switchgear (GIS).

[0042] For example, to carry out the method described above, the switching device has a control unit. This is designed as a data processing device as described above.

[0043] In summary, the advantage of such a switching device can be seen in the fact that it enables automatic detection of defects in the power supply of switching devices, particularly medium-voltage switching devices. This results in frequent and reliable detection of incorrect installations, misconfigurations, and device defects, particularly in the switching device and / or voltage source. For further advantages and technical features of the electrical switching device, reference is made to the description of the method, the computer program product, the data processing device, the figure, and the description of the figure.

[0044] Further details, features, and advantages of the subject matter of the invention emerge from the dependent claims and from the following description of the figure. The figure shows:

[0045] Fig. 1 is a diagram illustrating a method according to an embodiment of the present invention;

[0046] Figure 1 shows a diagram illustrating a method according to one embodiment of the present invention. Accordingly, Figure 1 illustrates a method for monitoring the switching-on characteristic of an electrical switching device. Such a method comprises at least the method steps: i) switching on the switching device, according to step 10; ii) monitoring the supply voltage during the switching-on process of the switching device, according to step 12; and iii) monitoring the switching voltage during the switching-on process of the switching device, according to step 14, wherein iv) according to step 16 the supply voltage and the switching voltage are monitored with regard to their voltage values ​​and the voltage values ​​are compared with predefinable target values ​​or target ranges.

[0047] In particular, the use of a microprocessor with analog-to-digital conversion records the time course of the supply and switching voltage. If the minimum voltage is detected, the error situation can be communicated to the user via display elements such as LEDs or a communication interface (e.g., USB or RS485). In particular, a graphical display of the time course of the voltage during the switch-on period can illustrate the configuration problem of an under-designed voltage source.

[0048] If the switching device already has the appropriate electronics for controlling the switching device, the described functionality can be easily implemented cost-effectively using appropriate firmware. If not, this function can be implemented in the switching device by means of an additional diagnostic device.

[0049] Regardless of the grammatical gender of a particular term, persons with male, female or other gender identity are included.

[0050] Although the invention has been illustrated and described in detail by means of the preferred embodiments, the invention is not limited by the disclosed examples and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

[0051] Reference symbol list 10 steps

[0052] 12 steps

[0053] 14 Step

[0054] 16 steps

Claims

Patent claims 1. Method for monitoring the switching-on characteristic of an electrical switching device, at least comprising the method steps: i) switching on the switching device; ii) monitoring the supply voltage during the switching-on process of the switching device; and iii) monitoring the switching voltage during the switching-on process of the switching device, wherein iv) the supply voltage and the switching voltage are monitored with regard to their voltage values ​​and the voltage values ​​are compared with predefinable target values ​​or target ranges.

2. Method according to claim 1, characterized in that in method step iv) it is monitored whether at least one of the supply voltage and the switching voltage falls below a predeterminable minimum value.

3. Method according to claim 1 or 2, characterized in that in method step iv) the time course of the supply and switching voltage is recorded.

4. Method according to one of claims 1 to 3, characterized in that method step iv) is carried out by means of an analog-digital converter. 5 . Method according to claim 4, characterized in that the converter is initialized before the switching device is switched on.

6. Method according to one of claims 1 to 5, characterized in that a warning is issued if at least one of the switching voltage and the supply voltage does not maintain a predeterminable distance from the setpoint values ​​or setpoint value ranges.

7. A computer program product comprising instructions which, when executed by a computer, cause the computer to carry out the method according to any one of claims 1 to 6.

8. A data processing device comprising a processor configured to carry out a method according to any one of claims 1 to 6.

9. Electrical switching device comprising a control unit, characterized in that the control unit comprises a data processing device according to claim 8.

10. Electrical switching device according to claim 9, characterized in that the electrical switching device is a power contactor.

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