System for monitoring a device

Abstract

The invention relates to a system for monitoring a device, comprising: a temperature sensor; a processing unit; an output unit; the temperature sensor acquires at least one temperature measurement of a component of the device during a heating phase of the component of the device; the temperature sensor provides the at least one temperature measurement to the processing unit; the processing unit selects a simulated transient temperature profile from a plurality of simulated transient temperature profiles, the plurality of simulated transient temperature profiles each relating to a different scenario of a simulated heating phase of a simulated component of a simulated device, the selection comprising a comparison of at least one temperature measurement to the plurality of simulated transient temperature profiles, the at least one temperature measurement simulating an equivalent time point in the simulated heating for a time point at which the temperature measurement was acquired; the processing unit determines that a hot spot is developing with respect to the component of the device, the determination comprising utilization of the selected simulated transient temperature profile of the simulated component of the simulated device; the output unit outputs an indication of a fault of the component of the device in dependence on the determination that the hot spot is developing.

Description

TECHNICAL FIELD

[0001] The present invention relates to a system for monitoring a device and a method of monitoring a device. BACKGROUND

[0002] The temperature of a power device, e.g. a low-, medium- or high-voltage switching device, needs to be kept within device-specific limits to avoid damage due to thermal stress.

[0003] Temperature monitoring, e.g. measurement using infrared (IR) sensors, is used to control whether these limits are adhered to. The measurement only provides information about the temperature state of the part of the device at the moment of measurement. However, it is often necessary to know how the temperature of this part will develop and whether the final temperature reached will be problematic.

[0004] An example is a service task being completed and the device being put back into operation. In this case, the device starts from the ambient temperature and, when the power is turned on, it will warm up. The highest temperature and thus the most critical situation is the steady state reached after a certain time.

[0005] However, if the connection is not correct, the heat generated by the current can exceed the temperature that is due, resulting in thermal stress and potential damage.

[0006] However, it is not possible to determine whether this potentially damaging situation will occur.

[0007] It would be desirable to address this problem. SUMMARY

[0008] It would therefore be advantageous to have an improved technique for monitoring a device.

[0009] The object of the present invention is solved by the subject matter of the independent claims, wherein further embodiments are incorporated in the dependent claims.

[0010] In a first aspect, there is provided a system for monitoring a device, the system comprising:

[0011] - a temperature sensor;

[0012] - a processing unit; and

[0013] - an output unit.

[0014] The temperature sensor is configured to acquire at least one temperature measurement of the component of the device during a heating phase of the component of the device. The temperature sensor is configured to provide the at least one temperature measurement to the processing unit. The processing unit is configured to select a simulated transient temperature profile of the simulated component of the simulated device from a plurality of simulated transient temperature profiles of simulated components of simulated devices. The plurality of simulated transient temperature profiles each relate to a different scenario with respect to a simulated heating phase of the simulated component of the simulated device. The selection of the simulated transient temperature profile comprises a comparison of the at least one temperature measurement at an equivalent time point to a time point of the acquisition of the temperature measurement in the simulated heating with the plurality of simulated transient temperature profiles. The processing unit is configured to determine that a hot spot is developing with respect to the component of the device. The determination comprises a utilization of the selected simulated transient temperature profile of the simulated component of the simulated device. The output unit is configured to output an indication of a fault associated with the component of the device based on the determination that the hot spot is developing.

[0015] In one example, the temperature sensor is an infrared camera, a surface acoustic wave sensor (SAW), or an RFID sensor.

[0016] In one example, the plurality of simulated transient temperature profiles each relate to a simulated heating of the simulated component of the simulated device beyond a heating phase for different scenarios. In other words, each simulated transient temperature profile relates to a simulated heating time that is later than the heating phase of the simulated component. In some cases, the time after the heating phase can be considered a steady state phase, but in some cases the heating phase can be considered an initial heating phase followed by a transition phase before reaching steady state.

[0017] In one example, the plurality of simulated transient temperature profiles each relate to a simulated heating of the simulated component of the simulated device to steady state for different scenarios.

[0018] In one example, the determination that a hot spot is developing with respect to the component of the device comprises extrapolating the selected simulated transient temperature profile of the simulated component of the simulated device beyond a time point in the simulated heating equivalent to the time point of the acquisition of the temperature measurement.

[0019] In one example, the determination that a hot spot is developing with respect to the component of the device comprises extrapolating the selected simulated transient temperature profile of the simulated component of the simulated device to a steady state of the simulated component.

[0020] In one example, the at least one temperature measurement comprises a plurality of temperature measurements, and wherein the plurality of temperature measurements are acquired simultaneously.

[0021] In one example, the temperature sensor is an infrared camera. The at least one temperature measurement comprises an infrared image of the component, and the plurality of simulated transient temperature profiles each comprise a plurality of infrared images of the simulated component.

[0022] In one example, the plurality of simulated transient temperature distributions are simulated in a process comprising utilization of finite element analysis.

[0023] In one example, the comparison of the at least one temperature measurement with the plurality of simulated transient temperature distributions comprises utilization of a matrix norm or a machine learning algorithm implemented by the processing unit.

[0024] In one example, the system comprises a current sensor configured to measure a current through the component. The selection of the simulated transient temperature distribution of the simulated component of the simulated device comprises utilization of the measured current through the component.

[0025] In one example, the system comprises an ambient air temperature sensor configured to measure an air or gas temperature in the vicinity of the component. The selection of the simulated transient temperature distribution of the simulated component of the simulated device comprises utilization of the measured air or gas temperature in the vicinity of the component.

[0026] In one example, the device is a low-, medium- or high-voltage switchgear.

[0027] In a second aspect, there is provided a method for monitoring a device, the method comprising:

[0028] a) obtaining, by a temperature sensor, at least one temperature measurement of a component of the device during a heating phase of the component of the device;

[0029] b) providing the at least one temperature measurement to a processing unit;

[0030] c) selecting, by the processing unit, a simulated transient temperature distribution of a simulated component of a simulated device from a plurality of simulated transient temperature distributions of the simulated component of the simulated device, wherein the plurality of simulated transient temperature distributions each relate to different scenarios with respect to a simulated heating phase of the simulated component of the simulated device, and wherein the selecting comprises comparing the at least one temperature measurement with the plurality of simulated transient temperature distributions at an equivalent time point in the simulated heating for a time point of the obtaining of the temperature measurement;

[0031] d) determining, by the processing unit, that a hot spot is developing with respect to the component of the device, and wherein the determining comprises utilizing the selected simulated transient temperature distribution of the simulated component of the simulated device; and

[0032] e) outputting, by an output unit, an indication of a fault associated with the component of the device based on the determining that the hot spot is developing.

[0033] The above aspects and examples will become clear and apparent from the following description of the embodiments described hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0034] An exemplary embodiment will be described below with reference to the following drawings:

[0035] Figure 1 A representation of a monitoring device is shown; and

[0036] Figure 2 A representation of a measured temperature profile for selecting an analog temperature profile is shown. DETAILED DESCRIPTION

[0037] Figures 1-2 A system for monitoring a device and a method for monitoring a device are related.

[0038] In one example, a system for monitoring a device comprises a temperature sensor, a processing unit, and an output unit. The temperature sensor is configured to acquire at least one temperature measurement of a component of the device during a heating phase of the component of the device. The temperature sensor is configured to provide the at least one temperature measurement to the processing unit. The processing unit is configured to select an analog transient temperature profile of an analog component of an analog device from a plurality of analog transient temperature profiles of the analog component of the analog device. The plurality of analog transient temperature profiles each relate to a different case with respect to an analog heating phase of the analog component of the analog device. Selecting the analog transient temperature profile of the analog component of the analog device from the plurality of analog transient temperature profiles comprises a comparison of at least one temperature measurement at an equivalent time point to a time point of the acquisition of the temperature measurement in the analog heating with the plurality of analog transient temperature profiles. The processing unit is configured to determine that a hot spot is developing with respect to the component of the device. The determination of the hot spot development comprises a utilization of the selected analog transient temperature profile of the analog component of the analog device. The output unit is configured to output an indication of a fault associated with the component of the device based on the determination that the hot spot is developing.

[0039] According to one example, the temperature sensor is an infrared camera, a surface acoustic wave sensor, or an RFID sensor.

[0040] According to one example, the plurality of analog transient temperature profiles each relate to an analog heating of the analog component of the analog device beyond the heating phase for different cases.

[0041] According to one example, the plurality of analog transient temperature profiles each relate to an analog heating of the analog component of the analog device to a steady state for different cases.

[0042] According to one example, determining that a hot spot is developing with respect to the component of the device comprises extrapolating the selected analog transient temperature profile of the analog component of the analog device beyond a time point in the analog heating equivalent to the time point of the acquisition of the temperature measurement.

[0043] According to one example, determining that the hot spot is developing with respect to the component of the device comprises extrapolating the selected simulated transient temperature profile of the simulated component of the simulated device to a steady state of the simulated component.

[0044] According to one example, the at least one temperature measurement comprises a plurality of temperature measurements, and the plurality of temperature measurements are acquired simultaneously. Thus, a temperature image can be acquired.

[0045] According to one example, the temperature sensor is an infrared camera, and the at least one temperature measurement comprises an infrared image of the component. The plurality of simulated transient temperature profiles each comprises a plurality of infrared images of the simulated component.

[0046] According to one example, the plurality of simulated transient temperature profiles are simulated in a process comprising utilization of finite element analysis.

[0047] According to one example, the comparison of the at least one temperature measurement with the plurality of simulated transient temperature profiles comprises utilization of a matrix norm or a machine learning algorithm implemented by the processing unit.

[0048] According to one example, the system comprises a current sensor configured to measure a current through the component. The selection of the simulated transient temperature profile of the simulated component of the simulated device comprises utilization of the measured current through the component.

[0049] According to one example, the system comprises an ambient air temperature sensor configured to measure an air or gas temperature in the vicinity of the component. The selection of the simulated transient temperature profile of the simulated component of the simulated device comprises utilization of the air or gas temperature measured in the vicinity of the component.

[0050] According to one example, the device is a low-, medium- or high-voltage switchgear.

[0051] The method for monitoring a device comprises:

[0052] a) acquiring, by a temperature sensor, at least one temperature measurement of a component of a device during a heating phase of the component of the device;

[0053] b) providing the at least one temperature measurement to a processing unit;

[0054] c) selecting, by the processing unit, from a plurality of simulated transient temperature profiles of a simulated component of a simulated device, a simulated transient temperature profile of the simulated component of the simulated device, wherein the plurality of simulated transient temperature profiles each relate to a different scenario with respect to a simulated heating phase of the simulated component of the simulated device, and wherein the selection comprises comparing the at least one temperature measurement with the plurality of simulated transient temperature profiles at an equivalent time point in the simulated heating for a time point of the acquisition of the temperature measurement;

[0055] d) determining, by the processing unit, that the hot spot is developing with respect to the component of the device, and wherein the determining comprises utilizing a selected simulated transient temperature profile of the simulated component of the simulated device; and

[0056] e) outputting, by the output unit, an indication of a fault associated with the component of the device based on the determining that the hot spot is developing.

[0057] In one example, the temperature sensor is an infrared camera, a surface acoustic wave sensor, or an RFID sensor.

[0058] In one example, the plurality of simulated transient temperature profiles each relate to simulated heating of the simulated component of the simulated device beyond a heating phase for different scenarios.

[0059] In one example, the plurality of simulated transient temperature profiles each relate to simulated heating of the simulated component of the simulated device to a steady state for different scenarios.

[0060] In one example, step d) comprises extrapolating the selected simulated transient temperature profile of the simulated component of the simulated device beyond a time point in the simulated heating equivalent to a time point at which the temperature measurement is taken.

[0061] In one example, step d) comprises extrapolating the selected simulated transient temperature profile of the simulated component of the simulated device to a steady state of the simulated component.

[0062] In one example, the at least one temperature measurement comprises a plurality of temperature measurements, and wherein the plurality of temperature measurements are taken simultaneously.

[0063] In one example, the temperature sensor is an infrared camera, wherein the at least one temperature measurement comprises an infrared image of the component, and wherein the plurality of simulated transient temperature profiles each comprise a plurality of infrared images of the simulated component.

[0064] In one example, the plurality of simulated transient temperature profiles are simulated in a process comprising utilization of finite element analysis.

[0065] In one example, in step c) comparing the at least one temperature measurement to the plurality of simulated transient temperature profiles comprises utilization of a matrix norm or a machine learning algorithm implemented by the processing unit.

[0066] In one example, the method comprises measuring, by a current sensor, a current through the component, and wherein step c) comprises utilizing the measured current through the component.

[0067] In one example, the method comprises measuring, by an ambient air temperature sensor, an air or gas temperature proximate to the component, and wherein step c) comprises utilizing the air or gas temperature measured proximate to the component.

[0068] Thus, the new device monitoring technique is able to draw conclusions about the future temperature of the power device or at least one or more components of the device. This is achieved in a particular example by measuring the temperature at an accessible point using a sensor, for example by an infrared camera or other sensing methods such as SAW, RFID, etc. This measurement is then compared to transient electro-thermal simulations of various cases. By having the measurement correspond to one of the pre-simulated cases, the future temperature can be looked up in the transient simulation of this case. From the simulation it can be known when and where the device eventually reaches a critical temperature. Thus, the time to failure is known. Thus, once this correlation is known, the future temperature can be inferred from the current sensor measurement, because the relevant simulation measurement corresponding to the actual measurement can be advanced in time for the particular case and the temperature of the future component is determined to assess, for example, whether a hot spot will lead to a failure.

[0069] It has been determined that this correlation can sometimes be derived from dedicated experiments during the product design phase. However, it is realized that this correlation only applies to the measured case (e.g. the experiment’s electrical contact resistance) and cannot be generalized to other cases or other devices. Furthermore, such experiments require a lot of time and are costly. Moreover, the critical point of the highest temperature is not always accessible experimentally, even in the design phase in a laboratory.

[0070] It is realized that instead of measurements, transient electro-thermal simulations (e.g. by finite elements FEM) can be used to establish the above-mentioned correlation between the measured temperature at the time of measurement and the future temperature.

[0071] Transient FEM simulations allow to analyze the entire device over time and are not limited to the current time and accessible locations. Cases can easily be changed. Thus, compared to experiments, the desired correlation can be determined for many more different cases. These devices can also be easily exchanged in the simulation. Thus, once the simulation approach is established, it is cheaper, more flexible, and more general in determining the desired correlation than experiments.

[0072] Figure 1 An example of the new technique overview is shown. This shows the comparison of a sensor measurement (right box) to a pre-simulated case lookup table (left box). Once a case (case) is determined, it is clear from the simulation whether, where, and when the device overheats.

[0073] The new monitoring system consists of the following elements:

[0074] 1. Temperature measurement results by sensors;

[0075] 2. A series of pre-simulated transient FEM simulations of different cases;

[0076] 3. An algorithm that compares the measured temperature with pre-simulated FEM simulations and determines which case corresponds to the measurement.

[0077] The sensor's measurement yields a temperature distribution. In the case of an IR camera, it comprises a temperature array corresponding to the number of pixels of the IR camera's optical elements.

[0078] The FEM simulation is a transient coupled electro-thermal simulation. Ohmic losses are calculated by solving Maxwell's equations. There are several options to calculate the temperature of the thermal part of the simulation:

[0079] • A simple heat conduction equation is solved. The heat exchange with the environment can be estimated by a heat transfer coefficient at the device's surface.

[0080] • Alternatively, a full CFD calculation can be done. This is more effort, but only necessary when convection and radiation cannot be estimated accurately enough by a heat transfer coefficient.

[0081] Then several cases are simulated according to possible failure cases. Different cases can be for example different electrical contact resistances. The temperature rises in different ways, depending on whether the electrical contacts are properly closed or not, for example after a service event, and the final steady-state temperature is also different. The transient simulations of the different cases can then be characterized by their failure probability, see the column of lookup tables in Figure 1 Some cases are unimportant, while others can lead to thermal damage.

[0082] During heating, the simulated transient temperature distribution is then compared to the temperature distribution measured by the sensor, see Figure 2 . This comparison can be done by a matrix norm or a machine learning algorithm.

[0083] Figure 2 The measured and simulated temperature distributions are illustrated. Each simulated case is compared to the measured case and the best match is determined.

[0084] The best match of the pre-simulated cases to the measurement is then assumed to be the current state of the device. This state can not always correspond to the same case (simulated case) throughout the heating process, as the temperatures of the different cases are similar at the beginning. However, after a while, the comparison should uniquely correspond to one case (case). This case is then selected and the future temperatures of the device can be looked up in this simulation. It is then also clear whether and when the device reaches a critical temperature and where. The failure time is thus known.

[0085] The lookup table can include additional information, for example data of other sensors. For example, the ambient air temperature in a compartment inside the switching device or the current value in a phase can be included.

[0086] While the application has been illustrated and described in detail in the drawings and foregoing description, such illustration and description is to be considered illustrative or exemplary only and not restrictive. The application is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practising the claimed application, from a study of the drawings, the disclosure, and the appended claims.

Claims

1. A system for monitoring equipment, the system comprising: - Temperature sensor; - Processing unit; - Current sensor; as well as - Output unit; The temperature sensor is configured to acquire at least one temperature measurement of the component of the device during the heating phase of the component. The temperature sensor is configured to provide the processing unit with the at least one temperature measurement result; The current sensor is configured to measure the current passing through the component; The processing unit is configured to select a simulated transient temperature distribution of a simulated component of a simulation device from a plurality of simulated transient temperature distributions of the simulation device, wherein each of the plurality of simulated transient temperature distributions relates to a different case with respect to a simulated heating phase of the simulated component of the simulation device, and wherein the selection includes a comparison of at least one temperature measurement result at an equivalent time point for the time point in which the temperature measurement result is acquired during the simulated heating with the plurality of simulated transient temperature distributions, and wherein the selection of the simulated transient temperature distribution of the simulated component of the simulation device includes the utilization of a measurement current through the component; The processing unit is configured to determine that a hot spot is developing relative to the component of the device, and the determination includes the utilization of a selected simulated transient temperature distribution of the simulated component of the simulation device, wherein determining that the hot spot is developing relative to the component of the device includes: extrapolating the selected simulated transient temperature distribution of the simulated component of the simulation device beyond a time point equivalent to the time point at which the simulated heating is acquired; and The output unit is configured to output an indication of a fault associated with the component of the device based on the determination that a hotspot is developing.

2. The system according to claim 1, wherein the temperature sensor is an infrared camera, a surface acoustic wave sensor, or an RFID sensor.

3. The system according to any one of claims 1 to 2, wherein each of the plurality of simulated transient temperature distributions relates to simulated heating outside the heating phase of the simulated component of the simulated device for different situations.

4. The system of claim 3, wherein each of the plurality of simulated transient temperature distributions relates to the steady-state simulated heating of the simulated components of the simulation device for different conditions.

5. The system according to any one of claims 1 to 2, wherein determining that the hotspot is developing relative to the component of the device comprises: Extrapolate the selected simulated transient temperature distribution of the simulation component of the simulation device to the steady state of the simulation component.

6. The system according to any one of claims 1 to 2, wherein the at least one temperature measurement result comprises a plurality of temperature measurement results, and wherein the plurality of temperature measurement results are acquired simultaneously.

7. The system of claim 2, wherein the temperature sensor is the infrared camera, wherein the at least one temperature measurement result includes an infrared image of the component, and wherein each of the plurality of simulated transient temperature distributions includes a plurality of infrared images of the simulated component.

8. The system according to any one of claims 1 to 2, wherein the plurality of simulated transient temperature distributions are simulated in a process including finite element analysis.

9. The system according to any one of claims 1 to 2, wherein the comparison of the at least one temperature measurement result with the plurality of simulated transient temperature distributions includes the use of matrix norm or a machine learning algorithm implemented by the processing unit.

10. The system according to any one of claims 1 to 2, wherein the system includes an ambient air temperature sensor configured to measure the air or gas temperature near the component, and wherein the selection of the simulated transient temperature distribution of the simulated component of the simulation device includes the utilization of the air or gas temperature measured near the component.

11. The system according to any one of claims 1 to 2, wherein the device is a low-voltage, medium-voltage, or high-voltage switchgear.

12. A method for monitoring equipment, the method comprising: a) During the heating phase of the components of the device, at least one temperature measurement result of the components of the device is obtained by a temperature sensor and the current through the components is measured by a current sensor; b) Provide the processing unit with the at least one temperature measurement result and the measurement current through the component; c) The processing unit selects a simulated transient temperature distribution of the simulated component of the simulation device from a plurality of simulated transient temperature distributions of the simulation component of the simulation device, wherein each of the plurality of simulated transient temperature distributions relates to a different case with respect to a simulated heating phase of the simulated component of the simulation device, and wherein the selection includes comparing at least one temperature measurement result with the plurality of simulated transient temperature distributions at an equivalent time point for the time point at which the temperature measurement result was acquired during the simulated heating, and the selection includes utilizing the measurement current through the component; d) The processing unit determines that a hotspot is developing relative to the component of the device, and wherein the determination includes utilizing a selected simulated transient temperature distribution of the simulated component of the simulation device, and the determination includes: extrapolating the selected simulated transient temperature distribution of the simulated component of the simulation device beyond the time point at which the simulated heating is equivalent to the time point of acquiring the temperature measurement result; and e) The output unit outputs an indication of a fault associated with the component of the device based on the determination that a hotspot is developing.

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