DE102020216013A1 - Monitoring of power electrical equipment - Google Patents

Abstract

The invention relates in particular to a monitoring arrangement (2) for a power electrical device (1) and a power electrical device (1) with such a monitoring arrangement (2). The monitoring arrangement (2) has an input (12) for an auxiliary voltage source (3), an output (13) for the auxiliary voltage source (3) and a sensor (8) connected between the input (12) and the output (13) and connected to a control unit (7). The sensor (8) is designed to detect a current flowing between the input (12) and the output (13) and to transmit it to the control unit (7) as a measured current value to recognize a characteristic course of an event in an auxiliary functional unit (4) of the power electrical device (1) supplied by the output (13) for the auxiliary voltage source (3) from measured current values. According to the invention, the control unit (7) is also designed to compare the identified characteristic curve with an expected characteristic curve and to output a maintenance signal depending on a deviation between the identified characteristic curve and the expected characteristic curve.

Description

technical field

The invention relates to a monitoring arrangement for a power electrical device, a power electrical device with such a monitoring arrangement, a method for monitoring a power electrical device and a data carrier with a computer program for carrying out the method.

Technical background

Power electrical devices such as air- or gas-insulated medium-voltage switchgear or substations usually include one or more auxiliary functional units in addition to a main functional unit such as circuit breakers or transformers. These auxiliary functional units support the main functional unit and allow, among other things, a change in the operating state of the main functional unit. For example, the circuit breaker can be opened or closed by spring drives, with springs installed in the spring drives being kept tensioned or compressed in order to be able to carry out a switching operation of the circuit breaker as quickly as possible. The spring drive can be triggered, for example, by a solenoid as a further auxiliary functional unit of the power-electrical device. The springs can then be tensioned or compressed again by other auxiliary functional units such as electric motors. In the case of substations, auxiliary functional units can be provided, for example, for changing a winding tap of a transformer winding. Other examples of auxiliary functional units are cooling units such as coolant pumps and the like.

The functioning of the main functional unit depends on that of the auxiliary functional units. If an auxiliary functional unit fails, the main functional unit can no longer be operated properly. Because of this, a great deal of maintenance is expended in order to prevent an unexpected failure of the power electric device.

The object of the invention is to provide means and methods that enable high reliability of a power electrical device with low operating costs.

The invention therefore introduces a monitoring arrangement for a power electrical device according to claim 1, a power electrical device with such a monitoring arrangement according to claim 8, a method for monitoring a power electrical device according to claim 11 and a data carrier with a computer program for carrying out the method according to claim 12. Preferred embodiments of the invention form the subject matter of the dependent claims.

Summary of the Invention

A first aspect of the invention relates to a monitoring arrangement for a power electrical device and having an input for an auxiliary voltage source, an output for the auxiliary voltage source and a sensor connected between the input and the output and connected to a control unit. The sensor is designed to detect a current flowing between the input and the output and to transmit it to the control unit as a measured current value. The sensor can be, for example, a Hall probe or a measuring resistor of known size and output a voltage signal proportional to the current flowing through the sensor as a current measurement value. It is also possible for the sensor to additionally include an analog/digital converter, so that the measured current value can be transmitted to the control unit as a digital value. The auxiliary voltage source is usually an independent functional unit of the electrical power device and is used to supply the (additional) auxiliary functional units of the electrical power device with electricity. The auxiliary voltage source can be supplied via a battery and/or a supply network and can in particular make one or more direct voltages available.

According to the invention, the control unit is designed to identify, in a series of measured current values, a characteristic course of an event in an auxiliary functional unit of the power electrical device that is supplied by the output for the auxiliary voltage source. For example, a switch-on event can be characterized by a brief increase in the current, with time periods and amplitudes that are characteristic of the type of event and its source (ie the auxiliary functional unit in which the event occurred) being given. In this case, the invention is based on the insight that the various events in the auxiliary functional units leave a kind of fingerprint in the current drawn by the auxiliary functional units.

According to the invention, the control unit is also designed to compare the identified characteristic curve with an expected characteristic curve and as a function to issue a maintenance signal in the event of a deviation between the identified characteristic curve and the expected characteristic curve. The control unit can, for example, output the maintenance signal to a remote control center via a wireless or wired communication interface, so that a suitable maintenance measure can be initiated from there.

The monitoring arrangement of the invention has the advantage that changes in the characteristic curves due to aging or other impairments of the auxiliary functional units can be noticed and conclusions can be drawn as to the need for a maintenance measure. As a result, maintenance measures can be initiated in good time before a functional failure of the auxiliary functional unit and the main functional unit caused as a result, although regular inspection and preventive replacement of wearing components of the auxiliary functional units or even the auxiliary functional units themselves are no longer required, which means that costs can be saved. The invention makes it possible to monitor a plurality of auxiliary functional units supplied by the auxiliary voltage source with just a single sensor, so that the monitoring arrangement of the invention can be implemented cost-effectively.

In this case, the control unit does not necessarily have to be arranged at the location of the power electrical device, but can itself be remote or implemented as an arrangement distributed over a number of units and locations. In this case, a control unit can be provided jointly for a number of power-electrical devices, so that knowledge about events in a power-electrical device can also be used for monitoring other power-electrical devices. This makes sense, for example, when the expected characteristic curves are modified during operation of the monitoring arrangement based on the events that have actually occurred, for example by using machine learning.

In principle, the control unit can distinguish and evaluate different types of events and different or similar events in different auxiliary function units. The invention advantageously enables this in that the sensor is arranged on the auxiliary voltage supply at a functionally central point of the power electrical device, at which the information about the events contained in the flowing current comes together. The control unit can also be designed to recognize events that overlap in time.

The sensor can be designed to detect the current with a sampling rate between 1 and 50 kHz, preferably between 5 and 30 kHz, particularly preferably between 8 and 20 kHz. With these sampling rates, on the one hand, sufficient measured current values are available for recognizing a characteristic course, and on the other hand, such a monitoring arrangement can still be implemented cost-effectively.

The control unit is preferably designed to assign the identified characteristic curve to an event type from a plurality of predetermined event types. This makes it possible to determine which type of event was detected by the monitoring arrangement, which in turn allows conclusions to be drawn about an auxiliary functional unit of the power-electrical device that typically executes the event as the source of the event. Because the causative auxiliary functional unit or a specific causative component of the auxiliary functional unit is identified based on the event type, it can also be determined about which functional unit or component a statement is made based on the deviation between the identified characteristic curve and the expected characteristic curve.

The control unit can be designed, for example, to form respective cross-correlations between the series of measured current values and a plurality of default curves, each of which describes one of the predetermined event types, and to recognize the characteristic curve in the series of measured current values depending on the respective results of the cross-correlations and assign the recognized characteristic course to one of the predetermined event types. As an alternative or in addition, the control unit of the monitoring arrangement can be equipped with a neural network which is designed to recognize the characteristic progression in the series of measured current values. Such a neural network can be used, in particular, within the framework of machine learning, as a result of which the quality of the maintenance signals from the monitoring arrangement can increase over time in terms of time and accuracy. This is the case in particular when recognized characteristic curves from a large number of power-electrical devices are combined and the expected characteristic curves are adapted over time by means of machine learning.

In addition, the control unit can be designed to determine a spectral representation of the series of measured current values and to identify the characteristic curve based on the spectral representation. Such embodiment variants can also be combined with the aforementioned approaches to machine learning.

The control unit is preferably designed to determine a degree of correspondence of the deviation between the detected characteristic curve and the expected characteristic curve with a plurality of predetermined error patterns and to output the maintenance signal if the degree of correspondence for at least one of the predetermined error patterns exceeds a threshold value . In this case, the control unit is also designed to use the maintenance signal to output information about the at least one error pattern for which the degree of agreement has exceeded the threshold value. The information can be used to determine the cause of the deviation of the detected characteristic curve from the expected characteristic curve and direct the maintenance measure to be carried out to eliminating the cause. For example, the information can help to identify and allocate a sagging spring of a spring drive, a sluggish gear or worn brushes of an electric drive unit, a delayed triggering relay or the like.

A second aspect of the invention relates to a power electrical device with a power electrical main functional unit, an auxiliary voltage source, at least one auxiliary functional unit for operating the main functional unit and a monitoring arrangement connected between the auxiliary voltage source and the at least one auxiliary functional unit according to the first aspect of the invention.

The power electrical main functional unit can, for example, be a switch (e.g. load switch or circuit breaker), a short-circuiter, an arc quencher or a transformer, but the invention can also be applied to other types of power electrical systems in the field of heavy current, medium voltage or high voltage technology.

The auxiliary functional unit can in particular be an auxiliary switch or an auxiliary motor.

• -- Erfassen eines Stromes einer Hilfsspannungsquelle in einer Serie von Strommesswerten;
• -- Erkennen eines charakteristischen Verlaufs in der Serie von Strommesswerten;
• -- Vergleichen des erkannten charakteristischen Verlaufs mit einem erwarteten charakteristischen Verlauf; und
• -- Ausgeben eines Wartungssignals in Abhängigkeit von einer Abweichung zwischen dem erkannten charakteristischen Verlauf und dem erwarteten charakteristischen Verlauf.

Another aspect of the invention introduces a method for monitoring a power electrical device. The method includes at least the following steps:

• -- detecting a current of an auxiliary voltage source in a series of current measurement values;
• -- Recognizing a characteristic progression in the series of current measurement values;
• -- Comparing the recognized characteristic curve with an expected characteristic curve; and
• -- Outputting a maintenance signal depending on a deviation between the detected characteristic curve and the expected characteristic curve.

The invention also relates to a data carrier with a computer program which, executed by a control unit of a power electrical device, carries out the method according to the invention.

character list

• 1 ein Ausführungsbeispiel einer erfindungsgemäßen leistungselektrischen Einrichtung;
• 2 ein Ausführungsbeispiel einer erfindungsgemäßen Überwachungsanordnung; und
• 3 ein Ausführungsbeispiel eines erfindungsgemäßen Verfahrens zum Überwachen einer leistungselektrischen Einrichtung.

The invention is explained in more detail below with reference to illustrations of exemplary embodiments. Show it:

• 1 an embodiment of a power electrical device according to the invention;
• 2 an embodiment of a monitoring arrangement according to the invention; and
• 3 an embodiment of a method according to the invention for monitoring a power electrical device.

Detailed description of the pictures

1 1 shows an exemplary embodiment of a power-electrical device 1 according to the invention. The power-electrical device 1 can be, for example, an air-insulated or gas-insulated high- or medium-voltage switchgear, a substation or the like. For this purpose, the power-electrical device 1 comprises a main functional unit 5, which can accordingly be a switch with vacuum interrupters, a transformer with a plurality of taps, or another power-electrical functional unit.

The power electrical device 1 also has two auxiliary functional units 4, which can be configured differently depending on the type of main functional unit 5. For example, the auxiliary functional units 4 can be auxiliary drives for tensioning or compressing the spring of a spring drive or a cooling device with a coolant compressor.

The auxiliary functional units 4 are powered by an auxiliary power supply 3, the auxiliary power supply 3 as needed Auxiliary functional units 4 can also provide several different voltage levels and voltage formats (DC voltage and / or AC voltage with different amplitudes, etc.) at the same time.

A monitoring arrangement 2 is connected between the auxiliary voltage source 3 and the auxiliary functional units 4, which monitors the current provided by the auxiliary voltage source 3 for the auxiliary functional units 4 in order to assess the auxiliary functional units 4 and in particular their technical state of health. If the auxiliary voltage source 3 provides a number of different voltages, the monitoring arrangement 2 can be designed to monitor a number or all of these different voltages.

The monitoring arrangement 2 is intended to detect events in the auxiliary functional units 4 based on variations in the power consumption of the auxiliary functional units 4, with a single monitoring arrangement 2 being sufficient for a number of auxiliary functional units 4, since the auxiliary functional units 4 are supplied from the same auxiliary voltage source 3. Although events occurring in close succession or at the same time can superimpose the variations in the current consumption, these can be separated from one another in terms of signaling.

These variations in power consumption have characteristic curves that allow the type of event, for example a switching event or the start-up of an electric drive, etc., to be identified without the monitoring arrangement 2 having to communicate with the auxiliary functional units 4, the main functional unit 5 or a local or remote control device connected to the power electronic device 1 and would have to be informed by those about the respective operational measures.

The monitoring arrangement 2 according to the invention can thus monitor a complex power-electrical device 1 with little effort and, in particular, can also be subsequently installed in a power-electrical device 1 with little effort. The monitoring arrangement 2 offers the advantage of being able to examine characteristic curves assigned to the same event type for long-term changes and other deviations from expected characteristic curves, which means that conclusions can be drawn about the state of health of the auxiliary functional units 4 supplied by the auxiliary voltage source 3. Accordingly, the monitoring arrangement 2 can output a maintenance signal which indicates, for example, the need for maintenance, the type of error that is expected or present and, if applicable, the type of maintenance required.

2 shows an exemplary embodiment of a monitoring arrangement 2 according to the invention. The monitoring arrangement 2 comprises a sensor 8 which is connected between an input 12 and an output 13 for the auxiliary voltage source 3 of the power electrical device 1 and is used to supply the current provided by the auxiliary voltage source 3 to the auxiliary functional units 4 capture. In the exemplary embodiment shown, the sensor 8 includes, merely by way of example, a measuring resistor 9 through which the current flows, and a voltage measuring unit 10 which detects the voltage caused by the current across the measuring resistor 9 . This voltage is proportional to the current, so it can be used as a measurement signal.

The sensor 8 can, for example, record measured current values with a clock frequency in the kilohertz range and transmit them to a control unit 7, which carries out the technical evaluation of the measured current values. In this case, the control unit 7 can be arranged locally or remotely from the sensor 8 . For example, it is possible to arrange only the sensor 8 of the monitoring arrangement 2 within the switchgear or substation, which forms the core of the power-electrical device, and to connect the other functional units of the monitoring arrangement 2 to the sensor 8 via a wired, wireless, optical or other data connection associate.

The control unit 7 can be connected to a memory 11, for example, in which program code and/or measured current values and temporary and persistent data generated during processing can be stored.

The monitoring arrangement 2 also has a communication interface 6 which is connected to the control unit 7 and via which a maintenance signal of the type described above can be output. In the case of particularly simple embodiments of the invention, however, the maintenance signal can also merely represent an audio or light signal, so that the communication interface 6 can accordingly be omitted.

3 1 shows an exemplary embodiment of a method according to the invention for monitoring a power electrical device 1. The method begins in a starting step S0 and continues with a first step S1, in which the current of the auxiliary voltage source 3 is detected in a series of current measurement values. This step S1 can be carried out continuously and in parallel with the further method steps.

In a subsequent step S2, the series of measured current values is examined for the presence of a characteristic curve and such a curve—if any—is recognized. In step S3, the identified characteristic curve is compared with an expected characteristic curve. In this case, an event type of the event causing the characteristic course can also be determined.

In step S4 it is checked whether a deviation between the identified characteristic curve and the expected characteristic curve exceeds a predetermined threshold value. If this is not the case, it is concluded that the auxiliary functional unit in which the causative event occurred is healthy and does not require any maintenance action. In this case, the method branches back to the start of the method. Otherwise, the process continues with step S5, in which a maintenance signal is output to indicate the need for a maintenance measure.

The invention was explained in more detail using illustrations of exemplary embodiments. The exemplary embodiments only serve to improve understanding of the invention and are not intended to restrict it, as it is exclusively defined by the following patent claims.

Reference List

1

power electrical device

2

surveillance arrangement

3

auxiliary power source

4

auxiliary engine

5

main functional unit

6

communication interface

7

control unit

8th

sensor

9

measuring resistor

10

voltage measurement unit

11

Storage

12

Entry

13

Exit

Claims (12)

A monitoring arrangement (2) for a power electrical device (1) and having an input (12) for an auxiliary voltage source (3), an output (13) for the auxiliary voltage source (3) and one between the input (12) and the output (13 ) switched and connected to a control unit (7) sensor (8), which is designed to detect a current flowing between the input (12) and the output (13) and to transmit it as a measured current value to the control unit (7), characterized in that that the control unit (7) is designed to recognize a series of measured current values from a characteristic course of an event in an auxiliary functional unit (4) of the power electrical device (1) supplied by the output (13) for the auxiliary voltage source (3), the recognized to compare characteristic curve with an expected characteristic curve and as a function of a deviation between the recognized characteristic curve and de m expected characteristic curve to issue a maintenance signal. The monitoring arrangement (2) of the preceding claim, wherein the sensor (8) is adapted to sense the current at a sampling rate of between 1 and 50 kilohertz, preferably between 5 and 30 kilohertz. The monitoring arrangement (2) of one of the preceding claims, in which the control unit (7) is designed to assign the identified characteristic course to an event type of a plurality of predetermined event types. The monitoring arrangement (2) of the preceding claim, in which the control unit (7) is designed to form respective cross-correlations between the series of current measurement values and a plurality of default curves, each of which describes one of the predetermined event types, and the characteristic curve in the series to detect current measurement values depending on the respective results of the cross-correlations and to assign the detected characteristic course to one of the predetermined event types. The monitoring arrangement (2) of one of the preceding claims, in which the control device (7) comprises a neural network which is designed to recognize the characteristic curve in the series of current measurement values. The monitoring arrangement (2) of one of the preceding claims, in which the control unit (7) is designed to determine a spectral representation of the series of measured current values and to recognize the characteristic course on the basis of the spectral representation. The monitoring arrangement (2) of any one of the preceding claims, wherein the control a unit (7) is designed to determine a degree of correspondence of the deviation between the detected characteristic curve and the expected characteristic curve with a plurality of predetermined error patterns and to output the maintenance signal if the degree of correspondence for at least one of the predetermined error patterns has a threshold value exceeds, wherein the control unit (7) is also designed to use the maintenance signal to output information about the at least one error pattern for which the degree of agreement has exceeded the threshold value. A power-electrical device (1) with a power-electrical main functional unit (5), an auxiliary voltage source (3), at least one auxiliary functional unit (4) for operating the main functional unit (5) and one connected between the auxiliary voltage source (3) and the at least one auxiliary functional unit (4). Monitoring arrangement (2) according to one of the preceding claims. The power electric device (1) of the preceding claim, wherein the power electric main functional unit (5) is a switch, a short circuiter, an arc quencher or a transformer. The power electrical device (1) of one of Claims 8 or 9 , wherein the at least one auxiliary functional unit (4) is an auxiliary switch or an auxiliary motor. A method for monitoring a power electrical device (1) and comprising the steps: -- detecting a current of an auxiliary voltage source (3) in a series of measured current values; -- Recognizing a characteristic progression in the series of current measurement values; -- Comparing the recognized characteristic curve with an expected characteristic curve; and -- Outputting a maintenance signal depending on a deviation between the detected characteristic curve and the expected characteristic curve. A data carrier with a computer program which, executed by a control unit (7) of a power electrical device (1), carries out the method of the preceding claim.

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