METHOD FOR IDENTIFYING ASYMMETRICAL VIBRATIONS WHEN OPERATING AN ELECTRICAL DEVICE CONNECTED TO A HIGH-VOLTAGE GRID

Abstract

A method for identifying asymmetrical vibrations during the operation of an electric device which is connected to a high-voltage grid: Operational noise of the electric device is detected using acoustic sensors which output measured values. The measured values and/or values derived therefrom are transmitted to a communication unit via a close-range communication connection and then transmitted to a data processing cloud via a far-range communication connection. The measured values and/or the values derived from the measured values are separated into frequency components by the data processing cloud using a Fourier transformation, thereby obtaining a frequency spectrum. Odd and even frequency components of the frequency spectrum are ascertained on the basis of a base frequency of the high-voltage supply grid and put into a ratio R relative to one another. The presence of asymmetrical vibrations is indicated if the ratio R exceeds a specified threshold.

Claims

1-8. (canceled)

9. A method of identifying asymmetrical vibrations during an operation of an electrical device which is connected to a high-voltage grid, the method comprising: acquiring operational noise of the electrical device using acoustic sensors which provide measurement values on an output side; transmitting the measurement values and/or values derived from the measurement values to a communication unit via a short-range communication connection; transmitting the measurement values and/or the values derived from the measurement values from the communication unit to a data processing cloud via a long-range communication connection; breaking down the measurement values and/or the values derived from the measurement values into their frequency components in the data processing cloud by way of a Fourier transformation so as to obtain a frequency spectrum; ascertaining odd and even frequency components of the frequency spectrum based on a fundamental frequency of the high-voltage grid and determining a ratio R between the odd and even frequency components; and if the ratio R exceeds a predetermined threshold value concluding a presence of asymmetrical vibrations of the electrical device.

10. The method according to claim 9, which comprises storing the measurement values and/or values derived from the measurement values in a memory unit of the communication unit.

11. The method according to claim 10, which comprises ascertaining a geographic location of the communication unit and of the electrical device connected thereto and transmitting the geographic location to the data processing cloud by way of an antenna for position determination, which is arranged in the communication unit.

12. The method according to claim 10, wherein the communication unit is a mobile telephone.

13. The method according to claim 9, which the communication unit is one of a plurality of communication units each having a memory for storing the measurement values and/or values derived from the measurement values.

14. The method according to claim 9, which comprises acquiring the acoustic signals at various locations in close vicinity to the electrical device.

15. The method according to claim 9, which comprises acquiring the acoustic signals over a predefined period.

16. A computer program for a computation device, the computer program being configured for executing the method according to claim 9.

17. A computer program product, comprising a non-transitory storage medium containing a computer program configured for executing the method according to claim 9 when the program is loaded into a computer.

Description

[0026] Further expedient embodiments and advantages of the invention are the subject matter of the following description of exemplary embodiments of the invention with reference to the figure of the drawing, with the same reference signs referring to functionally identical components, and wherein

[0027] FIG. 1 schematically illustrates an exemplary embodiment of the method according to the invention and

[0028] FIG. 2 schematically illustrates a further exemplary embodiment of the invention.

[0029] FIG. 1 shows an exemplary embodiment of the method according to the invention in which a transformer 1 is schematically illustrated as electrical device. The transformer 1 has a tank 2 that is filled with an insulating fluid such as an ester fluid or a mineral oil. A magnetizable core 3 is arranged in the tank 2 and forms a closed magnetic circuit. The limbs of the core 3 are each enclosed by two windings arranged concentrically to one another, only the outer high-voltage winding 4 of which is able to be seen. The windings are connected to the phases of a high-voltage grid carrying an AC voltage via bushings 5.

[0030] An expansion vessel 6 is used to compensate for temperature-induced volume fluctuations of the insulating fluid in the tank 2 of the transformer 1. A Buchholz relay 7 is able to be seen in the connecting line between the tank 2 and expansion vessel 6.

[0031] FIG. 1 also shows a portable acoustic sensor 2, which is illustrated purely schematically and which acquires the operating noise of the transformer 1 at four different locations A, B, C and D. The portable sensor 8 is connected to a communication unit 12, in this case a communication box, via a Bluetooth connection 11 as short-range communication connection. The communication box 12 is securely mounted on the outside to the wall of the tank 2. Said communication box has a storage unit on which the measurement values provided by the sensor 8 are stored in a spatially resolved manner. The communication box 12 is connected to a data processing cloud 9 via a long-range communication connection 13 every 2 minutes and sends the measurement values stored on its hard drive to a data processing cloud 9 via the long-range communication connection 13. Said data processing cloud carries out the analysis method described further above in order to detect asymmetrical vibrations.

[0032] Within the context of the invention, instead of a separate portable sensor 8, a mobile telephone can also be used for the purpose of sound measurement. To this end, the mobile telephone 8 contains software or an “app” that asks the person applying the method to perform the noise measurement over a predefined duration and then to change location in order to perform the measurement again there.

[0033] A microphone, not illustrated in the figures and already installed in the mobile telephone, is used for the noise measurement. The mobile telephone 8 stores the time-resolved acoustic signals generated by its microphone based on the measurement, after they have been digitized, in its storage unit, likewise not shown. The mobile telephone is subsequently connected to the data processing cloud 9 via the long-range connection and transmits the locally stored measurement values to the data processing cloud 9. Said data processing cloud comprises software that performs a Fourier transformation of the transmitted measurement values. This is followed by the formation of the ratio R, as already described above.

[0034] From the size of R, the method according to the invention derives whether and possibly to what extent asymmetrical vibrations are present and possibly to what order of magnitude the transformer is impacted by a DC current component. The user, by virtue of the result of the method, gains knowledge thereof and is then able to initiate appropriate countermeasures in order to suppress the possibly identified DC current component.

[0035] It is possible to access the data processing cloud using a laptop or computer 10 in order to obtain the result of the analysis.

[0036] FIG. 2 shows a further exemplary embodiment for carrying out the method according to the invention; a transformer 1 can again be seen as electrical device, said transformer substantially corresponding to the transformer shown in FIG. 1. However, in contrast to the transformer shown in FIG. 1, the transformer 1 in accordance with FIG. 2 has four sensors 8 arranged inside the tank 2. Each sensor 8 is connected to a communication unit 12, which is not securely fastened to the transformer 1 in the exemplary embodiment shown, via a short-range communication connection 11, which is again formed as a Bluetooth connection. Instead, the communication unit 12 is located in a nearby housing, which is not illustrated in the figures and which is placed approximately 20 m away from the transformer 1.

[0037] The communication unit 12 has four inputs so that all four sensors 8 are connected to the communication unit 12 at the same time. The noise or sound waves generated during operation of the transformer 1 are acquired by the sensors 8, which generate an analog electrical signal, in this case a current, depending on the amplitude of the sound waves. The analog signals are sampled and the sampling values obtained therefrom are digitized. The digitized values are referred to here as measurement values.

[0038] Said measurement values are transmitted to the communication unit 12 via the short-range communication connection 11. Said communication unit has a storage unit, which is not shown in the figures, in which the measurement values are stored.

[0039] In one variant of the method according to the invention, the measurement values are preprocessed, that is to say for example the measurement values transmitted at a two-second clock are averaged over a period of 2 min and the averaged values are stored in the storage unit. The communication unit 12 establishes a connection with the data processing cloud 9 via a long-range communication connection 13 every 2 min. The measurement values or the averaged measurement values or values derived from the measurement values are transmitted to the data processing cloud 9. Said data processing cloud then uses suitable software to examine the measurement values; in other words, a Fourier transformation is carried out and the spectrum thus obtained is examined for the presence of asymmetrical vibrations. The analysis method is described in more detail further above. Patent GC