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

Abstract

A method identifies asymmetrical vibrations during the operation of an electric device which is connected to a high-voltage grid. Vibrations of the electric device are detected using vibration sensors which provide measured values on the output side. The measured values and/or values derived from the measured values are transmitted to a communication unit via a close-range communication connection. The measured values and/or the values are transmitted by the communication unit to a data processing cloud via a far-range communication connection. 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 based on 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 for identifying asymmetrical vibrations when operating an electrical device being connected to a high-voltage supply grid, which comprises the steps of: acquiring vibrations which arise during operation of the electrical device by means of vibration pickups 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 by the data processing cloud by means of a Fourier transformation so as to obtain a frequency spectrum; ascertaining odd and even frequency components of the frequency spectrum on a basis of a fundamental frequency of the high-voltage supply grid and are set into a ratio R with one another; and indicating a presence of the asymmetrical vibrations if the ratio R exceeds a predetermined threshold value.

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

11. The method according to claim 10, which further comprises ascertaining a geographic location of the communication unit and the electrical device connected thereto and transmitting the geographic location to the data processing cloud by means of an antenna for position determination, which is disposed 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, wherein the vibration pickups each acquire the vibrations at different locations of the electrical device.

14. The method according to claim 9, which further comprises acquiring the vibrations over a predefined period.

15. A computer program for a computation device, the computer program comprising: computer executable instructions for executing the method according to claim 9.

16. A non-transitory storage medium storing a computer program having computer executable instructions for performing the method according to claim 9.

Description

[0027] 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

[0028] FIG. 1 schematically illustrates an exemplary embodiment of the method according to the invention and

[0029] FIG. 2 schematically illustrates a further exemplary embodiment of the invention.

[0030] 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 in each case connected to the phases of a high-voltage grid carrying an AC voltage via bushings 5.

[0031] 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.

[0032] FIG. 1 also shows a vibration pickup 2, which is illustrated purely schematically and which acquires the vibrations of the transformer 1 at two different locations A and B. The vibration pickup 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 vibration pickup 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 of the electrical device 1.

[0033] The data processing cloud 9 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. 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, has knowledge of the DC current component and is then able to initiate appropriate countermeasures in order to suppress the possibly identified DC current component.

[0034] It is possible to access the data processing cloud using a laptop or computer 10 in order to obtain the result of the analysis.

[0035] 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 vibration pickups 8 arranged inside the tank 2. Each vibration pickup 8 is connected to a communication unit 12, configured as a communication box, 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.

[0036] 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 vibrations 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 vibrations or oscillations.

[0037] 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.