Method and device for determining and/or monitoring the breakdown voltage of a transformer oil

1. A method for determining and/or monitoring the breakdown voltage of a transformer oil, comprising the steps of

a) performing an acoustic impedance measurement of the transformer oil, the impedance of a medium partially or entirely disposed in the transformer oil and capable of naturally vibrating and/or transmitting vibrations to the transformer oil being determined in at least one frequency band of defined frequency width; and

b) calculating a resonator quality factor for the frequency band based on the determination performed in step a); and

c) calculating an acoustic disbalance of the transformer oil based on the calculation performed in step b); and

d) ascertaining the breakdown voltage of the transformer oil based on the calculation performed in step c).

2. The method according to claim 1 ,

wherein the method comprises an additional step c1) after step c):

c1) registering at least one value of at least one characteristic physical property of the transformer oil.

3. The method according to claim 2 ,

wherein at least one value of the temperature of the transformer oil is registered in step c1).

4. The method according to claim 2 ,

wherein the method comprises an additional step c2) after step c1):

c2) calculating the water content and/or the relative saturation in the transformer oil.

5. The method according to claim 1 ,

wherein, in step a), the impedance is determined in four frequency bands each having a defined frequency width of 75 kHz.

6. The method according to claim 1 ,

wherein the method additionally comprises the step of:

e) displaying the ascertainment performed in step d).

7. A device for determining and/or monitoring the breakdown voltage of a transformer oil according to claim 1 , comprising

a) a first medium for performing an acoustic impedance measurement of the transformer oil, the impedance of the first medium, which is partially or entirely disposed in the transformer oil and capable of naturally vibrating or transmitting vibrations to the transformer oil, is determined in at least one frequency band of defined frequency width; and

b) at least one analyzing and/or evaluating unit for calculating a resonator quality factor for the frequency band, for calculating an acoustic disbalance of the transformer oil and for ascertaining the breakdown voltage of the transformer oil.

8. The device according to claim 7 ,

wherein the device comprises a second medium for registering at least one value of at least one characteristic physical property of the transformer oil.

9. The device according to claim 7 ,

wherein the device comprises an output unit for displaying the ascertainment performed by the analyzing and/or evaluating unit.

10. The device according to claim 1 ,

wherein the first medium, the second medium, the analyzing and/or evaluating unit and/or the output unit is disposed in one component.

11. The device according to claim 10 , wherein the component is a measuring chamber, a stick and/or an adapter.

12. The device according to claim 7 ,

wherein the device comprises a heating device.

13. A device of high-voltage technology, comprising transformer oil and a means for connecting the device to the device according to claim 7 , the connection being a direct connection.

14. The device of high-voltage technology of claim 13 , wherein the device of high-voltage technology comprises a transformer, a capacitor, a Petersen coil and/or a switch.