Method and device for monitoring vibrations of the winding overhang in a generator

1. A method for monitoring vibrations of a winding overhang in a power generator, comprising the following steps:

detecting with a sensor vibrations of the winding overhang during operation of the generator;

transforming vibration signals representative of the vibrations that are received from the sensor into a frequency range;

transforming multiple individual vibration signals from the frequency range into a modal range;

detecting a power generator operating parameter of the generator, the operating parameter including at least one of active power, reactive power and cooling gas temperature at the winding overhang;

at least one of selecting and adapting a reference response based on the detected power generator operating parameter; and

determining deviations of modal forms or individual rod vibrations in relation to the reference response based on vibration signals in the modal range.

2. The method as claimed in claim 1 , further comprising checking and/or storing the vibration signals and/or the operating parameters.

3. The method as claimed in claim 1 , wherein the vibration signals and/or the operating parameters are reduced, checked and/or stored.

4. The method as claimed in claim 1 , wherein the transformation into the modal range and/or the individual rod vibrations is carried out in multiple measuring planes.

5. The method as claimed in claim 1 , wherein the modal forms, and/or individual rod vibrations and/or the deviations thereof are subjected to a limiting value consideration.

6. The method as claimed in claim 1 , wherein the modal forms and/or individual ones of the rod vibrations are subjected to a trend observation.

7. The method as claimed in claim 1 , wherein characteristic values of the modal forms and/or individual ones of the rod vibrations are fed to a counter.

8. The method as claimed in claim 1 , further comprising assessing vibrations of the winding overhang based on at least one of the modal forms, and/or the individual rod vibrations, the vibration signals and/or the stored frequency signals.

9. The method as claimed in claim 1 , wherein a signal analysis is carried out with regard to system faults.

10. A device for monitoring vibrations of a winding overhang in a power generator, the device comprising:

at least one vibration sensor configured to detect vibrations of the winding overhang;

an evaluation unit configured to evaluate vibration signals from the sensor, the evaluation unit comprising:

a modal transformer configured to transform multiple individual vibration signals of the vibration signals into a modal range;

a selector configured to select or to adapt a reference response based on an operating parameter of the power generator, the operating parameter including at least one of active power, reactive power and cooling gas temperature at the winding overhang; and

a comparator configured to determine deviations of the modal forms and/or individual rod vibrations in relation to the reference response.

11. The device as claimed in claim 10 , wherein the sensor is a fiber-optic acceleration or vibration sensor, or a piezoelectric sensor.

12. The device as claimed in claim 10 , wherein the sensor is arranged centrally between two winding rods or control rods ( 16 b ) in the generator.

13. The device as claimed in claim 10 , further comprising:

further sensors configured to detect operating parameters of the generator, the operating parameters including the operating parameter, and the further sensors are arranged at the winding overhang and connected to the evaluation unit.

14. The device as claimed in claim 13 , wherein the selector is configured to select the reference response on the basis of a signal from at least one of the further sensors.

15. A device for monitoring vibrations of a winding overhang in a generator, the device comprising:

at least one vibration sensor configured to detect vibrations of the winding overhang;

an evaluation unit configured to evaluate vibration signals from the sensor, the evaluation unit comprising:

a modal transformer configured to transform multiple individual vibration signals of the vibration signals into a modal range;

a selector configured to select or to adapt a reference response based on an operating parameter of the generator, the operating parameter including at least one of active power and reactive power; and

a comparator configured to determine deviations of the modal forms and/or individual rod vibrations in relation to the reference response.