1. A computer implemented method comprising:
using multiple sensors to monitor a wind turbine generator and provide signals representative of operation of the wind turbine generator;
extracting signal level features from the signals;
extracting model based features from the signals;
calculating signal based conclusions, model based conclusions and spectral feature reinforcement based conclusions; and
fusing the conclusions to provide a fault detection indication.
2. The method of claim 1 wherein the signals representative of operation of the wind turbine generator comprise spectrum information of generator current, voltage and vibration.
3. The method of claim 2 wherein calculating conclusions comprises:
normalizing the spectrum information; and
extracting windows of normalized spectral information from each of current, voltage and vibration spectrum.
4. The method of claim 3 wherein fusing the conclusions comprises:
combining the normalized windowed spectral information to provide spectral signatures of faults; and
finalizing diagnostics based on detection from the spectral signatures.
5. The method of claim 4 and further comprising trending the spectral signatures over time along with normalized failure peak strengths to provide an estimate of fault progression.
6. The method of claim 1 wherein spectrum information is generated by at least one of fast Fourier transforms, time frequency analysis, and multimodal resolution analysis.
7. The method of claim 1 and further comprising receiving wind generator shaft speed information for use in fusing the conclusions.
8. The method of claim 1 and further comprising receiving temperature information for use in fusing the conclusions.
9. The method of claim 1 wherein fusing the conclusions comprises adding normalized values for voltage spectrum information, current spectrum information, and vibration spectrum information using a knowledge based transform.
10. A non-transitory computer readable storage device having instructions stored thereon to cause a computer system to implement a method, the method comprising:
using multiple sensors to monitor a wind turbine generator and provide signals representative of operation of the wind turbine generator;
extracting signal level features from the signals;
extracting model based features from the signals;
calculating signal based conclusions, model based conclusions and spectral feature reinforcement based conclusions; and
fusing the conclusions to provide a fault detection indication.
11. The non-transitory computer readable storage device of claim 10 wherein the signals representative of operation of the wind turbine generator comprise spectrum information of generator current, voltage and vibration.
12. The non-transitory computer readable storage device of claim 11 wherein calculating conclusions comprises:
normalizing the spectrum information; and
extracting windows of normalized spectral information from each of current, voltage and vibration spectrum.
13. The non-transitory computer readable storage device of claim 12 wherein fusing the conclusions comprises:
combining the normalized windowed spectral information to provide spectral signatures of faults; and
finalizing diagnostics based on detection from the spectral signatures.
14. The non-transitory computer readable storage device of claim 13 and further comprising trending the spectral signatures over time along with normalized failure peak strengths to provide an estimate of fault progression.
15. The non-transitory computer readable storage device of claim 10 wherein spectrum information is generated by at least one of fast Fourier transforms, time frequency analysis, and multimodal resolution analysis.
16. The non-transitory computer readable storage device of claim 10 and further comprising receiving wind generator shaft speed information for use in fusing the conclusions.
17. The non-transitory computer readable storage device of claim 10 and further comprising receiving temperature information for use in fusing the conclusions.
18. The non-transitory computer readable storage device of claim 10 wherein fusing the conclusions comprises adding normalized values for voltage spectrum information, current spectrum information, and vibration spectrum information using a knowledge based transform.
19. A system comprising:
a module to receive multiple sensors to monitor a wind turbine generator and provide signals representative of operation of the wind turbine generator;
a module to extract signal level features from the signals;
a module to extract model based features from the signals;
a module to calculate signal based conclusions, model based conclusions and spectral feature reinforcement based conclusions; and
a module to fuse the conclusions to provide a fault detection indication.
20. The system of claim 19 and further comprising:
a module to receive wind generator shaft speed information;
a module to receive temperature information;
a module to provide feature extraction from the signal level features comprising voltage and current;
a module to provide feature extraction from the signal level features comprising vibration signals; and
a module to provide feature extraction from a combination of voltage, current, and vibration, wherein the shaft speed information and temperature information are used by the module to fuse the conclusions to provide the fault detection indication.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1-16. (canceled)
17. Method for producing a watermark element for forming a shadow watermark image in a substrate by means of dewatering of a fibrous suspension, wherein the watermark element comprises a body with a relief side having a relief and a dewatering side positioned opposite the relief side, perforations being provided at least in the relief, a perforation comprising a channel with a channel inlet at the relief side and a channel outlet at the dewatering side, the method comprising:
forming perforations in the body in a mechanical manner by a mechanical machining process; and
introducing the relief in the intended relief side;
wherein the perforations are formed in such a way that the dewatering capacity, expressed as the open surface area of the channel inlet(s) per unit of surface area of the relief, is dependent on the height (h) of the channel inlet with respect to the dewatering side; and
wherein the higher the height, the lower the dewatering capacity.
18. Method according to claim 17, wherein the perforations comprise a channel that as a whole tapers conically from the channel outlet in the direction of the channel inlet, the channel outlets having an equally flow-through surface area.
19. Method according to claim 18, wherein the cross section of a channel inlet is linearly dependent on the height (h) of the channel inlet.
20. Method according to claim 17, wherein the perforations comprise channels having a cross section (c) that is constant over the length, the cross section being dependent on the height (h) of the channel inlet with respect to the dewatering side.
21. Method according to claim 17, wherein the perforations comprise channels having a cross section that is constant over the length, and the perforation density is dependent on the height (h) in the relief with respect to the dewatering side.
22. Method according to claim 17, wherein the radius of a perforation is linearly dependent on its vertical position in the relief.
23. Watermark element for forming a shadow watermark image in a substrate by means of dewatering of a fibrous suspension, the watermark element comprising:
a body with a relief side having a relief and a dewatering side positioned opposite the relief side;
perforations provided at least in the relief;
the perforations comprising a channel with a channel inlet at the relief side and a channel outlet at the dewatering side;
wherein the perforations are designed in such a way that the dewatering capacity, expressed as the open surface area of the channel inlet(s) per unit of surface area of the relief, is dependent on the height (h) of the channel inlet with respect to the dewatering side;
wherein the higher the height, the lower the dewatering capacity; and
wherein the cross section of a channel inlet is linearly dependent on the height (h) of the channel inlet.
24. Watermark element according to claim 23, wherein the perforations comprise a channel that as a whole tapers conically from the channel outlet in the direction of the channel inlet, the channel outlets having an equally flow-through surface area.
25. Watermark element according to claim 23, wherein the perforations comprise channels having a cross section (c) that is constant over the length, the cross section being dependent on the height (h) of the channel inlet with respect to the dewatering side.
26. Watermark element for forming a shadow watermark image in a substrate by means of dewatering of a fibrous suspension, the watermark element comprising:
a body with a relief side having a relief and a dewatering side positioned opposite the relief side;
perforations provided at least in the relief;
the perforations comprising a channel with a channel inlet at the relief side and a channel outlet at the dewatering side;
wherein the perforations are designed in such a way that the dewatering capacity, expressed as the open surface area of the channel inlet(s) per unit of surface area of the relief, is dependent on the height (h) of the channel inlet with respect to the dewatering side;
wherein the higher the height, the lower the dewatering capacity;
wherein the perforations comprise channels having a cross section which is constant over the length; and
wherein perforation density is dependent on the height (h) in the relief with respect to the dewatering side.
27. Watermark element for forming a shadow watermark image in a substrate by means of dewatering of a fibrous suspension, the watermark element comprising:
a body with a relief side having a relief and a dewatering side positioned opposite the relief side;
perforations provided at least in the relief;
the perforations comprising a channel with a channel inlet at the relief side and a channel outlet at the dewatering side;
wherein the perforations are designed in such a way that the dewatering capacity, expressed as the open surface area of the channel inlet(s) per unit of surface area of the relief, is dependent on the height (h) of the channel inlet with respect to the dewatering side;
wherein the higher the height, the lower the dewatering capacity; and
wherein the radius of a perforation is linearly dependent on its vertical position in the relief.
28. Dewatering screen for producing paper from a fibrous suspension, comprising one or more layers of screen material, the outer layer of which is provided with one or more watermark elements, produced in accordance with the method according to claim 17.
29. Dewatering screen according to claim 28, wherein at least the outer layer of which is a plate-shaped material with perforations.
30. Method for producing a sheet-shaped substrate with a watermark comprising forming a sheet by dewatering of a fibrous suspension on a dewatering screen according to claim 28.
31. Security paper provided with one or more watermarks, wherein at least one of the one or more watermarks is at least partially constructed from a collection of discontinuities of fibrous material having more than two different thicknesses, the amount of fibrous material in a discontinuity being proportional to the thickness thereof.
32. Document comprising security paper according to claim 31.
33. Dewatering screen for producing paper from a fibrous suspension, comprising one or more layers of screen material, the outer layer of which is provided with one or more watermark elements according to claim 23.