Electrical machine component monitoring system and method

• US 8,422,008 B2
• Filed: 09/29/2010
• Issued: 04/16/2013
• Est. Priority Date: 09/29/2010
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Xia, Hua, Koste, Glen Peter, Busboom, Axel, Kaminski, Christopher Anthony
• Primary Examiner(s): STAFIRA, MICHAEL PATRICK
• Application Number:
  US12/893,115
• Publication Number:
  US 20120075633A1
• Time in Patent Office: 930 Days
• Field of Search: 3562371-2375
• US Class Current: 356/237.1
• CPC Class Codes: G01D 5/35316 using a Bragg gratings
• CPC Class Codes: G01D 5/35387 using wavelength division multiplexing
• CPC Class Codes: G01R 31/34 Testing dynamo-electric machines
• CPC Class Codes: H02K 11/25 Devices for sensing temperature, or actuated thereby
• CPC Class Codes: H02K 11/35 Devices for recording or transmitting machine parameters, e.g. memory chips or radio transmitters for diagnosis
• CPC Class Codes: H02K 15/00 Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines

Abstract

An electrical machine component monitoring system includes a light source that provides an optical signal through a fiber optic cable and a fiber optic sensing component positioned on the electrical machine component or at a standoff distance from the electrical machine component to obtain a responsive optical signal representative of a condition of the electrical machine component. The system further includes a photodetector to receive the responsive optical signal from the fiber optic sensing component and to convert the responsive optical signal to an electrical signal. A processing circuitry is also provided in the system for determining information regarding dirt on the electrical machine component by analyzing the electrical signal.

Claims

1. An electrical machine component monitoring system comprising:

a light source for providing an optical signal through a fiber optic cable;

a fiber optic sensing component positioned on the electrical machine component or at a standoff distance from the electrical machine component for producing a reflected optical signal representative of a condition of the electrical machine component;

a photodetector for receiving the reflected optical signal from the fiber optic sensing component and converting the reflected optical signal to an electrical signal; and

processing circuitry configured to determine information regarding dirt on the electrical machine component by analyzing the electrical signal.

2. The monitoring system of claim 1, wherein the processing circuitry is configured to further determine information regarding motion of the electrical machine component by analyzing the electrical signal.

3. The monitoring system of claim 1, wherein the processing circuitry determines information regarding dirt on the electrical machine component based on a transmission loss amplitude and a central wavelength shift of the fiber optic sensing component.

4. The monitoring system of claim 1, wherein the dirt comprises dust, oil, grease, particles induced from hot-spot burnt polymer particles, particles resulting from worn out winding insulation, or combinations thereof.

5. The monitoring system of claim 1, wherein the electrical machine component comprises a generator end winding component.

6. The monitoring system of claim 1, wherein when the fiber optic sensing component is positioned on the electrical machine component and the fiber optic sensing component comprises a long-period grating structure and is responsive to changes in the refractive index of a surrounding medium.

7. The monitoring system of claim 6, wherein the fiber optic sensing component further comprises a short-period Bragg grating structure for providing a signal useful in determining a baseline temperature and variations in the baseline temperature of the fiber optic sensing component.

8. The monitoring system of claim 7, wherein the fiber grating structures comprise a fiber cladding circumferentially disposed about a central fiber core.

9. The monitoring system of claim 7, wherein the fiber grating structures are packaged with a fiberglass plate or electrically insulated material and attached to the electrical machine component.

10. The monitoring system of claim 1, wherein when the fiber optic sensing component is positioned at a standoff distance from electrical machine component and the fiber optic sensing component is sensitive to dirt.

11. The monitoring system of claim 10, wherein the fiber optic sensing component is insensitive to temperature, pressure, and hydrogen cooling gas flow variation.

12. The monitoring system of claim 10, wherein the standoff distance comprises a working point distance from the electrical machine component for determining information regarding dirt.

13. The monitoring system of claim 10, wherein the fiber optic sensing component that is sensitive to dirt comprises a first fiber optic sensing component located at a first standoff distance.

14. The monitoring system of claim 10, further comprising a second fiber optic sensing component sensitive to motion, wherein the second fiber optic sensing component comprises an optical lens located at a distance from the electrical machine component that is less than that of the first standoff distance.

15. The monitoring system of claim 14, wherein the processing circuitry determines information regarding the motion by obtaining a fast Fourier transform (FFT) of the reflected optical signal from the second fiber optic sensing component.

16. The monitoring system of claim 14, wherein the processing circuitry determines information regarding motion by calculating the difference between the maximum and minimum distance in an optical signal time response waveform.

17. The monitoring system of claim 10, wherein the processing circuitry determines information regarding the dirt based on a comparison of the electrical signals with previously obtained electrical signals obtained under calibrated conditions.

18. The monitoring system of claim 10, wherein the fiber optic sensing component comprises a fiber probe housing including an optical lens and a transparent window glass.

19. The monitoring system of claim 10, wherein the fiber optic sensing component comprises a dielectric material ferrule comprising a plastic ferrule, a silicon monocoil or a polyvinyl chloride (PVC) monocoil.

20. The monitoring system of claim 10, wherein the light source comprises a single-frequency light source, RBG laser, or multi-wavelength broadband light source.

21. The monitoring system of claim 10, wherein the fiber optic cable comprises a plurality of fiber optic cables for carrying the initial optical signal from an optical splitter to a plurality of positions on the electrical machine component and for carrying reflected optical signals from the plurality of positions on the electrical machine component to a photodetector array, wherein the photodetector array comprises a plurality of photodetectors and is configured to convert the reflected optical signals to electrical signals.

22. A method for an electrical machine component monitoring comprising:

providing an optical signal onto the electrical machine;

measuring a reflected optical signal from a fiber optic sensing component positioned on the electrical machine component or at a standoff distance from the electrical machine component; and

determining information regarding dirt on the electrical machine component by analyzing the reflected optical signal.

23. The method of claim 22 further comprising determining information regarding motion of the electrical machine component by analyzing the reflected optical signal.