SYSTEM AND METHOD FOR DETERMINING POLE SHIFT

• US 20140225576A1
• Filed: 02/08/2013
• Published: 08/14/2014
• Est. Priority Date: 02/08/2013
• Status: Active Grant

• Current Assignee: Baker Hughes Holdings LLC (Baker Hughes Company)
• Original Assignee: General Electric Company
• Inventors: Grant, John Wesley, Jensen, Raymond Verle
• Granted Patent: US 8,912,766 B2
• Time in Patent Office: Days
• US Class Current: 322/99
• CPC Class Codes: H02K 11/20 for measuring, monitoring, testing, protecting or switching rectifiers H02K11/04; power electronics H02K11/33
• CPC Class Codes: H02K 2201/03 Machines characterised by aspects of the air-gap between rotor and stator
• CPC Class Codes: H02P 9/006 Means for protecting the generator by using control H02H7/06 takes precedence; control effected upon generator excitation circuit to reduce harmful effects of overloads or transients H02P9/10

Abstract

A system includes a first proximity sensor and a controller. The first proximity sensor is disposed in a first location of a stator and configured to transmit a first signal representative of a first distance between the first proximity sensor and a plurality of rotor poles. The controller is communicatively coupled to the first proximity sensor. The controller is configured to derive a first plurality of instantaneous airgaps based on the first signal and to determine a difference between a first instantaneous airgap of the first plurality of airgaps and a second instantaneous airgap of the first plurality of airgaps. The first plurality of instantaneous airgaps includes a first plurality of measurements of gaps between the stator and the plurality of rotor poles when the rotor is rotating.

Claims

1. A system, comprising:

a first proximity sensor disposed in a first location of a stator and configured to transmit a first signal representative of a first distance between the first proximity sensor and a plurality of rotor poles;

a controller communicatively coupled to the first proximity sensor, wherein the controller is configured to derive a first plurality of instantaneous airgaps based on the first signal and to determine a difference between a first instantaneous airgap of the first plurality of airgaps and a second instantaneous airgap of the first plurality of airgaps, wherein the first plurality of instantaneous airgaps comprises a first plurality of measurements of gaps between the stator and the plurality of rotor poles when the rotor is rotating.

2. The system of claim 1, wherein the first proximity sensor is configured to transmit a rotational signal representative of a first traverse of an indicator of the rotor, and the controller is configured to assign each instantaneous airgap of the first plurality of instantaneous airgaps to a respective rotor pole of the plurality of rotor poles based at least in part on the rotational signal.

3. The system of claim 2, comprising a second proximity sensor disposed in a second location of the stator and configured to transmit a second signal representative of a second distance between the second proximity sensor and the plurality of rotor poles, wherein the controller is communicatively coupled to the second proximity sensor, the controller is configured to derive a second plurality of instantaneous airgaps based on the second signal, and the controller is configured to assign each instantaneous airgap of the second plurality of instantaneous airgaps to the respective rotor pole of the plurality of rotor poles based at least in part on the rotational signal.

4. The system of claim 1, wherein the second instantaneous airgap is adjacent the first instantaneous airgap.

5. The system of claim 1, wherein the controller is configured to derive a plurality of airgap baselines based on at least one operational state.

6. The system of claim 1, wherein the controller is configured to derive a learning model to compare with the first plurality of instantaneous airgaps, wherein the learning model comprises a heuristic model, a neural network, an expert system, a genetic algorithm, or fuzzy logic, or a combination thereof.

7. The system of claim 1, wherein the controller is configured to derive a learning model based on at least one operational state and to use the learning model to determine if the rotor and stator are operating within a threshold.

8. The system of claim 1, wherein the controller is configured to derive a geometry of the rotor based at least in part on the first plurality of instantaneous airgaps.

9. A method, comprising:

sensing a first plurality of instantaneous airgaps between a plurality of rotor poles and a stator by using a first proximity sensor;

assigning each instantaneous airgap of the first plurality of instantaneous airgaps to a respective rotor pole of the plurality of rotor poles; and

determining a difference between each assigned instantaneous airgap and a baseline airgap for the respective rotor pole.

10. The method of claim 9, comprising determining the baseline airgap, wherein the baseline airgap for the respective rotor pole is based at least in part on an operational state of the rotor.

11. The method of claim 10, wherein determining the baseline airgap is based at least in part on an ambient air temperature, an ambient water temperature, or a combination thereof.

12. The method of claim 10, wherein determining the baseline airgap for the respective rotor pole is based at least in part on one or more assigned instantaneous airgaps of the first plurality of instantaneous airgaps.

13. The method of claim 9, comprising storing the first plurality of instantaneous airgaps as reference data, wherein the baseline airgap is based at least in part on the reference data.

14. The method of claim 13, comprising:

sensing a second plurality of instantaneous airgaps between the plurality of rotor poles and the stator using a second proximity sensor;

assigning each instantaneous airgap of the second plurality of instantaneous airgaps to the respective rotor pole of the plurality of rotor poles; and

storing the second plurality of instantaneous airgaps as reference data.

15. The method of claim 13, wherein the baseline airgap is based at least in part on a statistical model and the reference data.

16. The method of claim 13, wherein the baseline airgap is based at least in part on the output of a learning model, wherein the learning model comprises a heuristic model, a neural network, an expert system, a genetic algorithm, or fuzzy logic, or a combination thereof.

17. The method of claim 9, comprising producing an operator-perceptible notification if the difference is greater than a threshold.

18. A system, comprising:

a non-transitory tangible computer-readable medium comprising executable code, the executable code comprising instructions for;

sensing a first plurality of instantaneous airgaps between a plurality of rotor poles and a stator using a first proximity sensor;

assigning each instantaneous airgap of the first plurality of instantaneous airgaps to a respective rotor pole of the plurality of rotor poles; and

determining a plurality of differences corresponding to the difference between each assigned instantaneous airgap and a baseline airgap for the respective pole.

19. The system of claim 18, comprising a user interface configured to display visualizations representative of the plurality of differences.

20. The system of claim 18, wherein the system comprises a hydro generator.