GENERATOR PROTECTION SYSTEM

• US 20120086947A1
• Filed: 10/08/2010
• Published: 04/12/2012
• Est. Priority Date: 10/08/2010
• Status: Active Grant

• Current Assignee: Michael L. Bazzone
• Original Assignee: Michael L. Bazzone
• Inventors: Bazzone, Michael L.
• Granted Patent: US 8,139,905 B1
• Time in Patent Office: Days
• US Class Current: 356/477
• CPC Class Codes: G01K 11/3206 at discrete locations in the fibre, e.g. using Bragg scattering
• CPC Class Codes: G01K 13/08 in rotary movement
• CPC Class Codes: G02B 6/02204 using thermal effects, e.g. heating or cooling of a temperature sensitive mounting body optical modulation using thermo-optic effect G02F1/0147
• CPC Class Codes: H04J 14/02 Wavelength-division multiplex systems

Abstract

A temperature sensor is disclosed. The sensor includes an optical fiber and at least one twin-grating structure formed on the optical fiber. Each twin-grating structure includes a first optical grating structure, a second optical grating structure adjacent the first optical grating structure, and a sensing cavity disposed between the first and second optical grating structures. Each twin-grating structure is selectively responsive to a unique wavelength of light to generate an optical interference fringe signal. For each twin-grating structure, an optical property of the twin-grating structure and a phase of the optical interference fringe signal generated by the twin-grating structure are determined by a temperature of the twin-grating structure.

Claims

1. A temperature sensor, comprising:

an optical fiber;

at least one twin-grating structure formed on the optical fiber, each twin-grating structure comprising;

a first optical grating structure, a second optical grating structure adjacent the first optical grating structure, and a sensing cavity disposed between the first and second optical grating structures, each twin-grating structure selectively responsive to a unique wavelength of light to generate an optical interference fringe signal;

wherein, for each twin-grating structure, an optical property of the twin-grating structure and a phase of the optical interference fringe signal generated by the twin-grating structure are determined by a temperature of the twin-grating structure.

2. The sensor of claim 1, comprising a plurality of twin-grating structures formed on the optical fiber.

3. The sensor of claim 1, comprising a polymer coating disposed over each twin-grating structure.

4. The sensor of claim 3, wherein the polymer coating comprises a polyamide coating.

5. The sensor of claim 1, comprising a tube to contain the optical fiber and to reduce non-temperature induced strain applied to the optical fiber.

6. A system, comprising:

at least one temperature sensor, each temperature sensor comprising;

an optical fiber;

at least one twin-grating structure formed on the optical fiber, each twin-grating structure comprising;

a first optical grating structure, a second optical grating structure adjacent the first optical grating structure, and a sensing cavity disposed between the first and second optical grating structures, each twin-grating structure selectively responsive to a unique wavelength of light to generate an optical interference fringe signal;

wherein, for each twin-grating structure, an optical property of the twin-grating structure and a phase of the optical interference fringe signal generated by the twin-grating structure are determined by a temperature of the twin-grating structure;

a laser source coupled to each temperature sensor to input light into the optical fiber, the laser source configured to output the unique wavelength of each twin-grating structure formed on the optical fiber;

for each temperature sensor, an optical detector coupled to the optical fiber, wherein when the laser source outputs the unique wavelength of a twin-grating structure formed on the optical fiber, the optical detector receives the optical interference fringe signal to generate a corresponding electrical interference fringe signal; and

a processor coupled to the optical detector of each temperature sensor, the processor programmed to, for each twin-grating-structure of each temperature sensor, extract a target fringe of the optical interference fringe signal based on a digital representation of the electrical interference fringe signal and track variation in a phase of the target fringe over time to determine variation in the temperature.

7. The system of claim 6, comprising a plurality of temperature sensors.

8. The system of claim 6, comprising at least one temperature sensor having a plurality of twin-grating structures formed on the optical fiber.

9. The sensor of claim 6, wherein at least one temperature sensor comprises a polymer coating disposed over the optical fiber.

10. The sensor of claim 9, wherein the polymer coating comprises a polyamide coating.

11. The sensor of claim 6, wherein at least one temperature sensor comprises a tube to contain the optical fiber and to reduce non-temperature induced strain applied to the optical fiber.

12. The system of claim 6, wherein the laser source comprises a tunable laser diode.

13. The system of claim 12, wherein the processor is programmed to control the laser diode to interrogate a temperature sensor by causing the laser diode to sweep over a working wavelength of the laser diode, the working wavelength comprising the unique wavelength of each twin-grating structure formed on the optical fiber of the temperature sensor.

14. The system of claim 13, wherein the processor is programmed to control the laser source in a wavelength division multiplexing (WDM) mode.

15. The system of claim 13, wherein the processor is programmed to control the laser source in a frequency division multiplexing (FDM) mode.

16. The system of claim 6, wherein a first temperature sensor is disposed in a stator core of a generator, and wherein the processor is programmed to monitor temperature variations of each twin-grating structure based on the tracked variation in the phases of the corresponding target fringes.

17. The system of claim 6, wherein a first temperature sensor is in contact with at least one parallel ring connection of a generator, and wherein the processor is programmed to monitor temperature variations of each twin-grating structure based on the tracked variation in the phases of the corresponding target fringes.

18. The system of claim 6, wherein a first temperature sensor is in contact with at least phase connection of a generator, and wherein the processor is programmed to monitor temperature variations of each twin-grating structure based on the tracked variation in the phases of the corresponding target fringes.

19. The system of claim 6, wherein a first temperature sensor is in contact with at least one stator coil connection of a generator, and wherein the processor is programmed to monitor temperature variations of each twin-grating structure based on the tracked variation in the phases of the corresponding target fringes.

23. The system of claim 6, wherein a first temperature sensor comprises one twin-grating structure and is disposed in a fluid flow of a power generator system, and wherein the processor is programmed to monitor temperature variations of the twin-grating structure based on the tracked variation in the phase of the corresponding target fringe.

24. The system of claim 6, wherein a first temperature sensor comprises one twin-grating structure and is disposed in an oil reservoir of a power generator system, and wherein the processor is programmed to monitor temperature variations of the twin-grating structure based on the tracked variation in the phase of the corresponding target fringe.

20. The system of 6, wherein a first temperature sensor is in contact with at least one main lead connection of a generator, and wherein the processor is programmed to monitor temperature variations of each twin-grating structure based on the tracked variation in the phases of the corresponding target fringes.

21. The system of 6, wherein a first temperature sensor is in contact with at least one end winding of a generator, and wherein the processor is programmed to monitor temperature variations of each twin-grating structure based on the tracked variation in the phases of the corresponding target fringes.

22. The system of 6, wherein a first temperature sensor is in contact with at least one lead box of a generator, and wherein the processor is programmed to monitor temperature variations of each twin-grating structure based on the tracked variation in the phases of the corresponding target fringes.