Fiber optic sensing system for grid-based assets

Patent metadata

Field	Value
Publication number	US-2021123775-A1
Application number	US-201916665015-A
Country	US
Kind code	A1
Filing date	Oct 28, 2019
Priority date	Oct 24, 2019
Publication date	Apr 29, 2021
Grant date	—

Abstract

A sensor system includes a sensor network comprising at least one optical fiber having one or more optical sensors. At least one of the optical sensors is arranged to sense vibration of an electrical device and to produce a time variation in light output in response to the vibration. A detector generates an electrical time domain signal in response to the time variation in light output. An analyzer acquires a snapshot frequency component signal which comprises one or more time varying signals of frequency components of the time domain signal over a data acquisition time period. The analyzer detects a condition of the electrical device based on the snapshot frequency component signal.

First claim

1 . A sensor system comprising:
a sensor network comprising at least one optical fiber that includes one or more optical sensors, the optical sensors arranged to sense vibration of an electrical device and to produce a time varying light output in response to the vibration; at least one detector configured to generate an electrical time domain signal in response to the time varying light output of at least one optical sensor of the sensor network; and an analyzer configured to:
acquire at least one snapshot frequency component signal comprising one or more time varying signals of frequency components of the time domain signal over a data acquisition time period; and
detect a condition of the electrical device based on the snapshot frequency component signal.

2 . The sensor system of claim 1 , wherein the analyzer is further configured to:
compare at least one snapshot frequency component signal to a known frequency component template corresponding to a condition of the electrical device; and detect the presence or amount of the condition based on the comparison.

3 . The system of claim 1 , wherein:
the electrical device is electrically connected to a power grid; and the snapshot frequency component signal includes a frequency of the power grid and one or more harmonics thereof.

4 . The system of claim 1 , wherein the analyzer is configured to perform a time-frequency transformation of the time domain signal.

5 . The system of claim 1 , wherein the analyzer is configured to detect the condition based on amplitudes or amplitude ratios of frequency components of the snapshot frequency component signal.

6 . The system of claim 1 , wherein the analyzer is configured to:
develop a trend of changes in the snapshot frequency component signal over time; and detect a change in the condition based on the trend.

7 . A method comprising:
optically sensing vibration of an electrical device and producing a time variation in light output from at least one optical sensor in response to the vibration; generating an electrical time domain vibration signal representing the time variation in light output; acquiring at least one snapshot frequency component signal comprising one or more a time varying frequency components of the time domain signal over a data acquisition time period; and detecting condition of the electrical device based on the snapshot frequency component signal.

8 . A sensor system comprising:
a sensor network comprising at least one optical fiber including one or more optical sensors, the optical sensors arranged to sense one or more parameters of an electrical device; at least one detector configured to generate an electrical time domain signal in response to a time variation in light output of at least one optical sensor of the sensor network; an analyzer configured to:
identify changes in a first parameter of the electrical device based on analysis of the time domain signal of the optical sensor over a first data acquisition period; and
identify changes in a second parameter of the electrical device based on analysis of the time domain signal of the optical sensor over a second data acquisition period that is shorter than the first data acquisition period.

9 . The system of claim 8 , wherein the first parameter is internal temperature of the electrical device and the second parameter is vibration of the electrical device.

10 . The system of claim 8 , wherein the first parameter is ambient temperature external and proximate to the electrical device and the second parameter is vibration of the electrical device.

11 . The system of claim 8 , wherein:
the at least one optical sensor comprises multiple optical sensors; the detector is configured to respectively detect multiple time domain signals of the multiple optical sensors over the first data acquisition period or the second data acquisition period; and the analyzer is configured to identify a parameter distribution within the electrical device based on analysis of the multiple time domain signals over the first data acquisition period or the second data acquisition period.

12 . The system of claim 11 , wherein the parameter distribution is a temperature distribution.

13 . The system of claim 8 , wherein the analyzer is configured to:
develop a correlation between vibration signals at different sensing points; and detect a change in the presence or amount of the condition based on a change in the correlation.

14 . The system of claim 8 , wherein the analyzer is configured to:
develop a correlation between two or more different sensed parameter signals; and detect a change in the presence or amount of the condition based on a change in the correlation.

15 . The method of claim 14 , wherein two or more different sensed parameter signals include a vibration signal and a temperature signal.

16 . A sensor system comprising:
a sensor network comprising at least one optical fiber that includes at least one optical sensor arranged to sense vibration of an electrical device and to produce a time variation in light output from the sensor in response to the vibration; at least one detector configured to generate an electrical time domain signal in response to the time variation in light output; and an analyzer configured to:
identify eigenfrequencies of the electrical device represented in the time domain signal; and
detect a condition of the electrical device based on a change in the eigenfrequencies.

17 . The sensor system of claim 16 , wherein the analyzer is configured to:
trend a characteristic of the eigenfrequencies over time; and determine the condition based on the trend.

18 . The sensor system of claim 17 , wherein the characteristic of the eigenfrequencies comprises one or more of amplitude, frequency, and damping condition upon pulse-like impact.

19 . A method comprising:
optically sensing vibration of an electrical device using at least one optical sensor and producing a time variation in light output from the optical sensor in response to the vibration; generating an electrical time domain signal representing the time variation in light output from the optical sensor; identifying one or more eigenfrequencies of the electrical device represented in the time domain signal; and detecting a condition of the electrical device based on the eigenfrequencies.

Assignees

• Palo Alto Res Ct Inc

Inventors

• Kiesel Peter
• Raghavan Ajay
• Karin Todd
• Chen Qiushu

Classifications

• G01M11/083

  by using an optical fiber in contact with the device under test [DUT] · CPC title

• G01L1/246

  using integrated gratings, e.g. Bragg gratings · CPC title

• G01L1/242

  the material being an optical fibre · CPC title

• G01D5/35345 Primary

  using Amplitude variations to detect the measured quantity · CPC title

• G01K11/32

  using changes in transmittance, scattering or luminescence in optical fibres · CPC title