Method for detecting coolant leaks in generators

Patent metadata

Field	Value
Publication number	US-9488629-B2
Application number	US-201414249581-A
Country	US
Kind code	B2
Filing date	Apr 10, 2014
Priority date	Apr 10, 2014
Publication date	Nov 8, 2016
Grant date	Nov 8, 2016

Abstract

A system and method for detecting a gas leak in a generator is provided. The system includes a source of a non-corrosive tracer gas, and a subsystem for introducing the non-corrosive tracer gas into the hydrogen cooled generator. An infrared imaging device is adapted to communicate with a notification device to display an image of at least a portion of the hydrogen cooled generator and the non-corrosive tracer gas. The infrared imaging device includes a cooled detector, and a filter with a spectral response between about 3 μm and about 5 μm. The detector and/or the filter is cooled to between about −80° C. and about −200° C. The gas leak will be indicated on the notification device. The generator may hydrogen cooled, and on-line or on-grid.

First claim

The invention claimed is:

1. A method for detecting a gas leak in a generator, the method comprising:
disposing an infrared imaging device having a cooled detector with a filter having a spectral response between 3 μm to 5 μm with a field of view encompassing at least a portion of the generator;
introducing a tracer gas into the generator, the generator is on-line and the tracer gas has an absorption spectrum of between 3 μm and 5 μm;
filtering radiation received by the infrared imaging device in the absorption spectrum of the tracer gas;
displaying a notification on a notification device, the displaying step including displaying a moving cloud on the notification device if a leak is detected, comparing one or more previous video frames with a current video frame, identifying a predetermined difference between the one or more previous video frames and the current video frame, assigning a foreground color to pixels having the predetermined difference, the foreground color having a contrast to the other pixels in a display of the notification device, displaying the pixels having the predetermined difference in the foreground color on the display, overlaid with the current video frame, and wherein the gas leak will be indicated by the notification on the notification device.

2. The method of claim 1 , wherein the disposing step includes using a movable cart that contains at least one of the infrared imaging device or the notification device to position the infrared imaging device or the notification device around the generator.

3. The method of claim 1 , wherein the generator is a hydrogen cooled generator, and wherein the step of introducing the tracer gas comprises removing some of the hydrogen to lower pressure in the generator by 2 PSI to 10 PSI.

4. The method of claim 3 , wherein the step of introducing the tracer gas comprises injecting carbon dioxide into the generator until the pressure in the generator rises by 2 PSI to 10 PSI.

5. The method of claim 1 , wherein the generator is a hydrogen cooled generator, the method further comprising:
controlling an injection flow of the non-corrosive tracer gas based upon feedback of a gas pressure, an H2 purity, and flow of an H2 scavenging pipe,
wherein an automatic tracer gas control system targets gradual reduction of the H2 purity while keeping the gas pressure inside of the generator substantially stable, and the gas pressure swing is within 5% of a gas pressure original value.

6. The method of claim 5 wherein the step of introducing the tracer gas further comprises:
injecting carbon dioxide into the generator, the generator having a cooling gas media of argon or nitrogen while the generator is on turning gears or on-line.

7. The method of claim 1 , wherein the generator is a hydrogen cooled generator and, wherein the step of introducing the tracer gas comprises injecting carbon dioxide into the generator until the hydrogen purity inside the generator is 90% to 95%.

8. The method of claim 1 , wherein the step of introducing the tracer gas comprises injecting carbon dioxide into the generator, monitoring the weight of carbon dioxide used, and ceasing injection of carbon dioxide when a predetermined weight has been reached.

9. The method of claim 1 , wherein the filter step includes filtering the radiation with a filter having a spectral response between 4.2 μm and 4.5 μm.

10. The method of claim 1 , the display step further comprising:
comparing one or more previous video frames with a current video frame;
identifying a predetermined difference between the one or more previous video frames and the current video frame;
assigning a foreground color to a border surrounding the pixels having the predetermined difference, the foreground color having a contrast to the other pixels in the display;
displaying the border, around the pixels having the predetermined difference, in the foreground color on a display of the notification device, the border overlaid with the current video frame.

11. The method of claim 1 , the display step further comprising:
comparing one or more video frames with an adjacent video frame;
identifying a predetermined difference between the one or more video frames and the adjacent video frame;
assigning at least one of, a foreground color to pixels having the predetermined difference or a foreground color to a border surrounding the pixels having the predetermined difference, the foreground color having a contrast to other pixels in the display;
displaying at least one of, the pixels having the predetermined difference in the foreground color on a display of the notification device or the border in the foreground color on the display around the pixels having the predetermined difference, overlaid with a current video frame.

12. A method for detecting a gas leak in a generator, the method comprising:
disposing an infrared imaging device having a cooled detector with a filter having a spectral response between 3 μm to 5 μm with a field of view encompassing at least a portion of the generator;
introducing a tracer gas into the generator, the generator is on-line and the tracer gas has an absorption spectrum of between 3 μm to 5 μm;
filtering radiation received by the infrared imaging device in the absorption spectrum of the tracer gas;
displaying a notification on a notification device, the displaying step including displaying a moving cloud on the notification device if a leak is detected, comparing one or more previous video frames with a current video frame, identifying a predetermined difference between the one or more previous video frames and the current video frame, assigning a foreground color to a border surrounding the pixels having the predetermined difference, the foreground color having a contrast to the other pixels in the display, displaying the border, around the pixels having the predetermined difference, in the foreground color on a display of the notification device, the border overlaid with the current video frame, and wherein the gas leak will be indicated by the notification on the notification device.

13. The method of claim 12 , wherein the disposing step includes using a movable cart that contains at least one of the infrared imaging device or the notification device to position the infrared imaging device or the notification device around the generator.

14. The method of claim 12 , wherein the generator is a hydrogen cooled generator, and wherein the step of introducing the tracer gas comprises removing some of the hydrogen to lower pressure in the generator by 2 PSI to 10 PSI.

15. The method of claim 12 , wherein the step of introducing the tracer gas comprises injecting carbon dioxide into the generator until the pressure in the generator rises by 2 PSI to 10 PSI.

16. The method of claim 12 , wherein the generator is a hydrogen cooled generator, the method further comprising:
controlling an injection flow of the non-corrosive tracer gas based upon feedback of a gas pressure, an H2 purity, and flow of an H2 scavenging pipe,
wherein an automatic tracer gas control system targets gradual reduction of the H2 purity while keeping the gas pressure inside of the generator substantially stable, and the gas pressure swing is within 5% of a gas pressure original value.

17. The method of claim 12 , wherein the step of introducing the tracer gas further comprises:
injecting carbon dioxide into the generator, the generator having a cooling gas media of argon or nitrogen while the generator is on turning gears or on-line.

18. The method of claim 12 , wherei

Assignees

• Gen Electric

Inventors

• Xu James Jun
• Grant James Jonathan
• Bjorklund Marlowe Cameron
• Clark James Wilson

Classifications

• G01N33/004 Primary

  CO or CO2 · CPC title

• G01N25/72

  Investigating presence of flaws · CPC title

• G01N21/3504

  for analysing gases, e.g. multi-gas analysis · CPC title

• G01M3/38

  by using light (G01M3/02 takes precedence) · CPC title

• G01M3/228 Primary

  for radiators · CPC title