U.S. patent application number 14/266189 was filed with the patent office on 2014-08-21 for apparatus and method for on-line, real-time analysis of chemical gasses dissolved in transformer oil.
This patent application is currently assigned to VIRGINIA POLYTECHNIC INSTITUTE & STATE UNIVERSITY. The applicant listed for this patent is Bo Dong, Jinamin Gong, Anbo Wang. Invention is credited to Bo Dong, Jinamin Gong, Anbo Wang.
Application Number | 20140233034 14/266189 |
Document ID | / |
Family ID | 47219033 |
Filed Date | 2014-08-21 |
United States Patent
Application |
20140233034 |
Kind Code |
A1 |
Dong; Bo ; et al. |
August 21, 2014 |
APPARATUS AND METHOD FOR ON-LINE, REAL-TIME ANALYSIS OF CHEMICAL
GASSES DISSOLVED IN TRANSFORMER OIL
Abstract
A method of providing real-time analysis of chemical gases in a
transformer oil has been disclosed. The method includes the steps
of providing an inspection probe adapted to measure a transmission
spectrum of a solvent oil in a transformer, placing the probe
inside a transformer, using the inspection probe to measure a
transmission spectrum of the solvent oil, and determining the
concentration of dissolved gases in the transmission oil.
Inventors: |
Dong; Bo; (Blacksburg,
VA) ; Wang; Anbo; (Blacksburg, VA) ; Gong;
Jinamin; (Blacksburg, VA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Dong; Bo
Wang; Anbo
Gong; Jinamin |
Blacksburg
Blacksburg
Blacksburg |
VA
VA
VA |
US
US
US |
|
|
Assignee: |
VIRGINIA POLYTECHNIC INSTITUTE
& STATE UNIVERSITY
Blacksburg
VA
|
Family ID: |
47219033 |
Appl. No.: |
14/266189 |
Filed: |
April 30, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13473227 |
May 16, 2012 |
8743365 |
|
|
14266189 |
|
|
|
|
61487767 |
May 19, 2011 |
|
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Current U.S.
Class: |
356/437 |
Current CPC
Class: |
G01N 33/2841 20130101;
G01N 21/59 20130101; G01N 21/33 20130101 |
Class at
Publication: |
356/437 |
International
Class: |
G01N 21/59 20060101
G01N021/59 |
Claims
1. A method of providing real-time analysis of chemical gases in a
transformer oil, comprising the steps of: (a) providing an
inspection probe adapted to measure a transmission spectrum of a
solvent oil in a transformer; (b) placing the probe inside a
transformer; (c) using the inspection probe to measure a
transmission spectrum of the solvent oil; and (d) determining the
concentration of dissolved gases in the transmission oil.
2. The method according to claim 1, wherein a gases unique
absorption when dissolved in oil or other solvents is used to
determent the concentration of dissolved gases in the transmission
oil.
3. The method according to claim 1, further including the step of
transmitting incident light through the inspection probe.
4. The method according to claim 3, wherein a ratio of light power
at an absorption region over that at a non-absorption region is a
function of the concentration of the dissolved gases.
5. The method according to claim 1, wherein the solvent oil enters
an interior of the inspection probe via apertures spaced along a
side of the inspection probe.
6. The method according to claim 1, wherein the inspection probe
includes a silica tube and first and second collimators disposed at
opposing ends of the silica tube, the first and second collimators
being aligned by the silica tube such that incident light is
transmitted through the first collimator, the tube, and the second
collimator to a spectrometer.
Description
[0001] This application is a Divisional of U.S. patent application
Ser. No. 13/473,227 filed on May 16, 2012 and claims the benefit of
Provisional Application No. 61/487,767 filed on May 19, 2011.
BACKGROUND OF THE INVENTION
[0002] This application relates to an apparatus and method for
on-line, real-time dissolved gas analysis of transformer oil.
[0003] A high voltage transformer is one of the most important and
expensive devices in the power industry. A single transformer
failure can easily drive costs to more than 10 million dollars.
Presently, high voltage transformers are monitored using on-line
dissolved gas analysis (DAG) of transformer oil in conjunction with
a transformer asset manager to diagnose faults occurred in
transformers and prevent catastrophic failures.
[0004] Current dissolved gas analysis (DGA) methods extract
dissolved gases out of the oil and measure the concentration of
these gases in gaseous phase. While this method is in line with the
IEEE guide on DGA for transformers, it is not convenient and cannot
provide in-situ information.
BRIEF SUMMARY OF THE INVENTION
[0005] These and other shortcomings of the prior art are addressed
by the present invention, which provides an apparatus and method
which allows more accurate and localized dissolved gas information
to be detected and used for transformer health condition monitoring
and diagnostics.
[0006] According to one aspect of the present invention, an
inspection probe for directly measuring a transmission spectrum of
a solvent oil in a transformer includes a tube having a plurality
of apertures spaced along a side of the tube to allow oil to pass
therethrough, and first and second optical collimators disposed at
opposing ends of the tube. The first and second collimators are
aligned by the tube such that incident light is transmitted through
the first collimator, the tube, and the second collimator to a
spectrometer.
[0007] According to another aspect of the invention, a method of
providing real-time analysis of chemical gases in a transformer oil
includes the steps of providing an inspection probe adapted to
measure a transmission spectrum of a solvent oil in a transformer,
placing the probe inside a transformer, using the inspection probe
to measure a transmission spectrum of the solvent oil, and
determining the concentration of dissolved gases in the
transmission oil.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The subject matter that is regarded as the invention may be
best understood by reference to the following description taken in
conjunction with the accompanying drawing figures in which:
[0009] FIG. 1 shows an inspection probe for measuring a
transmission spectrum; and
[0010] FIG. 2 shows normalized transmission spectra of transformer
oil using the probe of FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
[0011] Referring to the drawings, an exemplary inspection probe for
directly measuring a transmission spectrum of a solvent oil in a
transformer according to an embodiment of the invention is
illustrated in FIG. 1 and shown generally at reference numeral
10.
[0012] The inspection probe 10 because of its compact size,
immunity to electromagnetic interference, and high resistance to
electric stress and multiplexing properbility can be installed
inside high voltage transformers to give more accurate, prompt, and
localized analysis of the state of a transformer.
[0013] As shown, the probe 10 includes a straight silica tube 11
with holes 12 and dust filters 13 on its sidewall 14 to allow oil
to pass therethrough and first and second optical collimators 16,
17 installed at opposing ends of the tube 11. The collimators 16
and 17 are aligned by the silica tube 11 such that incident light
from a light source 18 can be transmitted through the first
collimator 16 via a fiber optic cable 19, the silica tube 11, and
the second collimator 17 to a spectrometer 20 with a low power loss
via a fiber optic cable 21. The dust filter 13 is made of
dielectric porous material which prevents invasion of large
particles into the light channel. It should be appreciated that the
dust filter 13 may be made of any suitable material for use with
the probe 10 and to prevent invasion of large particles.
[0014] Because the probe 10 is immune to electromagnetic
interference and can also resist large electric stresses inside
high voltage transformers, it can be installed much closer to fault
sources than current systems, which makes an analysis more accurate
and prompt. Since the probe 10 is very compact and multi-plexible,
multiple probes 10 may be installed at different locations in a
transformer to get localized information which aids in diagnosing a
fault source and its properties.
[0015] In use, the concentration of dissolved acetylene or other
gases (such as hydrogen, ethylene, methane, ethane, and carbon
monoxide) is obtained by directly measuring the transmission
spectrum of the solvent oil. The measurement uses a gases unique
absorption when dissolved in oil or other solvents. The advantage
of this method is that more accurate and localized dissolved gas
information can be detected, which is very useful for transformer
health condition monitoring and diagnostics. The probe 10, which is
intrinsically safe and immune to electromagnetic interference
(EMI), may be placed inside the transformer for real-time in-situ
DGA.
[0016] Referring to FIG. 2, a normalized transmission spectra
without and with acetylene dissolved inside transformer oil is
shown. Dissolved acetylene produces an absorption dip around a wave
number of about 4.095 .mu.m.sup.-1, the shape of the absorption dip
is quite stable and the depth of the dip is proportional to the
concentration of the dissolved acetylene according to both
Beer-Lambert law and our test results. Outside the absorption dip
region is a wide non-absorption region. The ratio of the light
power at absorption region over that at non-absorption region is a
function of the concentration of the dissolved acetylene and is not
sensitive to the fluctuation of the source power and transmission
loss, so the sensor can be regarded as self-calibrated.
[0017] Averaging may also be used to improve the signal-to-noise
ratio of the detected spectra. And, since the shape of
acetylene-absorption spectrum is quite stable, spectra correlation
technique can be adopted to improve the decoding accuracy of the
concentration of the dissolved acetylene.
[0018] It should be appreciated that the probe 10 structure is not
limited to the current design and that any suitable optical device
that can efficiently measure the transmission spectrum of
transformer oil may be used.
[0019] The foregoing has described an apparatus and method for
on-line, real-time analysis of chemical gases dissolved in
transformer oil. While specific embodiments of the present
invention have been described, it will be apparent to those skilled
in the art that various modifications thereto can be made without
departing from the spirit and scope of the invention. Accordingly,
the foregoing description of the preferred embodiment of the
invention and the best mode for practicing the invention are
provided for the purpose of illustration only and not for the
purpose of limitation.
* * * * *