US3680359A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transformer having incipient fault detector
Assignee: Cooper Industries LLC
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Filing: 1968-05-02
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Granted: 1972-08-01
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Expires: 1988-05-02
Abstract
Abstract A thermal conductivity gas analysis incipient fault detector for a gas-cushion transformer. The gas from the gas-cushion is continuously circulated to gas analysis cavities and then returned to the gas-cushion. The gas is analyzed by comparison of its thermal conductivity to the thermal conductivity of a standard gas.
Inventors
- 👤 John C Lynch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:50
CPC Classifications
H; H01; H01F; H01F27/00; H01F27/40; H01F27/402; H01F27/404; H01F27/406; H02; H02H; H02H5/00
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
204 words
A gas analysis apparatus for an inert gas cushion electrical transformer comprising, a block of thermally conductive material, first and second thermal conductivity cells, first and second thermistors respectively positioned within said first and second thermal conductivity cells, a known gas within said first conductivity cell and said inert gas from said cushion in said second thermal conductivity cell, detector means including a thermal conductivity bridge having said first and second thermistors in the arms thereof for detecting the presence of a gas in said second thermal conductivity cell having a thermal conductivity different from that of said known gas, means for heating said thermally conductive block, first conduit means connecting said gas cushion and said second thermal conductivity cell for delivering gas from said gas cushion to said second thermal conductivity cell, said first conduit means having a length positioned immediately adjacent said block, said length being sufficient to absorb the heat required to establish a thermal gradient of sufficient amount along said length that gas from said cushion convectively flows from said cushion to said second thermal conductivity cell and second conduit means connecting said gas cushion and said second cell for delivering gas from said second cell to said gas cushion.
Claim 2
Dependent Claim
204 words
A gas analysis apparatus for an inert gas cushion electrical transformer comprising, a block of thermally conductive material, first and second thermal conductivity cells, first and second thermistors respectively positioned within said first and second thermal conductivity cells, a known gas within said first conductivity cell and said inert gas from said cushion in said second thermal conductivity cell, detector means including a thermal conductivity bridge having said first and second thermistors in the arms thereof for detecting the presence of a gas in said second thermal conductivity cell having a thermal conductivity different from that of said known gas, means for heating said thermally conductive block, first conduit means connecting said gas cushion and said second thermal conductivity cell for delivering gas from said gas cushion to said second thermal conductivity cell, said first conduit means having a length positioned immediately adjacent said block, said length being sufficient to absorb the heat required to establish a thermal gradient of sufficient amount along said length that gas from said cushion convectively flows from said cushion to said second thermal conductivity cell and second conduit means connecting said gas cushion and said second cell for delivering gas from said second cell to said gas cushion.
Claim 3
Independent Claim
136 words
The method of detecting a fault in a transformer within a casing normally containing a inert gas cushion comprising the steps of flowing the gas from said gas cushion into a first analysis cell and from said first analysis cell back to said gas cushion, isolating said gas from the atmosphere external of the transformer during the flowing step, comparing the change in resistivity of a resistance element positioned in said first analysis cell when said resistance element is exposed to said gas to the resistivity of another resistance element positioned in a second analysis cell and exposed to a standard gas and maintaining the gas delivered to the first analysis cell at a constant temperature relative to the standard gas in the second analysis cell to compensate for any difference in temperature beTween said gases.
Claim 4
Independent Claim
136 words
The method of detecting a fault in a transformer within a casing normally containing a inert gas cushion comprising the steps of flowing the gas from said gas cushion into a first analysis cell and from said first analysis cell back to said gas cushion, isolating said gas from the atmosphere external of the transformer during the flowing step, comparing the change in resistivity of a resistance element positioned in said first analysis cell when said resistance element is exposed to said gas to the resistivity of another resistance element positioned in a second analysis cell and exposed to a standard gas and maintaining the gas delivered to the first analysis cell at a constant temperature relative to the standard gas in the second analysis cell to compensate for any difference in temperature beTween said gases.
Claim 5
Dependent Claim
154 words
In combination, a sealed transformer casing, dielectric liquid within said casing, a transformer core and coil assembly immersed in said liquid within said casing, an inert gas cushion within said casing above said liquid, and a gas analysis apparatus sealed from the surrounding atmosphere and comprising first and second thermal conductivity cells, a known gas within said first conductivity cell and said inert gas from said cushion in said second thermal conductivity cell, detector means for delivering an electrical signal proportionate to the difference in thermal conductivity of the gases in said first and second cells, first conduit means for delivering gas from said gas cushion to said second thermal conductivity cell, second conduit means for delivering gas from said second cell to said gas cushion, and heating means for heating said first conduit to establish a thermal gradient therein whereby the inert gas from said cushion is convectively circulated to said second cell.
Claim 6
Dependent Claim
154 words
In combination, a sealed transformer casing, dielectric liquid within said casing, a transformer core and coil assembly immersed in said liquid within said casing, an inert gas cushion within said casing above said liquid, and a gas analysis apparatus sealed from the surrounding atmosphere and comprising first and second thermal conductivity cells, a known gas within said first conductivity cell and said inert gas from said cushion in said second thermal conductivity cell, detector means for delivering an electrical signal proportionate to the difference in thermal conductivity of the gases in said first and second cells, first conduit means for delivering gas from said gas cushion to said second thermal conductivity cell, second conduit means for delivering gas from said second cell to said gas cushion, and heating means for heating said first conduit to establish a thermal gradient therein whereby the inert gas from said cushion is convectively circulated to said second cell.
Claim 7
Independent Claim
131 words
The method of detecting a fault in a transformer within a casing normally containing an inert gas cushion comprising the steps of flowing the gas from said gas cushion into a first analysis cell and from said first analysis cell back to said gas cushion, isolating said gas from the atmosphere external of the transformer during the flowing step, comparing the change in resistivity of a resistance element positioned in said first analysis cell when said resistance element is exposed to said gas to the resistivity of another resistance element positioned in a second analysis cell and exposed to a standard gas, equalizing the pressures of the inert gas and the standard gas and compensating for any difference in temperature between the standard gas and the gas from the gas cushion.
Claim 8
Independent Claim
131 words
The method of detecting a fault in a transformer within a casing normally containing an inert gas cushion comprising the steps of flowing the gas from said gas cushion into a first analysis cell and from said first analysis cell back to said gas cushion, isolating said gas from the atmosphere external of the transformer during the flowing step, comparing the change in resistivity of a resistance element positioned in said first analysis cell when said resistance element is exposed to said gas to the resistivity of another resistance element positioned in a second analysis cell and exposed to a standard gas, equalizing the pressures of the inert gas and the standard gas and compensating for any difference in temperature between the standard gas and the gas from the gas cushion.
Claim 9
Dependent Claim
175 words
In combination, a transformer casing sealed from the surrounding atmosphere, dielectric liquid within said casing, a transformer core and coil assembly immersed in said liquid within said casing, a gas cushion within said casing above said liquid, and a fault gas analysis apparatus sealed from the surrounding atmosphere and comprising first and second thermal conductivity cells, a known gas within said first conductivity cell, conduit means containing only gas from said gas cushion for delivering only gas from said gas cushion to said second thermal conductivity cell and for returning only said gas from the gas cushion from said second thermal conductivity cell to the gas cushion, a pump connected to said conduit means, said pump containing only gas from said cushion and pumping only gas from said cushion through said conduit means, pressure regulating means for equalizing the pressures between the gas from the gas cushion and the known gas, and detector means for delivering an electrical signal proportionate to the difference in thermal conductivity of the gases in said first and second cells.
Claim 10
Dependent Claim
175 words
In combination, a transformer casing sealed from the surrounding atmosphere, dielectric liquid within said casing, a transformer core and coil assembly immersed in said liquid within said casing, a gas cushion within said casing above said liquid, and a fault gas analysis apparatus sealed from the surrounding atmosphere and comprising first and second thermal conductivity cells, a known gas within said first conductivity cell, conduit means containing only gas from said gas cushion for delivering only gas from said gas cushion to said second thermal conductivity cell and for returning only said gas from the gas cushion from said second thermal conductivity cell to the gas cushion, a pump connected to said conduit means, said pump containing only gas from said cushion and pumping only gas from said cushion through said conduit means, pressure regulating means for equalizing the pressures between the gas from the gas cushion and the known gas, and detector means for delivering an electrical signal proportionate to the difference in thermal conductivity of the gases in said first and second cells.
Claim 11
Independent Claim
145 words
The method of detecting a fault in a transformer within a casing containing a gas comprising the steps of connecting said casing and a first analysis cell by a length of conduit containing said transformer gas, continuously heating said length of conduit to establish a thermal gradient along said conduit length to cause convective flow of the gas through the conduit to thereby continuously circulate the transformer gas from said casing into said first analysis cell and from said first analysis cell back to said casing; comparing the change in resistivity of a resitence element positioned in said first analysis cell when said resistence element is exposed to said transformer gas to the resistivity of another resistence element positioned in a second analysis cell and exposed to a standard gas and compensating for any difference in temperature between the reference gas and the transformer gas.
Claim 12
Independent Claim
145 words
The method of detecting a fault in a transformer within a casing containing a gas comprising the steps of connecting said casing and a first analysis cell by a length of conduit containing said transformer gas, continuously heating said length of conduit to establish a thermal gradient along said conduit length to cause convective flow of the gas through the conduit to thereby continuously circulate the transformer gas from said casing into said first analysis cell and from said first analysis cell back to said casing; comparing the change in resistivity of a resitence element positioned in said first analysis cell when said resistence element is exposed to said transformer gas to the resistivity of another resistence element positioned in a second analysis cell and exposed to a standard gas and compensating for any difference in temperature between the reference gas and the transformer gas.
References Cited (Backward Citations)
GB293705A
Cited
US1997659A
Cited
US1971038A
Cited
US2472645A
Cited
US2687036A
Cited
US3026713A
Cited
US3111388A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-01 | 1976-01-31 | 1976-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-01 | 1980-01-31 | 1980-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-01 | 1984-01-31 | 1984-08-01 | $7700.00 | Window Closed / Lapsed |