US3753087A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for testing and locating faults in insulation of an electrical apparatus and utilization of the method
Assignee: BBC Brown Boveri AG Switzerland
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Filing: 1971-06-01
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Granted: 1973-08-14
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Expires: 1991-06-01
Abstract
Abstract A method of testing insulation and pinpointing faults in a winding of electrical apparatus wherein by adjusting a test voltage, a change in the potential difference between the winding and an electrically conductive part is brought about. The purpose of this is to effect a striking and extinction of an electrical discharge at a point between the winding and electrical conductive part which exhibits a weak insulating characteristic which is detected by means of a discharge-indicating device.
Inventors
- 👤 Thian Tan Tjhing
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:29
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/08; G01R31/10; G01R31/12; G01R31/50
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
172 words
A method of testing an insulated winding incorporated in an electrical apparatus and pinpointing any fault which may exist in the insulation between any point along the winding and an electrically conductive component of the apparatus, the pattern of the voltage distribution along the winding being known, which comprises the steps of: applying a progressively increasing test voltage across the ends of said winding until a partial discharge strikes between the winding and the electrically conductive component of the apparatus, decreasing the test voltage until the partial discharge extinguishes, again increasing the test voltage to a level just under that at which a partial discharge would again be struck, adding to said test voltage an auxiliary voltage applied between one end of said winding and the electrically conductive component and which is varied until said partial discharge restrikes, and determining the location of the faulty turn in said winding where the partial discharge struck from the ratio of the test and auxiliary voltages and the total number of turns in the winding.
Claim 2
Independent Claim
172 words
A method of testing an insulated winding incorporated in an electrical apparatus and pinpointing any fault which may exist in the insulation between any point along the winding and an electrically conductive component of the apparatus, the pattern of the voltage distribution along the winding being known, which comprises the steps of: applying a progressively increasing test voltage across the ends of said winding until a partial discharge strikes between the winding and the electrically conductive component of the apparatus, decreasing the test voltage until the partial discharge extinguishes, again increasing the test voltage to a level just under that at which a partial discharge would again be struck, adding to said test voltage an auxiliary voltage applied between one end of said winding and the electrically conductive component and which is varied until said partial discharge restrikes, and determining the location of the faulty turn in said winding where the partial discharge struck from the ratio of the test and auxiliary voltages and the total number of turns in the winding.
Claim 3
Dependent Claim
31 words
A method of testing an insulated winding as defined in claim 1 wherein said test and auxiliary voltages are of the alternating current type and have the same phase and frequency.
Claim 4
Dependent Claim
49 words
A method of testing an insulated winding as defined in claim 1 wherein said test and auxiliary voltages are of the alternating type and have the same frequency and which includes the step of also varying the phase of said auxiliary voltage relative to that of said test voltage.
Claim 5
Independent Claim
170 words
A method of testing an insulated winding incorporated in an electrical apparatus and pinpointing any fault which may exist in the insulation between any point along the winding and an electrically conductive component of the apparatus, the pattern of the voltage distribution along the winding being known, which comprises the steps of: applying a progressively increasing test voltage across the ends of said winding until a partial discharge strikes between the winding and the electrically conductive component of the apparatus, decreasing the test voltage until the partial discharge extinguishes, again increasing the test voltage to a level just above that where the partial discharge would first strike, subtracting from said test voltage an auxiliary voltage applied between one end of said winding and the electrical conductive component and which is varied until said partial discharge extinguishes again, and determining the location of the faulty turn in said winding where the partial struck from the ratio of the test the auxiliary voltages and the total number of turns in the winding.
Claim 6
Independent Claim
170 words
A method of testing an insulated winding incorporated in an electrical apparatus and pinpointing any fault which may exist in the insulation between any point along the winding and an electrically conductive component of the apparatus, the pattern of the voltage distribution along the winding being known, which comprises the steps of: applying a progressively increasing test voltage across the ends of said winding until a partial discharge strikes between the winding and the electrically conductive component of the apparatus, decreasing the test voltage until the partial discharge extinguishes, again increasing the test voltage to a level just above that where the partial discharge would first strike, subtracting from said test voltage an auxiliary voltage applied between one end of said winding and the electrical conductive component and which is varied until said partial discharge extinguishes again, and determining the location of the faulty turn in said winding where the partial struck from the ratio of the test the auxiliary voltages and the total number of turns in the winding.
Claim 7
Dependent Claim
34 words
A method of testing an insulated winding as defined in claim 4 wherein said test and auxiliary voltages are of the alternating current type having the same frequency but displaced in phase by 180*.
Claim 8
Dependent Claim
50 words
A method of testing an insulated winding as defined in claim 4 wherein said test and auxiliary voltages are of the alternating current type and have the same frequency and which includes the step of also varying the phase of said auxiliary voltage relative to that of said test voltage.
Claim 9
Independent Claim
172 words
A method of testing an insulated winding incorporated in an electrical apparatus and pinpointing any fault which may exist in the insulation between any point along the winding and an electrically conductive component of the apparatus, the pattern of the voltage distribution along the winding being known, which comprises the steps of: applying a progressively increasing test voltage between one end of said winding and the electrically conductive component until a partial discharge strikes between the winding and the electrically conductive component of the apparatus, decreasing the test voltage until the partial discharge extinguishes, again increasing the test voltage to a level just under that at which a partial discharge would again be struck, adding to said test voltage an auxiliary voltage applied across the ends of said winding and which is varied until said partial discharge re-strikes, and determining the location of the faulty turn in said winding where the partial discharge struck from the ratio of the test and auxiliary voltages and the total number of turns in the winding.
Claim 10
Independent Claim
172 words
A method of testing an insulated winding incorporated in an electrical apparatus and pinpointing any fault which may exist in the insulation between any point along the winding and an electrically conductive component of the apparatus, the pattern of the voltage distribution along the winding being known, which comprises the steps of: applying a progressively increasing test voltage between one end of said winding and the electrically conductive component until a partial discharge strikes between the winding and the electrically conductive component of the apparatus, decreasing the test voltage until the partial discharge extinguishes, again increasing the test voltage to a level just under that at which a partial discharge would again be struck, adding to said test voltage an auxiliary voltage applied across the ends of said winding and which is varied until said partial discharge re-strikes, and determining the location of the faulty turn in said winding where the partial discharge struck from the ratio of the test and auxiliary voltages and the total number of turns in the winding.
Claim 11
Dependent Claim
31 words
A method of testing an insulated winding as defined in claim 7 wherein said test and auxiliary voltages are of the alternating current type and have the same phase and frequency.
Claim 12
Dependent Claim
50 words
A method of testing an insulated winding as defined in claim 7 wherein said test and auxiliary voltages are of the alternating current type and have the same frequency and which includes the step of also varying the phase of said auxiliary voltage relative to that of said test voltage.
Claim 13
Independent Claim
171 words
A method of testing an insulated winding incorporated in an electrical apparatus and pinpointing any fault which may exist in the insulation between any point along the winding and an electrically conductive component of the apparatus, the pattern of the voltage distribution along the winding being known, which comprises the steps of: applying a progressively increasing test voltage between one end of said winding and the electrically conductive component until a partial discharge strikes between the winding and the electrically conductive component of the apparatus, decreasing the test voltage until the partial discharge extinguishes, again increasing the test voltage to a level just above that where the partial discharge would first strike, subtracting from said test voltage an auxiliary voltage applied across the ends of said winding and which is varied until said partial discharge extinguishes again, and determining the location of the faulty turn in said winding where the partial discharge struck from the ratio of the test and auxiliary voltages and the total number of turns in the winding.
Claim 14
Independent Claim
171 words
A method of testing an insulated winding incorporated in an electrical apparatus and pinpointing any fault which may exist in the insulation between any point along the winding and an electrically conductive component of the apparatus, the pattern of the voltage distribution along the winding being known, which comprises the steps of: applying a progressively increasing test voltage between one end of said winding and the electrically conductive component until a partial discharge strikes between the winding and the electrically conductive component of the apparatus, decreasing the test voltage until the partial discharge extinguishes, again increasing the test voltage to a level just above that where the partial discharge would first strike, subtracting from said test voltage an auxiliary voltage applied across the ends of said winding and which is varied until said partial discharge extinguishes again, and determining the location of the faulty turn in said winding where the partial discharge struck from the ratio of the test and auxiliary voltages and the total number of turns in the winding.
Claim 15
Dependent Claim
34 words
A method of testing an insulated winding as defined in claim 10 wherein said test and auxiliary voltages are of the alternating current type having the same frequency but displaced in phase by 180*.
Claim 16
Dependent Claim
50 words
A method of testing an insulated winding as defined in claim 10 wherein said test and auxiliary voltages are of the alternating current type and have the same frequency and which includes the step of also varying the phase of said auxiliary voltage relative to that of said test voltage.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-13 | 1977-02-12 | 1977-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-13 | 1981-02-12 | 1981-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-13 | 1985-02-12 | 1985-08-14 | $7700.00 | Window Closed / Lapsed |