US3626281A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for the selective detection of the defective conduit or or conductors in a three-phase system
Assignee: Compteurs Schlumberger SA
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Filing: 1969-07-03
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Granted: 1971-12-07
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Expires: 1989-07-03
Abstract
Abstract A method for selecting a conductor or conductors of a threephase power transport line and device for operating the same which when an earth fault has been determined detects for which phase the negative sequence or inverse component makes with the zero sequence or homopolar component an angle less than 60* then for which of the detected phase the negative sequence or inverse and the positive sequence or direct components make an angle exceeding 90*, and which when a defect not earthed has been determined detects for which of the phases the angle between the inverse and direct components make an angle less than 60*.
Inventors
- 👤 Michel Henry Pierre Souillard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:58
CPC Classifications
G; G01; G01R; G01R29/00; G01R29/16; H; H02; H02H; H02H3/00; H02H3/26; H02H3/265; H02H3/32; H02H3/34; H02H3/343
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
296 words
A method for selecting defective conductors on a three-phase power transport line comprising the steps of: detecting the simple electrical component magnitudes (voltage, current, voltage drops) of each of the three-phase conductors; determining by computation the direct (or positive sequence), and inverse (or negative sequence) and homopolar (or zero sequence), symmetrical components of the simple electrical magnitudes thus detected; measuring the angular shift between the inverse and homopolar components of said simple electrical magnitudes in order to check the inverse component or components whose angular shift with the homopolar component of the same magnitude is less than 60* whereby in case said angular shift is lower than 60* thus is determined at least a privileged phase corresponding to a conductor which is the only one at fault in the case of a monophase fault between said conductor and the earth and the only one not in fault in the case of fault between the two other conductors and the earth; measuring further, the angular shift between the direct and inverse component of said privileged phase to check if it is bigger than 90* whereby in case said angular shift is bigger than 90* thus is ascertained that the phase is in fault to earth and that said phase is on the contrary not in fault if said angular shift is lower than 90*; and measuring also the angular shift between the inverse and direct components of said simple electrical magnitudes to check the one of the three inverse components whose angular shift with the corresponding direct component is lower than 60* whereby in case said angular shift is lower than 60* thus is detected once more a privileged phase corresponding to the conductor which is not at fault in the case of a fault between phases.
Claim 2
Independent Claim
296 words
A method for selecting defective conductors on a three-phase power transport line comprising the steps of: detecting the simple electrical component magnitudes (voltage, current, voltage drops) of each of the three-phase conductors; determining by computation the direct (or positive sequence), and inverse (or negative sequence) and homopolar (or zero sequence), symmetrical components of the simple electrical magnitudes thus detected; measuring the angular shift between the inverse and homopolar components of said simple electrical magnitudes in order to check the inverse component or components whose angular shift with the homopolar component of the same magnitude is less than 60* whereby in case said angular shift is lower than 60* thus is determined at least a privileged phase corresponding to a conductor which is the only one at fault in the case of a monophase fault between said conductor and the earth and the only one not in fault in the case of fault between the two other conductors and the earth; measuring further, the angular shift between the direct and inverse component of said privileged phase to check if it is bigger than 90* whereby in case said angular shift is bigger than 90* thus is ascertained that the phase is in fault to earth and that said phase is on the contrary not in fault if said angular shift is lower than 90*; and measuring also the angular shift between the inverse and direct components of said simple electrical magnitudes to check the one of the three inverse components whose angular shift with the corresponding direct component is lower than 60* whereby in case said angular shift is lower than 60* thus is detected once more a privileged phase corresponding to the conductor which is not at fault in the case of a fault between phases.
Claim 3
Dependent Claim
89 words
A method as set forth in claim 1 characterized in that for determining a fault to earth it comprises the further steps of detecting supplementarily for each conductor phase the existence of a homopolar electrical magnitude and of ascertaining the simultaneousness of the existence of said homopolar magNitude with, on one hand, the characteristic angular shift between said homopolar component and said inverse component and, on the other hand, the characteristic angular shift between said direct and inverse components, whereby the risk of detecting a fictitious fault is avoided.
Claim 4
Dependent Claim
69 words
A method as set forth in claim 1 characterized in that, for determining a fault between phases, it comprises the further steps of supplementarily detecting for each phase the presence of an overcurrent without any homopolar current, and of ascertaining the simultaneousness of said overcurrent with the characteristic angular shift between the direct and inverse components of said phase, whereby the risk of detecting a fictitious defect is avoided.
Claim 5
Dependent Claim
29 words
A method as set forth in claim 1 characterized in that the simple electrical magnitudes thus detected are taken among voltages, currents or voltage drops of each line conductor.
Claim 6
Dependent Claim
71 words
A method as set forth in claim 1 characterized in that it comprises the further steps of applying the currents flowing in each conductor to impedances having the same argument as the impedance of the powerline to which said conductors belong in the part of said powerline situated upstream from the point where said currents are detected whereby image-voltages are determined from which are formed said direct, inverse and homopolar components.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-06 | 1975-06-07 | 1975-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-06 | 1979-06-07 | 1979-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-06 | 1983-06-07 | 1983-12-07 | $7700.00 | Window Closed / Lapsed |