US3629613A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Commutation direction circuit
Assignee: General Electric Co
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Filing: 1970-10-01
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Granted: 1971-12-21
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Expires: 1990-10-01
Abstract
Abstract Disclosed is means for insuring proper commutation in an inverse parallel connected power thyristor switch. The switch includes selectively operable commutation means for interrupting a fault current in rapid response to a stop signal from an overcurrent detector, polarity detecting means which determine direction of current flow through the switch and control means operative in response to the polarity detector means which enables the stop signal to actuate the commutation means associated with the fault current conducting thyristor. Further, means are provided to ensure that the stop signal once given quickly terminates.
Inventors
- 👤 Edgar P Feige
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 10:10
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/10; H02H7/12; H02H7/1216; H02H3/00; H02H3/08
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
183 words
In a three-phase electric power system including a thyristor switch comprising, in each phase of the system, a pair of power thyristors, the thyristors of each pair being connected in inverse parallel relationship with one another and being adapted to alternately conduct current between an alternating voltage source and a load, fault current detecting means for providing a ''''Stop'''' signal in response to the magnitude of current in any phase attain a preselected level, selectively triggerable commutation means respectively connected to said power thyristors and operative when triggered for interrupting the flow of current therein, polarity detecting means adapted for determining which of said power thyristors is conducting current in each phase and for providing control signals indicative thereof, and control means coupled to the polarity detecting means for triggering selected commutation means in response to said ''''Stop'''' signal and in accordance with the signals from the polarity detecting means, the improvement comprising: signal duration limiting means connected between the fault current detecting means and the control means for ensuring that said ''''Stop'''' signal, once provided, exists for only a relatively short duration.
Claim 2
Dependent Claim
183 words
In a three-phase electric power system including a thyristor switch comprising, in each phase of the system, a pair of power thyristors, the thyristors of each pair being connected in inverse parallel relationship with one another and being adapted to alternately conduct current between an alternating voltage source and a load, fault current detecting means for providing a ''''Stop'''' signal in response to the magnitude of current in any phase attain a preselected level, selectively triggerable commutation means respectively connected to said power thyristors and operative when triggered for interrupting the flow of current therein, polarity detecting means adapted for determining which of said power thyristors is conducting current in each phase and for providing control signals indicative thereof, and control means coupled to the polarity detecting means for triggering selected commutation means in response to said ''''Stop'''' signal and in accordance with the signals from the polarity detecting means, the improvement comprising: signal duration limiting means connected between the fault current detecting means and the control means for ensuring that said ''''Stop'''' signal, once provided, exists for only a relatively short duration.
Claim 3
Dependent Claim
217 words
In a three-phase electric power system including a thyristor switch comprising in each phase of the system a pair of power thyristors, the thyristor of each pair being connected in inverse parallel relationship with one another and being adapted to alternately conduct current between an alternating voltage source and a load, fault current detecting means for providing a ''''Stop'''' signal in response to the magnitude of current in any phase attaining a preselected level, selectively triggerable commutation means respectively connected to said power thyristors and operative when triggered for interrupting the flow of current therein, polarity detecting means adapted for determining which of said power thyristors is conducting current in each phase and for providing control signals indicative thereof, said polarity detecting means being responsive to the direction of current in each phase only when the magnitude exceeds a predetermined threshold level and control means coupled to the polarity detecting means for triggering selected commutation means in response to said Stop signal and in accordance with the signals from the polarity detecting means, the improvement comprising: means for ensuring that said Stop signal, once provided, exists for only a relatively short duration so that once the selected commutation circuits are triggered in response to the Stop signal, the unselected commutation circuits are prevented from being triggered thereafter.
Claim 4
Dependent Claim
217 words
In a three-phase electric power system including a thyristor switch comprising in each phase of the system a pair of power thyristors, the thyristor of each pair being connected in inverse parallel relationship with one another and being adapted to alternately conduct current between an alternating voltage source and a load, fault current detecting means for providing a ''''Stop'''' signal in response to the magnitude of current in any phase attaining a preselected level, selectively triggerable commutation means respectively connected to said power thyristors and operative when triggered for interrupting the flow of current therein, polarity detecting means adapted for determining which of said power thyristors is conducting current in each phase and for providing control signals indicative thereof, said polarity detecting means being responsive to the direction of current in each phase only when the magnitude exceeds a predetermined threshold level and control means coupled to the polarity detecting means for triggering selected commutation means in response to said Stop signal and in accordance with the signals from the polarity detecting means, the improvement comprising: means for ensuring that said Stop signal, once provided, exists for only a relatively short duration so that once the selected commutation circuits are triggered in response to the Stop signal, the unselected commutation circuits are prevented from being triggered thereafter.
Claim 5
Dependent Claim
17 words
In the power system as specified in claim 2 wherein said duration is shorter than 1 millisecond.
Claim 6
Dependent Claim
52 words
In the power system as specified in claim 2 wherein the last-mentioned means is a signal duration limiter connected between the fault current detecting means and the control means, said limiter being adapted for limiting the duration of the Stop signal from said fault current detecting means to a short duration Signal.
Claim 7
Dependent Claim
18 words
In the power system specified in claim 4 wherein said short duration signal is less than 1 millisecond.
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) | 1974-12-20 | 1975-06-21 | 1975-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-20 | 1979-06-21 | 1979-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-20 | 1983-06-21 | 1983-12-21 | $7700.00 | Window Closed / Lapsed |