US3704392A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Network reclosing relay
Assignee: General Electric Co
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Filing: 1972-02-01
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Granted: 1972-11-28
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Expires: 1992-02-01
Abstract
Abstract A static protective relay comprises a reclosing unit for controlling a circuit breaker which when closed couples a primary feeder or a source of supply of a three-phase power distribution system to an alternating current secondary network through a network transformer. The reclosing unit senses when a voltage corresponding to the transformer voltage minus the network voltage is within a prescribed angular displacement range with respect to the network voltage and when its magnitude with respect to the network voltage is within a prescribed magnitude range. Upon the coincidence of both conditions, a reclose signal is provided to the network protector to cause it to connect the transformer to the network.
Inventors
- 👤 Muchuan M Chen
- 👤 William C Kotheimer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:49
CPC Classifications
H; H02; H02H; H02H11/00; H02H11/006; H02H3/00; H02H3/02; H02H3/06; H02H3/066
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
280 words
For use in a power distribution system including an alternating current secondary network applied at a plurality of points from one or more primary feeders, each of said points being connected to a primary feeder by means of a network protector and a transformer, a static relay for supervising a closing operation of the network protector comprising: a. first means responsive to the AC voltage on the network side of the network protector for providing a first signal during a predetermined interval in the cycle of said AC voltage, the limits of said interval being defined by a predetermined amount of angular displacement on one side of a reference point in the AC voltage cycle and by a predetermined displacement on the other side of said reference point, said reference point being at a predetermined angular position in said AC voltage cycle; b. second means for deriving from the system a first AC signal proportional to the difference between the voltage on the transformer side of the network protector and the voltage on the network side of the network protector; c. third means for providing a second signal at a predetermined point in the cycle of the first AC signal, the angular position of said predetermined point in the cycle of the first AC signal being equivalent to said angular position of the reference point in the AC voltage cycle; d. fourth means for providing a third signal only when the magnitude of the first AC signal is above a predetermined threshold level; and e. fifth means coupled to said second, third and fourth means for providing an output signal upon the coincidence of said first, second and third signals.
Claim 2
Dependent Claim
280 words
For use in a power distribution system including an alternating current secondary network applied at a plurality of points from one or more primary feeders, each of said points being connected to a primary feeder by means of a network protector and a transformer, a static relay for supervising a closing operation of the network protector comprising: a. first means responsive to the AC voltage on the network side of the network protector for providing a first signal during a predetermined interval in the cycle of said AC voltage, the limits of said interval being defined by a predetermined amount of angular displacement on one side of a reference point in the AC voltage cycle and by a predetermined displacement on the other side of said reference point, said reference point being at a predetermined angular position in said AC voltage cycle; b. second means for deriving from the system a first AC signal proportional to the difference between the voltage on the transformer side of the network protector and the voltage on the network side of the network protector; c. third means for providing a second signal at a predetermined point in the cycle of the first AC signal, the angular position of said predetermined point in the cycle of the first AC signal being equivalent to said angular position of the reference point in the AC voltage cycle; d. fourth means for providing a third signal only when the magnitude of the first AC signal is above a predetermined threshold level; and e. fifth means coupled to said second, third and fourth means for providing an output signal upon the coincidence of said first, second and third signals.
Claim 3
Dependent Claim
51 words
The static relay as specified in claim 1 wherein said fourth means also provides a fourth signal when the magnitude of the first AC signal is above a predetermined threshold level and wherein said fifth means provides an output signal upon the coincidence of said first, second, third and fourth signals.
Claim 4
Dependent Claim
119 words
The static relay as specified in claim 1 wherein said first means comprises: i. sixth means for deriving from the system a second AC signal proportional to the voltage on the network side of the network protector but shifted in phase by a first predetermined amount therefrom; ii. seventh means for deriving from the system a third AC signal proportional to the voltage on the network side of the network protector but shifted in phase by a second predetermined amount therefrom; and iii. eighth means coupled to said sixth and seventh means for establishing said predetermined interval, said interval being a time interval during which said second and said third AC signals bear a predetermined relationship to each other.
Claim 5
Dependent Claim
60 words
The static relay specified in claim 3 wherein said interval is defined by the time interval during which both of said second and third AC signals are of a predetermined polarity and wherein said reference point is the point at which the voltage on the network side of the network protector changes from said predetermined polarity to the opposite polarity.
Claim 6
Dependent Claim
33 words
The static relay as specified in claim 4 wherein said predetermined polarity is negative and wherein the limits of said interval are approximately 95* leading the reference point and approximately 15* lagging it.
Claim 7
Dependent Claim
52 words
The static relay as specified in claim 5 wherein said eighth means comprises: i. an AND gate; and ii. a wave squaring circuit; and wherein said third means comprises a pulse generator which produces a discrete energy pulse whenever said first AC signal changes from said predetermined polarity to the opposite polarity.
Claim 8
Dependent Claim
60 words
The static relay as specified in claim 6 wherein said fourth means comprises: i. rectifier means coupled to said second means; ii. filter means connected to said rectifier means; and iii. a level detector having two inputs, one of said inputs being supplied from said filter means and the other of said inputs being provided with a threshold level signal.
Claim 9
Dependent Claim
199 words
For use in a power distribution system including an alternating current secondary network applied to a plurality of points from one or more primary feeders, each of said points being connected to a primary feeder by means of a network protector and a transformer, a static relay for supervising a closing operation of the network protector comprising: a. means for providing a first voltage corresponding to the voltage on the network side of the network protector, a second voltage corresponding to the voltage on the transformer side of the network protector and a third voltage corresponding to the difference between said second and said first voltages; b. means for providing a first signal only when the angular displacement of the third voltage with respect to the first voltage is within an angular range, one limit of said range slightly lagging said first voltage and the other limit thereof leading said first voltage by approximately 95*; c. means for providing a second signal only when the magnitude of said third voltage exceeds a predetermined threshold level; d. adjustable timing means for providing an output signal only when said first and second signals have coincided for a preselected period of time.
Claim 10
Dependent Claim
199 words
For use in a power distribution system including an alternating current secondary network applied to a plurality of points from one or more primary feeders, each of said points being connected to a primary feeder by means of a network protector and a transformer, a static relay for supervising a closing operation of the network protector comprising: a. means for providing a first voltage corresponding to the voltage on the network side of the network protector, a second voltage corresponding to the voltage on the transformer side of the network protector and a third voltage corresponding to the difference between said second and said first voltages; b. means for providing a first signal only when the angular displacement of the third voltage with respect to the first voltage is within an angular range, one limit of said range slightly lagging said first voltage and the other limit thereof leading said first voltage by approximately 95*; c. means for providing a second signal only when the magnitude of said third voltage exceeds a predetermined threshold level; d. adjustable timing means for providing an output signal only when said first and second signals have coincided for a preselected period of time.
Claim 11
Dependent Claim
51 words
The static relay as specified in claim 8 additionally comprising: e. means for providing a third signal only when said third voltage exceeds a predetermined maximum level; and f. means for providing a reclose signal in response to the presence of said output signal and the absence of said third signal.
References Cited (Backward Citations)
US3312864A
Cited
US3532935A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-11-28 | 1976-05-29 | 1976-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-28 | 1980-05-29 | 1980-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-28 | 1984-05-29 | 1984-11-28 | $7700.00 | Window Closed / Lapsed |