US4249088A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic device for synchronization of prime mover with electrical grid
Assignee: General Electric Co
•
Filing: 1979-07-19
•
Granted: 1981-02-03
•
Expires: 1999-07-19
Abstract
Abstract A control circuit is disclosed for synchronizing a prime mover or electrical generator with an electrical grid or power line such that when the prime mover is connected to the grid; (a) the instantaneous phase and slip are within allowable limits; (b) the phase and slip expected at breaker closure, as contrasted to the instantaneous measured phase and slip, will be within given limits; (c) the phase and slip anticipated at the breaker closure instant are optimal for the given trajectory, i.e. when they are the closest to their most desired values during the given transition. The circuit includes a clock for measuring the phase difference between the power line voltage and the generator voltage and means for calculating the rate of change of the phase difference which is a measure of difference of the respective frequencies known as the slip. The trends of phase and slip are then extrapolated by the amount of time it takes the breaker to close and a command for breaker closure is issued when the above three conditions are simultaneously satisfied. Speed matching can be caused by having the circuit produce a signal to raise generator speed when the slip is less than a given lower limit and by producing a signal to reduce generator speed if the slip exceeds a set upper limit.
Inventors
- 👤 Ronald J. Kleba
- 👤 Stanislaw H. Bednarski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:02
CPC Classifications
H; H02; H02J; H02J3/00; H02J3/38; H02J3/40; H02J3/42
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
247 words
An automatic device for ensuring synchronization between the output voltage and an electrical generator and the voltage of a line to which the generator is to be connected at the instant of closure of a circuit breaker which connects said electrical generator to said power line; said circuit breaker having an energizable closing circuit which causes the closing of the circuit breaker contacts after some delay time; said automatic device comprising: first phase sensor means for sensing the instantaneous phase of the voltage of said generator; second phase sensor means for sensing the instantaneous phase of the voltage of said power line; slip determining means connected to said first and second phase sensor means for developing signals related to the slip between the instantaneous phases of said power line and said generator output voltages; trajectory determining means for determining the trajectory of slip and phase to anticipate the expected slip and phase at times in the future; signal output means responsive to said first and second phase sensor means, said slip determining means and said trajectory determining means for delivering a signal to said circuit breaker energizable closing circuit to initiate closing of said circuit breaker upon the simultaneous occurrence of the following three conditions: (1) at an instant the instantaneous phase and slip are within given limits, (2) the phase and slip expected at the instant of breaker closure are with given limits and (3) when the phase and slip are optimal for their particular trajectory.
Claim 2
Dependent Claim
247 words
An automatic device for ensuring synchronization between the output voltage and an electrical generator and the voltage of a line to which the generator is to be connected at the instant of closure of a circuit breaker which connects said electrical generator to said power line; said circuit breaker having an energizable closing circuit which causes the closing of the circuit breaker contacts after some delay time; said automatic device comprising: first phase sensor means for sensing the instantaneous phase of the voltage of said generator; second phase sensor means for sensing the instantaneous phase of the voltage of said power line; slip determining means connected to said first and second phase sensor means for developing signals related to the slip between the instantaneous phases of said power line and said generator output voltages; trajectory determining means for determining the trajectory of slip and phase to anticipate the expected slip and phase at times in the future; signal output means responsive to said first and second phase sensor means, said slip determining means and said trajectory determining means for delivering a signal to said circuit breaker energizable closing circuit to initiate closing of said circuit breaker upon the simultaneous occurrence of the following three conditions: (1) at an instant the instantaneous phase and slip are within given limits, (2) the phase and slip expected at the instant of breaker closure are with given limits and (3) when the phase and slip are optimal for their particular trajectory.
Claim 3
Dependent Claim
45 words
The device of claim 1 which further includes generator speed control means; said slip determining means connected to said generator speed control means to respectively increase or decrease generator speed to change the slip and to bring the slip into a predetermined range of values.
Claim 4
Dependent Claim
21 words
The device of claim 1 wherein said first and second phase sensor means include identical respective positive going zero crossing detectors.
Claim 5
Dependent Claim
21 words
The device of claim 2 wherein said first and second phase sensor means include identical respective positive going zero crossing detectors.
Claim 6
Dependent Claim
46 words
The device of claim 1 which further includes generator speed control means; said slip determining means connected to said generator speed control means to respectively increase or decrease the generator speed to change the slip and to bring the slip into a predetermined range of values.
Claim 7
Dependent Claim
21 words
The device of claim 5 wherein said first and second phase sensor means include identical respective positive going zero crossing detectors.
Claim 8
Dependent Claim
32 words
The device of claim 1 which further includes microcomputer means for determining the slip between the phases of said generator and power line and for determining said trajectory of slip and phase.
Claim 9
Dependent Claim
147 words
The process of connecting a power generator to an energized electric line when the two are synchronized in phase to within less than about 10 electrical degrees comprising, in combination; measuring the instantaneous phase of the output voltage of said generator; measuring the instantaneous phase of the voltage of said electric line; determining the slip between said generator and electric line; determining the trajectory of the instantaneous phase and slip; and producing a signal to initiate closing a circuit breaker to connect said generating to said line when; (a) the instantaneous phase and slip are within given limits; (b) the phase and slip which are expected at the instant the circuit breaker contacts close at some given delay time following said signal to close said circuit breaker are within given limits; and (c) the phase and slip are optimal for a given trajectory during a given transition.
Claim 10
Dependent Claim
147 words
The process of connecting a power generator to an energized electric line when the two are synchronized in phase to within less than about 10 electrical degrees comprising, in combination; measuring the instantaneous phase of the output voltage of said generator; measuring the instantaneous phase of the voltage of said electric line; determining the slip between said generator and electric line; determining the trajectory of the instantaneous phase and slip; and producing a signal to initiate closing a circuit breaker to connect said generating to said line when; (a) the instantaneous phase and slip are within given limits; (b) the phase and slip which are expected at the instant the circuit breaker contacts close at some given delay time following said signal to close said circuit breaker are within given limits; and (c) the phase and slip are optimal for a given trajectory during a given transition.
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) | 1984-02-03 | 1984-08-04 | 1985-02-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-03 | 1988-08-04 | 1989-02-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-03 | 1992-08-04 | 1993-02-03 | $7700.00 | Window Closed / Lapsed |