Patent US3886449A successfully refreshed from Google Patents.
US3886449A
Expired / Lapsed
US
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Power measurement circuit
Assignee: General Electric Co
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Filing: 1974-03-06
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Granted: 1975-05-27
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Expires: 1994-03-06
Abstract
Abstract A method and apparatus for detecting and measuring nonsynchronous frequency oscillatory power in a power transmission system. Current measuring devices and voltage measuring devices are connected to supply signals corresponding to instantaneous currents and voltages in the system. The current and voltage signals are combined in a multiplier to produce a signal proportional to instantaneous power in the system. The power signal is processed through a filter circuit to remove the average value component and the component at synchronous power generating frequency to produce an output signal representative only of non-synchronous frequency oscillatory power.
Inventors
- 👤 John F Wolfinger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:18
CPC Classifications
G; G01; G01R; G01R21/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
90 words
Apparatus for detecting non-synchronous frequency power oscillations in a power transmission system transmitting power at a synchronous power generating frequency, said apparatus comprising: first means for generating a first signal representative of total instantaneous power in said transmission system; second means for removing a frequency component of said first signal corresponding to said power generating frequency; and third means for removing an average value component from said first signal to produce a second signal representative of power oscillations in said transmission systems at frequencies other than said power generating frequency.
Claim 2
Dependent Claim
90 words
Apparatus for detecting non-synchronous frequency power oscillations in a power transmission system transmitting power at a synchronous power generating frequency, said apparatus comprising: first means for generating a first signal representative of total instantaneous power in said transmission system; second means for removing a frequency component of said first signal corresponding to said power generating frequency; and third means for removing an average value component from said first signal to produce a second signal representative of power oscillations in said transmission systems at frequencies other than said power generating frequency.
Claim 3
Dependent Claim
129 words
The apparatus as defined in claim 1 wherein said first means comprises: first and second current measuring devices connected respectively to provide first and second current signals representative of instantaneous currents in two phases of a three phase transmission system; first and second voltage measuring devices connected respectively to provide first and second voltage signals representative of instantaneous voltage differences between first and third phases and between second and third phases of said three phase transmission system, first and second multiplier circuits for combining said first current signal with said first voltage signal and for combining said second current signal with said second voltage signal to provide first and second power signals respectively; and adder means for combining said first and second power signals to produce said first signal.
Claim 4
Dependent Claim
15 words
The apparatus as defined in claim 1 wherein said second means comprises a notch filter.
Claim 5
Dependent Claim
15 words
The apparatus as defined in claim 1 wherein said third means comprises an integrating filter.
Claim 6
Independent Claim
94 words
A method for detecting non-synchronous frequency power oscillations in a power transmission system transmitting power at a synchronous power generating frequency, said method comprising the steps of: measuring instantaneous currents in said transmission system; measuring instantaneous voltages in said transmission system; multiplying said instantaneous currents and said instantaneous voltage to obtain a total instantaneous power signal; filtering said instantaneous power signal to remove a component caused by said power generating frequency; and filtering said instantaneous power signal to remove an average value component to produce a resultant signal repResentative of non-synchronous frequency power oscillations.
Claim 7
Independent Claim
94 words
A method for detecting non-synchronous frequency power oscillations in a power transmission system transmitting power at a synchronous power generating frequency, said method comprising the steps of: measuring instantaneous currents in said transmission system; measuring instantaneous voltages in said transmission system; multiplying said instantaneous currents and said instantaneous voltage to obtain a total instantaneous power signal; filtering said instantaneous power signal to remove a component caused by said power generating frequency; and filtering said instantaneous power signal to remove an average value component to produce a resultant signal repResentative of non-synchronous frequency power oscillations.
Claim 8
Dependent Claim
109 words
The method as defined in claim 5 wherein said power transmission system is a three phase system and said total instantaneous power signal is obtained by the steps of: measuring instantaneous currents in a first and a second phase; measuring instantaneous voltages between said first and a third phase and between said second and said third phase; multiplying said current in said first phase by said voltage between said first and third phase to produce a first power signal; multiplying said current in said second phase by said voltage between said second and third phase to produce a second power signal; and summing said first and second power signals.
References Cited (Backward Citations)
US3727132A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-26 | 1978-11-25 | 1979-05-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-26 | 1982-11-25 | 1983-05-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-26 | 1986-11-25 | 1987-05-27 | $7700.00 | Window Closed / Lapsed |