Patent US3599044A successfully refreshed from Google Patents.
US3599044A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Superhigh-speed relaying system and apparatus for protection of power systems
Assignee: Fuji Electric Co Ltd
•
Filing: 1970-04-30
•
Granted: 1971-08-10
•
Expires: 1990-04-30
Abstract
Abstract A superhigh-speed relaying system and apparatus for the protection of power systems featuring a directional distance relaying scheme, based essentially upon the simple equation representing the relationship among the voltage, current, resistance and inductance of a given power system: LdI/dt+RI E where E designates the voltage, I the current, R the resistance and L the inductance. This expression holds true when, in the event of the occurrence of a fault, the DC component is superposed upon the fault current. And, given the phase relationship between the voltage E and the current I, and the values for the inductance L and the resistance R, the direction of and the distance to the location of the fault are obtainable. Moreover, by the same expression, the inductance L is obtainable as a result of comparison made between the polarities and between the magnitudes of E and dI/dt when I O, whereas the resistance R is obtainable from comparison made between the polarities and between the magnitudes of E and I when dI/dt O.
Inventors
- 👤 Takeshi Takemura
- 👤 Kikuo Kawasaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:56
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/40
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
107 words
A superhigh-speed protective relaying system which comprises comparing between the instantaneous value of the voltage and the differential value of the current of a power system as to their polarities and quantities at the instant when the instantaneous value of the current is zero, comparing between the instantaneous value of the voltage and the instantaneous value of the current of the power system as to their polarities and quantities at the instant when the differential value of the current is zero, and discriminating whether the location of a fault is inside or outside the protected area of the power system on the basis of the above comparisons.
Claim 2
Dependent Claim
107 words
A superhigh-speed protective relaying system which comprises comparing between the instantaneous value of the voltage and the differential value of the current of a power system as to their polarities and quantities at the instant when the instantaneous value of the current is zero, comparing between the instantaneous value of the voltage and the instantaneous value of the current of the power system as to their polarities and quantities at the instant when the differential value of the current is zero, and discriminating whether the location of a fault is inside or outside the protected area of the power system on the basis of the above comparisons.
Claim 3
Dependent Claim
135 words
A superhigh-speed protective relaying system as claimed in claim 1, wherein said comparison between the instantaneous value of the voltage and the differential value of the current of a power system as to their polarities and quantities is executed at the instant when a fault occurs in the power system and when the instantaneous value of the current is zero. 3 A superhigh-speed protective relaying system as claimed in claim 1, which comprises a step of comparing between the voltage and current of a power system as to their polarities at the instant when increase in the absolute value of the instantaneous value of the current is detected following the occurrence of a fault in the power system, whereby the direction of the location of the fault is discriminated from the result of the comparison.
Claim 4
Dependent Claim
122 words
A superhigh-speed protective relaying apparatus comprising first means for comparing between the instantaneous value of the voltage and the differential value of the current of a power system as to their polarities and quantities at the instant when a fault occurs in the power system and when the instantaneous value of the current is zero, second means for comparing between the instantanEous value of the voltage and the instantaneous value of the current of the power system as to their polarities and quantities at the instant when the differential value of the current is zero, and means which produce output when the outputs of both of said first means and said second means are produced succeedingly within a predetermined length of time.
Claim 5
Dependent Claim
122 words
A superhigh-speed protective relaying apparatus comprising first means for comparing between the instantaneous value of the voltage and the differential value of the current of a power system as to their polarities and quantities at the instant when a fault occurs in the power system and when the instantaneous value of the current is zero, second means for comparing between the instantanEous value of the voltage and the instantaneous value of the current of the power system as to their polarities and quantities at the instant when the differential value of the current is zero, and means which produce output when the outputs of both of said first means and said second means are produced succeedingly within a predetermined length of time.
References Cited (Backward Citations)
US3099775A
Cited
US3163802A
Cited
US3369156A
Cited
US3475655A
Cited
US3474333A
Cited
US3543092A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-09 | 1975-02-08 | 1975-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-09 | 1979-02-08 | 1979-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-09 | 1983-02-08 | 1983-08-10 | $7700.00 | Window Closed / Lapsed |