US4063300A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Protective relay arrangements
Assignee: The General Electric Company PLC
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Filing: 1975-11-17
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Granted: 1977-12-13
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Expires: 1995-11-17
Abstract
Abstract A protective relay arrangement for an A.C. power system wherein the occurrence of a fault is detected by monitoring the phase or amplitude relation between at least one pair of signals which, when a fault occurs in the system, are functions of a current and/or voltage which would have occurred in the power system if the or each emf source in the system had a value equal to the pre-fault voltage at the point in the system where the fault has occurred.
Inventors
- 👤 Eric Paddison
- 👤 Leonardo Perez-Cavero
- 👤 Christopher George Wilson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 08:14
CPC Classifications
H; H02; H02H; H02H1/00; H02H1/0038; H02H1/0053; H02H3/00; H02H3/38; H02H3/382; H02H3/40
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
81 words
A protective relay arrangement for an A.C. power system comprising: circuit means for deriving at least one pair of signals which, when a fault occurs in the system, are functions of quantities which would have occurred in the system at the relaying point under fault conditions if the or each emf source in the system had a value equal to the pre-fault voltage at the point in the system where the fault has occurred; and comparator means for comparing said signals.
Claim 2
Dependent Claim
81 words
A protective relay arrangement for an A.C. power system comprising: circuit means for deriving at least one pair of signals which, when a fault occurs in the system, are functions of quantities which would have occurred in the system at the relaying point under fault conditions if the or each emf source in the system had a value equal to the pre-fault voltage at the point in the system where the fault has occurred; and comparator means for comparing said signals.
Claim 3
Dependent Claim
100 words
A protective relay arrangement according to claim 1 wherein each said signal is a function of at least one of a current I AF and a voltage V AF given by the expressions: I.sub.AF = I.sub.A - I.sub.L and V.sub.AF = V.sub.A - I.sub.L Z.sub.R where: I A is a current at the relaying point under fault conditions; I L is a pre-fault current at the relaying point; V A is a voltage at the relaying point; and Z R is an impedance replica of an impedance of a line section of the power system protected by the relay arrangement.
Claim 4
Dependent Claim
41 words
A protective relay arrangement according to claim 2 exhibiting a directional characteristic wherein said comparator means is a phase comparator and said circuit means provides the comparator means with inputs of the form I AF Z R1 and V AF .
Claim 5
Dependent Claim
50 words
A protective relay arrangement according to claim 2 exhibiting a directional characteristic wherein said comparator means is an amplitude comparator and said circuit means provides the comparator means with inputs of the form |I AF Z R1 + V AF | and |I AF Z R1 - V AF |.
Claim 6
Dependent Claim
47 words
A protective relay arrangement according to claim 2 exhibiting an angle impedance characteristic wherein said comparator means is a phase comparator and said circuit means provides the comparator means with inputs of the form V AF - I AF Z R1 and I AF Z R2 .
Claim 7
Dependent Claim
46 words
A protective relay arrangement according to claim 2 exhibiting an angle impedance characteristic wherein said comparator means is an amplitude comparator and said circuit means provides the comparator means with inputs of the form |2I AF Z R1 - V AF | and |V AF |.
Claim 8
Dependent Claim
46 words
A protective relay arrangement according to claim 2 exhibiting a reactance characteristic wherein said comparator means is a phase comparator and said circuit means provides the comparator means with inputs of the form V AF - I AF X R1 and I AF X R2 .
Claim 9
Dependent Claim
45 words
A protective relay arrangement according to claim 2 exhibiting a reactance characteristic wherein said comparator means is a phase comparator and said circuit means provides the comparator means with inputs of the form |2I AF X R1 - V AF | and |V AF |.
Claim 10
Dependent Claim
49 words
A protective relay arrangement according to claim 2 exhibiting an impedance characteristic wherein said comparator means is a phase comparator and said circuit means provides the comparator means with inputs of the form V AF - I AF Z R1 and I AF Z R2 + V AF .
Claim 11
Dependent Claim
42 words
A protective relay arrangement according to claim 2 exhibiting an impedance characteristc wherein said comparator means is an amplitude comparator and said circuit means provides the comparator means with inputs of the form |I AF Z R1 | and |V AF |.
Claim 12
Dependent Claim
45 words
A protective relay arrangement according to claim 2 exhibiting an angle admittance characteristic wherein said comparator means is a phase comparator and said circuit means provides the comparator means with inputs of the form V AF - I AF Z R1 and V AF .
Claim 13
Dependent Claim
48 words
A protective relay arrangement according to claim 2 exhibiting an angle admittance characteristic wherein said comparator means is an amplitude comparator and said circuit means provides said comparator means with inputs of the form |I AF Z R1 | and |2V AF - I AF Z R1 |.
Claim 14
Dependent Claim
50 words
A protective relay arrangement according to claim 2 exhibiting an offset mho characteristic wherein said comparator means is a phase comparator and said circuit means provides the comparator means with inputs of the form V AF - I AF Z R1 and V AF - I AF Z R2 .
Claim 15
Dependent Claim
54 words
A protective relay arrangement according to claim 2 exhibiting an offset mho characteristic wherein said comparator means is an amplitude comparator and said circuit means provides the comparator means with inputs of the form |I AF (Z R1 - Z 0 )| and |2V AF - I AF (Z R1 - Z 0 )|.
Claim 16
Dependent Claim
50 words
A protective relay arrangement according to claim 3 wherein said circuit means provides the comparator means with inputs of the form (I A - I L ) Z R1 and V A ' - I L Z R2 where V A ' is a pre-fault voltage at the relaying point.
Claim 17
Dependent Claim
53 words
A protective relay arrangement according to claim 4 wherein said circuit means provides the comparator means with inputs of the form |(I A - 2I L ) Z R1 + V A '| and |I A Z R1 - V A '|where V A ' is a pre-fault voltage at the relaying point.
Claim 18
Dependent Claim
62 words
A protective relay arrangement according to claim 11 wherein said circuit means provides the comparator means with inputs of the form V A - I A Z R1 and V A ' - I L Z R2 where V A is a voltage at the relaying point under fault conditions and V A ' is a pre-fault voltage at the relaying point.
Claim 19
Dependent Claim
80 words
A protective relay arrangement according to claim 12 wherein said circuit means provides the comparator means with inputs of the form |(V A ' - V A ) + (I A - I L ) Z R1 | and |V A + V A ' - (I A + I L ) Z R1 | where V A is a voltage at the relaying point under fault conditions and V A ' is a pre-fault voltage at the relaying point.
References Cited (Backward Citations)
US3210606A
Cited
US3303390A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-12-12 | 1981-06-13 | 1981-12-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-12-12 | 1985-06-13 | 1985-12-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-12-12 | 1989-06-13 | 1989-12-13 | $7700.00 | Window Closed / Lapsed |