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Patent US3885199A successfully refreshed from Google Patents.
US3885199A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Protective relaying device
Assignee: Hitachi Ltd
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Filing: 1973-07-02
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Granted: 1975-05-20
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Expires: 1993-07-02
Abstract
Abstract Two voltages essential for judgement of the necessity for protection are produced from a voltage and current suitable for protection of a transmission line through vector synthesis. One of the two voltages is chosen to be a reference voltage and the polarity of the other voltage is detected at every instant when the reference voltage changes from negative to positive polarity, when it reaches its positive peak, when it changes from positive to negative polarity and when it reaches its negative peak. When a series of the combinations of the polarities of the two voltages at predetermined sampling points coincide with a predetermined pattern, a fault is supposed to exist in the protective domain of the transmission line and a tripping signal is sent to the circuit breaker. The judgement of the fault is presented by a computer.
Inventors
- 👤 Haruo Nohara
- 👤 Junichi Makino
- 👤 Manabu Masuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:36
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/38; H02H3/382
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
179 words
A protective relaying device comprising: a first means for producing, from the voltage and current of the transmission line to be protected, two voltages essential for the protecTion of said line, one of said two voltages being a reference voltage; a second means for producing first timing signals indicative of the respective instants when said reference voltage changes from negative to positive polarity, when said reference voltage reaches its positive peak, when said reference voltage changes from positive to negative polarity and when said reference voltage reaches its negative peak and for producing first sign signals corresponding to the states of said reference voltage at said respective instants; a third means for producing second sign signals corresponding to the states of the other of said two voltages; a fourth means for renewing and holding said first and second sign signals each time said first timing signals are generated; and a fifth means for receiving said first and second sign signals to judge the necessity of protection on the basis of the combination of said first and second sign signals.
Claim 2
Dependent Claim
179 words
A protective relaying device comprising: a first means for producing, from the voltage and current of the transmission line to be protected, two voltages essential for the protecTion of said line, one of said two voltages being a reference voltage; a second means for producing first timing signals indicative of the respective instants when said reference voltage changes from negative to positive polarity, when said reference voltage reaches its positive peak, when said reference voltage changes from positive to negative polarity and when said reference voltage reaches its negative peak and for producing first sign signals corresponding to the states of said reference voltage at said respective instants; a third means for producing second sign signals corresponding to the states of the other of said two voltages; a fourth means for renewing and holding said first and second sign signals each time said first timing signals are generated; and a fifth means for receiving said first and second sign signals to judge the necessity of protection on the basis of the combination of said first and second sign signals.
Claim 3
Dependent Claim
45 words
A protective relaying device as claimed in claim 1, wherein said fifth means is a digital electric computer of universal type which is interrupted by and responsive to second timing signals slightly lagging in time from said first timing signals produced by said second means.
Claim 4
Dependent Claim
27 words
A protective relaying device as claimed in claim 1, wherein said fifth means is combined with a plurality of units each comprising said first to fourth means.
Claim 5
Dependent Claim
43 words
A protective relaying device as claimed in claim 3, wherein said fifth means is interrupted by and responsive to said second timing signals produced by a particular one of said plurality of second means and sequentially applies judgements for said plurality of units.
Claim 6
Dependent Claim
55 words
A protective relaying device as claimed in claim 1, wherein a sixth means is additionally provided which, when there is no reference signal, converts the sign signals delivered from said fourth means into a pattern which never occurs in the normal operation and wherein said fifth means gives the judgement of non-operation for said pattern.
Claim 7
Dependent Claim
28 words
A protective relaying device as claimed in claim 1, wherein said fifth means judges the necessity of the operative output through numerical conversion of the sign signals received.
Claim 8
Dependent Claim
56 words
A protective relaying device as claimed in claim 1, wherein said two voltages are represented as follows: V1 k1V and V2 Z2I - k2 V, where V1 and V2 are the two voltages, V is the voltage of the transmission line, I is the current of the transmission line, and k1, k2, and Z2 are constants.
Claim 9
Dependent Claim
17 words
A protective relaying device as claimed in claim 7, wherein said voltage V1 is the reference voltage.
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) | 1978-05-19 | 1978-11-18 | 1979-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-19 | 1982-11-18 | 1983-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-19 | 1986-11-18 | 1987-05-20 | $7700.00 | Window Closed / Lapsed |