US4868704A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for providing distance protection and distance measurement for a high voltage transmission line
Assignee: General Electric Co
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Filing: 1988-11-14
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Granted: 1989-09-19
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Expires: 2008-11-14
Abstract
Abstract a protective relay for detecting faults in electrical power distribution system generates a signal Δi(t) which is substantially equal to the magnitude of the power distribution system current i measured at a first time subtracted from the magnitude of the power distribution system current i measured at a second time, the second time occurring later than the first time. The signal Δi(t) is utilized to generate measurement of the distance of a fault to the relay and is also utilized to generate operate signals if the fault occurs within the zone protected by the relay.
Inventors
- 👤 Leonard P. Cavero
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:55
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/44; H02H3/40
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
441 words
A protective relay for detecting faults in an electrical power distribution system, said relay comprising: (a) means for receiving signals from an electrical power distribution system, which signals relate to at least one system voltage v and at least one system current i; (b) means for generating a signal di/dt which is substantially equal to a first derivative with respect to time of said system current; (c) means for generating a signal v r which is substantially equal to the sum of a line resistance R of said power distribution system multiplied by said system current i and a line inductance L multiplied by said di/dt signal; (d) means for generating a signal Δi which is substantially equal to the magnitude of the system current i measured at a first time subtracted from the magnitude of the system current i measured at a second time, said second time occurring later than said first time; (e) means for generating a signal dΔi/dt which is substantially equal to a first derivative with respect to time of said Δi signal; (f) means for generating a signal i f which is substantially equal to the sum of the signal Δi plus the signal dΔi/dt multiplied by a scaling function having a predetermined magnitude; (g) means for generating signals v(t 1 ), v r (t 1 ) and i f (t 1 ) which are substantially equal to the magnitude of the signals v, v r and i f respectively occurring at a first time t 1 ; (h) means for generating signals v(t 2 ), v r (t 2 ) and i f (t 2 ) which are substantially equal to the magnitude of the signals v, v r and i f respectively occurring at a second time t 2 , which second time occurs later than said first time; (i) means for generating a signal S 1 which is substantially equal to the signal V r (t 1 ) multiplied by the signal i f (t 2 ) minus the signal v r (t 2 ) multiplied by the signal i f (t 1 ); (j) means for generating a signal S 2 which is substantially equal to the signal v(t 1 ) multiplied by the signal i f (t 2 ) minus the signal v(t 2 ) multiplied by the signal i f (t 1 ); (k) means for providing a signal n set having a predetermined magnitude; and (1) means for generating an output signal O 1 when the magnitude of the signal n set multiplied by the signal S 1 is greater than the magnitude of the signal S 2 .
Claim 2
Dependent Claim
441 words
A protective relay for detecting faults in an electrical power distribution system, said relay comprising: (a) means for receiving signals from an electrical power distribution system, which signals relate to at least one system voltage v and at least one system current i; (b) means for generating a signal di/dt which is substantially equal to a first derivative with respect to time of said system current; (c) means for generating a signal v r which is substantially equal to the sum of a line resistance R of said power distribution system multiplied by said system current i and a line inductance L multiplied by said di/dt signal; (d) means for generating a signal Δi which is substantially equal to the magnitude of the system current i measured at a first time subtracted from the magnitude of the system current i measured at a second time, said second time occurring later than said first time; (e) means for generating a signal dΔi/dt which is substantially equal to a first derivative with respect to time of said Δi signal; (f) means for generating a signal i f which is substantially equal to the sum of the signal Δi plus the signal dΔi/dt multiplied by a scaling function having a predetermined magnitude; (g) means for generating signals v(t 1 ), v r (t 1 ) and i f (t 1 ) which are substantially equal to the magnitude of the signals v, v r and i f respectively occurring at a first time t 1 ; (h) means for generating signals v(t 2 ), v r (t 2 ) and i f (t 2 ) which are substantially equal to the magnitude of the signals v, v r and i f respectively occurring at a second time t 2 , which second time occurs later than said first time; (i) means for generating a signal S 1 which is substantially equal to the signal V r (t 1 ) multiplied by the signal i f (t 2 ) minus the signal v r (t 2 ) multiplied by the signal i f (t 1 ); (j) means for generating a signal S 2 which is substantially equal to the signal v(t 1 ) multiplied by the signal i f (t 2 ) minus the signal v(t 2 ) multiplied by the signal i f (t 1 ); (k) means for providing a signal n set having a predetermined magnitude; and (1) means for generating an output signal O 1 when the magnitude of the signal n set multiplied by the signal S 1 is greater than the magnitude of the signal S 2 .
Claim 3
Dependent Claim
177 words
A protective relay in accordance with claim 1 additionally comprising: (a) means for generating a signal Δi(t 1 ) which is substantially equal to the magnitude of the signal Δi occurring at said first time t 1 ; (b) means for generating a signal Δi(t 2 ) which is substantially equal to the magnitude of the signal Δi occurring at said second time t 2 ; (c) means for generating a signal S 3 which is substantially equal to the signal v r (t 1 ) multiplied by the signal Δi(t 2 ) minus the signal v r (t 2 ) multiplied by the signal Δi(t 1 ); (d) means for generating a signal S 4 which is substantially equal to the signal v(t 1 ) multiplied by the signal Δi(t 2 ) minus the signal v(t 2 ) multiplied by the signal Δi(t 1 ); and (e) means for providing an output signal n which is substantially equal to the magnitude of the signal S 4 divided by the magnitude of the signal S 3 .
Claim 4
Dependent Claim
141 words
The protective relay in accordance with claim 2 additionally comprising: (a) means for generating a signal S 5 which is substantially equal to the signal v r (t 2 ) multiplied by the signal Δi(t 1 ) minus the signal v r (t 1 ) multiplied by the signal Δi(t 2 ); (b) means for generating a signal S 6 which is substantially equal to the signal v(t 1 ) multiplied by the signal v r (t 2 ) minus the signal v(t 2 ) multiplied by the signal v r (t 1 ); (c) means for providing a signal R set having a predetermined magnitude; and (d) means for generating an output signal O 2 when the magnitude of the signal R set multiplied by the signal S 5 is greater than the magnitude of the signal S 6 .
Claim 5
Dependent Claim
81 words
The protective relay in accordance with claim 3 additionally comprising: (a) means for generating a signal ΔI pk which is substantially equal to a peak magnitude of the signal ΔI; (b) means for providing a signal V set having a predetermined magnitude; and (c) means for generating an output signal when the magnitude of the signal V set multiplied by the signal S 3 is greater than the magnitude of the signal ΔI pk multiplied by the signal S 4 .
Claim 6
Dependent Claim
334 words
A protective relay for detecting faults in an electrical power distribution system, said relay comprising: (a) means for receiving signals from an electrical power distribution system, which signals relate to at least one system voltage v an at least one system current i; (b) means for generating a signal Δi which is substantially equal to the magnitude of the system current i measured at a first time subtracted from the magnitude of the system current i measured at a second time, said second time occurring later than said first time; (c) means for generating a signal α which is proportional to a phase angle between said system voltage v and said system current i; (d) means for generating a signal β which is proportional to a phase angle of a line impedance of said electrical power distribution system; (e) means for generating a signal γ, which is proportional to a phase angle between said system current i and said signal ΔI; (f) means for generating a signal γ' which is substantially equal to the signal γ multiplied by a scaling function ε having a predetermined magnitude; (g) means for generating a signal which is substantially equal to the sine function of the signal α minus the signal γ'; (h) means for generating a signal which is substantially equal to a sine function of the signal β minus the signal γ'; (i) means for generating a signal S 1 which is substantially equal to said system voltage v multiplied by the sine function of the signals α minus γ'; (j) means for generating a signal S 2 which is substantially equal to the system current i multiplied by the sine function of the signals β minus γ'; (k) means for providing a signal Z r having a predetermined magnitude; and (1) means for generating an output signal when the magnitude of the signal Z r multiplied by the signal S 2 is equal to or greater than the magnitude of the signal S 1 .
Claim 7
Dependent Claim
334 words
A protective relay for detecting faults in an electrical power distribution system, said relay comprising: (a) means for receiving signals from an electrical power distribution system, which signals relate to at least one system voltage v an at least one system current i; (b) means for generating a signal Δi which is substantially equal to the magnitude of the system current i measured at a first time subtracted from the magnitude of the system current i measured at a second time, said second time occurring later than said first time; (c) means for generating a signal α which is proportional to a phase angle between said system voltage v and said system current i; (d) means for generating a signal β which is proportional to a phase angle of a line impedance of said electrical power distribution system; (e) means for generating a signal γ, which is proportional to a phase angle between said system current i and said signal ΔI; (f) means for generating a signal γ' which is substantially equal to the signal γ multiplied by a scaling function ε having a predetermined magnitude; (g) means for generating a signal which is substantially equal to the sine function of the signal α minus the signal γ'; (h) means for generating a signal which is substantially equal to a sine function of the signal β minus the signal γ'; (i) means for generating a signal S 1 which is substantially equal to said system voltage v multiplied by the sine function of the signals α minus γ'; (j) means for generating a signal S 2 which is substantially equal to the system current i multiplied by the sine function of the signals β minus γ'; (k) means for providing a signal Z r having a predetermined magnitude; and (1) means for generating an output signal when the magnitude of the signal Z r multiplied by the signal S 2 is equal to or greater than the magnitude of the signal S 1 .
Claim 8
Dependent Claim
147 words
The protective relay in accordance with claim 5 additionally comprising: (a) means for generating a signal which is substantially equal to the sine function of the signal α minus the signal γ; (b) means for generating a signal which is substantially equal to the sine function of the signal β minus the signal γ; (c) means for generating a first signal which is substantially equal to the magnitude of the signal v multiplied by the magnitude of the sine function of the signals α minus γ; (d) means for generating a second signal which is substantially equal to the magnitude of the signal i multiplied by the magnitude of the sine function of the signals β minus α; and (e) means for providing an output signal Z L which is substantially equal to the magnitude of the first signal divided by the magnitude of the second signal
Claim 9
Dependent Claim
142 words
The protective relay in accordance with claim 6 additionally comprising: (a) means for providing a signal which is substantially equal to the sine function of the signal β minus the signal α; (b) means for providing a signal S 3 which is substantially equal to the magnitude of the signal v multiplied by the magnitude of the sine function of the signals β minus α; (c) means for providing a signal S 4 which is substantially equal to the magnitude of the signal Δi multiplied by the magnitude of the sine function of the signals β minusγ; (d) means for providing a signal R set having a predetermined magnitude; and (e) means for generating an output signal when the magnitude of the signal R set multiplied by the signal S 4 is greater than the magnitude of the signal S 3 .
Claim 10
Dependent Claim
39 words
The protective relay in accordance with claim 7 additionally comprising means for generating a signal R fA which is substantially equal to the magnitude of the signal S 3 divided by the magnitude of the signal S 4 .
Claim 11
Independent Claim
175 words
An apparatus for measuring distance to a fault in an electrical power distribution system, said apparatus comprising: (a) means for receiving signals from an electrical power distribution system, which signals relate to at least one system voltage v and at least one system current i; (b) means for generating a signal Δi which is substantially equal to the magnitude of the system current prior to the occurrence of a fault subtracted from the magnitude of the system current following occurrence of the fault; (c) means for generating a signal v r which is substantially equal to a voltage measured across a line replica impedance; (d) means for generating a signal R fA having an angle which is substantially equal to a fault resistance angle and (e) means for providing an output signal n which is related to the distance to the fault and which is substantially equal to the magnitude of the system voltage v minus the magnitude of the signal Δi multiplied by the signal R fA divided by the signal v r .
Claim 12
Independent Claim
175 words
An apparatus for measuring distance to a fault in an electrical power distribution system, said apparatus comprising: (a) means for receiving signals from an electrical power distribution system, which signals relate to at least one system voltage v and at least one system current i; (b) means for generating a signal Δi which is substantially equal to the magnitude of the system current prior to the occurrence of a fault subtracted from the magnitude of the system current following occurrence of the fault; (c) means for generating a signal v r which is substantially equal to a voltage measured across a line replica impedance; (d) means for generating a signal R fA having an angle which is substantially equal to a fault resistance angle and (e) means for providing an output signal n which is related to the distance to the fault and which is substantially equal to the magnitude of the system voltage v minus the magnitude of the signal Δi multiplied by the signal R fA divided by the signal v r .
Claim 13
Dependent Claim
210 words
A distance relay responsive to the conditions of a fault on an alternating current power transmission line, said distance relay including means for measuring distance to a fault on said transmission line, said distance measuring means comprising: (a) means for receiving the signal which relate to a transmission line voltage v and a transmission line current i; (b) means for generating a signal Δi which is related to the magnitude of the transmission line current prior to occurrence of a fault on the transmission line subtracted from the magnitude of the transmission line current following occurrence of the fault; (c) means for generating a signal v r which is related to said transmission line current multiplied by a predetermined replica impedance; and (d) means for generating a signal n related to the distance to the fault, which signal is substantially equal to ##EQU18## where v(t 1 ), v r (t 1 ) and Δi(t 1 ) are the signals v, v r and Δi occurring at a first time t 1 , and v(t 2 ), v r (t 2 ) and Δi(t 2 ) are the signals v, v r and Δi occurring at a second time t 2 which is later than said first time t 1 .
Claim 14
Dependent Claim
210 words
A distance relay responsive to the conditions of a fault on an alternating current power transmission line, said distance relay including means for measuring distance to a fault on said transmission line, said distance measuring means comprising: (a) means for receiving the signal which relate to a transmission line voltage v and a transmission line current i; (b) means for generating a signal Δi which is related to the magnitude of the transmission line current prior to occurrence of a fault on the transmission line subtracted from the magnitude of the transmission line current following occurrence of the fault; (c) means for generating a signal v r which is related to said transmission line current multiplied by a predetermined replica impedance; and (d) means for generating a signal n related to the distance to the fault, which signal is substantially equal to ##EQU18## where v(t 1 ), v r (t 1 ) and Δi(t 1 ) are the signals v, v r and Δi occurring at a first time t 1 , and v(t 2 ), v r (t 2 ) and Δi(t 2 ) are the signals v, v r and Δi occurring at a second time t 2 which is later than said first time t 1 .
Claim 15
Dependent Claim
120 words
A distance relay in accordance with claim 10 additionally including variable distance reach means comprising: (a) means for establishing a predetermined minimum distance reach n 1 ; (b) means for establishing a predetermined maximum distance reach n 2 ; (c) means for generating a signal S SETd which is related to a variable distance reach; (d) means for generating a signal ni pk where i pk is substantially equal to a peak magnitude of the transmission line current i; and (e) means for generating a trip signal when n is less than or equal to n 1 , or ni pk is less than or equal to v SETd and n is less than or equal to n 2 .
Claim 16
Dependent Claim
32 words
A distance relay in accordance with claim 11 including means for generating a signal R fA which is substantially equal to ##EQU19## and which is substantially in phase with the fault resistance.
Claim 17
Dependent Claim
149 words
A distance relay in accordance with claim 12 additionally including means for generating a variable resistance reach, said variable resistance reach means comprising: (a) means for generating a signal R SET1 related to a predetermined minimum resistance reach; (b) means for generating a signal Δi pk which is related to a peak magnitude of the Δi signal; (c) means for generating a signal V SETr which is related to a variable resistance reach; (d) means for generating a signal R SET2 which is related to a predetermined maximum resistance reach; and (e) means for generating a trip signal when the signal R fA is less than or equal to the signal R SETa , or when the signal Δi pk multiplied by the signal R fA is less than the signal V SET and the signal R fA is less than or equal to the signal R SET2 .
Claim 18
Dependent Claim
81 words
A distance relay in accordance with claim 13 additionally including means for generating a signal R F related to the magnitude of fault resistance, which signal is substantially equal to ##EQU20## where Δi B is related to magnitude of the system current i measured at a second end of the transmission line prior to occurrence of a fault subtracted from the magnitude of the system current measured at the second end of the transmission line following a occurrence of a fault.
Claim 19
Dependent Claim
65 words
A distance relay in accordance with claim 13 additionally including means for generating a signal R F related to the magnitude of the fault resistance, which signal is equal to ##EQU21## where R fB is related to the magnitude of the fault resistance measured at a second end of the transmission line, and having an angle which is substantially equal to the fault resistance angle.
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) | 1992-09-18 | 1993-03-20 | 1993-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-18 | 1997-03-20 | 1997-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-18 | 2001-03-20 | 2001-09-19 | $7700.00 | Window Closed / Lapsed |