Ultra-high speed protective relay apparatus and method for providing single pole switching
First Claim
1. A protective relay for determining the location of a fault on the conductors of a three-phase ac electrical transmission line, comprising:
- means for providing first, second, and third incident-wave signals representative of the current produced on each conductor by a fault-launched incident traveling wave arriving at the relaying point from a first direction;
means for providing first, second, and third forward-wave signals representative of the current produced on each conductor by a fault-launched forward traveling wave arriving at the relaying point from a second direction;
comparator means for comparing said first, second, and third incident-wave signals with, respectively, said first, second, and third forward-wave signals to provide an indication of the direction to the fault and to provide an enable signal when the fault is in said first direction;
first filter means for filtering said first, second, and third incident-wave signals to provide a modal signal representing the total current produced on the transmission line by a first propagational mode of said first incident traveling wave; and
discriminator means for processing said first, second, and third incident-wave signals, said modal signal, and said enable signal to provide an indication of the location of the fault.
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Accused Products
Abstract
Protective relay apparatus and method for determining the faulted phase conductor of a three-phase ac electrical transmission line. The voltage and current on each conductor are measured and the steady-state ac electric power signal removed. The resulting filtered-voltage signals are multiplied by the characteristic admittance of the transmission line and then combined with the filtered-current signals to produce three current signals representative of the current on each conductor caused by an incident traveling wave and three current signals representative of the current on each conductor caused by a forward traveling wave. A comparator compares the six current signals to provide an indication of the direction to the fault and to provide an enable signal when the fault is on the protected line segment. The three incident-wave current signals are filtered to provide a modal signal representing the total current produced on the transmission line by a first propagational mode of the incident traveling wave. A discriminator processes the three incident-wave signals, the modal signal, and the enable signal to provide an indication of the faulted phase conductor.
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Citations
48 Claims
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1. A protective relay for determining the location of a fault on the conductors of a three-phase ac electrical transmission line, comprising:
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means for providing first, second, and third incident-wave signals representative of the current produced on each conductor by a fault-launched incident traveling wave arriving at the relaying point from a first direction; means for providing first, second, and third forward-wave signals representative of the current produced on each conductor by a fault-launched forward traveling wave arriving at the relaying point from a second direction; comparator means for comparing said first, second, and third incident-wave signals with, respectively, said first, second, and third forward-wave signals to provide an indication of the direction to the fault and to provide an enable signal when the fault is in said first direction; first filter means for filtering said first, second, and third incident-wave signals to provide a modal signal representing the total current produced on the transmission line by a first propagational mode of said first incident traveling wave; and discriminator means for processing said first, second, and third incident-wave signals, said modal signal, and said enable signal to provide an indication of the location of the fault. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46)
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47. A protective relay for determining the location of a fault on the conductors of a three-phase AC electrical transmission line, comprising:
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means for producing first, second and third voltage signals representing the voltage on each conductor due to a fault-launched incident traveling wave arriving at the relaying point from a first direction and due to a fault-launched forward traveling wave arriving at the relaying point from a second direction. first, second, and third filter means responsive to said first voltage signal, wherein said first, second, and third filter means represent the characteristic admittance of the transmission line; fourth, fifth, and sixth filter means responsive to said second voltage signal, wherein said fourth, fifth, and sixth filter means represent the characteristic admittance of the transmission line; seventh, eighth, and ninth filter means responsive to said third voltage signal, wherein said seventh, eighth, and ninth filter means represent the characteristic admittance of the transmission line; first summing means responsive to said first, fourth, and seventh filter means for producing a first voltage-derived current signal; second summing means responsive to said second, fifth, and eighth filter means for producing a second voltage-derived current signal; third summing means responsive to said third, sixth, and ninth filter means for producing a third voltage-derived current signal; means for producing first, second, and third current signals representing the current on each conductor due to said fault-launched incident traveling wave arriving at the relaying point from said first direction and due to said fault-launched forward traveling wave arriving at the relaying point from said second direction; fourth summing means for adding said first, second, and third voltage-derived current signals to, respectively, said first, second, and third current signals to produce first, second, and third forward-wave signals; subtractor means for subtracting said first, second, and third voltage-derived current signals from, respectively, said first, second, and third current signals to produce first, second, and third incident-wave signals; tenth filter means for filtering said first, second, and third incident-wave signals to provide a modal signal representing the total current produced on the transmission line by a first mode of said first, second, and third incident-wave signals; comparator means for comparing said first, second, and third incident-wave signals with, respectively, said first, second, and third forward wave signals to provide an indication of the direction to the fault and to provide an enable signal when the fault is in said first direction; means for generating a first trajectory, in a first X-Y plane, using said first and second incident-wave signals as X and Y coordinates, respectively, means for generating a second trajectory, in a second X-Y plane, using said second and third incident-wave signals as X and Y coordinates, respectively, means for generating a third trajectory, in a third X-Y plane, using said third and first incident-wave signals as X and Y coordinates, respectively, means providing threshold boundaries in each of said first, second, and third X-Y planes, including a first straight line having a negative one-half slope and an intercept at the origin of said first, second, and third X-Y planes and a second straight line having a negative two slope and an intercept at the origin of said first, second, and third X-Y planes, first threshold monitoring means for detecting the crossing of a threshold boundary by said first, second, and third trajectory for producing a first conductor-one conditional trip signal when said first trajectory crosses into an area of said first X-Y plane bounded by said X axis and said first straight line, for producing a first conductor-two conditional trip signal when said first trajectory crosses into an area of said first X-Y plane bounded by said Y axis and said second straight line, for producing a second conductor-two conditional trip signal when said second trajectory crosses into an area of said second X-Y plane bounded by said X axis and said first straight line, for producing a first conductor-three conditional trip signal when said second trajectory crosses into an area of said second X-Y plane bounded by said Y axis and said second straight line, for producing a second conductor-three conditional trip signal when said third trajectory crosses into an area of said third X-Y plane bounded by said X axis and said first straight line, and for producing a second conductor-one conditional trip signal when said third trajectory crosses into an area of said third X-Y plane bounded by said Y axis and said second straight line; means for generating a fourth trajectory in a fourth X-Y plane using said first incident-wave signal and said modal signal as X and Y coordinates, respectively; means for generating a fifth trajectory in a fifth X-Y plane using said second incident-wave signal and said modal signal as X and Y coordinates, respectively; means for generating a sixth trajectory in a sixth X-Y plane using said third incident-wave signal and said modal signal as X and Y coordinates, respectively; means providing threshold boundaries in each of said fourth, fifth, and sixth X-Y planes, including areas in the first and third quadrants wherein each area is bounded by a line having a one-third slope and an intercept at the origin of said fourth, fifth, and sixth X-Y planes, bounded by the Y axis, and bounded by a line having zero slope and a Y-axis intercept at a point determined such that traveling wave activity on the transmission line during non-fault conditions does not cause said fourth, fifth, and sixth trajectories to cross a threshold boundary; second threshold monitoring means for detecting the crossing of a threshold boundary by said fourth, fifth, and sixth trajectory for producing a third conductor-one conditional trip signal when said fourth trajectory crosses a threshold boundary of said fourth X-Y plane, for producing a third conductor-two conditional trip signal when said fifth trajectory crosses a threshold boundary of said fifth X-Y plane, and for producing a third conductor-three conditional trip signal when said sixth trajectory crosses a threshold boundary of said sixth X-Y plane; first AND gate means responsive to said first, second, and third conductor-one conditional trip signals and said enable signal for producing a conductor-one primary trip signal indicating that the fault is in said first direction on the first conductor; second AND gate means responsive to said first second, and third conductor-two conditional trip signals and said enable signal or producing a conductor-two primary trip signal indicating that the fault is in said first direction on the second conductor; third AND gate means responsive to said first, second, and third conductor-three conditional trip signals and said primary trip signal for producing a conductor-three primary trip signal indicating that the fault is in said first direction on the third conductor; first OR gate means responsive to said conductor-one, conductor-two, and conductor-three primary trip signals for producing an output signal; NOT gate means responsive to said output signal for producing an inverted output signal; delay means responsive to said primary trip signal for producing a delayed signal; fourth AND gate means responsive to said inverted output signal and said delayed signal for producing a three-phase trip signal indicating that the fault is in said first direction but said protective relay is unable to determine the conductor on which the fault is located.
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48. A method of determining the location of a fault on the conductors of a three-phase ac electrical transmission line, comprising the steps of:
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providing first, second, and third incident-wave signals representative of the current produced on each conductor by a fault-launched incident traveling wave arriving at the relaying point from a first direction; providing first, second, and third forward-wave signals representative of the current produced on each conductor by a fault-launched forward traveling wave arriving at the relaying point from a second direction; comparing said first, second, and third incident-wave signals with, respectively, said first, second, and third forward-wave signals to provide an indication of the direction to the fault and to provide an enable signal when the fault is in said first direction; filtering said first, second, and third incident-wave signals to provide a modal signal representing the total current produced on the transmission line by a first propagational mode of said first incident traveling wave; and processing said first, second, and third incident-wave signals, said modal signal, and said enable signal to provide an indication of the location of the fault.
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Specification