Protective relay with synchronized phasor measurement capability for use in electric power systems
First Claim
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1. A protective relay using, comprising:
- an acquisition circuit for obtaining at least one of the following;
(1) voltage values and (2) current values, from an electric power system;
a sampling circuit for sampling the voltage or current values at selected intervals of time, wherein the sampling is based on an absolute time reference; and
a communication system for transmitting messages containing synchronized phasor values from said protective relay to a host device.
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Abstract
The relay system obtains voltage and current values from a power line and uses a first sampling element to sample the voltage and current values at selected intervals of time. The resulting sampled signals are used for power system-wide protection, control, monitoring and metering. The sampled signals are then resampled at a rate which is a selected multiple of the power system frequency. The results of the resampling are used by processing circuitry for protection functions including fault determinations.
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Citations
16 Claims
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1. A protective relay using, comprising:
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an acquisition circuit for obtaining at least one of the following;
(1) voltage values and (2) current values, from an electric power system;
a sampling circuit for sampling the voltage or current values at selected intervals of time, wherein the sampling is based on an absolute time reference; and
a communication system for transmitting messages containing synchronized phasor values from said protective relay to a host device. - View Dependent Claims (2, 3, 4)
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5. A protective relay using synchronized phasor measurements for protection of electric power systems, comprising:
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an acquisition circuit for obtaining at least one of the following;
(1) voltage values and (2) current values, from the power system;
a sampling circuit for sampling the voltage or current values at selected intervals of time, wherein the sampling is based on an absolute time reference; and
a calculation system using said sampled signals to produce synchronized voltage or current phasor values and then using said synchronized voltage or current phasor values to perform selected protection functions for the power system. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12)
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13. A protective relay using synchronized phasor measurements for protection of electric power systems, comprising:
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an acquisition circuit for obtaining at least one of the following;
(1) voltage values and (2) current values, from the power system;
a sampling circuit for sampling the voltage or current values at selected intervals of time, wherein the sampling is based on an absolute time reference; and
a calculation system using said sampled signals to produce synchronized voltage or current phasor values and then using said synchronized voltage or current phasor values to perform selected protection functions for the power system, wherein the relay includes a receiving circuit for receiving voltage or current values from another relay which is remote from said protective relay and wherein the calculation system is responsive to the voltage or current values from said protective relay and from said another relay to perform selected protection functions for the power system involving the protective relay and said another relay. - View Dependent Claims (14, 15, 16)
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Specification