Protective relay device, system and methods for Rogowski coil sensors
First Claim
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1. A protective system for a current path in an electrical power system, the system comprising:
- a Rogowski coil that generates an output voltage signal corresponding to current flow in the current path;
a microprocessor that receives the output voltage signal in frequency domain and that processes the output voltage signal to obtain a frequency domain representation of the current flow in the current path without integration of the output voltage signal in the time domain; and
a protection device that determines whether a fault condition exists in the electrical power system based on the obtained frequency domain representation of the current flow, the protection device causing the current path to be interrupted when the fault condition is detected.
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Abstract
Relay devices, systems and methods for obtaining an accurate representation of a current monitored with a Rogowski coil, without integration of the Rogowski coil output voltage signal in the time domain.
71 Citations
20 Claims
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1. A protective system for a current path in an electrical power system, the system comprising:
- a Rogowski coil that generates an output voltage signal corresponding to current flow in the current path;
a microprocessor that receives the output voltage signal in frequency domain and that processes the output voltage signal to obtain a frequency domain representation of the current flow in the current path without integration of the output voltage signal in the time domain; and
a protection device that determines whether a fault condition exists in the electrical power system based on the obtained frequency domain representation of the current flow, the protection device causing the current path to be interrupted when the fault condition is detected. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- a Rogowski coil that generates an output voltage signal corresponding to current flow in the current path;
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8. A protective system for a current path in an electrical system, the system comprising:
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a Rogowski coil that generates an output voltage signal proportional to a time derivative of a current flow in the current path; a microprocessor that receives the output voltage signal and that processes the output voltage signal in the frequency domain to obtain a frequency domain representation of the current flow in the current path without integration of the output voltage signal in the time domain, the processing of the output voltage signal comprising the steps of modifying at least one frequency component of the output voltage signal by a scalar multiplier, and digitally shifting the phase of the output voltage signal by approximately 90 degrees; and a relay device that causes the current path to be interrupted based on the obtained frequency domain representation of the current flow. - View Dependent Claims (9, 10, 11, 12)
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13. A protective relay system for managing an electrical system, the system comprising:
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a conductor that defines a current path in the electrical system; a Rogowski coil that receives the conductor and that generates an analog output voltage signal proportional to a time derivative of current flow in the current path; and a digital relay device that receives the analog output voltage signal, digitizes the signal, and processes the digitized output voltage signal in the frequency domain to obtain a frequency domain representation of the current flow without integration of the output voltage signal in the time domain, the processing of the digitized output voltage signal comprising the steps of modifying at least one frequency component of the output voltage signal by a scalar multiplier, and digitally shifting the phase of the output voltage signal by approximately 90 degrees, wherein the digital relay device causes the current path to be interrupted when a fault condition is detected based on the obtained frequency domain representation of the current flow. - View Dependent Claims (14, 15, 16)
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17. A protective system for an electrical network, comprising:
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a Rogowski coil monitoring a current path in an electrical system; and means for processing an output voltage signal of the Rogowski coil in the frequency domain to obtain a frequency domain representation of a current signal corresponding to a time derivative of current flow in the current path, the means for processing obtaining the frequency domain representation of the current signal by modifying at least one frequency component of the output voltage signal by a scalar multiplier, and digitally shifting the phase of the output voltage signal by approximately 90 degrees, the means for processing obtaining the frequency domain representation of the current signal without integrating the output voltage signal in the time domain. - View Dependent Claims (18, 19, 20)
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Specification