Methods and apparatus for protecting electrical reactors
AssigneeElectric Power Research Institute, Inc.
InventorEric A. Udren
Life of this patent
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Abstract
A method of, and apparatus for, detecting shorted turns in an electrical reactor. The impedance of the reactor, and its rate of change, are monitored. A reduction in impedance which exceeds a predetermined rate of change indicates the impedance change is due to shorted turns, and not to some normal cause, such as temperature.
Claims28
A method of detecting shorted turns in an electrical reactor, comprising the steps of:
- providing voltage and current signals representative of the voltage across and the current through, the electrical reactor, respectively,
- determining the apparent electrical impedance of the reactor from the voltage and current signals,
- determining the rate of change of the apparent electrical impedance of the reactor,
- and detecting when the rate of change of a decrease in apparent impedance exceeds a predetermined magnitude.
Apparatus for protecting an electrical reactor connected to a source of alternating potential via a circuit breaker, comprising:
- first means for providing voltage and current signals responsive to the voltage across, and the current through the electrical reactor,
- second means responsive to said first means for providing signals indicative of the apparent impedance of the electrical reactor,
- third means responsive to said second means for providing a signal responsive to the rate of change of the apparent impedance,
- and fourth means responsive to said third means for providing a trip signal for the circuit breaker when the rate of change of a drop in apparent impedance falls within a predetermined range.
A method of detecting shorted turns in an electrical reactor, comprising the steps of:
- providing voltage and current signals representative of the voltage across and the current through, the electrical reactor, respectively,
- determining the apparent electrical reactance of the reactor from the voltage and current signals,
- determining the rate of change of the apparent electrical reactance of the reactor,
- and detecting when the rate of change of a decrease in apparent reactance exceeds a predetermined magnitude.
Apparatus for protecting an electrical reactor connected to a source of alternating potential via a circuit breaker, comprising:
- first means for providing voltage and current signals responsive to the voltage across, and the current through, the electrical reactor,
- second means responsive to said first means for providing signals indicative of the apparent reactance of the electrical reactor,
- third means responsive to said second means for providing a signal responsive to the rate of change of the apparent reactance,
- and fourth means responsive to said third means for providing a trip signal for the circuit breaker when the rate of change of a drop in apparent reactance falls within a predetermined range.
Dependencies are inferred from the claim text.