METHOD, APPARATUS AND COMPUTER-READABLE CODE FOR DETECTING AN INCIPIENT GROUND FAULT IN AN ELECTRICAL PROPULSION SYSTEM
First Claim
1. Apparatus for detecting an incipient ground fault that may occur in an electrical propulsion system of a traction vehicle, said electrical propulsion system comprising a plurality of electrical devices and a direct current (dc) bus, each individual electrical device being potentially subject to an incipient ground fault in at least one electrical phase thereof, said apparatus comprising:
- a first sensor configured to sense a ground leakage signal associated with a ground of the propulsion system;
a second sensor configured to sense a voltage difference across a positive rail and a negative rail of the direct current bus;
a correlator coupled to the first sensor to receive the ground leakage signal, and further coupled to receive at least one signal indicative of a respective energization state of a respective electrical phase for each respective one of the plurality of electrical devices, said correlator configured to individually correlate the ground leakage signal with each received phase energization state signal, and supply an individual correlation signal between the ground leakage signal and each received phase energization state signal;
a processor coupled to the correlator for processing each of the individual correlation signals supplied by the correlator and extract a correlation value from the supplied correlation signals, said correlation value, when outside a threshold range, being indicative of an incipient ground fault in a respective phase of one of the plurality of electrical devices; and
a module for dynamically adjusting the threshold range for detecting an incipient ground fault, the adjusting based on a magnitude and/or a rate of change of the magnitude of the sensed voltage difference across the positive and negative rails of the direct current bus.
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Accused Products
Abstract
Method, apparatus and computer-readable code are provided for detecting a location of an incipient ground fault in an electrical propulsion system. The apparatus may include a sensor configured to sense a respective ground leakage signal associated with a ground of the propulsion system. The apparatus may further include a second sensor configured to sense a voltage difference across a positive rail and a negative rail of the direct current bus. A correlator is coupled to the first sensor to receive the ground leakage signal, and further coupled to receive at least one signal indicative of a respective energization state of a respective electrical phase for each respective one of the plurality of electrical devices. The correlator is configured to individually correlate the ground leakage signal with each received phase energization state signal, and supply an individual correlation signal between the received ground leakage signal and each received phase energization state signal. A processor is coupled to the correlator for processing each of the individual correlation signals supplied by the correlator and extracting a correlation value from the supplied correlation signals. The correlation value, when outside a threshold range, is indicative of an incipient ground fault in a respective phase of one of the plurality of electrical devices. A module is provided for dynamically adjusting the threshold range for detecting an incipient ground fault. The adjusting may be based on a magnitude and/or a rate of change of the magnitude of the sensed voltage difference across the positive and negative rails of the direct current bus.
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Citations
10 Claims
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1. Apparatus for detecting an incipient ground fault that may occur in an electrical propulsion system of a traction vehicle, said electrical propulsion system comprising a plurality of electrical devices and a direct current (dc) bus, each individual electrical device being potentially subject to an incipient ground fault in at least one electrical phase thereof, said apparatus comprising:
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a first sensor configured to sense a ground leakage signal associated with a ground of the propulsion system;
a second sensor configured to sense a voltage difference across a positive rail and a negative rail of the direct current bus;
a correlator coupled to the first sensor to receive the ground leakage signal, and further coupled to receive at least one signal indicative of a respective energization state of a respective electrical phase for each respective one of the plurality of electrical devices, said correlator configured to individually correlate the ground leakage signal with each received phase energization state signal, and supply an individual correlation signal between the ground leakage signal and each received phase energization state signal;
a processor coupled to the correlator for processing each of the individual correlation signals supplied by the correlator and extract a correlation value from the supplied correlation signals, said correlation value, when outside a threshold range, being indicative of an incipient ground fault in a respective phase of one of the plurality of electrical devices; and
a module for dynamically adjusting the threshold range for detecting an incipient ground fault, the adjusting based on a magnitude and/or a rate of change of the magnitude of the sensed voltage difference across the positive and negative rails of the direct current bus. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for detecting an incipient ground fault that may occur in an electrical propulsion system of a traction vehicle, said electrical propulsion system comprising a plurality of electrical devices and a direct current (dc) bus, each individual electrical device being potentially subject to an incipient ground fault in at least one electrical phase thereof, said method comprising:
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sensing a ground leakage signal associated with a ground of the propulsion system;
sensing a voltage difference across a positive rail and a negative rail of the direct current bus;
monitoring at least one signal indicative of a respective energization state of a respective electrical phase for each respective one of the electrical devices;
individually correlating the ground leakage signal with each phase energization state signal;
generating an individual correlation signal between the ground leakage signal and each phase energization state signal;
determining a correlation value from the generated correlation signals, said correlation value, when outside a threshold range, being indicative of an incipient ground fault in a respective phase of one of the plurality of electrical devices; and
dynamically adjusting the threshold range for detecting an incipient ground fault, the adjusting based on a magnitude and/or a rate of change of the magnitude of the sensed voltage difference across the positive and negative rails of the direct current bus.
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10. An article of manufacture comprising a computer program product comprising a computer-usable medium having a computer-readable code therein for detecting an incipient ground fault that may occur in an electrical propulsion system of a traction vehicle, said electrical propulsion system comprising a plurality of electrical devices and a direct current (dc) bus, each individual electrical device being potentially subject to an incipient ground fault in at least one electrical phase thereof, said computer-readable code comprising:
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computer-readable code responsive to a sensed ground leakage signal associated with a ground of the propulsion system;
computer-readable code responsive to a sensed voltage difference across a positive rail and a negative rail of the direct current bus;
computer-readable code for monitoring at least one signal indicative of a respective energization state of a respective electrical phase for each respective one of the electrical devices;
computer-readable code for individually correlating the ground leakage signal with each phase energization state signal;
computer-readable code for generating an individual correlation signal between the ground leakage signal and each phase energization state signal;
computer-readable code for determining a correlation value from the generated correlation signals, said correlation value, when outside a threshold range, being indicative of an incipient ground fault in a respective phase of one of the plurality of electrical devices; and
computer-readable code for dynamically adjusting the threshold range for detecting an incipient ground fault, the adjusting based on a magnitude and/or a rate of change of the magnitude of the sensed voltage difference across the positive and negative rails of the direct current bus.
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Specification