Fault detection method and apparatus
First Claim
1. An arrangement for detecting upstream protective device operations in an electrical circuit via the circuit conditions at a particular location of the circuit comprising:
- decision means responsive to predetermined circuit conditions at the particular location for providing at least first and second representations corresponding to the detection of respective first and second different types of operations of upstream protective devices, said first representation corresponding to a fault downstream of the particular location that causes operation of an upstream protective device that temporarily opens the circuit for a time interval that exceeds a first time duration, said second representation corresponding to a fault downstream of the particular location that causes operation of an upstream protective device that opens the circuit for a time interval that exceeds a second time duration greater than said first time duration, said decision means comprising first means for determining an occurrence of said first type of operation based an on occurrence of a predetermined overcurrent condition followed by a loss of a predetermined circuit parameter for said first time duration, said decision means further comprising second means for determining an occurrence of said second type of operation on the basis of a predetermined overcurrent condition followed by a loss of a predetermined circuit parameter for said second time duration.
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Accused Products
Abstract
Method and apparatus are provided responsive to the circuit parameters at one or more locations of an electrical power transmission and/or distribution network for detecting protective device operation. The detection of the protective device operation is utilized to locate faults and also to ascertain the status of protective devices. This information is useful in automated power systems for desirable isolation and sectionalizing of faults for optimum restoration of the network. A fault detection unit of the present invention is responsive to sensed circuit parameters and provides at least first and second outputs indicative of protective device operations that open the circuit. The first output is provided upon the occurrence of an overcurrent followed by the loss of a circuit parameter, such as voltage, for a specified time duration. In a preferred arrangement, the timing for a specified time duration is started when the overcurrent ends. Thus, rapid detection is achieved since the specified time duration need not include the maximum operating time of the protective device. The second output is provided if the conditions for the first output are satisfied and the loss of the circuit parameter continues for a specified extended time interval corresponding to the sequence of operation of the upstream protective device so as to establish protective device operation. For example, the first output in one illustrative arrangement corresponds to the opening of a recloser while the second output corresponds to the lockout of the recloser. In a preferred arrangement, a third output is provided upon the occurrence of an overcurrent for a specified time duration. A fourth output is provided upon the occurrence of an overcurrent for a specified time duration and the presence of voltage after the occurrence of the first output for purposes of detecting downstream fuse operation on power systems utilizing fuse-saving arrangements.
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Citations
42 Claims
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1. An arrangement for detecting upstream protective device operations in an electrical circuit via the circuit conditions at a particular location of the circuit comprising:
decision means responsive to predetermined circuit conditions at the particular location for providing at least first and second representations corresponding to the detection of respective first and second different types of operations of upstream protective devices, said first representation corresponding to a fault downstream of the particular location that causes operation of an upstream protective device that temporarily opens the circuit for a time interval that exceeds a first time duration, said second representation corresponding to a fault downstream of the particular location that causes operation of an upstream protective device that opens the circuit for a time interval that exceeds a second time duration greater than said first time duration, said decision means comprising first means for determining an occurrence of said first type of operation based an on occurrence of a predetermined overcurrent condition followed by a loss of a predetermined circuit parameter for said first time duration, said decision means further comprising second means for determining an occurrence of said second type of operation on the basis of a predetermined overcurrent condition followed by a loss of a predetermined circuit parameter for said second time duration. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of detecting protective device operation in an electrical circuit comprising:
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monitoring circuit parameters at predetermined points of the circuit; and determining operation of protective devices upstream of said predetermined points via the monitored circuit parameters, said determining step comprising detecting circuit-opening operation of an upstream protective device to provide first and second predetermined statuses, said first predetermined status corresponding to detecting circuit opening of a first predetermined type, said second predetermined status corresponding to detecting circuit-opening operation of a second predetermined type, said first predetermined status including a detection of a predetermined overcurrent condition followed by a loss of voltage and/or current, said second predetermined status including the detection of said first predetermined status and additionally a continued loss of voltage and/or current for an extended time duration. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23)
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24. A method of detecting first and second types of operation of an upstream protective device in an electrical circuit comprising:
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detecting the occurrence of a predetermined overcurrent condition and an end of the predetermined overcurrent condition; determining after the end of the predetermined overcurrent condition a loss of a predetermined circuit parameter for a first predetermined time duration to establish the first type of operation of the protective device; and thereafter continuing to monitor a continued loss of the predetermined circuit parameter for a second predetermined time duration to establish the second type of operation of the protective device, the predetermined overcurrent condition comprising the occurrence of an overcurrent level greater than a predetermined level for a third predetermined time duration. - View Dependent Claims (25, 26, 27, 35)
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28. An arrangement for detecting first and second types of operation of upstream protective devices in an electrical circuit comprising:
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means for detecting the occurrence of a predetermined overcurrent condition and the end of the predetermined overcurrent condition; and means for determining after the end of the overcurrent condition the loss of voltage and/or current to establish the first type of operation of an upstream protective device and for determining after the end of the overcurrent condition the loss of voltage and/or current for a first predetermined time duration to establish the second type of operation of upstream protective devices, said determining means further comprising means responsive after the establishing of the first type of operation to establish a downstream device operation in response to the detection of a predetermined overcurrent level for a second predetermined time duration followed by a detection of predetermined voltage conditions. - View Dependent Claims (29, 30, 31)
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32. A method for detecting downstream protective device operation in an electrical circuit via the circuit conditions at a particular location of the circuit comprising
detecting a first predetermined overcurrent condition; -
detecting a second condition including a loss of voltage and/or current after an end of said first predetermined overcurrent condition; detecting in response to said second condition a third predetermined overcurrent condition; and detecting after the end of said third predetermined overcurrent condition an presence of a predetermined voltage condition. - View Dependent Claims (33, 34)
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36. An arrangement for detecting upstream protective device operations in an electrical circuit via the circuit conditions at a particular location of the circuit comprising:
decision means responsive to predetermined circuit conditions at the particular location for providing at least first and second representations corresponding to a detection of respective first and second different types of operations of upstream protective devices, said first representation corresponding to a fault downstream of the particular location that causes operation of an upstream protective device that temporarily opens the circuit for a time interval that exceeds a first time duration, said second representation corresponding to a fault downstream of the particular location that causes operation of an upstream protective device that opens the circuit for a time interval that exceeds a second time duration greater than said first time duration, said decision means comprising first means for determining an occurrence of said first type of operation based on an occurrence of a predetermined overcurrent condition followed by a loss of a predetermined circuit parameter for said first time duration, said decision means further comprising second means for determining an occurrence of said second type of operation on the basis of a predetermined overcurrent condition followed by a loss of a predetermined circuit parameter for said second time duration, said decision means further comprising third means responsive to a return of said predetermined circuit parameter during the timing of either said first or second time duration for a third predetermined time duration for returning said decision means to a predetermined initial monitoring state, said third predetermined time duration being different for the return of said predetermined circuit parameter during each of said first and second time durations.
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37. An arrangement for detecting upstream protective device operations in an electrical circuit via the circuit condition at a particular location of the circuit comprising:
decision means responsive to predetermined circuit conditions at the particular location for providing at least first and second representations corresponding to a detection of respective first and second different types of operations of upstream protective devices, said first representation corresponding to a fault downstream of the particular location that causes operation of an upstream protective device that temporarily opens the circuit for a time interval that exceeds a first time duration, said second representation corresponding to a fault downstream of the particular location that causes operation of an upstream protective device that opens the circuit for a time interval that exceeds a second time duration greater than said first time duration, said decision means comprising first means for determining an occurrence of said first type of operation based on an occurrence of a predetermined overcurrent condition followed by a loss of a predetermined circuit parameter for said first time duration, said decision means further comprising second means for determining an occurrence of said second type of operation on the basis of a predetermined overcurrent condition followed by a loss of a predetermined circuit parameter for said second time duration, the electrical circuit further including a plurality of phases, said decision means comprising means responsive to each phase for individually providing said first and second representations, the electrical circuit further including a neutral, said decision means comprising means responsive to the neutral for providing said first and second representations.
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38. A method of detecting first and second types of operation of an upstream protective device in an electrical circuit comprising:
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detecting the occurrence of a predetermined overcurrent condition and an end of the predetermined overcurrent condition; determining after the end of the predetermined overcurrent condition a loss of a predetermined circuit parameter for a first predetermined time duration to establish the first type of operation of the protective device; thereafter continuing to monitor a continued loss of the predetermined circuit parameter for a second predetermined time duration to establish the second type of operation of the protective device; and providing second data when said second type of operation has been established, and providing first data when said first type of operation has been established provided that said second type of operation has not been established.
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39. A method of detecting first and second types of operation of an upstream protective device in an electrical circuit comprising:
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detecting the occurrence of a predetermined overcurrent condition and an end of the predetermined overcurrent condition; determining after the end of the predetermined overcurrent condition a loss of a predetermined circuit parameter for a first predetermined time duration to establish the first type of operation of the protective device; thereafter continuing to monitor a continued loss of the predetermined circuit parameter for a second predetermined time duration to establish the second type of operation of the protective device; and thereafter detecting a predetermined overcurrent for a third predetermined time duration and a presence of voltage after an end of the predetermined overcurrent to establish a downstream device operation.
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40. A method of detecting first and second types of operation of an upstream protective device in an electrical circuit comprising:
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detecting the occurrence of a predetermined overcurrent condition and an end of the predetermined overcurrent condition; determining after the end of the predetermined overcurrent condition a loss of a predetermined circuit parameter for a first predetermined time duration to establish the first type of operation of the protective device; and thereafter continuing to monitor a continued loss of the predetermined circuit parameter for a second predetermined time duration to establish the second type of operation of the protective device, said first type of operation being a temporary opening of the circuit by a protective device and said second type of operation being a permanent opening of the circuit.
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41. A method of detecting first and second types of operation of an upstream protective device in an electrical circuit comprising:
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detecting the occurrence of a predetermined overcurrent condition and an end of the predetermined overcurrent condition; determining after the end of the predetermined overcurrent condition a loss of a predetermined circuit parameter for a first predetermined time duration to establish the first type of operation of the protective device; and thereafter continuing to monitor a continued loss of the predetermined circuit parameter for a second predetermined time duration to establish the second type of operation of the protective device, said second predetermined time duration being greater than the maximum temporary open time of an upstream protective device.
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42. A method of detecting first and second types of operation of an upstream protective device in an electrical circuit comprising:
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detecting the occurrence of a predetermined overcurrent condition and an end of the predetermined overcurrent condition; determining in response to the detecting of the end of the predetermined overcurrent condition a continuous absence of a predetermined circuit parameter throughout a first predetermined time duration to establish the first type of operation of the protective device; and thereafter continuing to monitor a continued absence of the predetermined circuit parameter throughout a second predetermined time duration to establish the second type of operation of the protective device.
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Specification