US4491782A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for locating faults in electric cables
Assignee: Balfour Beatty PLC
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Filing: 1982-04-02
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Granted: 1985-01-01
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Expires: 2002-04-02
Abstract
Abstract Apparatus for detecting and locating a fault in an electric cable or cable installation using a pulse-echo or impulse current technique comprises a low voltage pulse generator for injecting a series of pulses into a cable or cable installation; a digital store and memory for recording a predetermined number of pulses and for digitizing and storing the waveforms obtained under two different conditions of the cable; means for terminating the recording of pulses a predetermined time after a fault condition is detected; and means for retrieving the signals obtained under the two separate conditions, comparing them and thus locating the position of the fault.
Inventors
- 👤 Edward J. Bellis
- 👤 Philip F. Gale
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 00:01
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/08; G01R31/11
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
201 words
Apparatus for detecting and locating, using a pulse-echo technique, unstable and transitory faults as well as stable faults in an energised power distribution electric cable installation which apparatus comprises: (a) means for detecting two different conditions from the voltampere characteristics of the electric cable, one of said two different conditions being before fault appears in one of the power distribution cables of the installation and the other of said two different conditions being whilst a fault is present in one of the power distribution cables of the installation; (b) means for injecting a series of pulses into the energised power distribution cable installation under both different conditions of the installation to obtain pulse-echo signals; (c) an analogue to digital converter for digitising the pulse-echo signals obtained under said two different conditions of the installation; (d) memory means for storing the digitised signals and for recording a predetermined number of pulses; (e) means for terminating the recording of pulses a predetermined time after a fault condition is detected; and (f) means for comparing the waveforms of signals obtained under the two said conditions in order that the distance of the fault in said power distribution cable of the installation can be determined.
Claim 2
Dependent Claim
201 words
Apparatus for detecting and locating, using a pulse-echo technique, unstable and transitory faults as well as stable faults in an energised power distribution electric cable installation which apparatus comprises: (a) means for detecting two different conditions from the voltampere characteristics of the electric cable, one of said two different conditions being before fault appears in one of the power distribution cables of the installation and the other of said two different conditions being whilst a fault is present in one of the power distribution cables of the installation; (b) means for injecting a series of pulses into the energised power distribution cable installation under both different conditions of the installation to obtain pulse-echo signals; (c) an analogue to digital converter for digitising the pulse-echo signals obtained under said two different conditions of the installation; (d) memory means for storing the digitised signals and for recording a predetermined number of pulses; (e) means for terminating the recording of pulses a predetermined time after a fault condition is detected; and (f) means for comparing the waveforms of signals obtained under the two said conditions in order that the distance of the fault in said power distribution cable of the installation can be determined.
Claim 3
Dependent Claim
22 words
Apparatus as claimed in claim 1 wherein the apparatus also comprises means for recording a power frequency waveform simultaneously with the pulses.
Claim 4
Dependent Claim
35 words
Apparatus as claimed in claim 1 or 2, wherein the predetermined time allows eight pulses to be injected after a fault condition is detected, and the memory records sixteen consecution pulses at any one time.
Claim 5
Dependent Claim
26 words
Apparatus as claimed in claim 1, wherein the apparatus also comprises a triggering circuit which is responsive to the level of current flowing in the cable.
Claim 6
Dependent Claim
25 words
Apparatus as claimed in claim 1, wherein a circuit is connected to the cable or cable installation which is capable of simulating a cable fault.
Claim 7
Dependent Claim
200 words
Apparatus for detecting and locating, using an impulse-current technique, unstable and transitory faults as well as stable faults in an energised power distribution electric cable installation which apparatus comprises: (a) means for detecting two different conditions from the voltampere characteristics of the electric cable, one of said two different conditions being before fault appears in one of the power distribution cables of the installation and the other of said two different conditions being whilst a fault is present in one of the power distribution cables of the installation; (b) means for injecting a series of pulses into the energised power distribution cable installation under both different conditions of the installation to obtain impulse-current signals; (c) an analogue to digital convertor for digitising the signals obtained under said two different conditions of the installation; (d) memory means for storing the digitised signals and for recording a predetermined number of pulses; (e) means for terminating the recording of pulses a predetermined time after a fault condition is detected; and (f) means for comparing the waveforms of signals obtained under the two said conditions in order that the distance of the fault in said power distribution cable of the installation can be determined.
Claim 8
Dependent Claim
200 words
Apparatus for detecting and locating, using an impulse-current technique, unstable and transitory faults as well as stable faults in an energised power distribution electric cable installation which apparatus comprises: (a) means for detecting two different conditions from the voltampere characteristics of the electric cable, one of said two different conditions being before fault appears in one of the power distribution cables of the installation and the other of said two different conditions being whilst a fault is present in one of the power distribution cables of the installation; (b) means for injecting a series of pulses into the energised power distribution cable installation under both different conditions of the installation to obtain impulse-current signals; (c) an analogue to digital convertor for digitising the signals obtained under said two different conditions of the installation; (d) memory means for storing the digitised signals and for recording a predetermined number of pulses; (e) means for terminating the recording of pulses a predetermined time after a fault condition is detected; and (f) means for comparing the waveforms of signals obtained under the two said conditions in order that the distance of the fault in said power distribution cable of the installation can be determined.
Claim 9
Dependent Claim
22 words
Apparatus as claimed in claim 6 wherein the apparatus also comprises means for recording a power frequency waveform simultaneously with the pulses.
Claim 10
Dependent Claim
36 words
Apparatus as claimed in claim 6 or claim 7, wherein the predetermined time allows eight pulses to be injected after a fault condition is detected, and the memory records sixteen consecutive pulses at any one time.
Claim 11
Dependent Claim
26 words
Apparatus as claimed in claim 6, wherein the apparatus also comprises a triggering circuit which is responsive to the level of current flowing in the cable.
Claim 12
Dependent Claim
25 words
Apparatus as claimed in claim 6, wherein a circuit is connected to the cable or cable installation which is capable of simulating a cable fault.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-01-01 | 1988-07-02 | 1989-01-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-01-01 | 1992-07-02 | 1993-01-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-01-01 | 1996-07-02 | 1997-01-01 | $7700.00 | Window Closed / Lapsed |