METHOD AND DEVICE FOR DIAGNOSTICS OF ELECTRIC POWER SUPPLY CABLE LINE FAULTS Russian patent published in 2015 - IPC G01R31/08 

FIELD: power engineering.

SUBSTANCE: invention relates to electric power engineering, particularly, to detection of faults in electric power engineering and can be used for diagnostics and preliminary localisation of faults in underground supply cable lines rated up to 35 kV. This method comprises the feed of probing monochromatic signal to every conductor of cable line. Probing monochromatic signal voltage is kept constant. Frequency starting from lower frequency is smoothly varied from 3·10² to 3·10⁷ Hz for cable length of up to 100 km, from 3·10³ to 3·10⁷ Hz for cable length of 10 km and from 3·10⁴ to 3·10⁷ Hz for cable length of up to 1 km. Conductor current is controlled at cable line inlet in conductor whereto probing monochromatic signal is fed, as well as potential at other conductors. Current increase at cable line inlet to some maximum and invariable potential at other conductors mean cable conductor breakdown, decrease in insulance or earth fault. Increase in current at cable line inlet to some maximum and potential variation at one of the other conductors mean short circuit between cable conductors.

EFFECT: higher precision of measurements, simplified process, lower material input and costs for power supply recovery.

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