METHOD FOR DETECTING THE DEFECT OF ELECTRIC CABLE Russian patent published in 2018 - IPC G01R31/11 

FIELD: measurement technology.

SUBSTANCE: invention relates to electrical measurements and can be used to detect and localize a defect in the form of a coarse portion of an electrical cable. Before using the cable, the cable is probed with a voltage pulse, and a control reflectogram is obtained with probing and reflected from the cable end pulses. Defective reflectogram is obtained with a probing, reflected from the wet section pulse and with the pulse reflected from the end of the cable. Pulse, which is reflected from the wet section, is isolated against the background of random noise. Compare the defective and control reflectograms. Determine the distance to the point of beginning of the wet section according to the coordinate, where the voltage function deviates to negative values on the defective reflectogram between the probing and reflected from the cable end pulses. Specify the point of the beginning of the wet section along the coordinate of the largest negative deviation of the voltage function of the defective reflectogram relative to the control reflectogram between the probing and reflected from the cable end pulses. Determine the length of the wet section according to the formula: d=(x^d_p-x^k_p)/0.083; where d is the length of the wet section, m; x^d_p – coordinate on the defective reflectogram of the peak of the pulse reflected from the end of the cable, m; x^k_p – coordinate on the control reflectogram of the peak of the pulse reflected from the end of the cable, m; 0.083 is the empirical coefficient for the cable. Defect is assessed according to the condition: d/L≤0.5; where d is the length of the cable section, m; L – cable length, m. If the condition is met, then the defect is considered non-critical. If the condition is not met, the defect is considered critical.

EFFECT: improved accuracy of determining the defect, the possibility of determining the length of the cable wet section.

1 cl, 3 dwg