The invention discloses a cable defect detection method and
system based on double-path
coupling frequency domain reflection, and the method comprises the steps: enabling a
signal generator to generate two groups of correlated sine frequency sweeping signals, namely a test
signal S1 and a reference
signal S2; s1 is injected into the head end of the cable, and a reflected signal R1 is collected; respectively extracting the spectrum characteristics of the amplitudes and the phase differences of the R1, the S1 and the S2 by adopting a double-path signal comparison device, carrying out comprehensive judgment, and determining the
reflection spectrum characteristic of the R1; the
reflection coefficient spectrum is optimized through a
window function, and signal features are obtained; converting the optimized
frequency spectrum into a
time domain reflection waveform, and extracting reflection peak
time information; and calculating defect positions by combining electromagnetic
wave propagation velocity. According to the cable defect detection method and
system based on double-path
coupling frequency domain reflection, high-precision detection of a long-distance cable is realized; and two paths of
coupling signals are introduced for comparison, so that the accuracy of phase measurement is improved, and an efficient nondestructive detection scheme is provided for
power grid operation and maintenance and the like.