Cable defect detection system and method based on pulse sine wave

Abstract

The invention discloses a cable defect detection system and method based on pulse sine wave, the system comprises a sine wave generator with fixed frequency, the output end of the sine wave generator is connected with a high-frequency voltage amplifier, and the output end of the high-frequency voltage amplifier is connected with a high-frequency switch; the output end of the high-frequency switch is respectively connected with the coupler and the controller, the output end of the coupler is respectively connected with the high-voltage cable to be detected and the three-way joint, a bare conductor is arranged between the high-frequency voltage amplifier and the high-frequency switch, and a space stray capacitor is formed between the plate electrode and the bare conductor. The plate electrode is respectively connected with the high-frequency capacitor and the high-frequency cable, the plate electrode and the high-frequency capacitor form a high-frequency voltage divider, and the output end of the three-way connector is connected with the signal acquisition and analysis system.Detection signals are amplified, detection of defects at different positions of the cable is realized, and the signal detection sensitivity of small defects is improved.

Description

technical field [0001] The invention relates to the field of electrical equipment sensing detection, in particular to a cable defect detection system and method based on a pulse sine wave. Background technique [0002] Cables are an important part of the power grid system. Due to differences in the quality, use environment, and service life of different cables, some cables may have some defects. Therefore, the detection of cable defects is of great significance to ensure the safe and reliable operation of the power grid. [0003] At present, the detection methods for cable defects mainly include time domain reflectometry (TDR) and frequency domain reflectometry (FDR). [0004] Frequency Domain Reflectometry (FDR): FDR is a cable fault detection and location method based on frequency domain signals to detect insulation damage that affects the local capacitance and impedance of the cable. The FDR sends a variable frequency signal and calculates the line impedance based on the...

AI Technical Summary

Problems solved by technology

Changes in the cable structure due to faults change the impedance, causing some of the incident wave to be reflected back to the transmitter

Due to the need for detection by reflected waves, TDR technology is only suitable for low-resistance short-circuit faults or high-resistance open-circuit faults, and cannot detect small defects that do not cause cable short circuits or breaks

[0006] The reason why the traditional TDR method cannot detect small defects is that the amplitude change of the reflected signal caused by small defects is small

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