Combined optical fiber EFPI broadband PD ultrasonic detection system

Abstract

The invention relates to a combined optical fiber EFPI broadband PD ultrasonic detection system. The system comprises a light source, an optical fiber 1 / 2 optical splitter, an optical fiber, an optical fiber coupler, a first optical cable head, a first 16-core optical cable, a second optical cable head, an optical fiber EFPI sensing combined probe, a third optical cable head, a second 16-core optical cable, a fourth optical cable head, a multi-path photoelectric detector, a first coaxial cable, a broadband signal superposition and amplification device, a second coaxial cable and a high-speed data acquisition device. Compared with the prior art, the system has the advantages that the problem that an EFPI sensor working at the existing resonant frequency can only be used for narrow-band measurement of ultrasonic signals is solved, and the frequency band requirement of the partial discharge ultrasonic signals of 20 kHz to 500 kHz is met.

Description

technical field [0001] The invention relates to the field of broadband PD ultrasonic detection, in particular to a combined optical fiber EFPI broadband PD ultrasonic detection system. Background technique [0002] The extrinsic Fabry-Perot Interferometer (EFPI) fiber optic sensor is a set of sensitive diaphragm structure that converts ultrasonic waves into mechanical vibrations, and then converts mechanical vibrations into optical parameter changes by using Fabry-Perot interference technology. The high-performance acoustic ultrasonic detection system converted, collected, and demodulated by photoelectric detectors and other related instruments has been used to detect partial discharge (PD) ultrasonic signals generated by internal insulation defects of large-scale power equipment. like figure 1 As shown, the sensor's Fab cavity probe is generally composed of a core body containing an optical fiber, a circular sleeve and a sensitive diaphragm (ultrasonic coupling vibration e...

AI Technical Summary

Problems solved by technology

[0007] Due to the frequency of ultrasonic signals of PD generated by internal insulation defects of power equipment, the frequency of PD ultrasonic signals is tens to hundreds of kHz. The general technical conditions of the instrument recommend that the working frequency measurement range of the sensor should be 20kHz to 500kHz, which makes the existing ultrasonic detection method and system based on a single optical fiber EFPI sensor have missed detection problems in practical applications. Insensitive, it is easy to cause the test results to fail to determine whether there is an insulation defect, resulting in a vicious accident of insulation breakdown caused by untimely maintenance

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