Distributed acoustic sensing (DAS) technology realizes the real-time monitoring of the optical cable or pipeline by using the backward Rayleigh scattering signal in the optical fiber. The technology is based on a phase-sensitive optical time domain reflector (Φ -OTDR) to reconstruct and detect events such as sound or vibration by detecting the backscattering signal generated when coherent pulse light propagating through the optical fiber. In the optical cable monitoring, the DAS system can accurately restore the sound information around the optical cable, such as vehicles, man-made damage, etc., and filter through the intelligent analysis function, interference signals, to ensure the accurate identification of events. For pipeline monitoring, DAS technology can simultaneously measure various parameters, such as acoustics, temperature, pressure, strain and hole noise, and quickly and accurately detect and classify leakage events, third-party interference and other threats, providing a strong guarantee for the safe operation of the pipeline.

With the continuous development of science and technology, the use of electric power electrical equipment safety has been constantly concerned. Optical fiber temperature measurement in the power system and oil and gas pipeline application range gradually into people's vision, but for the operation principle we know little, the following to introduce the principle of fluorescent fiber temperature measurement, distributed fiber temperature measurement principle, fiber grating temperature measurement principle. Optical fiber temperature measurement can not only be used in the field of electric power, petroleum and petrochemical, but also in the field of scientific research and experiment. Based on the fluorescence lifetime of the temperature measurement of the optical fiber, generally speaking, the outer electrons of the fluorescent material molecules are in a relatively stable state, when the excited light is illuminated, the electron absorption energy transition will appear. After the excitation light disappears, it is allowed to return to the ground state, but the energy keeps radiating, creating fluorescence. For its specific temperature measurement, the temperature of the material surface is related to the decay of the fluorescence afterglow itself, and the so-called afterglow decay is actually the fluorescence lifetime. There is a direct relationship between the length of the fluorescence lifetime and the temperature. After the temperature of the fluorescent substance is determined, the actual afterglow retention time is the lifetime, which itself is monotonous with the current signal. Therefore, through the characteristic curve, the corresponding material can be selected as the probe, and through the relationship between the detected current value and the time stent, the surface temperature can be clearly defined, and then the temperature of the monitoring point can be determined. In the project implementation, compared with the normal operating temperature detection, the temperature after the failure increases abnormally, so the detection significance is greater.