Parallel distribution optical fibre raster temp. sensing method and its system

Abstract

The invention relates to full parallel distributing type optical fiber grating temperature sensing method and its system. The method includes the following steps: processing high speed modulation for the wide band light source to form pulse sequence with certain width and duty ratio; adopting parallel connection for the sensor each of which is corresponding with different time delay optical fiber; making the pulse light source signal enter into the sensor array by splitter; making each reflected light signal of the sensor enter into photo-electricity detecting unit by one and the same fiber coupler or optical circulator; receiving a series of pulsing signals in one light source modulating cycle each of which is corresponding with one sensor; gaining light signal center wavelength information by a special filter; detecting each of them to gain corresponding sensor temperature information.

Description

technical field [0001] The invention relates to the field of temperature measurement, and mainly refers to a fully parallel distributed optical fiber grating temperature sensing method and system thereof for monitoring ambient temperature changes by detecting changes in the wavelength of optical signals. Background technique [0002] The safety and maintenance of the power system has always been a major issue related to international people's livelihood. According to the analysis of a large number of electrical accidents, more than 90% of the accidents are caused by excessive temperature of equipment joints or contacts. The fire caused by overheating caused a large area of ​​factory buildings to be burned and forced to shut down, and the country lost more than one billion yuan every year. However, due to reasons such as electromagnetic interference and humidity, there is still a lack of effective means for temperature detection of power equipment. [0003] In the existing ...

AI Technical Summary

Problems solved by technology

[0004] The patent application with publication number CN2599554Y is easily affected by electromagnetic interference during signal transmission, and the system reliability is insufficient; the patent application with publication number CN2599547Y introduces a photoelectric conversion system that requires battery power at the sensor end, the battery must be replaced regularly, and the explosion-proof performance is insufficient; The patent application with publication number CN1363828A adopts the same fiber grating series connection method, so it cannot accurately distinguish the sensing signal returned by each fiber grating. It can only judge whether there is an abnormal temperature detection point on each fiber grating string, and cannot obtain Accurate temperature value of each detection point; patents 200510021118.3 and 200410075518.8 use fiber gratings with different central wavelengths in series, although real-time temperature measurement of multiple detection points can be realized at the same time, and the signal transmission is anti-interference, but it is in a single channel Multiple grating sensors with different central wavelengths are connected in series on the optical fiber. The number of sensors that can be connected in series on a single optical fiber is restricted by the width of the light source and the temperature measurement range; The bending of the optical fiber must be greater than a certain bending radius. Due to the narrow installation space near the temperature measuring point of the power system, it is difficult to install the fiber grating sensor in series; at the same time, the fiber grating sensor with different central wavelengths cannot be interchanged and has no consistency. , which creates operational complexity and high costs in processing, calibration and user use

Images