Fiber optic temperature sensor, Intelligent monitoring system, Distributed fiber optic manufacturer in China
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Introduction to the functions and principles of distributed fiber optic temperature measurement system
Detection principle of distributed fiber optic temperature monitoring system
The principle of a fiber-optic distributed temperature sensing system is that as the temperature of the detection point changes, the intensity of Raman scattered light scattered in the opposite direction in the fiber optic also changes after applying a pulse laser. Then, these scattered light are filtered and converted into electrical signals. This process converts the optical signal into an electrical signal, amplifies the electrical signal, and then converts it through the system to output data through a signal processor. The scattering velocity of Raman scattered light waves is constant, and the location of monitoring points is calculated by calculating the time it takes for the scattered waves to return. When a certain pulse laser is applied in the optical fiber, the laser photons have energy. After interacting with molecules, the molecules are excited and release a certain amount of energy. The energy difference between them causes a change in the frequency of the released photons. By sensing the change in this energy, the signal changes are displayed, and the temperature change at the monitoring point is calculated.
Principle of fiber optic distributed temperature sensing system
Fiber optic transmission refers to the transmission of information through the transmission of light through optical fibers. In physics, it can be understood that changes in the propagation medium occur during the propagation of light, and reflection and refraction occur when the refractive index of the propagation medium is not equal. In order to ensure minimal information transmission loss, it is necessary to achieve total reflection of light waves in optical fibers, and laser energy concentration has monochromaticity and directionality, so it can be used as a light source for this project. Considering the phenomenon of fiber dispersion, a shorter fiber length was designed to make the fiber as straight as possible to reduce energy loss, and a fixed frequency laser transmitter was selected. At present, most optical fibers are made of quartz as raw material, and special data fibers are used to enhance Raman scattering, with a small amount of high concentration germanium added.
Hardware and software system hardware structure of fiber optic distributed temperature sensing
The optimization of system hardware is the foundation for improving temperature measurement systems, including sensing optical fibers, photoelectric conversion devices, information processors, and computers. Firstly, improvements were made to the sensing optical fiber. In order to ensure the transmission of Raman scattering signals during the experiment, germanium was added to the quartz optical fiber, and the length of the fiber was shortened while making it as straight as possible. Secondly, use laser emitters with small volume and high stability in high temperature and magnetic interference environments. Thirdly, replace commonly used photodiodes (PINs) with high gain avalanche photodiodes (APDs), and select the optimal operating point near the avalanche breakdown point to ensure both signal gain and sensitivity of the photoelectric converter. Fourthly, optimize the signal amplification circuit, enhance the frequency selection ability of the circuit, improve the signal resolution and amplification ability, while minimizing power consumption as much as possible.
The hardware of the system is the foundation, and the system software is an indispensable key in the detection process. The temperature changes in high-voltage switchgear are constantly occurring, so real-time monitoring technology should be adopted. Temperature warning values should be set according to the actual situation, and possible dangers should be monitored and dealt with in a timely manner. The temperature changes on each working day should be recorded, and comprehensive analysis and treatment should be carried out to nip the danger in the bud. Using Windows system and SQL database, integrating multiple functions such as data management, data querying, real-time monitoring, signal alarm, etc., and being able to detect problems in the system, considering all possible faults.
The principle of temperature measurement system for distributed fiber optic system is that the system can continuously monitor the temperature inside the cabinet at fixed points and accurately measure the temperature changes of the measured points. This provides a basis for preventive maintenance of switchgear and reduces safety hazards.
