Distributed optical fiber temperature measurement system

Abstract

The invention discloses a distributed optical fiber temperature measurement system, which comprises a light source device, a sensing optical fiber, an optical signal processing device, a data acquisition device, a signal processing and computing device, a display and alarm device, a communication and data processing device and a system control center, a plurality of light sources emit light pulses to enter the sensing optical fiber, the sensing optical fiber converts temperature changes into optical signals, the optical signals are converted into electric signals through the optical signal processing equipment, the electric signals are converted into digital signals through the data acquisition equipment, and then the digital signals are transmitted to the signal processing and calculating equipment to be processed to obtain temperature values. The temperature value is transmitted to the display and alarm device, sound-light alarm is triggered when the temperature is abnormal, and data is transmitted to a remote control center to be monitored and managed by means of the communication and data processing device. According to the invention, the sensitivity and the response speed of temperature measurement can be improved by setting a synchronous control technology and assisting cooperation of a plurality of light sources.

Description

Technical Field

[0001] The invention belongs to the technical field of optical fiber temperature measurement, and specifically relates to a distributed optical fiber temperature measurement system. Background Art

[0002] The distributed fiber optic temperature measurement system is a monitoring system based on fiber optic sensing technology that uses the scattering characteristics of light in optical fiber to measure temperature. It mainly uses optical fiber as a sensing medium and lays it in areas where temperature monitoring is required. It emits light pulses to the optical fiber and collects the returned scattered light carrying temperature information. After optical signal processing and data acquisition, the signal processing and computing equipment uses a specific algorithm to accurately calculate the temperature value of each point along the optical fiber, thereby realizing real-time and continuous monitoring of temperature in a wide range of areas. It is widely used in temperature monitoring and early warning in many fields such as electric power, petrochemicals, transportation tunnels, and large buildings.

[0003] Existing distributed fiber optic temperature measurement systems usually rely on a single light source and traditional signal processing methods, which makes it difficult to accurately capture small changes in temperature, further causing deviations between the measurement results and the actual temperature, affecting the accuracy of research and monitoring. At the same time, the system's response speed is relatively slow and cannot meet the needs of rapid alarm and timely fire-fighting measures. Summary of the invention

[0004] The purpose of the present invention is to provide a distributed optical fiber temperature measurement system to solve the problem that the optical fiber temperature measurement technology in the existing distributed optical fiber temperature measurement system has relatively low sensitivity, does not respond quickly enough to slight temperature changes, and cannot meet the requirements of some occasions with extremely high requirements for rapid response to temperature changes and real-time monitoring.

[0005] The technical solution adopted by the present invention is as follows: A distributed optical fiber temperature measurement system includes a light source device, a sensing optical fiber, an optical signal processing device, a data acquisition device, a signal processing and computing device, a display and alarm device, a communication and data processing device, and a system control center. The light source device uses a synchronous control technology to synchronize the emission of optical pulses by multiple light sources, which are introduced into the sensing optical fiber through an optical fiber connection device. The sensing optical fiber converts temperature changes into optical signal changes and transmits them back. The optical signal processing device receives the optical signal and converts it into an electrical signal. The data acquisition device converts it into a digital signal, which is then transmitted to the signal processing and computing device. The temperature value is obtained through complex algorithm processing. On the one hand, the temperature value is transmitted to the display and alarm device and intuitively presented on the display terminal of the system control center. Once the temperature is abnormal, an audible and visual alarm is triggered. On the other hand, with the help of the communication and data processing device, the data is transmitted to the remote control center through the network interface and in compliance with the data encryption and transmission protocol for remote monitoring and management.

[0006] Among them, the light source equipment is equipped with multiple groups of high-power narrow pulse lasers and high-precision, high-stability driving circuits, and adopts synchronous control technology at the same time, so that multiple groups of high-power narrow pulse lasers pass through high-precision, high-stability driving circuits through a high-precision clock signal as a reference. The driving circuit of each light source uses this clock signal as a reference to trigger the emission of light pulses, which are then propagated in the sensing optical fiber.

[0007] The sensing optical fiber includes a special sensing optical fiber, an optical fiber connection and fixing device. The light pulse emitted by the light source device enters the special sensing optical fiber, and uses Raman scattering, thermo-optical effect, etc. to convert temperature changes into changes in optical signal characteristics.

[0008] Among them, the optical signal processing equipment includes a light detector, a preamplifier, and a filter. The light detector receives the optical signal carrying temperature information returned from the sensing optical fiber and converts it into a weak electrical signal. The preamplifier increases the strength of the electrical signal, and the filter removes noise to make the processed electrical signal purer.

[0009] Among them, the data acquisition equipment includes a high-speed data acquisition card and a clock synchronization device. The high-speed data acquisition card samples the electrical signal output by the optical signal collection and processing module at a high sampling frequency and converts it into a digital signal. The clock synchronization device ensures that data acquisition is accurately synchronized with the moment when the light source emits the light pulse, so that the collected data accurately corresponds to the position of the sensor optical fiber.

[0010] Among them, the signal processing and computing equipment includes a digital signal processor and a field programmable gate array. The digital signal processor and the field programmable gate array receive digital signals from a data acquisition device, use a temperature calculation algorithm based on Raman scattering light intensity ratio, analyze and process the signals, and accurately calculate the temperature value.

[0011] Among them, after receiving the digital signal through a specific interface, the digital signal processor and the field programmable gate array in the signal processing and computing device will first filter and reduce noise on the signal, remove interference, and then normalize the signal to unify the signal intensity range. Then, based on the Raman scattering principle, the intensity values ​​of Stokes light and anti-Stokes light are separated and extracted from the signal, and the extracted light intensity values ​​are substituted into the mathematical model of the relationship between the Raman scattering light intensity ratio and temperature to calculate the temperature, and the iterative algorithm and calibration data are used to optimize the results.

[0012] Among them, in the Raman scattering principle, there is a specific mathematical relationship between temperature and the intensity ratio of Stokes light and anti-Stokes light. The common formula is: , where T is the temperature, h is Planck's constant, v is the frequency of light, k is the Boltzmann constant, and I AS and I S are the intensities of anti-Stokes light and Stokes light, respectively,AS and λ S are the wavelengths of anti-Stokes light and Stokes light respectively, C is a constant related to the characteristics of the optical fiber, and the digital signal processor and the field programmable gate array substitute the extracted Stokes light and anti-Stokes light intensity values ​​into the formula for calculation.

[0013] Among them, the light source equipment, sensor optical fiber, optical signal processing equipment, data acquisition equipment, signal processing and computing equipment and communication and data processing equipment are all arranged in the system host, and the sensor optical fiber is arranged in the monitoring area, and the display and alarm equipment and the system control center are placed in the monitoring room.

[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: In the present invention, synchronous control technology and the assistance of multiple light sources are adopted. Through the synchronous control technology, multiple light sources are made to emit light pulses at the same time, which can increase the intensity of the light signal and make it more anti-interference when transmitted in the optical fiber. In the case of certain loss or external interference in the optical fiber, the superposition signal generated by the multiple light sources is also easier to be accurately detected, thereby providing a basis for more accurate measurement of temperature changes. The light pulses emitted by different light sources have different characteristics such as wavelengths or frequencies. Through the synchronous control technology, they work together to generate multiple light signal transmission modes in the optical fiber. The response characteristics of these different modes of light signals to temperature changes are different. The system can comprehensively utilize these differences to obtain richer measurement information, thereby improving the resolution of slight temperature changes. The synchronous control technology enables multiple light sources to emit light pulses at the same time and detect the temperature information in the optical fiber at the same time. This parallel detection method greatly shortens the time for the system to obtain temperature data. The cooperation of multiple light sources can also bring advantages in the signal processing link. Through synchronous control, the system can more efficiently collect, process and analyze the light signals generated by multiple light sources, avoiding the waiting time and data accumulation delay in the signal processing process of a single light source. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of the present invention. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0017] Reference Figure 1A distributed optical fiber temperature measurement system includes a light source device, a sensing optical fiber, an optical signal processing device, a data acquisition device, a signal processing and computing device, a display and alarm device, a communication and data processing device, and a system control center. The light source device uses synchronous control technology to synchronize the emission of optical pulses by multiple light sources, which are introduced into the sensing optical fiber through an optical fiber connection device. The sensing optical fiber converts the temperature change into an optical signal change and transmits it back. The optical signal processing device receives the optical signal and converts it into an electrical signal. The data acquisition device converts it into a digital signal. The digital signal is then transmitted to the signal processing and computing device, and the temperature value is obtained through complex algorithm processing. On the one hand, it is transmitted to the display and alarm equipment and presented intuitively on the display terminal of the system control center. Once the temperature is abnormal, an audible and visual alarm will be triggered. On the other hand, with the help of communication and data processing equipment, the data is transmitted to the remote control center through the network interface and in accordance with the data encryption and transmission protocol for remote monitoring and management. By setting synchronous control technology and multiple light sources in the light source equipment, multiple light sources enhance the intensity of light signals, and their different characteristics generate diverse light signals. Comprehensive utilization can obtain more temperature information, accurately capture tiny changes, realize parallel detection through synchronous control, quickly obtain temperature data, optimize the signal processing process, and respond to temperature changes in time.

[0018] Reference Figure 1 As shown, the light source equipment is equipped with multiple groups of high-power narrow pulse lasers and high-precision, high-stability driving circuits, and adopts synchronous control technology at the same time, so that multiple groups of high-power narrow pulse lasers pass through high-precision, high-stability driving circuits through a high-precision clock signal as a reference. The driving circuits of each light source use this clock signal as a reference to trigger the emission of light pulses, and then propagate in the sensing optical fiber. The high-power narrow pulse laser can output higher energy and more stable light pulses, enhance the interaction with the sensing optical fiber, make the light signal changes caused by temperature changes more significant, and improve the system's sensitivity to temperature change detection. At the same time, it is equipped with a high-precision, high-stability driving circuit, which can more accurately adjust the frequency, pulse width and power of the light pulse to ensure the consistency and repeatability of the light pulse, thereby improving the system's response speed and measurement accuracy to small temperature changes.

[0019] Reference Figure 1 As shown, the sensing optical fiber includes a special sensing optical fiber, an optical fiber connection and a fixing device. The light pulse emitted by the light source device enters the special sensing optical fiber, and the temperature change is converted into a change in the characteristics of the optical signal by using Raman scattering, thermo-optical effect, etc. The special sensing optical fiber uses micro-nano optical fiber, which is small in size and has a stronger interaction with the external environment, and can amplify the modulation effect of temperature on the optical signal.

[0020] Reference Figure 1As shown, the optical signal processing equipment includes a photodetector, a preamplifier, and a filter. The photodetector receives the optical signal carrying temperature information returned from the sensing optical fiber and converts it into a weak electrical signal. The preamplifier increases the strength of the electrical signal, and the filter removes noise to make the processed electrical signal purer. The photodetector is a highly sensitive avalanche photodiode that can quickly and accurately convert weak optical signals into electrical signals.

[0021] Reference Figure 1 As shown, the data acquisition equipment includes a high-speed data acquisition card and a clock synchronization device. The high-speed data acquisition card samples the electrical signal output by the optical signal collection and processing module at a high sampling frequency and converts it into a digital signal. The clock synchronization device ensures that the data acquisition is accurately synchronized with the light source emitting light pulses, so that the collected data accurately corresponds to the position of the sensor optical fiber. The high-speed data acquisition card can sample the optical signal at an extremely high frequency and can obtain data points more densely, thereby capturing the subtle optical signal changes generated during the rapid rise or fall of temperature. Through high-frequency sampling, the system can obtain richer signal details. When calculating the temperature, analysis and processing based on more data points can effectively reduce measurement errors and improve measurement accuracy. Clock synchronization The device can ensure that data acquisition is strictly synchronized with the light pulse emitted by the light source, so that the light signals returned from different positions of the sensing optical fiber can accurately correspond to their positions in the optical fiber during acquisition. After the light source emits a light pulse, after a certain time delay, the temperature information at different positions is returned in the form of light signals. The clock synchronization device ensures that the acquisition card can accurately record the light signal corresponding to each time point, so as to accurately determine the position of the optical fiber from which the signal comes, and then accurately calculate the temperature at that position. The high-precision clock synchronization device enables the system to accurately distinguish light signals from adjacent positions, avoiding position confusion caused by time asynchrony, thereby ensuring the spatial temperature measurement resolution of the system, and can clearly distinguish the temperature differences in different tiny areas in the building structure.

[0022] Reference Figure 1 As shown, the signal processing and computing equipment includes a digital signal processor and a field programmable gate array. The digital signal processor and the field programmable gate array receive digital signals from the data acquisition equipment, use a temperature calculation algorithm based on the Raman scattering light intensity ratio, analyze and process the signals, and accurately calculate the temperature value. Based on the accurate relationship model between the Raman scattering light intensity ratio and temperature, combined with multi-dimensional information such as optical phase changes, the collected data are quickly and complexly analyzed and processed, thereby improving the accuracy and speed of temperature calculation and quickly responding to small changes in temperature.

[0023] Reference Figure 1As shown, after receiving digital signals through specific interfaces, the digital signal processor and field programmable gate array in the signal processing and computing equipment will first filter and reduce noise on the signal, remove interference, and then normalize the signal to unify the signal intensity range. Then, based on the principle of Raman scattering, the intensity values ​​of Stokes light and anti-Stokes light are separated and extracted from the signal, and the extracted light intensity values ​​are substituted into the mathematical model of the relationship between the Raman scattering light intensity ratio and temperature to calculate the temperature. At the same time, the iterative algorithm and calibration data are used to optimize the results. By combining filtering and noise reduction, normalization, iterative algorithms and calibration data, the system can adapt to different measurement environments and requirements. Whether it is a high temperature or high humidity environment, or a scene with different requirements for measurement accuracy and speed, the system can provide accurate temperature measurement by adjusting parameters and algorithms. At the same time, when there is a new algorithm or technology, it is convenient to replace the iterative algorithm or update the calibration data. At the same time, each processing step is relatively independent, which is convenient for troubleshooting and repair, and improves the flexibility and maintainability of the system.

[0024] Reference Figure 1 As shown, in the Raman scattering principle, there is a specific mathematical relationship between temperature and the intensity ratio of Stokes light and anti-Stokes light. The common formula is: , where T is the temperature, h is Planck's constant, v is the frequency of light, k is the Boltzmann constant, and I AS and I S are the intensities of anti-Stokes light and Stokes light, respectively, AS and λ S are the wavelengths of anti-Stokes light and Stokes light respectively, C is a constant related to the characteristics of the optical fiber, and the digital signal processor and the field programmable gate array substitute the extracted Stokes light and anti-Stokes light intensity values ​​into the formula for calculation. The formula is universal and applicable to various distributed optical fiber temperature measurement systems based on the Raman scattering principle. By adjusting some parameters in the formula, it can adapt to different types of optical fibers, different measurement environments and different application requirements. The programmability of the digital signal processor and the field programmable gate array enables the system to easily adjust parameters and optimize functions to meet the requirements for temperature measurement in different scenarios. Whether it is long-distance pipeline monitoring or temperature detection in a small space, accurate temperature measurement can be achieved through flexible configuration.

[0025] Reference Figure 1As shown, the light source equipment, sensor optical fiber, optical signal processing equipment, data acquisition equipment, signal processing and computing equipment, and communication and data processing equipment are all arranged in the system host, and the sensor optical fiber is arranged in the monitoring area. The display and alarm equipment and the system control center are all placed in the monitoring room. The light source equipment, optical signal processing equipment, data acquisition equipment, signal processing and computing equipment, and communication and data processing equipment are arranged in the system host, which realizes high integration, shortens the physical distance between each device, shortens the signal transmission path, reduces the interference of the signal during the transmission process, and improves the stability and reliability of the system. The display and alarm equipment and the system control center are placed in the monitoring room. The monitoring room has good environmental control and safety protection measures, which is convenient for operators to centrally manage and monitor the system.

[0026] Specifically, before the system is put into operation, the system preparation should be carried out first, the system host integrating multiple devices should be properly placed, the sensor optical fiber should be carefully laid in the monitoring area and connected to the host, and the display and alarm equipment and the system control center should be arranged in the monitoring room and the line connection should be completed. Then the parameters of each device should be set, the emission power, pulse frequency and multi-light source synchronization parameters of the light source device should be set, the sampling frequency and clock synchronization parameters of the data acquisition device should be configured, the algorithm parameters of the signal processing and computing device should be set, and the display format, accuracy and alarm threshold of the display and alarm device should be set. During the system operation stage, multiple groups of light source devices cooperate with the synchronous control technology to emit light pulses according to the settings. The light pulses obtain temperature information through the sensor optical fiber and return. The optical signal processing device converts them into electrical signals and pre-processes them. The data acquisition device collects digital signals at high speed under clock synchronization and transmits them to the signal processing and computing device. The latter uses an algorithm based on the Raman scattering light intensity ratio to process the signal and calculate the temperature value, and optimizes the results through iterative algorithms and calibration data. Finally, the calculated temperature data is transmitted to the display and alarm device in the monitoring room for presentation. Once the temperature exceeds the threshold, an alarm is triggered. At the same time, the communication and data processing equipment can transmit the data remotely to realize remote monitoring and management.

[0027] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A distributed optical fiber temperature measurement system, comprising a light source device, a sensing optical fiber, an optical signal processing device, a data acquisition device, a signal processing and computing device, a display and alarm device, a communication and data processing device and a system control center, characterized in that: The light source device uses synchronous control technology to synchronize the emission of light pulses by multiple light sources, which are then introduced into the sensing optical fiber through an optical fiber connection device. The sensing optical fiber converts temperature changes into optical signal changes and transmits them back. The optical signal processing device receives the optical signal and converts it into an electrical signal. The data acquisition device converts it into a digital signal, which is then transmitted to the signal processing and computing device. The temperature value is obtained through complex algorithm processing. On the one hand, the temperature value is transmitted to the display and alarm device and visually presented on the display terminal of the system control center. Once the temperature is abnormal, an audible and visual alarm is triggered. On the other hand, with the help of communication and data processing equipment, the data is transmitted to the remote control center through the network interface and in compliance with the data encryption and transmission protocol for remote monitoring and management.

2. A distributed optical fiber temperature measurement system according to claim 1, characterized in that: The light source device is provided with multiple groups of high-power narrow pulse lasers and high-precision, high-stability driving circuits, and adopts synchronous control technology at the same time, so that the multiple groups of high-power narrow pulse lasers pass through the high-precision, high-stability driving circuits through a high-precision clock signal as a reference. The driving circuits of each light source use this clock signal as a reference to trigger the emission of light pulses, which are then propagated in the sensing optical fiber.

3. A distributed optical fiber temperature measurement system as claimed in claim 1, characterized in that: The sensing optical fiber includes a special sensing optical fiber, an optical fiber connection and fixing device. The light pulse emitted by the light source device enters the special sensing optical fiber, and uses Raman scattering, thermo-optical effect, etc. to convert temperature changes into changes in optical signal characteristics.

4. A distributed optical fiber temperature measurement system according to claim 1, characterized in that: The optical signal processing device includes a light detector, a preamplifier, and a filter. The light detector receives the optical signal carrying temperature information returned from the sensing optical fiber and converts it into a weak electrical signal. The preamplifier increases the strength of the electrical signal, and the filter removes noise to make the processed electrical signal purer.

5. A distributed optical fiber temperature measurement system as claimed in claim 1, characterized in that: The data acquisition equipment includes a high-speed data acquisition card and a clock synchronization device. The high-speed data acquisition card samples the electrical signal output by the optical signal collection and processing module at a high sampling frequency and converts it into a digital signal. The clock synchronization device ensures that data acquisition is accurately synchronized with the moment when the light source emits the light pulse, so that the collected data accurately corresponds to the position of the sensor optical fiber.

6. A distributed optical fiber temperature measurement system according to claim 1, characterized in that: The signal processing and computing device includes a digital signal processor and a field programmable gate array. The digital signal processor and the field programmable gate array receive digital signals from a data acquisition device, use a temperature calculation algorithm based on Raman scattering light intensity ratio, analyze and process the signals, and accurately calculate the temperature value.

7. A distributed optical fiber temperature measurement system as claimed in claim 6, characterized in that: After receiving the digital signal through a specific interface, the digital signal processor and field programmable gate array in the signal processing and computing device will first filter and reduce noise on the signal to remove interference, and then normalize the signal to unify the signal intensity range. Then, based on the Raman scattering principle, the intensity values ​​of Stokes light and anti-Stokes light are separated and extracted from the signal, and the extracted light intensity values ​​are substituted into a mathematical model of the relationship between the Raman scattering light intensity ratio and temperature to calculate the temperature, and the iterative algorithm and calibration data are used to optimize the results.

8. A distributed optical fiber temperature measurement system as claimed in claim 7, characterized in that: In the Raman scattering principle, there is a specific mathematical relationship between temperature and the intensity ratio of Stokes light and anti-Stokes light. The common formula is: , where T is the temperature, h is Planck's constant, v is the frequency of light, k is the Boltzmann constant, and I AS and I S are the intensities of anti-Stokes light and Stokes light, respectively, AS and λ S are the wavelengths of anti-Stokes light and Stokes light respectively, C is a constant related to the characteristics of the optical fiber, and the digital signal processor and the field programmable gate array substitute the extracted Stokes light and anti-Stokes light intensity values ​​into the formula for calculation.

9. A distributed optical fiber temperature measurement system as claimed in claim 1, characterized in that: The light source equipment, sensor optical fiber, optical signal processing equipment, data acquisition equipment, signal processing and computing equipment and communication and data processing equipment are all arranged in the system host, and the sensor optical fiber is arranged in the monitoring area, and the display and alarm equipment and the system control center are all placed in the monitoring room.

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