Distributed optical fiber temperature measurement system DTS-BLY-5S
One: Introduction to the system
The distributed optical fiber temperature measurement system DTS-BLY-5S is a continuous distributed optical fiber temperature sensing system (Distributed Temperature Sensing System, DTS), which uses advanced OTDR technology and the temperature-sensitive characteristics of Raman scattered light to detect edge Based on the temperature changes at different positions of the optical fiber, real distributed measurement is realized. The linear optical fiber differential fixed temperature fire detector can not only warn of hidden fire hazards in time, but also accurately locate the location of the fire. As a mature distributed temperature measurement method, the linear optical fiber differential fixed temperature fire detector has the advantages of long measurement distance, high measurement accuracy, fast response speed, anti-electromagnetic interference, suitable for explosion and other dangerous places, and can be widely used High-voltage cable online monitoring, power carrying capacity analysis, traffic tunnel fire monitoring, oil and gas storage tank fire monitoring, coal conveying belt fire monitoring, dam leakage monitoring and other fields.
Two: measurement principle
The temperature measurement of the distributed optical fiber temperature measurement system DTS-BLY-5S is based on the spontaneous Raman scattering effect. After the high-power narrow-pulse width laser pulse LD is incident on the sensing fiber, the laser interacts with the fiber molecules to produce extremely weak backscattered light. The scattered light has three wavelengths, namely Rayleigh and anti-stokes. Stokes) and stokes (Stokes) light; among them, anti-stokes is temperature sensitive and is the signal light; stokes is not sensitive to temperature and is the reference light. The signal light scattered back from the sensing fiber passes through the beam splitting module WF again to isolate the Rayleigh scattered light, pass the temperature-sensitive anti-stokes signal light and the temperature-insensitive stokes reference light, and are received by the same detector (APD) , The temperature can be calculated according to the ratio of the light intensity of the two. The position determination is based on the optical time domain reflectance OTDR technology, and the position of the optical fiber corresponding to the scattered signal can be determined by using high-speed data collection and measuring the echo time of the scattered signal.
Three: system features and functions
The distributed optical fiber temperature measurement system DTS-BLY-5S has the following technical advantages:
1 : Rapidity
The system temperature measurement and positioning speed are very high. In order to improve the measurement time, the advantages of high-speed weak signal processing technology are adopted. The single measurement time is as short as 3s and the response speed is fast.
2 : Distribution characteristics
The distributed optical fiber temperature measurement system can provide continuous and dynamic monitoring of temperature change signals at every 0.5 meter point within a range of more than ten kilometers, and temperature alarm values at all levels can be set arbitrarily.
3 : Advancement
The system is currently a distributed temperature measurement product with high performance indicators, strong functionality, high reliability and advanced technology. The key components are preferably imported performance components, and the core algorithm has been strictly tested.
4 : Accuracy
The typical temperature resolution of the system is up to 0.5°C, the temperature accuracy is 1°C, and the spatial resolution is up to 0.5m.
5 : Flexibility
The system is a real-time online monitoring method; the alarm signal at any point in the monitoring range is uploaded to the fire alarm controller for no more than 30 seconds; the monitoring system provides a continuous dynamic monitoring signal, and the system can set multi-level temperature point alarms, that is, the system Supports multi-level alarms, such as initial alarm at 30°C, pre-alarm at 40°C, and measures taken at 50°C. The alarm point temperature parameter can be set according to different environments; there are multiple alarms with differential and constant temperature, and the alarm parameters can be carried out according to customer needs Zone setting, flexible alarm.
6 : Compatibility
The host of the system is an open communication protocol and provides a communication interface connected with the workstation. The disaster prevention and alarm workstation in the central control room displays all information such as temperature curve, alarm position, alarm temperature and so on in Chinese-style graphics and text; the system can pass RS232, RS485, built-in Relay, RJ45 or other industrial protocols and other output forms are linked with PC, fire alarm system and other control equipment to carry out sound and light alarm, and the signal output is accurate and complete.
7 : Security
The optical cable distributed temperature monitoring system has a safety record function, which can store historical data within one year and can be effectively audited. Single-ended operation, remote diagnosis, low-end system remote diagnosis can be provided by specialized engineers through the LAN; if the optical fiber is damaged, the DTS system can locate the damaged point immediately, and splice it through the optical fiber fusion splicer without stopping the measurement. It is very important for the effective implementation of online monitoring; to detect the intrinsic safety of the optical cable, the use of optical signals will not cause mutual electromagnetic interference with the power cable.