Distributed optical fiber sensing monitoring of diversion tunnel stone-collecting pit siltation
A technology of distributed optical fiber and water diversion tunnel, which is applied in the direction of measuring devices and instruments, can solve the problems of high precision, unfavorable, and increased errors in sediment monitoring in the pit, and achieve the goal of ensuring effective reliability, high cost, and sufficient heating energy Effect
Inactive Publication Date: 2016-07-06
SICHUAN UNIV
View PDF3 Cites 5 Cited by
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
[0007] 2) The optical demodulator for Raman fiber optic sensing is not fully suitable for small local temperature mutations in hydropower projects - occasions with high precision requirements (for stone collection pits, in view of the limited depth of the pit (about 1-2m), the monitoring of sedimentation in the pit Relatively high precision requirements)
The temperature measurement accuracy of the demodulator is ±1°C (short range) [4] , especially the Raman scattering light intensity is very weak, which limits its spatial resolution to the meter level (1m), which is particularly unfavorable for the observation of steep valley distributions such as leakage and cooling, and the temperature effect will be averaged within the resolution range to increase the error
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View moreImage
Smart Image Click on the blue labels to locate them in the text.
Smart ImageViewing Examples
Examples
Experimental program
Comparison scheme
Effect test
Embodiment Construction
[0054] The temperature signal of each sensing optical fiber is sequentially detected, analyzed and processed online by an optical demodulator in the monitoring center, and provides first-hand information for the scientific decision-making of diversion tunnel water cutoff, stone collection pit cleaning plan and operation .
[0055] The observation operation of the optical fiber leakage monitoring system is carried out in partitions, and it is automatically implemented with the help of the optical switch set up with the optical demodulator. For the selected observation area, power transmission and heating takes about 10 to 30 minutes, and the temperature rise of the optical fiber gradually stabilizes, and the host can collect data, which takes about 1 to 5 minutes.
[0056] (*4 National Natural Science Foundation of China project achievements).
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More PUM
Login to View More Abstract
The invention discloses a distributed optical fiber sensing monitoring technical scheme and system based on a high signal-to-noise ratio reinforcing heating method. The distributed optical fiber sensing monitoring technical scheme and system are used for automatically remote measuring the siltation volume and distribution of a diversion tunnel stone-collection pit. The monitoring is precise and accurate, waterproof, and durable. The distributed optical fiber sensing monitoring technical scheme and system are stable in a long time and have the economic and reasonable cost performance. The system adopts a reinforcing heating photoelectric composite cable, and ensures that an optical fiber temperature rise value suddenly changes at a water-sand interface. The difference of the temperature rise above and below the interface is about more than 15-40 DEG C, and an Raman type DTS light demodulator or a high precision Brillioun-Rayleigh light time domain analyzer PPP-BOTDA / Hybrid Brillioun-Raleigh system TW-COTDR is matched. The signal-to-noise ratio reaches more than 10, and it is enough to prevent a temperature abnormal signal at the water-sand interface from being submerged in observation errors. The reliability of siltation thickness and form observation results is ensured. The optimization arrangement and the implementation mode of the technical scheme are provided. Sensitive optical cables are laid at both sides of a stone-collecting room and on a downstream wall surface in a grouping-oblique manner so as to increase the sensitivity, the safety margin and the engineering practicality.
Description
technical field [0001] The invention relates to a distributed optical fiber sensing technology type and system for monitoring the sedimentation of a stone pit in a water diversion tunnel, aiming at realizing the automatic online remote measurement of the sedimentation in a stone pit. Background technique [0002] In hydropower projects, especially underground power stations, unlined diversion tunnels are often used when geological conditions permit, with stone collection pits at the end. The sedimentation status of the rock collection pit is directly related to the safety and efficiency of the power plant. If the pit is full and is not cleaned in time, the rock collection pit will lose its function and endanger the safety of equipment such as water turbines; if it is cleaned too early and too frequently, the benefits of water diversion and economic Significant loss [1,2] . [0003] In order to obtain information on sedimentation in the stone pit, a suspended observation bo...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More Application Information
Patent Timeline
Login to View More Patent Type & AuthorityApplications(China)
IPC IPC(8): G01D21/02
CPCG01D21/02
Inventor唐天国刘浩吾王琛孙曼陈江
OwnerSICHUAN UNIV