基于分布式光纤传感器的管涌监测系统

针对水利工程输水堤坝管涌难以实时监测的问题,结合分布式光纤传感器应变检测灵敏度高及FPGA并行运算快的特点,设计了基于光纤全分布式传感器与FPGA数字解调算法的堤坝管涌实时探测系统。首先利用双Mach-Zehnder干涉组成的光纤全分布式传感应变检测系统感知管涌导致的应变,之后通过计算由应变导致的调制信号到达两光电探测器的时间差确定管涌渗漏点。系统采用频率分选机制在信号调理电路实现信号筛选,评定渗漏程度,由FPGA实现数据采集、滤波、存储及解调,有效缩短了解调时间及定位误差。结果表明,系统可对2公里范围内的管涌渗漏事件进行有效定位报警,定位误差在±8m以内。

Leakage Monitoring System Based on Distributed Optical Fiber Sensor

Real-time monitoring the seepage point of dams is an important problem in hydraulic engineering. The dis-tributed fiber optic sensor has the characteristics of high sensitivity in strain detection. FPGA has the characteristics of fast parallel operation. In this paper,a real-time detection system of dike piping based on fiber-optic full distributed sensor and FPGA digital Demodulation algorithm is designed. Firstly,a distributed fiber optic sensing system based on double Mach-Zehnder interferometer is used to detect strain caused by piping. And then,the strain causes the signal to be modulated and the modulation signal arrives at the two detectors'time is different,by calculating the difference to locate the leakage point. The system uses frequency sorting mechanism in signal conditioning circuit to realize signal screening,to assess the degree of leakage. Using FPGA to realize data acquisition,filtering,storage and demodulation, it effectively shortens the demodulation time and positioning error. The results show that the system can effectively lo-cate and alarm the leakage events in 2 km range,the positioning error is within ±8 meters.