基于Φ-OTDR的煤层气管线外界入侵振动检测系统

Coalbed Methane Transport Pipeline Intrusion Detection System Based on Φ-OTDR

为实现长距离煤层气管线外界入侵振动检测,采用基于相位敏感型光时域反射原理(Φ-OTDR)的分布式光纤振动传感系统,融合FPGA与USB2.0技术开展传感数据的实时采集与高速传输,并通过时间-空间二维分析来获得振动信号典型特征,进而实现煤层气输送管道危险源的实时检测。实验结果表明,本系统可借助差分信号波峰位置实现精确定位,系统的频率响应范围是可覆盖入侵振动特征频率的1 Hz～3 k Hz,且在4 km和9 km光纤位置处的定位误差均可保持在20 m范围以内,因此本系统可有效检测到输送管道外界入侵振动。

In order to realize real-time monitoring of intrusion vibration of long-distance coalbed methane(CBM)transmission pipelines,a distributed optical fiber vibration sensing system based on Phase Sensitive Optical Time Domain Reflectometry(Φ-OTDR)is used,which integrates FPGA with USB2.0 technologies for achieving real-time acquisition and high-speed transmission.Through the two-dimensional time-space analysis,the typical characteristics of the vibration signals can be obtained,then the real-time detection of hazard source of coalbed gas transmission pipelines will be achieved.The experimental results show that the system can locate accurately through peak positions of differential signals.The frequency response range of the system is 1 Hz^3 kHz and can cover the characteristic frequency of the intrusion vibration,and the positioning errors at both the 4 km and 9 km fiber positions can be maintained within the range of 20 m.Therefore,the system can detect the intrusion vibration of the pipelines effectively.