基于相位敏感光时域反射的海底电缆外部扰动监测方法

Submarine Cable External Disturbance Monitoring Method Based on Phase-sensitive Optical Time-domain Reflectometry

海底电缆是连接陆地和海洋电网的重要纽带,锚击、渔网拖曳等外力破坏是其安全稳定运行的主要威胁。为监测海底电缆外部扰动,基于相位敏感光时域反射技术,设计外差相干型的扰动监测装置,采用正交解调和移动方差平均法识别和定位扰动信号,并进行试验验证与现场应用。结果表明:所提方法可有效提取传感光纤中的背向散射光幅值与相位信息;外部扰动造成的相位变化,会引起幅值波动与相位跳变;采用移动方差平均算法提取幅值波动区,可实现外部扰动定位;基于扰动点相位信息,可反演得到扰动时域波形。外差相干型探测技术可用于海底电缆外部扰动监测。

Submarine cable is important for the connection of the offshore wind farm and the land power grid,and it is vulnerable to external disturbances such as anchor striking and dragging by fish net.To monitor the external disturbance of submarine cable,this study designs the disturbance monitoring device with the heterodyne coherent detection structure based on phase-sensitive optical time-domain reflectivity technology,and uses an IQ demodulation and moving variance mean location method to identify and locate the disturbance signals.The results show that the proposed method can effectively extract the backscattering light amplitude and phase information.The external disturbance leads to amplitude and phase fluctuation.Then,the external disturbance is located with a moving variance averaging algorithm on amplitude fluctuations.Based on the phase of the disturbance area,the time-domain waveform can be deduced.It is verified this technology can be used for submarine cable disturbance detection.