基于三次样条函数的光栅传感光缆舞动波长估计

Galloping Wavelength Estimation of Fiber-optic Grating Sensor Based on Cubic Spline Function

摘要:

基于光栅传感的分布式光纤复合架空地线(OPGW)健康监测得到了广泛研究。针对OPGW光缆舞动事件,提出一种基于三次样条函数拟合的舞动波长预测方法。首先,通过理论推导,建立光栅传感相位变化量与舞动波长的数学联系；然后,利用仿真分析理想舞动情况下信号三次样条函数拟合前后的相移信号结果,初步证明了所提方法的有效性；最后,将其应用在某220kV线路,对比分析典型弱风环境及强风环境下的舞动监测强度图。实际监测结果表明,所选取方法能够有效改善强度图信号特征,可得出强风条件下档距内舞动波长约为200m,弱风条件下档距内舞动波长约50m。该方法为舞动事件的图像识别智能监测提供技术参考,具有较好的应用前景。

Abstract:

Distributed optical fiber composite overhead ground wire (OPGW) health monitoring based on FBG (fiber Bragg grating) sensor has been widely studied. In this paper, a wave prediction method based on cubic spline function fitting is proposed for OPGW galloping cable event. Firstly, the mathematical relation between the phase variation of sensor and the galloping cable wavelength was established through theoretical derivation. Then, the simulation results of the phase shift signal before and after the cubic spline function fitting under ideal galloping condition were analyzed, and the effectiveness of the proposed method was proved. Finally, it was applied to a 220kV line, and the intensity graphs of galloping monitoring in typical weak wind environment and strong wind environment were compared and analyzed. According to the actual monitoring results, the method selected in this paper can effectively improve the signal characteristics of intensity graphs, and it can be concluded that the wavelength within the range is about 200m under strong wind condition, and the wavelength within the range is about 50m under weak wind condition. This method provides technical reference for intelligent monitoring of image recognition of cable galloping events and has strong application prospect.