基于弱反射光纤光栅的OPGW杆塔倾斜监测阵列

Tilt Monitoring Array for OPGW Transmission Tower Based on Ultra-Weak Fiber Bragg Grating

恶劣环境下的OPGW输电杆塔倾斜监测有着重要的工程意义。基于超弱反射率的光纤光栅,结合波分/空分复用提出一种酒杯型杆塔倾斜传感阵列监测技术。首先,从理论入手推导了光栅波长、应变和杆塔倾角的数学联系;然后,基于COMSOL有限元仿真分析了风振作用及舞动不均匀张力情况下杆塔的应力变化;最后,利用对比实验标定了倾角传感器基本参数,将其应用在内蒙古东部某220 kV线路酒杯型上输电杆塔上进行倾斜监测,得到初步倾斜监测结果。实际监测结果表明,所提出方法能够有效监测杆塔倾斜,弱反射光栅的应变灵敏度系数约为1.2 pm/με,倾角传感器的灵敏度系数值为0.051 8 nm/°,并成功得到一般情况下杆塔倾角约为2.64°的监测结果。该方法为OPGW输电线路的多参数健康监测提供了技术参考,具有较强的工程应用前景。

The tilt monitoring for OPGW(fiber optic composite overhead ground wire)transmission tower under harsh environment has important engineering significance.In this paper,based on ultra-weak reflected FBG(fiber Bragg grating),combined with wavelength-division/air-division multiplexing,we propose a inclinometer array monitoring technology for OPGW tower.Firstly,the mathematical relation of FBG wavelength,strain and tower angle is deduced theoretically.Then,based on COMSOL finite element simulation,the stress variation of the tower under the condition of wind excitation and uneven tension is analyzed.Finally,the basic parameters of the inclinometer are calibrated by comparison test,and the sensor is applied to a 220 kV transmission tower in eastern inner mongolia province for tilt monitoring,and the preliminary results of tilt monitoring are obtained.The actual monitoring results show that the proposed method can effectively monitor the tower inclination,the strain sensitivity coefficient of the ultra-weak reflected FBG is about 1.2 pm/με,the sensitivity coefficient of the inclination sensor is 51.8 pm/°,and the monitoring results of the tower inclination is about 2.64°under normal circumstances.This method provides a technical reference for multi-parameter health monitoring of OPGW transmission lines and has a strong engineering application prospect.