雷击条件下OPGW内光偏振态信号的形成和传播特性

由于雷击光纤复合架空地线(OPGW)时其外绞线上的电流行波传播速度比光纤内光信号的传播速度快,因此这一过程会在OPGW雷击光偏振态信号波头前产生调制形成伪波头,从而给定位带来误差。为此,提出了"伪波头"的概念,并对其形成和传播特征进行了研究;通过理论和仿真计算了雷击OPGW时光偏振态信号的形成过程,并对比研究了实验室模拟雷击OPGW试验和OPGW光传感雷击监测系统现场实测的雷击数据。结果表明:所提出的伪波头现象确实存在,并且会给雷击定位精度造成实质性影响;距离雷击点越远,伪波头影响的时长就越长;雷电流幅值越大,伪波头偏起的幅度就越大。研究结果说明传统的行波法波头标定方法可能并不完全适用,该研究可为基于OPGW雷击点定位方法的实际应用提供参考。

Formation and Propagation Characteristics of Light Polarization Signal in OPGW Under Lightning Condition

When lightning strikes optical fiber composite grounding wire(OPGW),the propagation speed of lightning current traveling wave on the outer strand is faster than that in the fiber optical.This process will produce a pseudo wave front ahead of the light polarization signal caused by lightning and thus bring a positioning error.Consequently,we proposed the concept of pseudo wave front for the first time,and studied its formation and propagation characteristics.Moreover,we simulated the formation process of lightning current traveling wave,and comparatively researched the wave formation characteristics between simulated lightning experiment and on-site lightning monitoring experiment.The results show that the pseudo head phenomenon presented in this paper does exist,and it will cause substantial impact on the positioning accuracy of lightning stroke.The farther the distance from the lightning point is,the longer the impact length of the pseudo head will be;the larger the amplitude of the lightning current is,the greater the offset amplitude of the pseudo head will be.The traditional calibration methods for traveling wave head may sometimes be inapplicable,and the research can provide a reference for the practical application of lightning location method based on OPGW.