闭环全光纤电流互感器阶跃响应上升时间研究

Research on Step Response Rise Time of Closed-loop Full Optical-fiber Current Transformer

应用于柔性直流输电工程的闭环全光纤电流互感器(FOCT)为满足工程应用,需使用长距离保偏光缆实现偏振光信号的远距离传输,对其阶跃响应上升时间的影响尚未论证。此处从工作原理及输出特性两个方面分析了闭环FOCT采用M阶滑动平均滤波器特性、阶跃响应上升时间,并进行了仿真及试验验证,结果表明:影响阶跃响应上升时间的关键因素为光路渡越时间和滑动平均滤波器阶数,滤波器积分时间与闭环FOCT阶跃响应上升时间正相关;增加300m保偏光缆后闭环FOCT阶跃响应上升时间显著增加,通过控制滑动平均滤波器的积分时间可使闭环FOCT阶跃响应上升时间及测量性能与不增加长距离保偏光缆保持一致,解决了闭环FOCT增加保偏光缆引起阶跃响应上升时间增加的问题,满足柔性直流输电工程对其快速响应及特性稳定的需求。

The closed-loop full optical-fiber current transformer(FOCT)used in flexible DC transmission projects needs to use long distance polarization-maintaining cable to achieve long distance transmission of polarized light signal and the influence of its step response rise time has not been demonstrated.The characteristics and step response rise time of the M order moving average filter adopted by closed-loop FOCT are analyzed from two aspects of working principle and output characteristics,simulation and test verification are carried out.The results show that the key factors affecting the step response rise time are the transit time of optical circuit and the moving average filter order,the filter integration time is positively correlated with the step response rise time of closed-loop FOCT.After adding 300 m polarization-maintaining cable,the rise time of the closed-loop FOCT step response significantly increases.By controlling the integration time of the moving average filter,the rise time and measurement performance of the closed-loop FOCT step response can be consistent with that of the non increasing long distance polarization-maintaining cable,which solves the problem of step response rise time increase caused by adding polarization-maintaining cable to the closed-loop FOCT,meets the requirements of flexible DC transmission projects for its fast response and stable characteristics.