光学电压互感器中双光路不平衡及微弱信号检测的研究

Research on weak signal detection and imbalance of dual optical path of optical voltage transducer

针对光学电压互感器中常见的信号提取及双光路传输过程中存在的不平衡问题进行了研究。介绍了基于电光Pockels效应的光学电压互感器的基本原理,分析了系统中噪声的主要来源、微弱信号提取的难点以及双光路不平衡带来的系统误差。摒弃已经相对成熟的直流调制技术,改用交流调制来改善输出信噪比,给出了仿真框图,并将双光路不平衡差异考虑进去,提出了'低频处理,高频配平'的思想。仿真结果证明利用此方法可以适当地提高光学电压互感器的输出信噪比。

This paper researches the common signal extraction of optical voltage transducer and the imbalance during the transmission of dual optical path, gives an introduction to the basic principle of optical voltage transducer based on electro-optic Pockels effect, and analyses the main source of noise in the system and the difficulty in extracting the weak signal and the system error resulted from the imbalance of dual optical path. Furthermore, instead of applying the mature DC modulation, it offers a method to improve SNR by AC modulation and additionally works out the simulation block diagram. Then considering the differences in the dual optical path which are imbalanced, it offers the idea of low-frequency processing and high-frequency balancing. The result of simulation proves that using this method can improve the output SNR of optical voltage transducer to some extent.