基于双鉴相器相位解调的光纤干涉型局放超声传感方法  

Optical Fiber Interferometric Sensing Technology for Partial Discharge Ultrasound Based on Dual Phase Detectors Phase Demodulation Method

作　　者：陈章霖 谢洋洋 王渊 刘昊 史荣斌 马国明 Chen Zhanglin;Xie Yangyang;Wang Yuan;Liu Hao;Shi Rongbin;Ma Guoming(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University ,Beijing 102206 China)

机构地区：[1]新能源电力系统全国重点实验室(华北电力大学),北京102206

出　　处：《电工技术学报》2023年第23期6514-6524,共11页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金(51977075);中国科协青年人才托举工程(YESS20160004);霍英东教育基金会高等院校青年教师基金(161053);中央高校基本科研业务费专项资金(2022YQ003)资助项目。

摘　　要：光纤外差干涉传感输出信号频率为百兆赫兹量级,传统软件解调方法采样设备成本高、数据量大、实时性差,制约了该技术在局部放电超声传感的广泛应用。该文提出了一种基于双鉴相器协同工作的相位硬件解调方法,降低了系统采样率、减少了采集数据量、实现了实时解调,相比传统微分-交叉相乘软件解调方法快1124倍。分析了低频载波幅值和采样精度对测量结果的影响,实现了0.005°的相位最低检测下限。搭建光纤超声传感平台,开展了对比试验,结果表明,该文所提相位解调方法线性拟合度达到0.999,信噪比较传统微分-交叉相乘解调方法高15 dB,检测下限拓展58%,为局部放电超声传感提供了一种高信噪比、低检测下限、实时检测的相位解调方法。Real-time monitoring of transformer status is essential for the stable operation of the power system.Immunity to electromagnetic interference,high sensitivity and high insulation enable optical fiber sensing to be widely used in power transformer monitoring.Among them,heterodyne interferometer method uses optical frequency shifter to modulate signal to high frequency.This allows the effects of environmental disturbances on interferometer to be effectively suppressed and brings the advantages of high sensitivity and lower minimum detectable limit.The frequency of optical heterodyne interferometer sensing signal is hundreds of megahertz.Traditional software demodulation method has the disadvantages of high cost and large data volume.Thus,the optical heterodyne interferometer is restricted in the detection of partial discharge ultrasound.This paper proposes a phase demodulation method based on dual phase detectors,which reduces the sampling rate and data volume,and realizes real-time demodulation.Firstly,the characteristics of the phase detector is analyzed.When the phase difference of two input signal is around 0°and±180°,the output voltage has a nonlinear relationship with the phase difference.To avoid of the nonlinear region,a phase demodulation method based on dual phase detectors was proposed.Whenever a phase detector works at nonlinear region,the other will provide accurate measurement of phase signal.Secondly,bandpass filters are connected to the phase detectors.The low-frequency carrier with high amplitude is filtered out and the weak high-frequency phase voltage signal is preserved,so that the measuring range can be reduced to improve the sampling accuracy.Thirdly,both output signals of the two band-pass filters have attenuation and distortion because of nonlinear regions,but the nonlinear regions of the output signals are staggered from each other.An algorithm to avoid nonlinear regions is used to obtain a stable signal.The algorithm uses the method of envelope to identify the position of the nonlinear

关 键 词：相位解调 光纤传感 局部放电 外差干涉 超声检测 

分 类 号：TM855[电气工程—高电压与绝缘技术] TP212[自动化与计算机技术—检测技术与自动化装置]