基于非本征光纤法布里-珀罗干涉仪的局放声发射传感器设计

Partial Discharge Acoustic Emission Sensor Design Based on Extrinsic Fiber Fabry-Perot Interferometer

采用耦合石英膜和光纤接头构成非本征法布里-珀罗干涉仪(EFPI)传感器,检测液-固复合绝缘电介质中的局部放电声发射信号。为解决目前EFPI传感器灵敏度低的问题,依据弹性力学原理和有限元分析方法确定EFPI膜片结构设计方法,并制作传感器样品。建立以分布式反馈(DFB)激光器为光源的EFPI正交强度解调系统。以绝缘油针-板电极局部放电为信号源,利用压电陶瓷(PZT)传感器与EFPI样品进行对比测试。结果表明,EFPI传感器局放检测灵敏度取决于传感器频响带宽和静压灵敏度,完善了EFPI膜片设计方法,获得局放检测灵敏度与PZT相近的EFPI传感器。

An extrinsic Fabry-Perot interferometer（EFPI） consisted of coupling quartz diaphragm and fiber optic pigtails is designed to detect acoustic signal generated by partial discharge（PD） in liquid-solid dielectric insulation.To solve the problem of low sensitivity, based on the theory of elasticity the structure parameters of EFPI diaphragm are determined using finite element analysis method, and EFPI samples are manufactured. In order to demodulate acoustic signal, a quadrature intensity demodulation system is established using distribute feedback（DFB） laser.A piezoelectric transducer（PZT） and EFPI sensor contrast measurement system is designed using needle-plate electrode to produce partial discharge. Results show that the sensitivity of EFPI sensor is determined by response frequency and static pressure sensitivity of EFPI. Design method of EFPI diaphragm is improved, and an EFPI sensor which has the same sensitivity as PZT for partial discharge detection is designed.