基于EFPI的数字配电网超声检测传感器

Ultrasonic Detection Sensor of Digital Distribution Network Based on EFPI

针对数字配电网设备存在的局部放电(partial discharge,PD)超声信号检测需求,研究并设计了一种基于非本征型法布里-珀罗干涉(extrinsic Fabry-Perot interferometric,EFPI)的超声波传感器,用于检测PD产生的超声波信号。通过仿真软件COMSOL模拟了不同膜片厚度以及膜片半径的光纤法布里-珀罗(Fabry-Perot,F-P)传感器的灵敏度和固有频率,选择了最佳的结构参数并制作了EFPI传感器。仿真结果表明,传感器的灵敏度可以达到106.6 nm/kPa,固有频率为234.85 kHz。当频率为30 kHz和40 kHz的超声波信号分别加到传感器上时,EFPI超声波传感器检测到的频率分别为29.97 kHz和39.92 kHz。实验结果表明,该传感器可以准确地检测高压模拟罐体中PD产生的超声波信号,且可检测最小放电量为53 pC,具有体积小、频响范围宽、检测灵敏度高的特点,有良好的应用前景。

In order to meet the demand of partial discharge ultrasonic signal detection of digital distribution network equipment,an ultrasonic sensor based on extrinsic Fabry Perot interferometric(EFPI)is developed to detect the ultrasonic signal generated by partial discharge.Through the simulation software COMSOL,the sensitivity and natural frequency of the optical fiber Fabry Perot(F-P)sensors with different diaphragm thicknesses and diaphragm radius are simulated.And the EFPI sensors are fabricated with the selected optimal structural parameters.The simulation results show that the sensor can reach 106.6 nm/kPa in sensitivity and 234.85 kHz in natural frequency.When the ultrasonic signals with a frequency of 30 kHz and 40 kHz are added to the sensor respectively,the corresponding frequencies detected by EFPI ultrasonic sensor are 29.97 kHz and 39.92 kHz.The experimental results show that the sensor,which has the characteristics of small size,wide frequency response range and high detection sensitivity,can accurately detect the ultrasonic signal generated by local discharge in the high-voltage simulating tank with a minimum detectable discharge of 53 pC,and will have good application prospects.