Ultrasonic Detection Sensor of Digital Distribution Network Based on EFPI

Abstract

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.

Keywords

• extrinsic fabry perot interferometric sensor
• partial discharge
• sensitivity
• natural frequency
• discharge quantity