Extrinsic Fabry-Perot Sensor for Partial Discharge Acoustic Detection in Liquid

Abstract

Partial discharge online detection technology can reflect the insulation status of electrical equipment. The extrinsic fiber Fabry-Perot sensor uses a diaphragm cavity to sense the changes in interference intensity caused by the sound waves generated by partial discharge. It has stronger resistance to electromagnetic interference, longer transmission distance, and smaller structure, comparing with traditional ultrasonic sensors. With so many advantages, it undoubtedly becomes the focus of research on partial discharge ultrasonic detection. This paper first explores the sensitivity mechanism of optical fiber Fabry-Perot sensors to acoustic signals. Then, according to the change laws of the resonance frequency of the diaphragm with the size parameters, a fiber optic Fabry-Perot partial discharge sensor based on the structure of the nickel circular diaphragm and the quartz tube is developed. The fabricated Fabry-Perot sensor is placed in water, and the acoustic signals from the piezoelectric ceramic transducer driven by the signal generator are detected; the partial discharge ultrasonic signals generated by the pin-plate electrode model in transformer oil are also tested. And the tests have achieved the desired results.