Study on the fiber optic EFPI ultrasonic transducer with a beam-supported membrane structure for PD measurement

In this paper, according to the advantages and disadvantages of acoustic partial discharges (PD) detection shown in IEC TS 62478, a novel fiber optic extrinsic Fabry-Perot interferometer (EFPI) ultrasonic transducer with a beam-supported membrane structure was designed and developed to measure acoustic emission (AE) signals of PD in transformer oil. Based on the MEMS processing technology, the silicon-On-Insulator (SOI) was used to fabricate the diaphragm structure of the supporting beam and control the Fabry-Perot (FP) cavity length accurately to develop the transducer probe with the designed dimension parameters. Experimental results in laboratory with UHF measurement simultaneously show that the developed EFPI ultrasonic transducer with a beam-supported membrane structure is feasible and practical used for PD AE detection.