A Fiber Optic Acceleration Sensor for Low-Frequency Vibration Detection and Its Application in Reactor Vibration

To address the limitations of piezoelectric accelerometers in measuring low-frequency vibrations under high-voltage conditions, this paper introduces a fiber optic accelerometer vibration sensor based on the Fiber Optic Extrinsic Fabry-Perot Interferometer (EFPI). After determining the material, size, and other parameters, modal and frequency response analyses of the sensitive unit were performed, revealing a natural frequency of 11,637 Hz. Additionally, COMSOL simulations were used to model the transmission of low-frequency vibration signals to the sensitive unit. The results demonstrated a strong correlation between the central displacement of the sensitive unit and the external vibration signals. A low-frequency vibration test platform was then constructed where both piezoelectric and fiber optic accelerometers were used to measure low-frequency vibration signals. The findings indicate that the fiber optic accelerometer is capable of measuring low-frequency vibration acceleration, with a sensitivity of approximately 1V/0.1g. Using this sensor, vibration tests were performed on a 25kV, 5.3kA high-voltage reactor. The measurements revealed that the vibration acceleration at the upper end of the reactor reached 0.53g, while at the side end it reached 0.21g.