A Multiplexing Optical Partial Discharge Sensing System for Power Transformer Using a Single Photodetector

Optical ultrasonic sensor multiplexing for partial discharge (PD) detection based on a single photodetector is a challenging task. In this paper, we propose a novel multiplexed optical ultrasonic sensing system based on swept frequency interferometry. Optical ultrasonic sensor multiplexing is achieved using different carrier frequencies that depend on the length differences between the sensing fibers and the reference fiber. Only one photodetector is required for multiple-point optical fiber ultrasonic sensing. The experimental results indicate that the ultrasonic signals generated by a partial discharge defect model can be simultaneously detected. Then, the PD defect was accurately localized based on the arrival times of an ultrasonic signal at the multiplexed sensors.