An Optical Sensing Method for Built-in Broadband Sound Signal

Timely and effective monitoring of arc discharge defects can quickly take measures to ensure the safe operation of transformers. when the arc discharge occurs inside the transformer, it is accompanied by ultrasonic signal and audible signal, and audible signal will be produced in large quantities at the later stage of discharge. by sensing the audible sound, the whole process of arc discharge, especially the development of sound signal in the later stage of discharge, can be monitored to avoid serious faults. but at present, most of the sensing methods for arc discharge acoustic signal still focus on the monitoring of ultrasonic signal, but ignore the perception of audible signal. in order to solve the problem that the existing methods are susceptible to electromagnetic interference and cannot be built into the transformer to accurately identify arc defects, a fiber grating sound sensing system based on a wide audio acquisition range of 1~60KHz is proposed through the design of fiber grating sensing system. the acoustic signal frequency band is mainly distributed in 2~10 KHz and 50~60 KHz, which can collect audible sound and ultrasonic at the same time. at the same time, double fiber grating method is used for temperature compensation to avoid the influence of temperature on the accuracy of acoustic sensor results. finally, the sensitive perception of arc discharge acoustic signal can be realized, and the further development of transformer fault can be quickly blocked.