Research On The Characteristics Of Are Discharge Voiceprint In Transformer Based On Fiber Grating Sensing

Power transformers are critical in the transmission and distribution process,and are also one of the devices that cause the most power system failures.Transformer internal arc discharge can lead to power system failures and cause major safety accidents.It is of far-reaching practical significance to study the early detection method of transformer internal arc discharge to reduce the hazards generated by arc discharge.In this paper,the measurement method of transformer arc discharge acoustic signal and the characteristics of arc discharge voiceprint are studied,which provides the basis for the on-line detection method of transformer arc discharge acoustic signal.This paper first analyzes the principle of fiber grating sensor,studies the sensitive characteristics of fiber grating to external physical quantities,focuses on the principle of fiber grating perception of acoustic waves,compares and analyzes two sensing systems based on optical power demodulation,determines the influence of the parameters of each device in the fiber sensing system on the sensor performance through theoretical formula derivation,determines the optimal structure of fiber grating acoustic sensing system based on optical power demodulation Finally,for the fiber grating cross-sensitive characteristics,analyze the interference factors affecting the accuracy of the fiber grating acoustic sensor,put forward the corresponding solution measures,and lay the foundation for the detection of transformer arc discharge acoustic signal.Based on the basic structure of the fiber grating sensing system,the specifications of the main devices of the demodulation system are determined,and the fiber grating acoustic sensing system is built.By studying the physical properties of the fiber grating,screening and optimizing the parametric characteristics of the fiber grating,analyzing the influence of the length of the fiber grating grid area on the detection bandwidth of the sensor,and determining the basic performance of the fiber grating sensor.Finally,the bare fiber grating is protected and encapsulated,and the corresponding sensing probe is developed.The basic parameters of the sensor calibration analysis,in the 15-60kHz frequency band range of the sensor sensitivity calibration comparison test,the results show that the sensor’s overall frequency response curve better than the same type of sensor,the basic parameters to meet the requirements.The sensor’s audible detection performance was also analyzed,and the experimental results showed that the sensor’s detection performance in the audible frequency range of 5-20 kHz is relatively stable.In order to verify the basic performance of the sensor,the corresponding test platform is built,and the stability of the developed fiber grating acoustic sensor and the corresponding anti-interference test are carried out.The results show that the sensor has good long-term stability and can effectively avoid the interference of lowfrequency vibration,temperature and optical noise and other physical quantities.The test results show that the developed sensor can detect the audible sound and ultrasonic signal generated by the arc discharge,which confirms the effectiveness of the sensor.