Study on Detection Characteristics of Partial Discharge Detection System Based on Microfiber Coupler Sensor

The detection of the partial discharge (PD) in the power transformer is of great significance to the safe and stable operation of the transformer. optical fiber ultrasonic sensors have received widespread attention because they can be built into transformers to detect PD. As a kind of optical fiber ultrasonic sensor, the microfiber coupler sensor (MFCS) has developed due to its advantages of small size, low cost and easy demodulation. A PD detection system based on MFCS was proposed, but the detection characteristics and practical application of the system still need further research. In order to improve the detection sensitivity of the system, the conditioning circuit in the system has been studied. The results show that the amplifying part in the conditioning circuit has a greater impact on the detection sensitivity of the system. At the same time, the withstand voltage characteristics of the MFCS in the system are studied. The results show that the breakdown voltage of the MFCS is higher than the breakdown voltage of the transformer oil and the oil-quartz insulating medium. In addition, the influence of the installation position of MFCS on the detection signal is studied, and the results show that the sensor was placed on the inner wall and outer wall of the transformer, the quality of the PD signals detected by the sensor placed on the inner wall is better. The research on the detection characteristics of the system enables it to be more widely used in PD detection.