A comparative study on partial discharge ultrasonic detection using fiber Bragg grating sensor and piezoelectric transducer

Piezoelectric transducers (PZT) detecting ultrasonic as a traditional method of high voltage equipment partial discharge detection has drawbacks of low sensitivity and low detection efficiency. In order to overcome these disadvantages, an ultrasonic detection system is developed based on fiber Bragg grating (FBG). Because of the high sensitivity, the good insulation ability and immune to electromagnetic interference, the optical sensor can be put into the transformer and detect the weak partial discharge signal directly. In this paper, experiments were developed to obtain the responses of the ultrasonic detection system with 10-mm-length, and a comparison between 10-mm-length FBG and PZT of sensitivity was carried out as well. The results showed that ultrasonic detection system with 10-mm-length FBG has a better performance than PZT in the bandwidth of 20 kHz~500 kHz. And the max sensitivity of FBG is -79.503 dB at 180 kHz (0 dB is defined as 1V/uBar), which proves the feasibility and effectiveness of the proposed detection method in the partial discharge detection.