Partial discharge acoustic emission detector using mandrel-connected fiber Bragg grating sensor

This paper proposes and investigates a partial discharge (PD) detector based on fiber Bragg grating (FBG) sensor and a mandrel to detect and localize PD in power transformers. An identification of PD in the early stages is important, so using high-resolution sensor is considerable. A Teflon hollow mandrel with attached FBG is chosen as the inner transformer PD detector. The design of the sensor in terms of materials, dimensions, and the shape is chosen; it receives signal strength according to the obtained distance and angle. Standard deviation of angle data is <0.4  mV and as the distance increases, the received signal strength decreases exponentially and oscillatory. Simulation results verify the performance of the proposed sensor in the detection of the transformer PD signals. The proposed sensor is experimentally tested. It succeeded in detecting PD, and can simultaneously detect four frequencies of acoustic signal in the range of 14 to 350 kHz, which is superior to similar sensors.