Research on the optical signal characteristics at different discharge stages in transformer oil based on fluorescent fiber detection

The optical signal emitted by the discharge in oil is an important symptom of the operating status of transformers. A transformer oil discharge optical signal detection system based on fluorescent optical fibers and silicon photomultiplier are designed in this paper. The characteristics of optical signals, ultrasonic signals, ultra-high frequency signals, and pulse current signals of corona discharge, spark discharge, and arc discharge in a transformer model are compared and studied. The experimental results show that as the discharge increases, the amplitude of the above signals also increases accordingly, the amplitude of optical signals has a certain degree of randomnesst, but there is an approximate linear relationship with the pulse current signal. Optical signals have higher detection sensitivity for hazardous high-energy arc discharges, which can be used as a signal to reflect the severity of discharge failure, and can be used to provide relevant trip signals for relaying protection devices to reduce the probability of transformer explosion accidents.