System Using Fluorescent Fiber for Partial Discharge Detection in Transformer

On the basis of the physical phenomena of optical effect generated by partial discharge and characteristics of sensing weak light of certain wavelength of the fluorescent fiber,we developed a system using fluorescent fiber sensors for detecting partial discharge signals,analyzed the principle of partial discharge sensed by fluorescent fiber,and presented the main parameters of sensors and the system components.Moreover,we set up a platform for simulating partial discharge in transformer oil in the laboratory.Compared to ultra-high frequency method,the measured results show that,the partial discharge pulses detected by the two methods occur around the positive and negative voltage peak under the needle-plate defects in a power frequency period in oil,and the pulse number is consistent with the phase position.The partial discharge signals detected by ultra-high frequency method mainly reflects amplitude of pulses,namely,the ψ-u-n three-dimensional spectrum.The partial discharge signals detected by optical method mainly reflects energy of pulses,namely,the ψ-p-n three-dimensional spectrum.Since fluorescent fiber sensors can be easily buried in the transformer winding,it has broad application prospects on partial discharge online monitoring under internal complex insulation structure.