Study on the Difference of Multi-parameter Characteristics of Oil-immersed Transformer under Internal Discharge and External Disturbance

Transformer is the core equipment of power system. It is a hot research topic to monitor the transformer operation status and construct protection strategies by means of high frequency pulse current (HFPC), ultrahigh frequency (UHF) signal and acoustic signal (AE). However, the above signals are susceptible to external disturbance of the transformer at the same time. The above multi-parameter characteristics of oil-immersed transformer under internal discharge and external disturbance are analyzed through experiments in this paper. It is found that HFPC and UHF signals of internal discharge have stronger synchronization than external disturbance, and the main frequency of AE signal is higher.