PD characteristics and defect type recognition of “rapidly-developing” fault in oil-pressboard insulation

With the high voltage grade of UHV transformers and wide area of high field intensity, the discharge phenomenon that the average apparent discharge and the number of discharge pulses of per second increase rapidly often occurs within the transformer oil-pressboard insulation. In order to effectively analyze the discharge characteristics of this type of discharge faults and enhance the recognition technology of discharge types, three kinds of simulated defects were prepared and a small simulation experimental platform was built in this paper. Based on the power frequency data of PD, PRPD spectrum was drawn to analyze the discharge characteristics of “rapidly-developing” faults. According to improved D-S evidence theory, the features information between high frequency pulse and UHF pulse are fused to achieve the high accuracy recognition of defect types.