Partial Discharge Characteristics of Typical Floating Defects in Full-size Power Transformer
Partial discharge(PD)defects can gradually deteriorate during operation and even lead to high energy dis-charge faults,which seriously threatens safe operation of transformer.In this paper,the PD test platform is set up based on a full-size 110 kV transformer,and three kinds of suspending discharge defects as suspending metal parti-cles of high voltage lead,metal tip suspending near the high voltage lead and electrostatic ring suspension are de-signed.The step-boosting voltage method is adopted to test,and the variation of pulse current,ultrahigh frequency(UHF)and acoustic signals during PD development is recorded and compared as well as analyzed.It is found that the intense discharge stage of the three suspension defects is not obvious,the discharge energy before breakdown is relatively low,and the phenomenon of main frequency left-shift does not appear in the frequency-band of acoustic sig-nal.Although the three defects are suspension potential discharge,yet their PD characteristics are obviously different.It is necessary to consider the defect situation in the true transformer in case of extracting defect characteristics,and the joint diagnosis of UHF and audible-ultrasonic signal can effectively identify suspension discharge.In this paper,the rules and characteristics of typical suspension discharge are obtained by defect simulation on a full-size trans-former for the first time,which can provide a certain reference for online monitoring and fault alarm of transformer.
万方数据
维普
