One case study in this paper shows how to identify wet insulation system in an on-load tap changer (OLTC) by Polarisation/Depolarisation Current (PDC) analysis. It emphasizes the importance of filling a new transformer with good oil having very low conductivity. The other two case studies on transformers without oil (before oil refilling) demonstrate how aging type of solid insulation can be identified by the PDC technique.
展开▼
