Investigation of Transformer Failure Factors and Mitigation Technique

摘要

This paper discusses a study on transformer failure that has been carried out on commercial 1500kVA 33/11kV in TNB (Malaysian Electricity Supplier) network distribution system. The damage experienced by the transformer under study is suspected due to the transient surge from overvoltage phenomenon activities. The source of surge transient overvoltage has been identified from 33kV and 11kV side. This paper also presents the detail probable causes on the surge transient element such as from internal overvoltage generation, Ferranti effect and Ferroresonance activity. External surge transient overvoltage activities from direct lightning stroke to line conductors (33kV and 11kV) and the transformer grounding system are also being elaborated. Recommendation to present such failure and how to improve the network distribution system are also discussed.