Frequency Response Analysis of the Transformer Subjected to Twice Short-circuit Impulse Tests Under Two Different Connection Schemes

Power transformer is a key equipment in power system. Ensuring the safety operation of transformer is beneficial to decrease the economic loss and casualties. In this paper, twice short-circuit impulse tests are performed on a 10kV transformer. After each test, frequency response analysis (FRA) measurements based on two different terminal connection schemes, namely end to end voltage ratio (EE) and transfer voltage ratio (TF) ways, are conducted to record the FRA results. The impacts of short-circuit on transformer will be investigated by the change of FRA curves. In addition, a numerical index will be utilized to find out the more sensitive measurement connection way to the variation of the traces. The contributions of this paper can give a complement for the current interpretation of the FRA signatures.