Priti G, Sindekar AS
Sweep Frequency Response Analysis (SFRA) is an established tool for determining the core deformations, bulk winding movement relative to each other, open circuit and short circuit turns, residual magnetism, deformation within the main transformer winding, axial shift of winding etc. This test is carried out on the transformer without opening it and is an off line test. A change in frequency response as measured by SFRA technique indicates a physical change inside the transformer, the cause of which then needs to be identified and investigated.