Diagnosis and Analysis of a 220kV Transformer Winding Deformation Defect

This paper introduces a severe medium voltage winding deformation defect of a 220kV power transformer, which is detected by conducting routine tests. The frequency response analysis (FRA), low-voltage short-circuited impedance test and winding capacitance test is comprehensively employed for the winding deformation diagnosis and positioning. In consideration of the actual short-circuit impacts and the anti-short circuit ability, the transformer is replaced and returned to its factory for further disassembly inspection and maintenance. From the aspects of short-circuit impact statistics, deformation test approaches, coil material control and anti-short circuit ability management, the corresponding technical measures and daily maintenance suggestions are proposed in details to prevent main transformers from short-circuit damage.