Investigation of the influence of residual magnetic flux on FRA of transformer

摘要

The frequency response analysis (FRA) of transformer has been expected to be a good method for diagnosing the transformer condition. As the transformer impedance is affected by the configuration, the change of the impedance will be a good indicator for the change of the transformer configuration. On FRA measurement, the windings without measuring is set with an open-circuit or a short-circuit. In this paper, the experimental result about the open-circuit of FRA which can diagnose core defects etc. is described. Specifically, the influence on the impedance measurement by residual magnetic flux (RMF) and an injection voltage level are described.