Research On Differential Protection Of Transformer And Inrush Problem

Differential protection has been a major protection of the transformer. How to prevent the inrush causing malfunction in differential protection is a key and difficult problem. After studying thoroughly on the theory of transformer magnetizing inrush current, this thesis analyzes the advantages and shortcomings of several methods to differentiate magnetizing inrush current. PSB in Matlab is applied to realize the simulations of magnetizing inrush current.Moreover, the physical mechanism of the sympathetic interaction between two transformers caused by inrush transients and its influence on differential protections are analyzed. Afterwards, possible protection strategies are presented.