Oliveira, L. M. R.Cardoso, A. J. Marques2014-05-202014-05-202012Oliveira, L.M.R.; Cardoso, A.J.M.Power Transformers Differential Protection Using the p-q Power Theory, In Technological Innovation for Value Creation, 283-290, ISBN: 978-3-642-28254-6. Berlin, Heidelberg: Springer , 2012.978-3-642-28254-6AUT: LOL01124;http://hdl.handle.net/10400.1/4002This paper describes the application of the p-q power theory to the differential protection of power transformers. The information provided by the harmonic content of the differential active and reactive power components is used to detect winding insulation failures and to distinguish them from magnetizing inrush current transients. A variety of test cases is presented in the paper, demonstrating the effectiveness of the protection strategy.engTransformersDifferential protectionP-q power theorybook part2014-05-19