ABSTRACT
The method of symmetrical components is a powerful mathematical abstraction that enables one to interpret the behavior of and find solutions for three-phase electrical systems, as long as their responses can be considered linear. This is a very important constraint that makes sure that the independent response of the system can be obtained at any point of interest as the superposition of the responses to the positive-sequence, negative-sequence and zero-sequence excitations. In power transformers, the response is not always linear, as is the case when saturation affects parameters. In such conditions, actual system behavior is estimated with conventional tools, such as symmetrical components, and non-linear analysis methods are available for most general cases. A relationship between the different phase sequence components of a given phase sequence is given by positive sequence.
