Simulation of computer on the relationship between the characteristics and link equation of the longitudinal differential protection of transformer

Differentiation protection is the successful operation of the main protection of all the electrical equipments, it has the characteristics of high sensitivity, better selectivity etc. The paper is on the basis of the whole statement on the theory of longitudinal differential protection of transformer, when the transformer in which the current at both ends have phase-angle difference cuts short outside the protection area, the reason why the difference of transformer won´t move by wrong is ignored in practice. This paper discusses the concept of relative equation and discusses that the phases difference of different phase current will not affect the establishment of the equation when external short circuit happens. From the view that the power exchange point works relatively independently. At the same time, it points out the relationship between whether the protection moves or not and the relative equation when internal short circuit happens. This paper analyzes the amplitude of collection current, and put forward the resolutions of the imbalanced current in the longitudinal differential protection of transformer, it draws the conclusion that it won´t move.