Research On Extension Recognition Method For Transformer Sympathetic Inrush

Differential protection has been widely used as the main protection of transformer,but it is often misoperated by unbalanced current.In recent years,the accident of transformer differential protection misoperation caused by air drop transformer occurs frequently.The reason why for the accident is closely related to the coordination effect between transformer and transformer.The identification of inrush current is not suitable for sympathetic inrush.Therefore,it is of great practical significance to study the transformer and inrush current and put forward effective identification methods.Extension theory is a method developed rapidly in recent years to solve the problem of contradiction.In this theory,the extension matter element model is used to qualitatively analyze the characteristic parameters contained in things,and the correlation degree of the characteristic parameters is determined quantitatively by the extension set theory,which provides a kind of identification for the solution and the identification of the sympathetic inrush formal,modeling,qualitative and quantitative methods.The main contents of this paper are as follows:1.The electrical model of generating and responding inrush is established,and the transient process and mechanism of inrush current are expounded,and the characteristic information of inrush current is summarized.2.Use Matlab/Simulink power system simulation platform to build simulation model,and carry out simulation research for different working conditions of transformer.3.Apply the extension recognition method in the extenics theory to the identification of the inrush current,determine the implementation steps of the method of the identification and the identification of the inrush,and verify the effectiveness of the recognition method by an example.Extension set theory in extenics theory can classify and identify objects based on the characteristics of objects.The characteristic information contained in the sympathetic inrush and the internal fault current are different,so the concept of the extension set and the characteristic matter element is introduced in this paper,which is of great significance to the processing of the characteristic information of the sympathetic inrush and the internal fault current.The introduction of correlation function can describe these key feature information quantitatively,and it is a formula to express the sympathetic inrush and the characteristics of the sympathetic inrush characteristics.The extension identification method of sympathetic inrush provides a new tool and method for identification of transformer sympathetic inrush.