Y, D Vector Transform The Impact Of Transformer Differential Protection And Interturn Short Circuit Simulation Studies

This paper mainly focuses on the differential protection for transform. The main contents are as following:(1) We analyse the sensitivity difference of two transformations when all kinds of shortcircuit faults occur in the Y side of a transform. In this paper we use a simple and usual system model to start our study. First of all, we decompose the fault network to positive, negative and zero sequence networks, then with several transformantions we get the currents measured in the CTs. So we can get the differential currents flowing through the relays. Because of the different transformations, we get different differential currents. By compare theirs magnitude , we can tell which transformation offer more large current which means high sensitivy. By using the similar method we can get the difference of sensitivity in other complicated faults.(2) We presents how to make the simulation of transformer with internal faults by the simulation software ATP in details. First, the model of transformer with internal fault is introduced. Then the steps how to make the simulation by ATP are presented, including how to discern the ATP input file and how to modify it. And a single-phase transformer internal fault simulation result is also presented.