Frequency Response Analysis For Winding Deformation Of Power Transformer

Transformer is one of the important equipments in the power system, and its running state influence the system's security directly. The transformer can be collided when being transported or installed, and shorted abruptly when running, which can be lead to the winding deformed. The winding deformation is one of the familiar faults of the transformer, and it harm the power system secure operation. For the purpose of detecting the latent accidents in time, it becomes very important to diagnose the winding deformation.As one of the methods of diagnosing the winding deformation, the frequency response analysis method is presently being widely used in many countries besides China. By far there are no settled scales or uniform criteria that can be abided by to diagnose winding deformation, while its use is mainly depended on the comparison of the frequency response curve. And by far the frequency response analysis the winding deformation of transformer is off line, when diagnosing the winding deformation, the transformer must be off line operation, which lead to unnecessary power cut; meantime because the detection is not in time when the winding has deformed, which lead to the worst winding deformation. So that the main purpose of the paper is attempt to use the frequency response analysis the winding deformation of transformer on line operation.In the first chapter of the paper, the methods and their advantage and defects of diagnosing the winding deformation are summarized. Subsequently, the development of frequency response analysis method is presented. In the second chapter, the structure of transformer is described, and the method of calculating the short current is put forward. Subsequently, on the basis of instantaneous forced analysis to short circuit of power transformer, the paper present the essentiality of diagnosing the winding deformation of power transformer after short circuit.In the third chapter, input by current supply, the equivalent model of the winding is simulated using PSPICE, the relation between the frequency response curves and the change of parameters is to be obtained by means of altering parameters of different site's inductance and capacitance.In the fourth chapter, at firstly, the practical model of winding is simulated for searching the relation between the frequency response curves and the altering parameters of different site's inductance and capacitance. Subsequently, the theory of using orthogonal polynomials to estimate the transfer function is introduced. The effects of the winding deformation imposed on the distribution of poles and zeros are analyzed integrating the experimental data of simulation, at last, the entire strategy of filtration is introduced simply.In the fifth chapter, at firstly, on the basis of research and analysis the resonance phenomenon of winding, identification the section of winding deformation is by frequency response curves; Subsequently, the way of frequency splitting of frequency response analysis method is studied.In the last chapter, the whole text is summarized and some questions to be perfected are put forward.