Research Of Winding Deformation Detection Using Current Source

Transformer is the one of hardcore equipments in the power system, and its running state affects on the power system's security directly. The collision which is occurred when the transformer was transported or installed and the shorted current which occurred when the power systems were shorted abruptly all can lead to the winding deformation. The winding deformation is one of the most familiar faults, it compromise the security of the power system severely. In order to detect the winding deformation and avoid the failure in time, it becomes very important to diagnose the winding deformation.The frequency response analysis has been widely used as a simple and effective detecting method in many countries besides china. In the practical application, the winding deformation diagnosis mainly depends on the comparison of the response curves, which based on the practical experience. And by far, the transformer must be cut off from system when the winding deformation detection is operated. So it will lead to the unnecessary power cut. At the same time, the running transformer's winding has already deformed but could not be detected immediately. The winding deformation would be aggravated, and formed the severe hidden trouble. The main purpose of this paper is an attempt to use the frequency response analysis on line.The paper introduced winding deformation detection methods which have being widely used home and abroad presently and summarized their advantages and disadvantages, and forecasted the development trend of the frequency response analysis.The structure of power transformer and the calculation method of shorted current were followed introduced in the paper. Based on the analysis of transient power which affect on winding when the transformer was shorted, the principle of deformation was analyzed and the forms of deformation were listed.In paper's software simulation, the current source was used as input power of the equivalent model. The change laws of frequency response curves caused by parameters changes of inductance in capacitance in different section of winding model were carefully studied, In the practical winding model testing study section, the study steps were taken as same as the software simulation study.In paper's fifth section, the theories of using orthogonal polynomials to estimate the transfer function based on the principle of least square methodology is introduced, then the zeros and poles are obtained from the transfer function, which can used for estimate the winding deformation. At the last of this section, the paper applied the recursive least square methodology to the transfer function estimation in order to suit for the on-line detection.The last of the paper, the whole text was summarized and the prospect of the frequency response analysis was presented.