Inter-Turn Short-Circuit Fault Location For Transformer Winding Based On Power Loss Method And Traving Wave Analysis

Inter-turn insulation failure is a common fault of transformer winding. Although the initial failures of tiny inter-turn short circuit do not affect the stable operation of the transformer, it will quickly degenerate into serious transformer winding fault and seriously affect the security and stability of power grid operation without timely detection and treatment, for this reason, it is of great theoretical and practical significance to diagnose the fault of minor inter-turn short circuit timely. However, the scarcity of method in fault location of transformer has a serious impact on the efficiency of the fault investigation and maintenance. This paper attempts to introduce the traveling wave analysis technique and put forward a method based on traveling wave for inter-turn short-circuit fault location of transformer winding.Given the traveling wave analysis method can not identify the fault types of transformer winding, this paper adopts the power loss method to detect the inter-turn insulation fault. In order to solve the problem that the traveling wave signal is easily affected by the high low frequency noise of the transformer, this paper presents an improved differential-based empirical mode decomposition (referred DEMD) denoising method based on correlation coefficients and Savitzky-Golay (referred SG) filtering to filter transformer's noise. Compared with other methods, it shows that this method has the advantage of noise processing in both high and low frequency. Moreover, the feature of energy and waveform variation of the traveling wave which changes with fault location on the whole, is extracted by energy ratio method and similarity analysis which combines wavelet packet decomposition and uniform incidence degree algorithm. On this basis, positioning results are obtained by mappings between fault characteristics and fault location which is established by genetic neural network.Finally, the fault location method is verified by the simulation model. A transformer windings model of inter-turn short-circuit established by the model of transformer and multi-conductor transmission line (referred MTL) in MATLAB/simulink, solves the problem that the MTL model based on programming is difficult to simulate.The simulation results show that this method can effectively realize the Inter-turn short-circuit fault location for transformer winding, and it has a high degree of accuracy.