Inter-turn Short Fault Location For Transformer Winding Based On Traveling-wave

The power transformer is one of the important components in power plants and substations, once the fault occurs, it will cause a large area of power failure, which has a great impact on the economic stability of the power system. According to relevant statistics, most of the faults of the transformer are caused by the fault of the windings, and inter-turn short circuit fault is the most important winding fault. Minor inter-turn short circuit does not affect the operation of the transformer, but it is the symptom and manifestation of transformer winding insulation deterioration. Long term fault operation will lead to further deterioration of insulation, and lead to transformer windings burned out even scrapped. So it is of great theoretical significance and practical application value to diagnose and locate the fault of transformer winding inter-turn fault.In recent years, with the successful application of the traveling wave positioning technology in the fault location of transmission lines and generators, the research upsurge of the traveling wave technology has been set up at home and abroad. Considering transformer windings and generator windings in the offline case have similar structural characteristics. In this paper, the traveling wave theory is introduced into transformer fault diagnosis, and inter-turn short circuit fault location method is put forward based on traveling wave reflection wave voltage amplitude.According to the structure of pancake winding transformer, when a single low voltage pulse is injected to the end of the winding wire, the refraction and reflection of the traveling wave can occur at the turn of the winding, in the injection port to obtain the traveling wave reflection signal, the corresponding peak voltage amplitude is extracted from the collected traveling wave reflection signal, which is used as the electric signal of the fault diagnosis. Through the analysis and calculation, it is concluded that the variation of the wave impedance increases and the corresponding voltage reflection coefficient increases with the turn to turn short circuit. According to the change of the reflected voltage caused by the inter-turn short circuit, the fault location of the inter-turn short circuit fault is realized.Application of traveling wave analysis method must be based on multi conductor transmission line (MTL) model, this paper analyzes the transmission characteristics of the traveling wave in the transformer windings. Considering the multi conductor transmission line model which is realized by programming, it is not easy to simulate the inter turn short circuit fault. In this paper, the MTL model of transformer winding is built by using the multi conductor transmission line in Simulink, and the simulation test is carried out, the simulation results confirm the correctness and feasibility of the proposed method.