The Analysis Of The Vibration Characteristics Of The Power Transformer Windings

Transformer has an important role in transmission, substation in a power system, which willdirectly affect the safe operation of the operation of the grid. Transformer winding and core fault isa major fault of the transformer, and a large proportion of total failure. Transformer windingoperation status’ monitoring and diagnosis, which not only can find winding transformer fault inadvance, but also supply the traditional preventive tests.The issue use the model of S11~M~500/35and Yyn0transformer for the study. Study thevibration mechanism transformer windings and core. Design transformer winding faults accordingto the winding force and common fault type. Study the vibration signals of transformer winding andcore in the tank surface. Get the amplitude and frequency of distribution transformer vibrationanalysis of vibration signal by using Fast Fourier Transform. Deeply study the diagnostic methodsof local mean decomposition method and Euclidean distance combination, use it diagnosing thefault of transformer winding.Measure the vibration signals of transformer core and windings by the no-load and load test,test the transformer vibration signal of different points with different voltages and currents. UsingFast Fourier Transform analysis the vibration signal transformer core and windings to obtainvibration frequency transformer core is100Hz, and contain high harmonics of200Hz~800Hz;vibration frequency transformer windings is100Hz, and contain high harmonics of200Hz~500Hz,additionally comprising50Hz harmonics. The vibration signal frequency distribution of core andwinding basically unchanged after transformer winding has been fault.According to the results of analysis of transformer vibration signals, transformer core vibrationsignal at1/2position in the distance from the bottom surface is most obvious. It can be a goodreflection of the vibration characteristics of the core. The impact core can be neglected that windingfault cause on the vibration of the transformer. Transformer’s core fundamental frequency vibrationamplitude and the square of the voltage is linear relationship. But the most obvious vibration signalof transformer winding is at1/6position in the distance from the bottom surface, and the vibrationamplitude variation is also the maximum in this place before and after the transformer windingfaults, so the vibration measurement points of transformer windings should be selected in thisposition. The fundamental frequency vibration amplitude of transformer windings and the square of the load current is also into a linear relationship. And the relationship has nothing to do with thewinding fault.Fourier transform method can convert the time domain signal into a frequency domain signalfor analysis, which has played a groundbreaking role in signal processing, but the method is lack oflocal information in non-stationary, non-linear signal disposing, so the choice of this topic a newtime-frequency analysis method, that is the local mean decomposition method, which can be theraw signal into various product function （PF） signal. Make the PF component energy as featurevalues, and form a feature vector. Combined with Euclidean distance method to diagnosetransformer winding faults, and be diagnosed based on: When the Euclidean distance d>0.5iswinding fault, d<0.3for winding normal.