Simulation And Experimental Research On Winding Deformation Modeling For Power Transformer

The transformer is one of the important electrical equipment in the power system.It is important for grid security to operate safely.According to various statistics on transformers,the transformer winding is the main part of the fault.Frequency response analysis is an important means to detect transformer winding deformation.This paper is based on the FRA method to detect the deformation and simulation of the power transformer windings.It has both important theoretical value and practical significance.In this paper,the influence of iron core on the FRA test results is studied by simulation modeling and experimental measurement.Firstly,the interlayer effect of the core is described in this paper.A twodimensional model of the complex permeability of the iron core based on the Interlaminar effects is established.The modified core complex permeability formula is derivedThen,considering the influence of the iron core,the inductance parameters and mutual inductance of the power transformer windings are calculated by the modified core complex permeability formula.The transformer winding conductance and resistance parameters are calculated by analytical method.The analytic method and finite element method are used to calculate the inter-turn capacitance value,the intercake capacitance value and the capacitance value to the ground of the power transformer winding.And the error analysis is carried out in principle,which shows that the finite element method has higher precision.It is determined that the finite element method is used in calculating the winding capacitance parameters.The laboratory 35 kV display damage transformer is used as the research entity.The transformer is regarded as the equivalent distribution parameter circuit.Based on the cake,a chain circuit model of power transformer winding distribution parameters was established.Finally,the MATLAB software is used to simulate the distribution parameter model of power transformer windings.The laboratory self-made power transformer winding deformation detection system and the impedance analyzer are used to conduct the actual test on the laboratory 35 kV display damage transformer.This paper analyzes the results measured using these two devices.The simulation is compared with the measured admittance transfer function obtained by experiment with the impedance analyzer.It shows that the core has an influence on the FRA detection result.Considering the iron core effect can effectively improve the accuracy of the model.