Abstract:The lumped parameter model of double winding power transformer windings is analyzed.Based on the topology structure of equivalent circuit,a method to completely express the equivalent circuit by using impedance branch matrix and admittance branch matrix is given.Through Kirchhoff's law and matrix operation,the mathematical relations among voltage,current and various parameters are deduced.Finally,the axial displacement and radial deformation of common faults in transformer windings are analyzed,which provides reference for simulating the types and degrees of mechanical faults in windings.