A simulation mathematical model of a traction transformer with tapped secondary windings

This paper deals with the problem of accounting for changes in the magnetic flux leakage of traction transformer windings under discrete cyclic load switching of traction winding sections during the simulation of continuous processes. It is proposed to take into account this change by introducing a fictitious mutual inductance and active components of the mutual impedance between the windings, which can be determined using the theory of a multiwinding transformer. A method for mathematical representation and computer simulation of the traction transformer with tapped secondary windings is considered based on the notation of the system of differential equations in the state space. Expressions for the calculation of the leakage inductance of the transformer windings and mutual inductances that take into account the change in the magnetic field of the winding leakage in the case of the discrete cyclic load switching of the tapped secondary windings. An algorithm for calculation of matrix elements of the equation of state is constructed. A simulation mathematical model of the traction transformer is developed in the Matlab/Simulink environment that takes into account the winding leakage field variation under discrete cyclic switching of the load of sections of traction windings. The adequacy of the proposed simulation mathematical model is proven by comparison of short-circuit currents obtained as a result of the simulation with currents of traction transformer short-circuit field tests.