Calculating the parameters of balun in traction power supply system alternating-current with variable load

Abstract

The alternative current traction substation is considered when primary transformer’s windings are connected in a star and secondary windings connected in delta. Real case, when system is supplied from traction transformer of type TDNG 25000/110 is considered.   A traction load is supplied from one side of delta connection. This creates asymmetrical mode in power supply, decreases power factor and increases copper losses in the system. Simulation of electromagnetic processes on visual model shows a considerable asymmetry in voltages and currents of transformer. Searching optimization based on Nelder-Mead algorithm is implemented on Simulink all at the same time with visual model of traction substation on SimPowerSystem. As searching optimization result are found parameters of simmetrizating device, which provides balanced voltages and currents on transformer’s windings. It carried out a series of calculations balun parameters for different load cases. Results of search engine optimization are presented in the form of tables and graphs that can be used to determine the parameters of the balun for any value of the load factor. Control calculation showed high accuracy of the proposed method .Reactive power in system is completely compensated and copper losses in supply system are minimized.