Nowadays, ensuring the stability of energy grids is one of the key challenges in modern power engineering, especially in the context of the growing share of renewable energy sources. This instability also affects traction power systems, which are increasingly integrated into the overall infrastructure. Modern traction substations therefore contribute to greater reliability and efficiency of the entire traction grid. At the same time, the control algorithm enables power to be distributed among a larger number of traction substations that cooperate under the same load within a traction section. The power TSSs distribution are based on PQ characteristics, ensuring an allocation that takes into account the nominal power, or overload time of each TSS, mainly in the case of semiconductor topologies. The proposed solution of control algorithm has been evaluated by a mathematical model of cooperating TSS to the traction grid.

This paper presents a mathematical model of AC traction substations (TSS) 25 kV / 50 Hz and their power sharing cooperation using Rail Power Conditioner (RPC) technology. The actual traction grids topologies bring the problem of cooperation of TSS due to differences in their output voltages. Therefore, it is necessary to isolate the traction catenary sections by neutral sections near the switching station between the TSS to prevent a power overflow due to the voltage difference. To enable the sharing of the power of these sections, RPC converters are used, which are placed in the area of the neutral section or directly to the TSS site with a suitable topology. This research deals with an efficient way of controlling this RPC, using proportional resonant controllers, which are widely used in the field of traction grids. This proposed control algorithm has been tested on a developed mathematical model of a traction network with two TSS, where the real conditions in traction grids are included and considered.

This paper describes the advanced AC traction substations topologies using of power electronics components. The traction substations allow the power flow control from the superior power grid to the traction grid. The main part of the paper is to present the output power control of only the sensitive substations, which appropriately distributes the traction load power between the connected substations. The designed control method is tested on a mathematical model of a single-track 25 kV/50 Hz traction grid with three traction substations. The model respects realistic traction site parameters and can be extended to any number of power nodes. The results are analyzed for selected steady and transient states.

The paper is focused on topologies of traction substations for AC railway traction system especially for 25kV, 50Hz (respectively 60Hz). The current progress of power electronic field of study allows to use semiconductor converters as a part of distribution power grid (i.e. for HVDC), for traction issue but also for traction substations. This expansion is related to topologies of TSS, where power electronics are used for symmetrization, compensation, filtration of harmonics of higher order, TSS cooperation, recuperation back to distribution power grid if it is allowed, etc. Conventional transformer topologies used to this day for electrical railway supplies are described in the beginning. The state of the art of TSS, using a power electronic component and the most promising topologies at the same time, is described in the second half of the paper. The main benefit of the paper is comparison of the TSS selected topologies and evaluation of the properties.

This paper describes the realization variants of the new traction drive for AC-power system with high-voltage matrix converter and medium frequency transformer (i.e. MFT). These topologies allow minimizing the weight of the traction transformer in railroad vehicles. Special attention is given to serial connection of input single-phase high voltage matrix converters fed MFT transformers. The control method involving the reduction of MFT magnetic saturation has been discussed.

This paper presents research motivated by industrial demand for special novel high voltage traction drive topology devoted to minimization of traction transformer weight against classical locomotives operates on both 25kV/50Hz and 15kV/162/3Hz trolley voltages. This paper deals with testing of whole traction converter prototype in configuration: two single phase matrix converter + medium frequency transformer + single phase voltage-source active rectifier in selected transient states and verifying of proper function of control algorithms. The new control of traction converter based on inserting zero vectors has been proposed to smooth taken trolley current.