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This paper investigates the issue of voltage distortion in the 0.4 kV power supply at electric centralization (EC) posts. Significant voltage distortion may trigger an emergency switch to the backup feeder, potentially leading to failures in railway automation and telemechanic systems. To analyze this problem, a series of field measurements were conducted to assess the quality and harmonic composition of the supply voltage at an EC post. The experimental results revealed a direct correlation between the degree of voltage distortion and the load current on the adjacent traction substation. Using computer simulation tools, a detailed model of the traction substation, including the power supply lines to the EC post, was developed. Based on this model, optimal parameters for a passive LC filter tuned to suppress the 11th and 13th harmonic components - dominant under the 12-pulse rectification scheme - were calculated. A prototype harmonic filter was then constructed and integrated into the power supply line of the EC post. Post-installation field measurements were carried out to evaluate the voltage quality improvement. The results confirm the effectiveness of the selected filter in reducing both the total harmonic distortion (THD) of the voltage and the individual harmonic components of the 11th and 13th orders. During the entire four-month trial operation period, no emergency power transfers were recorded at the EC posts. The findings of this study can be applied to similar systems within DC-electrified railway networks, taking into account variations in rectification schemes and non-traction load power supply configurations.

There is a trouble that electrical energy of trains which have a recuperative braking uses partly for DC railway, because there are not different consumers of the electrical energy in this time. The method was offered, it allows to find optimal parameters of a stationary energy storage, which locates on a traction substation. This method can be used for designing and determination efficiency of an energy storage.

There is the way for increasing efficiency of recuperative braking, using an energy storage device on electrical locomotives of DC railway. This device must store a part of recuperative energy. In the article the approach was considered, which allows to find parameters of an energy storage device, this device must be placed on electrical locomotives of DC railway, a part of recuperative energy can be returned to electrical network.

A method to an assessment of influence on the expenditure of electrical energy for traction of trains, parameters of graphic time-table in the conditions of using the regenerative braking is being considered in the article. The retrieval of version with the minimal using of energy is based on the modeling of graphic time-table by different train-to-train intervals in the conditions of burst-mode access’ organization on the railway section. By results of modeling it is proposed to represent the derived dependence by changing of electrical energy’s expenditure on parameters of graphic time-table in the form of analytic function of several variables n-order forthe following using by normative plotting of movement for the purpose of curtailing electrical energy’s expenditure for traction on the trains.

The article considers one of the ways of improving the energy efficiency of AC electrical system railways 25 kV, 50 Hz. The proposed approach allows to determine the optimal location and capacity of an unregulated device for compensation reactive power according to the criterion of minimum active power losses in a traction electrical system. Modeling of trains on the site was made using instant schemes. Description of the traction power supply system implemented by the node potential method and Steinmetz’s symbolic method. Optimal value of reactive power for all possible locations of a compensating device was calculated numerically by an optimization method of Hooke-Jeeves according to the criterion of minimum active power losses in the traction network. The mathematical model allows to consider the elements of the traction network, schedules of trains, change of traction loads of electric locomotives, schemes of overhead network. The proposed approach was considered on the example test problem, which solution allowed to determinate the optimal location and required value of reactive power of an technical device. The placement of a compensating device in a certain place will allows to minimize the power loss in the contact network, track circuit and traction transformers from the flow of the reactive component of the current in average for all instant schemes with various traction loads. An unregulated technical device for compensating reactive power which is located between two traction substations reduces energy consumption for traction of trains on the 1 - 2 %.