Improvement of External and Traction Power Supply System’s Efficiency by Normalizing the Schemes

Abstract

The article deals with improvement off the efficiency of external and traction power supply systems using for example indicators of traction substations for a real electric transmission line segment of a traction network of 25 kV. The analysis of the functioning of a real section of electrified railways with traction substations, two of which are connected according to the "feeding" scheme is providing in the article. The currents in the wind-ings of traction transformers are calculate for these substations. The proportion of the currents values of the most loaded winding to the two less loaded is 2: 1. The coefficient asymmetry of currents of transformer wind-ings operating on existing traction substations is equal to 1. The results prove a significant currents asymmetry of transformers windings and phases of electric transmission lines which leads to an increasing voltage unbal-ance. New schemes for connecting traction substations for the considered section of electrified railways have been developed in order to improve the quality indicators of electrical energy. New connection schemes for three traction substations, determined according to the requirements for connecting to the external and trac-tion power supply system are presents in the article. The calculation for new schemes of connecting traction substations, similar to the previously considered option, has been performed. The values of winding currents, power transmission line phases and coefficient asymmetry were obtained for new substation connection schemes. The proposed schemes for connecting traction substations provide a decrease in the coefficient asym-metry of the winding currents from 1 to 0.5 and a decrease in the current modulus in the most loaded windings by 1.5 times. New schemes for connecting traction substations reduce the currents of the most loaded windings and phases of the power transmission line, as well as the asymmetry of currents, which ensures an improvement in the efficiency of the external and traction power supply systems of the real traction network.