Main Trends of Technical Development of a Direct-Current Traction Power Supply System and Its Adaptation to High Speed Motion

Abstract The main trends of technical development and improvement of dc traction power supply systems are considered. Methods and programs are developed that make it possible to study the electromagnetic processes in rectifier–inverter units of traction substations and the self-excited source voltage inverter of induction traction drive and determine and predict the levels of harmonic components of the current in both dc–ac converters themselves and that in the traction network. This makes it possible to determine the electromagnetic effect of various power semiconductor converters on communication devices and railway automation and ground the choice of circuits and protection parameters ensuring electromagnetic compatibility. Analysis and synthesis of electromagnetic processes and the main characteristics of multipulse converters reveals that 24-pulse rectification circuits with serial connection of three-phase bridges are the most effective for a dc traction power supply system with a 24-kV voltage traction network. The introduction of 24-pulse rectifiers makes it possible to decrease power loss in the traction network and reduce the consumption of reactive energy from the primary power supply system. These rectifiers provide not only an increase the traction substation efficiency, but also refinement of electric energy in the primary power supply system and traction network. The latter makes it possible to use simpler and more economical smoothing filters that ensure electromagnetic compatibility of the new dc traction power supply system with communication devices, railway automation, and other infrastructure.