A Review of the Energy Efficiency Improvement in DC Railway Systems

This study is focused on the topical issue of increasing the energy efficiency in DC railway systems, in the context of global concerns for reducing the CO2 emissions by minimizing the energy consumption and energy loss. The main achievements in this complex issue are synthesized and discussed in a comprehensive review, emphasizing the implementation and application of the existing solutions on concrete case studies. Thus, all specific subtopics related to the energy efficiency are covered, starting with power quality conditioning and continuing with the recovery of braking energy, of which a large part is lost in the classic DC-traction substations. The solutions of onboard and wayside storage systems for the braking energy are discussed and compared, and practical examples are given. Then, the achievements in transforming the existing DC-traction substations in reversible substations with capabilities of power quality improvement are systematically reviewed by illustrating the main results of recent research on this topic. They include the equipment available on the market and solutions validated through implementations on experimental models. Through the results of this extensive review, useful reference and support are provided for the research and development focused on energy efficient traction systems

New Power Optimization Possibilities Of Static Converter And Asynchronous Motor Driving Systems

In this paper there are given a few mathematical relations for the power analysis in un-sinusoidal regime. If the voltage is sinusoidal and the current is unsinusoidal, the apparent power will be ascertained by the active power, the fundamental displacement factor and on the current distortion factor. If the voltage and the current are un-sinusoidal, there will exist the optimum values for real parts of harmonics impedances that will minimize the apparent power. More interesting is the possibility of minimization the apparent power at constant mechanical powe

High Performance Shunt Active Power Filter: Design Consideration and Experimental Evaluation

The paper presents an active power filter with high performance, achieved by the authors. To obtain these performances some contributions were brought, both in the power part and in the control part, those are highlighted. First, some design considerations of interface filter are done. Next, the experimental setup is presented and a lot of experimental determinations for different conditions of voltage and load are shown. These and some indices calculated show that, indeed, the achieved filtering platform has very good performances