Modern Transportation Systems and Technologies

The development of high-speed passenger transportation is a result of increased capacity of traction power supply systems, traction electric drives of rolling stock, and the intensity of electric and magnetic fields and their influence on passengers, maintenance staff, other equipment, and automation and communication systems. In the premises, we shall solve urgent problems, i.e. assess the electromagnetic environment near high-speed railway routes and inside the rolling stock in areas, where passengers, staff, and equipment are located, and ensure electromagnetic compatibility of equipment, at the stage of engineering decision-making and designing high-speed networks.

The paper presents the maximum permissible levels of electromagnetic fields provided by national and foreign regulations and the intensity of electric and magnetic fields of traction power supply systems and on-board power supply equipment of high-speed railways and magnetic levitation transportation systems. In addition, it reviews electromagnetic safety and compatibility of these systems and equipment.

Background. The main way to improve the performance of railway systems is to increase the speed. When increasing speed, we reduce labor costs, turnaround time and increase profit. In passenger transportation, the most efficient are high-speed railways (HSR, or высокоскоростные магистрали in Russian). Over the past 60 years, the high-speed railway network has been actively developing in various countries of the world, allowing to analyze statistics on their construction and operation.

AIM. To identify the patterns of high-speed railway development that will allow optimizing high-speed transportation solutions both during the construction of the first Russian HSR (St. Petersburg–Moscow) and further development of the HSR network in Russia.

MATERIALS AND METHODS. Statistics of the International Union of Railways (UIC); statistics of national railway companies. Mathematical methods include least square method, covariance method, and Pearson correlation analysis.

RESULTS. A mathematical description of HSR expansion was developed based on a case study of Japan.

CONCLUSION. The study may be used to assess the global development of HSRs.

Background. Improving the quality and reliability of power channeling and transfer elements of power supply systems.

AIM. To develop a method to predict processes occurring in cable insulation systems based on advanced insulation materials and the key environmental parameters in limited access conditions.

MATERIALS AND METHODS. The processes of destruction of insulation elements are studied based on chemical kinetics laws. The results obtained using reliability theory and mathematical statistics methods are analyzed and classified by mathematical, simulation, and physical modeling.

RESULTS. We determined approximated dependencies that connect the failure criteria of insulation systems and the key design parameters. The authors verified and proved the applicability of the proposed approach to predict the performance of remote insulation systems based on information provided during the wiring delivery.

CONCLUSION. The proposed method allows determining the operational reliability of insulation at the design and manufacturing stage of a cable structure based on the insulation quality in the as-delivered condition, resistance to process influences and design parameters of hard-to-reach or remote power generation facilities.

AIM. The paper discusses the process environment of liquefied natural gas (LNG) cold energy recovery from the fuel system of a standalone refrigerated container (reefer container). To evaluate the efficiency of LNG cold energy utilization.

MATERIALS AND METHODS. The authors determined the refrigeration potential of the LNG regasification process and a developed a thermal design of the refrigeration plant.

RESULTS. The paper describes a cascade refrigeration plant with LNG and carbon dioxide circuits. The authors assess the expected effect of cold energy utilization during LNG regasification in the refrigeration system of a refrigerator.

CONCLUSION. The results allow to assess the efficiency of LNG refrigeration potential utilization in refrigerator vehicles.

AIM. To determine the conditions when a three-phase transformer of a fundamentally new design has stabilizing properties and the deviation of the transformer output voltage at overload currents.

MATERIALS AND METHODS. We developed an electromagnetic design of a three-phase transformer with stabilizing properties using ELCUT software and analyzed the processes occurring in the transformer using an equivalent magnetic circuit.

RESULTS. When the rated secondary current changed by 20%, the output voltage only changed by 0.14%.

CONCLUSION. There is a need for a comprehensive assessment of the electrodynamic stability and thermal resistance of a three-phase transformer with stabilizing properties in transient processes.

BACKGROUND. The paper discusses a single-phase bridge self-excited inverter operating into active inductive load. The load voltage is generated by switching the key circuit elements; the current shape is determined by the load parameters and characterized by the higher harmonic spectrum. In practice, the calculations are often focused on the effective inverter load current of a non-sinusoidal shape; its determination is associated with known computational difficulties.

AIM. To develop a method to calculate the effective value load current of a self-excited inverter that does not require decomposition of the current curve into a harmonic series and its subsequent summation.

METHODS. The effective inverter load current was calculated using the theory of residues.

RESULTS. The load current of a self-excited inverter calculated based on expressions obtained using the theory of residues allows to reduce the amount of computation and ensures high accuracy, which is confirmed by experimental studies.

AIM. To determine the optimal magnetic field configuration ensuring scalability and high load on the support HTS bearing.

MATERIALS AND METHODS. Numerical analysis of HTS bearings was performed in Comsol Multiphysics modeling environment.

RESULTS. The authors determined magnetic field distributions for various configurations of magnetic HTS bearing assemblies, including a ring magnet, cubic magnets, and sectorial permanent magnets. The authors determined vertical and lateral load curves for different shapes of HTS bearings.

CONCLUSION. It was found that sectorial permanent magnets with a magnetic circuit is the optimal solution to achieve the highest stability and load-bearing capacity of a superconducting bearing while maintaining the scalability.