Subway Traction Power Supply System Based on PWM Rectifier

At present, PWM rectifier is widely used in various high power and high voltage situations because of its high energy, low harmonic content, constant voltage and bidirectional energy. The energy supply system of subway traction power supply system based on PWM rectifier shows the topology of a dual transformer with three winding transformers and four PWM rectifiers in parallel, which is superior to the modular model. Finally, the correctness of the control strategy is verified by Matlab/Initial simulation.

Application of Traction Power Supply for Metro Rail Transit Based on Electromagnetic Sensing Technology

With the gradual acceleration of modernization, metro projects have been opened for the development and construction of urban areas. How to ensure the smooth operation of subway project in public service has become the focus of urban public safety service research. In view of this content, this paper studies the subway field of urban rail transit operation and improves the public safety of urban rail transit operation. Firstly, the factors affecting the track traction power supply are analyzed, the anti-interference technology of ring array electromagnetic sensor is added, and the research scheme is formulated according to the track potential research standard to ensure the operation of the power supply system. Then, the electromagnetic sensor traction algorithm is used to detect the subway track power supply signal, and the working characteristics and advantages of single electromagnetic induction and double electromagnetic induction are analyzed. The experimental results show that compared with the traditional electromagnetic sensor power supply signal detection algorithm, the content of this paper can judge whether the power supply is normal according to electromagnetic induction, detect whether the subway traffic deviates from the track traction coordinates, and understand the size of the deviation from the track. It improves the efficiency of traction power supply detection, stabilizes the running track of subway traffic, and is conducive to the protection and development of urban public safety.

DC traction power substation using eighteen-pulse rectifier transformer system

<span lang="EN-US">Twelve-pulse rectification system had been widely integrated in today’s DC traction power sub-station (DC-TPSS). This configuration had successfully mitigated low order harmonic distortion. As some research findings had confirmed that the dc voltage and current ripple factors may further minimize by increasing the number of rectification pulses to 18, 24, or 36. This paper had presented a simulation study to investigate the prospect of implementing an eighteen-pulse rectification system in a DC-TPSS. The theory of phase-shifting transformer used to produce an 18-pulse rectifier is presented with simulation verification. Simulation result shows that 3.69% of grid current distortion index is recorded without installing any filters. In addition, the dc voltage and current ripple may also be further reduced for about 30% compared to a conventional twelve-pulse rectification system.</span>

Analysis of compensating devices efficiency in ac traction power supply systems

The article describes the main methods of reactive power compensation used in 27.5 kV AC traction power supply systems on the railways of the Russian Federation. The cases of installation of the longitudinal and transverse capacitive compensation devices at traction substation and sectiolizing post are considered in this paper. Based on experimental data their effectiveness has been analysed by comparing the main parameters of the traction power supply system before and after the installation of the compensating devices. The main effect in terms of power consumption reduction is achieved through application of reactive power cross-compensation devices. The results of the analysis show that the total electricity consumption in the researched area decreased by 23 % and the proportion of higher harmonic elements of voltage decreased by 15 %.

Forecasting of the efficiency indicators of the use of boiler and furnace fuel in the non-traction power engineering of railway transport based on the model of temporaryth row

The article considers the solution of the problem of constructing forecast values for a long period of changes in the value of the specific consumption of boiler and furnace fuel by boilers for a geographically distributed company-Russian Railways, taking into account the use of various types for the main types of fuel used in the generation of thermal energy: natural gas, heating oil, coal and brown coal. A mathematical model based on time series using the Bollinger method is proposed, which includes elements of extrapolation and modeling. An example of calculating the change in the values of specific consumption in the future until 2035 in the whole railway network is given. A simulation of the change in this value is performed for the variant fractions of substitution of one type of fuel with another. The possibility of determining long-term forecast indicators using a time series model is shown.

Application of the recurrent mathematical model for estimating the electric-traction NetWare parameters at their dynamic change

The article is devoted to the possibility of applying the methods of successive approximations in the analysis of the instantaneous scheme of the electric-traction netware. The described approach makes it possible to improve the accuracy of modeling the dynamic modes of traction power supply sections operation, and also makes it possible to significantly improve the process of modeling diagnostic and control systems for electric rolling stock at the design stage, based on a more accurate model of dynamically changing input parameters of the electric-traction netware, depending on their required level.

Selection of electricity storage devices for mobile DC traction substations

The aim of the study is to review the sources covering the problems of accumulating electricity on the railways and to find new solutions to reduce the use of electricity in traction power supply system. The article analyses some existing types of electric energy storage devices (capacitive, inertial, superconducting inductive, electrochemical, fuel cells and pumped storage power plants), their common installation locations, advantages, and disadvantages. The possibility of using them in railway traction power supply systems, in particular in mobile traction substations, is also assessed. In addition, the article lists the parameters on the basis of which the optimum type of storage device can be selected for the given conditions. The study concludes that the use of some types of energy storage devices in mobile traction substations is acceptable when regenerative braking can be used at the site, and this method of energy saving can be recommended in the engineering of new or reconstruction of existing traction substations. It has been found that capacitive and inertial (flywheel) electrical energy storage units are the most suitable in terms of parameters for installation of traction power supply systems.

Appropriate Distraction Strength For Metatarsophalangeal Joint Arthroscopy

This study is to investigate the natural metatasophalangeal joint (MTP) distance, the appropriate degree of distraction and the associated factors including age, gender, body mass index(BMI). Regarding natural MTP joint space size, the MTP-2 joint had the largest joint size (2.39 ± 0.37 mm). The MTP-5 joint had the smallest joint size (1.59 ± 0.34 mm). In MTP joint arthroscopy, traction power of 10 lbs is sufficient for appropriate distraction for all MTP joints while traction power of 5 lbs is an appropriate power for distraction of the MTP-2 joint. Manual traction is generally not appropriate for distraction because it is not consistent or sufficient. Less distraction power is required for males than for females, especially for MTP-1, MTP-3, and MTP-4 joints.