scholarly journals A Novel Co-Phase Power Supply System for Electrified Railway Based on V Type Connection Traction Transformer

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1214
Author(s):  
Shaofeng Xie ◽  
Yiming Zhang ◽  
Hui Wang
Keyword(s):  
Power Supply ◽  
High Speed ◽  
Power Supply System ◽  
Single Phase ◽  
Supply System ◽  
Technical Problems ◽  
Electrified Railway ◽  
Traction Power Supply ◽  
Universal Applicability ◽  
Neutral Section

Power quality and neutral section are two technical problems that hinder the development of electrified railway to high-speed and heavy railway. The co-phase power supply technology is one of the best ways to solve these two technical problems. At present, a V type connection traction transformer is widely used in a power frequency single-phase AC traction power supply system, especially in high-speed railway. In this paper, a new type of co-phase power supply system for electrified railway based on V type connection traction transformer is proposed. One single-phase winding in the V type connection traction transformer is used as main power supply channel, and three ports are used as compensation ports. Neutral section is no longer set with traction substation, and the train is continuously powered through. The independent single-phase Static Var Generators (SVGs) are used to compensate the three-phase imbalance caused by single-phase traction load. When necessary, the power factor can be improved at the same time. The principle, structure, control strategy, and capacity configuration of the technical scheme are analyzed in this paper, and the effectiveness of the scheme is verified by using the measured data of electrified railway. The advantage of this scheme lies in the universal applicability of the V type connection traction transformer, and the flexibility of the SVG device.

scholarly journals A Novel Co-Phase Power-Supply System Based on Modular Multilevel Converter for High-Speed Railway AT Traction Power-Supply System

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 253
Author(s):  
Si Wu ◽  
Mingli Wu ◽  
Yi Wang
Keyword(s):  
Power Supply ◽  
High Speed ◽  
Power Supply System ◽  
Supply System ◽  
High Speed Railway ◽  
Traction Power Supply System ◽  
Traction Power Supply ◽  
Supply Mode ◽  
Power Supply Mode ◽  
Traction Power

The existing problems of the traction power-supply system (i.e., the existence of the neutral section and the power quality problems) limit the development of railways, especially high-speed railways, which are developing rapidly worldwide. The existence of the neutral section leads to the speed loss and traction loss as well as mechanical failures, all of which threaten the fast and safe operation of the train and the system. Meanwhile, the power quality problems (e.g., the negative sequence current, the reactive power, and the harmonic) can bring a series of problems that cannot be ignored on the three-phase grid side. In response, many researchers have proposed co-phase power-supply schemes to solve these two problems simultaneously. Given that the auto-transformer (AT) power-supply mode has become the main power-supply mode for the high-speed railway traction power-supply system, it has a bright future following the rapid development of the high-speed railway. In addition, there is no co-phase power-supply scheme designed for AT power-supply mode in the existing schemes. Therefore, the main contribution of this paper is to propose a specifically designed power-supply mode more suitable for the AT, as well as to establish the control systems for the rectifier side and the inverter side. In addition, for the proposed scheme, the operation principle is analyzed, the mathematical model is built, and the control system is created, and its functionality is verified by simulation, and its advantages are compared and summarized finally. The result proves that it can meet functional requirements. At the same time, compared with the existing co-phase power-supply scheme, it saves an auto-transformer in terms of topology, reduces the current stress by 10.9% in terms of the current stress of the switching device, and reduces the power loss by 0.25% in terms of the entire system power loss, which will result in a larger amount of electricity being saved. All of this makes it a more suitable co-phase power-supply scheme for the AT power-supply mode.

Comprehensive Analysis of Active Electrified Railway Compensation

2011 ◽  
Vol 204-210 ◽  
pp. 1675-1678
Author(s):  
Guo Wang ◽  
Ming Xing Tian ◽  
En En Ren ◽  
Li Na Ding
Keyword(s):  
Power Supply ◽  
Power Supply System ◽  
Supply System ◽  
Negative Sequence ◽  
Active Compensation ◽  
Traction Power Supply System ◽  
Compensation Principle ◽  
Railway Traction ◽  
Electrified Railway ◽  
Traction Power Supply

Traction load in electrified railway result in the power supply system contains a lot of negative sequence, harmonic and reactive current. It is necessary to analysis the compensation principle based on active compensation of electrified railway traction power supply system. According to the relation between primary winding and secondary winding of regular traction transformer, we deduced general voltage and general current transform formula, and then deduced completely and negative sequence compensation formulas. It also gives the method of reduce active compensation capacity.

scholarly journals Research on Control Strategy of AC-DC-AC Substation Based on Modular Multilevel Converter

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Fei Chang ◽  
Zhongping Yang ◽  
Fei Lin
Keyword(s):  
Power Supply ◽  
Power Supply System ◽  
Single Phase ◽  
Supply System ◽  
Multilevel Converter ◽  
Traction Power Supply System ◽  
Three Phase ◽  
Phase Converter ◽  
Traction Power Supply ◽  
Traction Power

Significant disadvantages in power quality especially the unbalance problem and neutral sections restrict the evolution of conventional traction power supply system. A new traction power supply system based on three-phase to single-phase converter is studied, which can transfer active power from three-phase grid to single-phase catenary. One catenary section could be utilized in the new traction power supply system instead of the multiple split sections in conventional system. Three-phase to single-phase converter is the core equipment of new traction power system. MMC (modular multilevel converter) structure of AC-DC-AC substation is proposed in this paper. To solve the problem of the capacitor voltage balancing in MMC, a parallel sorting algorithm based on field programmable gate array (FPGA) is studied. And the correctness and effectiveness of the algorithm are verified by experiments. In addition, it is inevitable that the AC grid voltage will be unbalanced caused by the fault in the new system. Therefore, this paper focuses on the analysis of the effect of the unbalanced grid voltage on the operating characteristics of the MMC system. Finally, the correctness of the theoretical analysis is verified by simulation.

scholarly journals Improving the quality of voltage in the system of traction power supply of direct current

2015 ◽  
Vol 35 (3) ◽  
pp. 63-70 ◽  
Author(s):  
Viktor G. Sychenko ◽  
Dmitry O. Bosiy ◽  
Eugene M. Kosarev
Keyword(s):  
Power Supply ◽  
High Speed ◽  
Power Supply System ◽  
Heavy Traffic ◽  
Supply System ◽  
Traction Network ◽  
Traction Substations ◽  
Traction Power Supply ◽  
Traction Power

Purpose of the work is improved approaches to ensure the required quality parameters of voltage in the traction network based on modern technologies and equipment in the application of power distribution system. Actuality. The introduction of high-speed traffic, increase weight standards Train necessitates increasing the carrying capacity of railways. Often the carrying capacity of existing sections electrified at 3.0 kV DC power supply unit limits. Such limitations include voltage decrease on the electric current collector below the allowable value for the normal operation of 2700 (2900 for high-speed V) and heating the contact wires, thereby losing their mechanical strength. Existing power supply system of RS, which have considerable installed traction substations, can not provide the required level of power density traction network for high-speed movement within 1.5 - 2 MW / km and, respectively, the required voltage quality. At the same time, the daily loading of a powerful traction substations in providing intensive schedule of trains does not exceed 20-25%, while the energy loss in traction network peak load increases and reaches 10-15% of the energy consumed. Thus, the existing system of power traction networks is not sufficiently effective and economical, even with the application of existing methods to strengthen them. In our view, the main limiting factor for a given quality of voltage in the traction network is the use of centralized power. From this, the development of measures to improve the quality of voltage in the traction network in the implementation of high-speed traffic in a growing scarcity of energy resources is an urgent task. Scientific novelty. Using distributed power supply system with adjustable supply points combined into intelligent power supply, which enables adaptive change the characteristics of the transfer, conversion and consumption and optimize the mode of functioning of the traction power supply is suggested for improving the quality of voltage in the traction network in the implementation of high-speed and heavy traffic. Practical significance. Improving the quality of voltage in the traction network by using the proposed circuit design traction power supply will ensure the desired mode voltage and power characteristics of the traction network in the implementation of high-speed and heavy traffic while reducing electricity losses by 20-30%.

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