Electric Traction Power Research Articles

The application of active filters supported by Pulse Width Modulated Inverters in the harmonic simulation of the high power electric traction

The paper shows the present results of a long term research work. The authors are working on the modelling of active filtering of harmonics caused by the railways. To simulate the harmonic penetration and filtering effects of the power electric traction the combination of frequency and time dependent model should be used. This novel method, called double domain simulation is improving the accuracy of the frequency domain simulation. To calculate the sophisticated model of the electric locomotive and active harmonic filter as a non-linear load a time dependent model must be used. The traction supply system together with the equivalent supply network impedance could be calculated in frequency domain. An iteration algorithm is developed converting the variables in every iteration step between the time and frequency domain.

Effect on power quality of the high power electric traction (Double domain computer simulation vs. site measurements).

The paper shows the present results of a long term research work. The authors are working on the modelling of penetration of harmonics caused by the railways. In a former paper [1] a detailed model of the traction system was discussed in frequency domain. However this paper presents the combination of frequency and time dependent model. This novel method, called double domain method is used to improve the accuracy of the frequency domain simulation. To calculate the sophisticated model of the electric locomotive as a non-linear load a time dependent model must be used. The traction supply system together with the equivalent supply network impedance could be calculated in frequency domain. An iteration algorithm is developed to converting the variables in every iteration step between the time and frequency domain.

An In-Depth Investigation of Innovative Electric Traction Power Supply Systems for Mass Rapid Transit

This article discusses the outcomes of a study conducted to explore new power supply sources for subway trains. The power supply system for traction is an integral and inseparable component of subway rail infrastructure, encompassing both its management and operation. As a result, the specific choice of a power supply type has a lasting impact, either positive or negative, on the overall performance of a subway system. Consequently, researching power supply for traction presents a considerably more intricate challenge when compared to other railway transportation systems. In this study, the results obtained shed light on the pros and cons of utilizing the 25,000 V / 50 Hz system in comparison with the 1,500 V DC system, with a particular focus on traffic capacity and the efficiency of supplying traction power.

A novel quasi‐hot standby fault‐tolerant control strategy for cascaded H‐bridge rectifier

AbstractCascaded H‐bridge rectifier (CHBR) is widely used in high‐power fields such as STATCOM and power electric traction transformer (PETT) due to its high efficiency and easy expandability. With the high‐reliability operation requirements of power equipment, the fault‐tolerance capability has gradually become a research hotspot nowadays. In order to improve the reliability of the power supply, cascaded H‐bridge rectifier should restore as soon as possible after a fault. However, the traditional fault‐tolerant strategies have a great effect on the grid side and a long recovery time. This paper proposed a quasi‐hot standby fault‐tolerant control strategy. Compared with the traditional strategies, the quasi‐hot standby fault‐tolerant control strategy has a faster recovery speed after the malfunction, and its transient recovery process has less impact on the power grid. Simulation and experiment results show the effectiveness and good recovery performance of the proposed fault‐tolerant control strategy.

Measures for Construction Quality Control of Railway Electric Traction Power Supply Project

Measures for Construction Quality Control of Railway Electric Traction Power Supply Project

Analysis of power losses in catenary wires in AC electric traction power supply systems when installing a device for shunt compensation of reactive power

The research is aimed at studying the catenary wires power losses change by transverse capacitive compensation with considering the movement of trains on the intersubstation zone. Calculations instantaneous and average catenary wires power losses while passing through the intersubstation zone one train and two successive trains are presented in this article. Losses are determined for two cases: when installed compensating device and in its absence. The values of the differences of these losses are founded. The computer simulation in MATLAB-Simulink software was implemented. According to the results of calculations graphs were built, illustrating the change of catenary wires power losses while moving trains on the intersubstation zone when installed compensating device and without it, as well as the differences between the said losses. Average values of catenary wires power losses were determined by integrating these functions and their comparison is carried out. Calculations have shown that by selecting compensating device power by the average reactive power consumed by a train, its intersubstation zone passage with constant current causes the same average catenary wires power losses as in the absence of the compensating device. Increasing the number of trains, simultaneously located on the intersubstation zone at the same compensating device power, entails a reduction of catenary wires power losses with respect to a similar situation without the compensating device, but at the same time reactive power is compensated only partially.

A new methodology to study the pantograph–catenary dynamics in curved railway tracks

The pantograph–catenary system is responsible to provide an uninterrupted energy supply to power electric traction railway vehicles. The analysis of the dynamic behaviour of the catenary and pantograph, as well as its interaction, has been the objective of active research to improve energy collection quality. This work proposes an approach for the fully three-dimensional dynamic analysis of pantograph–catenary interaction in general railway tracks including curves. The catenary model and the trajectory of the pantograph base are defined with respect to the track geometry considering the conventional definition used by the rail industry, i.e. the track curvature, cross-level and vertical position. The pantograph is modelled using a multibody formulation being its base motion constrained to follow the generalised trajectory from the railway vehicle roof. The finite element method is used to model the catenary. A co-simulation procedure is set to establish the coupled dynamics of the two systems. In order to demonstrate the methodology, setup models for curved catenaries, analyse modelling implications and highlight applicability, realistic case studies of pantograph–catenary interaction in high-speed rail operations are presented and discussed. In the process, significant differences are found in the dynamic response of the catenary in curved and straight tracks.

Aspect of load variability in determining power losses in the DC electric traction power supply system

The article discusses issues related to the variability of traction load and its impact on power losses in DC traction substations. Presented is the method of determining the influence of current averaging, which often happens in traction calculations. It has been shown that the averaging of the current has a significant impact on the inaccuracy of calculations or measurements of power and energy in DC traction power systems. The issues of variability of traction load are presented.

Load Sharing and Wayside Battery Storage for Improving AC Railway Network Performance With Generic Model for Capacity Estimation—Part 2

This paper investigates the use of large-scale wayside energy storage to reduce operational costs of ac electric traction power networks. This paper also introduces a method of estimating the battery capacity, based on manufacturer's charging and discharging specifications. The battery model is simple and easy to incorporate into load flow simulation algorithms. The concept and the battery model are validated through a feasibility study within Aurizon's heavy haul electric railway network.

Series Active Filter Design Based on Asymmetric Hybrid Modular Multilevel Converter for Traction System

This paper presents a comparative analysis of a new topology based on an asymmetric hybrid modular multilevel converter (AHMMC) with recently proposed multilevel converter topologies. The analysis is based on various parameters for medium voltage-high power electric traction system. Among recently proposed topologies, few converters have been analysed through simulation results. In addition, the study investigates AHMMC converter which is a cascade arrangement of H-bridge with five-level cascaded converter module (FCCM) in more detail. The key features of the proposed AHMMC includes: reduced switch losses by minimizing the switching frequency as well as the components count, and improved power factor with minimum harmonic distortion. Extensive simulation results and low voltage laboratory prototype validates the working principle of the proposed converter topology. Furthermore, the paper concludes with the comparison factors evaluation of the discussed converter topologies for medium voltage traction applications.

Parameters of DC high-speed circuit-breakers

DC high-speed circuit-breakers (HSCB) are the basic protection to cut off short-circuit and overload currents. People’s and railway infrastructure devices’ safety depend on their reliability and parameters. High-speed circuit-breakers, like any other electrical devices, display several electrical and mechanical characteristic parameters, which in many cases are interconnected. The article features these parameters of DC high-speed circuit-breakers that affect the operation safety of electric traction power supply systems. Moreover, it presents ways of their determination basing on laboratory and operational tests. Furthermore, requirements to be met directly and indirectly by DC high-speed circuit-breakers imposed by legal and standardization documents are described. Correlations between the breakers’ construction and their parameters are outlined. Basing on tests of leading European producers’ breakers, the article presents the impact of parameters of circuit where they are tested as regards HSCB parameters. It also deals with the problem of coordination of short-circuit protection and breaking currents of low values with respect to high-speed circuit-breakers used in Poland.

Test of hybrid power system for electrical vehicles using a lithium-ion battery pack and a reformed methanol fuel cell range extender

This work presents the proof-of-concept of an electric traction power system with a high temperature polymer electrolyte membrane fuel cell range extender, usable for automotive class electrical vehicles. The hybrid system concept examined, consists of a power system where the primary power is delivered by a lithium ion battery pack. In order to increase the run time of the application connected to this battery pack, a high temperature PEM (HTPEM) fuel cell stack acts as an on-board charger able to charge a vehicle during operation as a series hybrid. Because of the high tolerance to carbon monoxide, the HTPEM fuel cell system can efficiently use a liquid methanol/water mixture of 60%/40% by volume, as fuel instead of compressed hydrogen, enabling potentially a higher volumetric energy density.In order to test the performance of such a system, the experimental validation conducted uses a down-sized version of the battery pack used in the Mitsubishi iMiEV, which is subjected to power cycles derived from simulations of the vehicle undergoing multiple New European Drive Cycles (NEDC).

Estimation of indirect CO2 emissions of a hydrogen-powered medium size vehicle for the NEDC cycle

Reduction in greenhouse effect gases emission is a major source of concern nowadays. Internal combustion engines, as the most widely used power generation mean for transportation, represent a large share of such gases, which motivates active research efforts for alternative solutions. In this regard, PEM fuel cells represent a promising prospect and are thoroughly investigated, whether experimentally or through numerical simulation. The present work presents a simulation of the power potential of a PEM fuel cell, which is integrated to the full power electric traction chain of a medium size car. The cell potential is modelled by taking into account the different types of polarization. The driving performances of the vehicle and its hydrogen consumption are evaluated through a simple mathematical model and an application is performed for the New European Driving Cycle (NEDC) standard driving cycle. A preliminary sizing of the proton exchange membrane fuel cell (PEMFC) membrane area for the chosen vehicle is presented, along with that of a hydrogen storage tank for a typical autonomy. The main goal of the simulation is to estimate CO2 indirect emissions due to the production of the needed hydrogen for the cycle via an electrolyser, compared with the case of a gasoline fueled vehicle. This is performed solely on a ‘fuel tank to wheel’ basis in order to have comparable figures. The results indicate that the environmental advantage of hydrogen cars is quite questionable if hydrogen is produced using carbon-based energy sources. Copyright © 2009 John Wiley & Sons, Ltd.

Static Frequency Converter for SEPTA's Wayne Junction Traction Substation

In Philadelphia and its vicinity the Southeastern Pennsylvania Transportation Authority (SEPTA) operates a rapid transit commuter system known as the Regional High Speed Lines. This system has two divisions: Philadelphia Division (formerly Penn Central) and Reading Division (formerly Reading Railroad). In the next few years the electric traction power demand of the Reading Division is expected to increase, and therefore, additional power supply capability is required. The system is supplied at 25 Hz by frequency converters located at Wayne Junction substation, and the power augmentation could be achieved either by tapping power from the Amtrak system or by installing additional frequency converters. For both technical and operational reasons, the converter alternative was preferred; the project associated with provision of the first such unit is described. Two types of equipment were considered: conventional rotary converters and modern thyristor operated static converters. The new equipment was required to be fully compatible with the existing rotaries and backup line, to be available for scheduled operation by November 1984, and to be designed to have a low life cycle cost. A detailed technical and economical analysis indicated that the static frequency converter was the most suitable type, and a specification for its design and manufacture was prepared.