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The frequency domain measurement of radiated emissions from electric railways (from 9 kHz up to 150 kHz) has been omitted from the main part of the relevant standard (lack of repeatability and reproducibility of the results is mentioned as the reason). This paper describes the radiated emissions measured from three electric trains to emphasize the importance of the suitable time length selection (by comparing specific durations of the recorded data: 1 min and 5 min) and the influence of calculation methods of the resultant spectrum in frequency domain (RMS, mean, and Max of spectrum). The results revealed the requirement of unique definitions for pre-, during-, and post-measurement factors so that the repeatable and reproducible results could be achieved. The prerequisites for having less uncertain results are as follows: (1) pure background measurement (in energized and de-energized state of the catenary); (2) precoordinated operation mode, speed, and power of the train during the measurement; (3) precise details of the analysis step. A unique analysis method is required (to be clearly elaborated in the relevant standards) to obtain comparable results between different working groups engaged with the radiated-emission measurements from a train in a frequency range of 9 kHz to 150 kHz. [ABSTRACT FROM AUTHOR]

As electricity demand increases, especially in transportation, renewable sources such as solar energy become more important. The direct integration of solar energy in rail transportation mostly involves utilizing station roofs and track side spaces. This paper proposes a novel approach by proposing the integration of photovoltaic systems directly on the roofs of trains to generate clean electricity and reduce dependence on the main grid. Installing solar photovoltaic (PV) systems on train rooftops can reduce energy costs and emissions and develop a more sustainable and ecological rail transport system. This research focuses on the Milan Cadorna-Saronno railway line, examining the feasibility of installing PV panels onto train rooftops to generate power for the train's internal consumption, including lighting and air conditioning. In addition, it is a solution to reduce the power absorbed by the train from the main supply. Simulations conducted using PVSOL software 2023 (R7) indicate that equipping a train roof with PV panels could supply up to almost 10% of the train's auxiliary power needs, equating to over 600 MWh annually. Implementing the suggested system may also result in a decrease of more than 27 tons of CO2 emissions per year for one train. To optimize the performance of PV systems and maximize power output, the gravitational search algorithm (GSA) as an evolutionary-based method is proposed alongside a DC/DC boost converter and its performance is compared with two other main maximum power point tracking (MPPT) methods of perturb and observe (PO), and incremental conductance (INC). The accuracy of the suggested algorithm was confirmed utilizing MATLAB SIMULINK R2023b, and the results were compared with those of the PO and INC algorithms. The findings indicate that the GSA performs better in terms of accuracy, while the PO and INC algorithms demonstrate greater robustness and dynamic response. [ABSTRACT FROM AUTHOR]

Energy shortage is one of the major concerns in today's world. As a consumer of electrical energy, the electric railway system (ERS), due to trains, stations, and commercial users, intakes an enormous amount of electricity. Increasing greenhouse gases (GHG) and CO2 emissions, in addition, have drawn the regard of world leaders as among the most dangerous threats at present; based on research in this field, the transportation sector contributes significantly to this pollution. Railway Energy Management Systems (REMS) are a modern green solution that not only tackle these problems but also, by implementing REMS, electricity can be sold to the grid market. Researchers have been trying to reduce the daily operational costs of smart railway stations, mitigating power quality issues, considering the traction uncertainties and stochastic behavior of Renewable Energy Resources (RERs) and Energy Storage Systems (ESSs), which has a significant impact on total operational cost. In this context, the first main objective of this article is to take a comprehensive review of the literature on REMS and examine closely all the works that have been carried out in this area, and also the REMS architecture and configurations are clarified as well. The secondary objective of this article is to analyze both traditional and modern methods utilized in REMS and conduct a thorough comparison of them. In order to provide a comprehensive analysis in this field, over 120 publications have been compiled, listed, and categorized. The study highlights the potential of leveraging RERs for cost reduction and sustainability. Evaluating factors including speed, simplicity, efficiency, accuracy, and ability to handle stochastic behavior and constraints, the strengths and limitations of each optimization method are elucidated. [ABSTRACT FROM AUTHOR]

Nowadays, nations are moving toward the electrification of the transportation section, and the widespread development of EV charging stations and their infrastructures supplied by the grid would strain the power grid and lead to overload issues in the network. To address this challenge, this paper presents a method for utilizing the braking energy of trains in railway stations to charge EVs located in strategic areas like park-and-ride regions close to railway stations improving energy efficiency and preventing grid overload. To validate the feasibility of the proposed system, a metro substation in Milan city is considered as a case study located in outskirts of the city and contains large number of parking space for vehicles. Three different scenarios are evaluated including DC fast charging station, AC low charging station and collaborative hybrid energy storage based AC charging station as EV charging station type. The results are studied for different EV population number, charging rate and the contractual power grid. Meanwhile, the possibility of proposed system in participating as V2G technology and taking advantage of the EV's batteries to provide ancillary support to accelerating trains is investigated regarding peak shaving objective. The results indicated that the suggested interconnected system operates effectively when a significant quantity of EVs are parked at the station. However, the results revealed that the performance of the proposed system is notably influenced by other factors and a limited number of EVs during the early morning and late evening periods. Overall, this study confirms the feasibility of energy transfer between two types of transportation means in intermodal areas. [ABSTRACT FROM AUTHOR]

Featured Application: This work belongs to the field of railway electrification engineering. The results have certain reference value for reducing the rail potential to ensure the safe operation of electrified railways. For high-speed railways, the rail potential, i.e., the electrical potential difference between the rail and the ground, can be considerably higher than that of conventional speed electric railways and become a safety risk to the signaling devices along the line, because of the large train currents and the high rail–ground leakage resistance. Proper countermeasures must be taken to decrease the rail potential to a safe level. This paper first provides a brief theoretical discussion of the principles of how the rail potential arises and how to suppress it. Then, a program, TRANAS, that was developed for traction network analysis is used to calculate the effects of various suppression countermeasures for an AT feeding system, which include cross-bonding of tracks, inserting CPWs, grounding using catenary masts, laying bare buried ground wires and connecting to dedicated grounding grids, which are evaluated based on the calculation results. The use of buried ground wires shows good prospects for solving electric safety problems in an integrated way, which is investigated in detail. The fact that GWs can suppress the rail potential is attributed to the decrease in the leakage resistance of the return circuit, meaning a relatively small cross-section will be enough for them. [ABSTRACT FROM AUTHOR]

Copyright of Railway Standard Design is the property of Railway Standard Design Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For high-speed railways, the rail potential, i.e., the electrical potential difference between the rail and the ground, can be considerably higher than that of conventional speed electric railways and become a safety risk to the signaling devices along the line, because of the large train currents and the high rail–ground leakage resistance. Proper countermeasures must be taken to decrease the rail potential to a safe level. This paper first provides a brief theoretical discussion of the principles of how the rail potential arises and how to suppress it. Then, a program, TRANAS, that was developed for traction network analysis is used to calculate the effects of various suppression countermeasures for an AT feeding system, which include cross-bonding of tracks, inserting CPWs, grounding using catenary masts, laying bare buried ground wires and connecting to dedicated grounding grids, which are evaluated based on the calculation results. The use of buried ground wires shows good prospects for solving electric safety problems in an integrated way, which is investigated in detail. The fact that GWs can suppress the rail potential is attributed to the decrease in the leakage resistance of the return circuit, meaning a relatively small cross-section will be enough for them.

• Identify OCR wave speed through experimental tests and simulation. • Wave speed resonance is observed as train speed nears wave speed. • Key OCR parameters affecting wave speeds are identified. The overhead conductor rail system (OCR) is an important current-transmitting structure for electric trains in tunnels. As the train speed increases, the wave propagation behaviour in the OCR plays an ever-increasingly important role in affecting the current collection quality. This paper is the first endeavour to numerically and experimentally explore wave behaviours in the OCR. With the help of a finite element model, the spatial propagation and frequency-domain characteristics of the wave propagation are investigated. Based on the time-space distribution of waves, the wave speed of the OCR is identified. Subsequently, a full-scale experimental test is conducted to identify a real-life OCR's wave speed for the first time. The relative error between the simulated and experimental speed is only 5.50 %, highlighting the effectiveness of the presented model. Then, the influence of wave propagation on the interaction performance of pantograph-OCR is analysed. A significant reduction of the interaction performance is observed when the train speed approaches the wave speed. Through sensitivity analysis, the bending stiffness, the linear density, and the span length are identified as sensitive parameters affecting the wave speed. [ABSTRACT FROM AUTHOR]

To better recycle the regenerative braking energy (RBE) and improve the power quality (PQ) in asymmetric AC-fed railways, a novel multiplex back-to-back energy storage system (MB2ESS) with fault-tolerance ability is proposed, where individual subsystems not only independently operate as self-controlled entities, but also collaborate with adjacent subsystems to resist system disturbances and local faults. On this basis, a hierarchical optimization control method with three-layer structure is designed for the flexible and effective operation of MB2ESS, including the global optimization layer based on finite state machine, the regional decision-making layer with event-driven distributed coordination controller, and the local execution layer via multi-converter autonomous control. It can be used to seamlessly switch different operation modes, coordinately manage the multidirectional transmission of RBE, dynamically control PQ optimization compensation, and rapidly perform fault response behaviors. Subsequently, through typical scenarios, comparative study, and field case of a traction substation in Beijing-Shanghai Railway, the feasibility and effectiveness of proposed scheme are verified. The engineering capability assessment results also show that this scheme can effectively make up for the structure and function deficiencies of conventional railway energy storage systems, which has well adaptability and application potential. [ABSTRACT FROM AUTHOR]

The regional press played a crucial role in the turbulent atmosphere of the late 19th century. Moreover, it was the only medium of mass communication through which the public could be informed about the latest events in the town of Olomouc and its surroundings. The key periodicals of the Olomouc environment include the Czech newspapers Olomoucký Pozor and Našinec and the German Die Neue Zeit and Mährisches Tagblatt, which slowly became a national battleground of the local population. These newspapers were pillars of the Olomouc journalistic scene, reflecting the tense mood of the ethnically divided city, usually according to the political or national focus of the particular paper. Local periodicals thus portrayed everyday events from the point of view of individual national groups, which through their newspapers tried to discredit each other, and illustrated individual events adequately to their ideological stance. The pages of the press frequently included purposely formulated articles based on the long-term tendencies and objectives of the two nationalities. As tensions increased, events that were at first glance quite apolitical became the subject of controversy. Even such an achievement of modern society as the introduction of fully electrified public transport in the city soon turned into a political and national topic, which for some time filled the front pages of both Czech and German Olomouc periodicals. [ABSTRACT FROM AUTHOR]

High-order harmonic resonance is a key issue in the traction power supply systems (TPSS) of electric railways for safe operation. The effective evaluation of the resonance frequency is critical for taking measures to suppress harmonic resonance. In this paper, the influence of the distributed parameters of traction networks on resonance frequencies based on accurate calculation is proposed. The quantitative assessments of the distributed impedance and admittance are investigated. Furthermore, the theoretical calculation is directly verified using field tests at a high voltage level equal to 25 kV. The results show that the resonance frequencies of the TPSS are mainly affected by the distributed parameters, including the self-admittance and self-impedance of the contact wires, and the self-admittance of the positive feeders. In addition, the admittance connected in parallel has a greater effect than the series-connected impedance. The calculation method is also adapted to TPSS connected to renewable energy. [ABSTRACT FROM AUTHOR]

Copyright of Railway Standard Design is the property of Railway Standard Design Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To solve the three-phase unbalance and reactive power problems in the electric railway power supply system, this paper proposes a Scott transformer based hypotenuse hybrid traction power system (Scott-HHPS). Compared with other co-phase traction power supply systems, the Scott-HHPS could achieve the same compensation objective with smaller active compensation capacity. The paper analyzes the basic principle and makes a comparison between the Scott-HHPS and typical co-phase power supply system. The mathematical relationships among the load current, power factor and capacity demand in condition of power factor variation and regenerative braking are analyzed. In order to further reduce the compensation capacity of the Scott-HHPS, the partial compensation strategy in respect to the index of power factor and unbalance is proposed. Besides, an instantaneous current detection method based on the theorem of conservation of power is adopted to simplify the control algorithms. Simulations and experiments are both constructed and the results demonstrate that the Scott-HHPS can effectively improve the power quality in the electric railway power supply system.

The inherent resonant frequency of a traction power supply system (TPSS) needs to be accurately identified in order to provide crucial information for resonance suppression, safe operation, and system optimization of electrified railways. In this paper, implementation of experiments was carried out in actual railway systems to evaluate the inherent harmonic resonances of the TPSS. The field tests were based on a harmonic generator (HG) constructed with cascaded H-bridge converters (CHBCs). Compared to other experimental setups, the field tests of this paper, which were performed in the 25kV practical system, can provide straightforward results in a wide frequency range up to 5000 Hz. Such a wide frequency range is necessary for assessing and taking effective measures to address the harmonic resonance problem. The results of this paper will supply valuable data for the modeling of TPSSs and the stability analysis of train converters contributing to improvement of the power quality of electric railways.

Measurements of (inter)harmonic impedances of the traction power supply system (TPSS) play important roles in the validation of TPSS modeling, suppression of resonances, stability analysis of locomotives converters, etc. A harmonic generator (HG) and its construction are proposed in this article to directly measure the impedance of TPSSs. Compared to other experimental setups, the HG can emit a fully controlled single-tone (inter)harmonic current at the high voltage level in a wide frequency range, i.e., at least covering 150–3750 Hz. Field tests have been carried out in the actual 2 × 25 kV railway considering the influence of locations and lengths that are scarcely presented in existing literatures. Both the implementation process and test waveforms have verified the effectiveness and feasibility of the HG. The test results, which denotes that locations do not change the resonant frequency while railway lengths will shift resonant frequencies distinctly, can be a basis for developing techniques aimed to improve the power quality. [ABSTRACT FROM AUTHOR]

Many new types of locomotives are put to use in electric railway systems, resulting in instability problems such as high-order harmonic resonance occurring as a consequence of the interaction between the electrical locomotive (including electrical multiple units) and the traction network. In order to investigate this problem, this paper adopts the impedance-based approach to analyze the stability properties of the system interaction. The detailed impedance of the traction network is obtained by taking its distributed parameters into account. Then the locomotive converter with single-phase transient current control algorithm (TCCA), which can represent the locomotive when performing the impedance-based stability analysis, is modeled as the dq-frame impedance by single-phase dq decomposition. By plotting bode diagrams of the impedance for the traction network and the locomotive separately, and calculating the phase margin at the intersection point of the magnitude of the two impedances, the stability of the locomotive-network system is evaluated and thus the high-order harmonic resonance can be predicted. Moreover, a time-domain model of locomotive-network systems is established in this paper, which can reproduce the high-order harmonic resonance in the time domain as a first validation step of the analysis. Finally, a field test in a traction substation of the Beijing-Harbin Railway is carried out to finally validate the effectiveness of the proposed method. The stability analysis method in this paper is simple and effective without the need for a complex calculation of some norms or Eigenvalues. As a result, the high-order harmonic resonance can be predicted before a new type of locomotive is put into use.

The wide adoption of a new type of electric trains results in multiple frequency-scale instability problems, such as low-frequency oscillation (LFO), harmonic resonance, and harmonic instability. Among them, LFO has been commonly reported at electric railway depots with multiple-energized electric trains around the whole world, thus attracting widespread research attention. LFOs cause adverse effects on the system stability and protection infrastructure of both the traction network and electric trains. This article presents a comprehensive review of LFOs that consider both academic theoretical analysis and industrial engineering requirements. A unified mathematical model of the traction network and electric train is derived with a view to revealing the mechanism and factors that induce LFOs when these two systems interact. The article also draws deep insights from results of experimental measurements and industrial mitigation schemes already implemented in Chinese railway systems. A variety of mitigation techniques and recommendations based on theoretical principles and practical constraints are presented. [ABSTRACT FROM AUTHOR]

An electric railway vehicle is supplied with electricity by an OCL (Overhead Contact Line) through the contact strip of its pantograph. This transmitted electricity is then used to power the electrical equipment of the railway vehicle. This contact strip wears out due to contact with the OCL. In particular, deformations due to chipping and material loss occur because of friction with the fittings on the OCL. These deformations on the contact strip affect its power transmission quality because of contact loss with the OCL. However, it is difficult to monitor the contact strip during operation and judge its condition in order to implement accident prevention measures. Thus, in this study, we developed a contact strip monitoring method based on image processing for inspection. The proposed method measures the deformation in the contact strip based on an algorithm that determines the wear on the deformed contact strip using deep learning and image processing. The image of the contact strip is acquired by installing a camera and laser to capture the pantograph as it passes the setup. The proposed algorithm is able to determine the wear size by extracting the edges of the laser line using deep learning and estimating the fitted line of the deformations based on the least squares method. [ABSTRACT FROM AUTHOR]

The identification of risks linked to electromagnetic compatibility (EMC) in the electric railway is a major concern in identifying EMC problems and analyzing the unintentional various external disturbing sources as well as the probability of occurrence of interference, the level of interference along the railway system. The purpose of this analysis is to determine the electromagnetic interaction coupling generated by the high voltage (HV) lines located along the railway line by analyzing the voltage induced in the signaling transmission cables such as the european rail traffic management system/european train control system (ERTMS/ETCS) through the multi-conductor transmission line (MTL) theory which may have an impact on the transmitting information. Dubanton method and approximate calculation will be applied and simulated through COMSOL Multiphysics tool in order to analyze if the protection distance and coupling conditions are respected by the railway standards. [ABSTRACT FROM AUTHOR]

Certain applications of power electronics for railway vehicle traction systems and fixed installations are reviewed and future possibilities considering technical and social trends around railway industry are mentioned in this paper. First of all, some particularities of railway load and traction power supply system are summarized as problems to be solved by power electronics technologies. Such technologies for fixed installations and vehicle traction systems are presented and future possibilities for higher performance, minimization, and improved resilience of railway system are pointed out. © 2020 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

Harmonic resonances in traction power supply systems (TPSSs) have attracted great attention due to their potentially destructive impact on the safe and stable operation of railways. Based on operation data acquired from Chinese railways, this paper presents a comprehensive review of this issue considering both academic and engineering requirements. Analyzing actual incidents, the general patterns and effects of TPSS resonances are derived. The relation between the TPSS and the locomotive is illustrated by circuit models. Relevant methods for modeling locomotives and TPSSs are discussed. Both advanced resonance analysis methods giving general influence factors and a simplified resonance analysis explaining resonance features in a practical manner are discussed. Multiple ground-based and on-board solutions for resonance elimination are presented. At last, preidentifying resonances in actual systems is investigated for addressing the open topic of resonance prevention. [ABSTRACT FROM AUTHOR]

Abstract In 2006, the first Lithium-ion battery in Japan was installed in traction power supply system by the West Japan Railway Company and now more than 20 energy storage systems have already been installed in traction power supply system in Japan. In this article, the recent Japanese trends of regenerative energy utilization are summarized not only in DC railway but also in AC railway. We, East Japan Railway Company, have installed three energy storage systems for DC railway and one railway static power conditioner (RPC), not energy storage system, for AC railway for regenerative energy utilization. The effects of these systems are also shown quantitatively in this paper.

Electromagnetic Compatibility (EMC) disturbance produced by power transmission lines (TL) near the railway installation can generate electromagnetic coupling between the high voltage power line and the signalization cables. In this paper, the voltage induced is analyzed in the signaling system cables located along the high-speed line due to the proximity of an extra high voltage power line. An approximate and Dubanton method have been used in order to have a correct result of the mutual inductance. The proposed technique is compared with the sensitivity threshold of the railway devices in order to check if the presence near high voltage lines will not interfere with the normal operation of the railway equipment. The performance of the Electromagnetic radiation is presented through simulation results. [ABSTRACT FROM AUTHOR]

Assuming that a wireless sensor is installed to determine the state of facilities along a railway, we verified the possibility of applying environmental energy as a power source for the sensor. We measured different types of environmental energy and calculated the potential electric energy that can be generated from each type. The application of different methods of power generation to a wireless sensor power supply was studied on the basis of the calculated amount of power generated. As a result, we found that solar power generation has sufficient potential for this purpose. We also found that power generation methods such as vibration power generation and magnetic field power generation can be applied according to the installation location, the frequency of measurement/communication, and the data collection method used. [ABSTRACT FROM AUTHOR]

Highlights • An accurate SSM based bilinear modeling (BM) method for dynamic performance and control of RPFC. • Discrete-time model of RPFC and it's control based on a modified model predictive control method. • The Real-time FPGA based implementation of RPFC using the real features and behavior of ERS. • Dual-loop dq frame based reference current extraction to reduce the network disturbance effects. • Stability analysis of RPFC using Lyapunov analysis for nonlinear behavior of RPFC. Abstract Railway power flow controllers (RPFCs) are known as a power electronics based full-fledged compensator in the field of electric railway systems (ERSs). They have attracted experts attention over the last years due to their outstanding performance in dealing with power quality (PQ) problems. The complexity, randomness and uncertainty characteristic of ERS and traction loads have led the control of RPFC to be difficult. In this paper, a precise modeling method based on space-state model (SSM) and dynamic switching pattern is presented. Applying the extracted equivalent model and mathematical equations, a modified model predictive control (MMPC) method is proposed to improve the compensation and dynamic performance of RPFC. To eliminate the low frequency oscillation (LFO) and other external disturbance effects, a dual-loop modified d-q frame control is implemented with frequency locked capability. Precise simulations have been provided to verify the modeling and proposed control procedure performance. Moreover, a real-time laboratory setup based on RT-LAB and Opal-RT is provided to confirm the simulation results and theoretical analysis according to the desired specifications of the real ERS. [ABSTRACT FROM AUTHOR]

Harmonic overvoltage in electric railway traction networks can pose a serious threat to the safe and stable operation of the traction power supply system (TPSS). Existing studies aim at improving the control damping of grid-connected converters, neglecting the impedance frequency characteristics (IFCs) of the actual TPSS. The applicable frequency range of these studies is relatively low, usually no more than half of the switching frequency, and there is a large gap with the actual traction network harmonic overvoltage frequency range of 750 Hz–3750 Hz. In this paper, first, the IFCs of the actual TPSS in the wide frequency range of 150 Hz–5000 Hz are obtained through field tests, and the resonant frequency distribution characteristics of TPSS are analyzed. After that, the aliasing effect of the sampling process and the sideband effect of the modulation process of the digital control of the grid-connected converter are considered. Based on the relative relationships among the inherent resonant frequency of the TPSS, sampling frequency and switching frequency, an impedance matching analysis method is proposed for the wide frequency range of the vehicle–grid coupling system. By this method, the sampling frequency and switching frequency can be decoupled, and the harmonic overvoltage of traction network in the frequency range of two times switching frequency and above can be directly estimated. Finally, the method proposed in this paper is validated by the comparative simulation analysis of seven different cases.

An electric railway vehicle is supplied with electricity by an OCL (Overhead Contact Line) through the contact strip of its pantograph. This transmitted electricity is then used to power the electrical equipment of the railway vehicle. This contact strip wears out due to contact with the OCL. In particular, deformations due to chipping and material loss occur because of friction with the fittings on the OCL. These deformations on the contact strip affect its power transmission quality because of contact loss with the OCL. However, it is difficult to monitor the contact strip during operation and judge its condition in order to implement accident prevention measures. Thus, in this study, we developed a contact strip monitoring method based on image processing for inspection. The proposed method measures the deformation in the contact strip based on an algorithm that determines the wear on the deformed contact strip using deep learning and image processing. The image of the contact strip is acquired by installing a camera and laser to capture the pantograph as it passes the setup. The proposed algorithm is able to determine the wear size by extracting the edges of the laser line using deep learning and estimating the fitted line of the deformations based on the least squares method.

Highlights • Smart-grid based based electrical railway network through the use of a Yd transformer with multiple phase connections. • Intelligent control method for RPFC implementing the central Steinmetz-based intelligent (SICS) control system. • Calculating the optimal amounts of active and reactive powers transferring in different phases. • The SICS proposed method performance verification by the FPGA-based real-time laboratory setup results. • Significantly reduction of RPFC converter's power rating and installation costs. Abstract Adoption of smart grids has led to significant opportunities in the optimal operation of systems and energy consumption in utility grid loads. Among the various grid loads, electrical railway networks (ERNs) are known as one of the most important and critical end users due to their high power consumption. Energy management and power quality domination in such a network are already concerns of researchers. The railway power flow controller (RPFC) is a commonly used system to manage the optimal energy consumption and power quality problems of ERNs. This paper presents a comprehensive study of an RPFC power rating and a new compensation strategy with the objective of reducing the installed capacity in several consecutive traction power substations (TPSs). This technique is implemented through the use of a Yd transformer with multiple phase connections and the central Steinmetz-based intelligent control system (SICS). Through coordination with the internal control systems, the optimal mode of the active and reactive powers transferring in different phases is calculated by the central SICs and applied to each TPS. The proposed control strategy substantially diminishes the RPFC converter's power rating and installation costs. A real-time laboratory platform for the smart-grid based proposed method is provided using Opal-RT emulator to confirm the theoretical analysis with the desired precision representing the real power system behavior. [ABSTRACT FROM AUTHOR]

Current distribution in the electric traction system is an important factor regarding the electromagnetic influences on the surrounding metallic structures. The current value directly determines the magnetic field and consequently coupling of the systems. A single rail traction system can be equipped with return conductor. The return current flowing through return conductor has an opposite direction of supply current and decreases coupling and interferences. This paper presents the AC current distribution for both designs, with and without return conductor. Also, the soil resistivity is varied. The higher the soil resistivity, the higher is the amount of return current in rails and return conductor. The different construction of return conductor results in different impedance of return path. The relations of return conductor construction and return current value are analysed. Lightning can directly impact different traction system elements such as contact network, tower or return wire. The current distributions in several cases of lightning impacting different traction system elements are presented. [ABSTRACT FROM AUTHOR]

Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

SUMMARY Hybrid power source three-level inverter is proposed as a main circuit system with energy storage device for increasing regenerative power. This paper proposes a charge and discharge control method to utilize the regenerated energy. The proposed method is verified by experimental tests with a scaled-down model and numerical simulation. [ABSTRACT FROM AUTHOR]

Improving the traction performance of the electric railway vehicles requires an analysis to reduce their aerodynamic resistance. These vehicles cannot be set in motion without an external power source, which demonstrates that the supply system is a key-element to their operation. The power source is located on the rooftop which basically results in an increase of their aerodynamic resistance. The present study discusses the aerodynamic resistance of the electric railway equipment such as pantographs, automatic circuit breaker, insulators, etc. The analyze is based on the equipment installed on the electric locomotive LE 060 EA of 5100 kW which is operational in Romania, emphasizing the pantographs role in capturing of electricity.

In 2006, the first Lithium-ion battery in Japan was installed in traction power supply system by the West Japan Railway Company and now more than 20 energy storage systems have already been installed in traction power supply system in Japan. In this article, the recent Japanese trends of regenerative energy utilization are summarized not only in DC railway but also in AC railway. We, East Japan Railway Company, have installed three energy storage systems for DC railway and one railway static power conditioner (RPC), not energy storage system, for AC railway for regenerative energy utilization. The effects of these systems are also shown quantitatively in this paper. [ABSTRACT FROM AUTHOR]

In this paper different type of traction transformer from the transformer family is considered in the traction system. Mainly in traction power supply systems of electric railway have many issues like voltage unbalance, high active and reactive power, harmonics, etc. This problem can be solved by implementing a co phase system with a suitable traction transformer. The traction transformers that are discussed are YNvd transformer, Impedance matching transformer and Leblanc transformer. So different traction transformers are modelled and analysed using MATLAB. In this paper Active power compensator is also modelled and discussed. The simulation results of co phase traction system using different type of traction transformer are compared for better performance. Modelling and simulation is done using MATLAB R20010a software. [ABSTRACT FROM AUTHOR]

This article is a brief biography of the American inventor Thomas Alva Edison (1847-1931) with special reference to his involvement with X-rays. His work involved the invention of the phonograph, the design of an electric power plant, an electric railway, the incandescent light bulb, a fluoroscope, and motion pictures. Selected quotations attributed to Edison complete this biography of this remarkable inventor who took out a total of 1,093 American patents. [ABSTRACT FROM AUTHOR]

Three-phase induction motors are widely used in electric traction systems. The impacts of the traction vehicles equipped with three-phase induction motors on power quality are much different from the impacts of vehicles with DC traction motors. In this paper, the effects of the traction vehicle operation with three-phase induction motors on power quality in a 110 kV transmission network are investigated. The electric traction system 25 kV, 50 Hz and the traction vehicle with three-phase induction motors were modeled including AC/DC rectifier and DC/AC inverter based on IGBT technology. The parameters of those power electronic elements directly determine the current and voltage waveforms, and consequently power quality parameters. Measurements and calculations of power quality parameters were presented. Three operation modes of traction vehicle were considered including acceleration, constant drive and regenerative breaking. During the test drives, the values of total harmonic distortion, unbalance, flicker and power factor were obtained. [ABSTRACT FROM AUTHOR]

Simulation tools allow changes in electrical network, timetabling, and train speed profiles, which is fundamental for the planning and development of electric railways. When simulating electric railways, it may be challenging to adequately represent their nonlinear characteristics resulting from the rectifier substations, overvoltage protection circuits, and the continuous changes of the load according to the train position. The power exchange between trains and the change of the rail resistance between them require high temporal resolution and thus results in high computational complexity. Given these goals and challenges, the main objective of this work is to develop a sufficiently simple, fast to simulate, yet accurate, simulation method based on real-world assumptions. Further, the simulation method should be extendable to energy storage systems (ESSs) and control to allow designing control methods for energy management to maximise the energy efficiency of electric railways. This article describes the development of a framework for modelling the power flow within an electric rail network referenced to a case study example. In this article, a test scenario is presented comprising of eight trains running on a double rail track in order to verify the model against expected observations. The simulation model includes two DC traction substations separated by 2 km and three passenger stations separated by 1 km. The model operation requirements and parameters are based on the Yizhuang Line in Beijing Metro. The simulation methodology developed for this work differs from other methods reported in pertinent literature as it facilitates modifications to the model by avoiding the common approach of forming iterative methods for solving the power flow. The proposed test scenario allows the model to be verified for accuracy. The verification is accomplished via different methods and the obtained results confirm that the proposed modelling approach is accurate as the error between the supplied and consumed energy is only 0.11%. [ABSTRACT FROM AUTHOR]

The line-side converter, which can represent an ac–dc–ac drive electric vehicle when analyzing the low-frequency oscillation in electric railways, is modeled in dq frame with the proposed single-phase dq-decomposition method. With this model, an underdamped mechanism of the vehicle-grid interaction is confirmed. Besides, a low-frequency stability prediction approach is presented, based on the dominant-pole analysis and verified by the simulation and the testing result. The proposed modeling method and prediction approach benefit in three aspects: It is more convenient to rebuild the model with a change of either the line-side converter controller or the system condition, much quicker to predict the low-frequency instability and more explicit to guide the modification of the controller software to damp the low-frequency oscillations. [ABSTRACT FROM AUTHOR]