scholarly journals Modeling of Electrified Transportation Systems Featuring Multiple Vehicles and Complex Power Supply Layout

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8196
Author(s):  
Aleksander Jakubowski ◽  
Leszek Jarzebowicz ◽  
Mikołaj Bartłomiejczyk ◽  
Jacek Skibicki ◽  
Slawomir Judek ◽  
...  
Keyword(s):  
Power Supply ◽  
Power Transmission ◽  
Computation Time ◽  
Transportation Systems ◽  
Urban Systems ◽  
Modeling Methodology ◽  
Novel Approach ◽  
Multiple Vehicles ◽  
Traction Power Supply ◽  
The Impact

The paper proposes a novel approach to modeling electrified transportation systems. The proposed solution reflects the mechanical dynamics of vehicles as well as the distribution and losses of electric supply. Moreover, energy conversion losses between the mechanical and electrical subsystems and their bilateral influences are included. Such a complete model makes it possible to replicate, e.g., the impact of voltage drops on vehicle acceleration or the necessity of partial disposal of regenerative braking energy due to temporary lack of power transmission capability. The modeling methodology uses a flexible twin data-bus structure, which poses no limitation on the number of vehicles and enables modeling complex traction power supply structures. The proposed solution is suitable for various electrified transportation systems including suburban and urban systems. The modeling methodology is applicable i.a. to Matlab/Simulink, which makes it broadly available and customizable, and provides short computation time. The applicability and accuracy of the method were verified by comparing simulation and measurement results on an exemplary trolleybus system operating in Pilsen, Czech Republic. Simulation of daily operation of an area including four supply sections and maximal simultaneous number of nine vehicles showed a good conformance with the measured data, with the difference in the total consumed energy not exceeding 5%.

scholarly journals Electromagnetic fields related to high speed transportation systems

2018 ◽  
Vol 4 (2) ◽  
pp. 152-166 ◽  
Author(s):  
Roland Kircher ◽  
Johannes Klühspies ◽  
Ryszard Palka ◽  
Eckert Fritz ◽  
Kenji Eiler ◽  
...  
Keyword(s):  
Energy Balance ◽  
Electromagnetic Fields ◽  
Health Risks ◽  
Power Supply ◽  
High Speed ◽  
Transportation Systems ◽  
Geometrical Parameters ◽  
Potential Health ◽  
Maglev System ◽  
The Impact

Issue: The potential health risks on passengers and the environment related to electromagnetic fields caused by the operation of electrically driven high speed transportation systems has become a major issue. Especially the magnetic flux density or induction can generate physiological effects in body tissues. Aim: In this paper, we compare calculated and experimental values of electromagnetic fields in rail-wheel systems such as ICE with the Maglev-systems Transrapid and the JR Maglev-system, based on available data. Method: To estimate the impact on passengers, the field contributions generated by the power supply system as well as by the drive and suspension systems are taken into account. For the comparison, the peak values of the electromagnetic fields have been considered. Results: The results show, that there are no health risks from the electric fields. Regarding the magnetic induction, the calculated the peak values remain well below the limits given by national regulations. In the case of the Transrapid and the JR Maglev system, the measured peak values in the environment and inside the vehicle depend on the levitation and the guidance technology and the geometrical parameters. The JR Maglev system requires effective magnetic shielding measures which are connected with heavy materials. Since such materials may have a negative influence on the energy balance and the economics of operation, R&D efforts are focusing on the optimization of materials and the structure of shields. Conclusion: In high speed transportation systems there are no potential risks from electrical fields. Regarding magnetic fields, the induction generated by the power supply and the drive system remain well below the frequency dependent limits. The situation is different for magnetic levitation systems, depending on the suspension and guidance technology. Especially the JR Maglev requires effective shielding measures. The shielding materials may have a negative impact on the energy balance.

scholarly journals Multiplex networks in metropolitan areas: generic features and local effects

2015 ◽  
Vol 12 (111) ◽  
pp. 20150651 ◽  
Author(s):  
Emanuele Strano ◽  
Saray Shai ◽  
Simon Dobson ◽  
Marc Barthelemy
Keyword(s):  
New York ◽  
Metropolitan Areas ◽  
Transportation Systems ◽  
Urban Systems ◽  
Street Network ◽  
Multilayer Network ◽  
Large Cities ◽  
Planning Decisions ◽  
Negative Side Effects ◽  
The Impact

Most large cities are spanned by more than one transportation system. These different modes of transport have usually been studied separately: it is however important to understand the impact on urban systems of coupling different modes and we report in this paper an empirical analysis of the coupling between the street network and the subway for the two large metropolitan areas of London and New York. We observe a similar behaviour for network quantities related to quickest paths suggesting the existence of generic mechanisms operating beyond the local peculiarities of the specific cities studied. An analysis of the betweenness centrality distribution shows that the introduction of underground networks operate as a decentralizing force creating congestion in places located at the end of underground lines. Also, we find that increasing the speed of subways is not always beneficial and may lead to unwanted uneven spatial distributions of accessibility. In fact, for London—but not for New York—there is an optimal subway speed in terms of global congestion. These results show that it is crucial to consider the full, multimodal, multilayer network aspects of transportation systems in order to understand the behaviour of cities and to avoid possible negative side-effects of urban planning decisions.

scholarly journals Allocation of 0.4 kV PTL Sectionalizing Units under Criteria of Sensitivity Limits and Power Supply Reliability

2021 ◽  
Vol 11 (24) ◽  
pp. 11608
Author(s):  
Alina Vinogradova ◽  
Alexander Vinogradov ◽  
Vadim Bolshev ◽  
Andrey Izmailov ◽  
Alexey Dorokhov ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Power Supply ◽  
Power Transmission ◽  
Short Circuit ◽  
Reducing Power ◽  
Power Transmission Lines ◽  
Electrical Networks ◽  
The Cost ◽  
The Impact ◽  
Supply Reliability

Sectionalizing 0.4 kV power transmission lines (PTL) improves power supply reliability and reduces electricity undersupply through the prevention of energy disconnection of consumers in the event of a short circuit in the power line behind the sectionalizing unit (SU). This research examines the impact of sectionalizing on power supply reliability and reviews the literature on sectionalizing unit allocation strategies in electrical networks. This paper describes the experience of the use of sectionalizing units with listing strengths and weaknesses of adopted technical solutions and describes the new structure of sectionalizing units. A new methodology is proposed, whereby there are two criteria for allocating SU in 0.4 kV power transmission lines. The first criterion is the sensitivity limits against single-phase short circuits used for calculating the maximum distance at which SU can be installed. The second criterion is power supply reliability improvement, evaluating the cost-effectiveness of installing sectionalizing equipment by reducing power supply outage time. The established methodology was put to the test on an actual electrical system (Mezenka village, Orel area, Russia), which demonstrated that the installation of a sectionalizing unit paid off.

scholarly journals Communication technology of crisis management in conditions of mass disruption of power supply in the period of «ice rains»

2020 ◽  
Vol 13 (3) ◽  
pp. 197-206
Author(s):  
R. R. Zizayeva ◽  
A. Ye. Uzhanov
Keyword(s):  
Crisis Management ◽  
Power Supply ◽  
Power Transmission ◽  
Natural Factor ◽  
Power Company ◽  
Geographical Scale ◽  
Communication Work ◽  
Information And Communication ◽  
Restoration Work ◽  
The Impact

A technology is presented for crisis management and handing reputation and image consequences for the JSC IDGC Holding power company in connection with the man-caused accident of 2010 – 2011 (the most extended and painful for power supply of the Russian population), which occurred under the impact of a natural factor in the form of "ice rain" on power transmission engineering systems. Based on the results of a comprehensive analysis of the PR situation, the nature of the crisis has been revealed, which, in terms of its geographical scale, the extent of mass outages of consumers from power supply sources, and the scope of repair and restoration work, was unprecedented in the Russian Federation over the previous 30 year period. It is estimated that the restoration of performance of the electricity network infrastructure took three months (January through March of 2011) and involved huge information and communication resources, mobilization of staff and additional pool of specialists with a total number of more than 3 thousand people. The research methodology is consistent with conventional boundaries, with a full set of approaches typical of research of a systemic social phenomenon, such as the company's communication activities and in interfacing with the essential characteristics of business reputation. As a hypothesis, a convincing and proven assumption has been put forward that mass disruptions of power supply under the influence of natural elements can become a decisive factor for a fundamental shift in public opinion in favor of the power grid company, if the crisis PR program is based on creative ideas for the involvement of journalists, experts, environmentalists, deputies, other stakeholders and opinion leaders in the process of emergency response. By way of example of analysis of communication work in conditions of mass power supply disruption in the zone of responsibility of JSC IDGC Holding, a system of recommendations is suggested for the PR service activities during the crisis period.

Improvement of External and Traction Power Supply System’s Efficiency by Normalizing the Schemes

2021 ◽  
Vol 64 (4-5) ◽  
pp. 72-78
Author(s):  
Nikolai Grigoriev ◽  
◽  
Ivan Ignatenko ◽  
Vladimir Kovalev ◽  
Polina Trofimovich ◽  
...  
Keyword(s):  
Transmission Line ◽  
Power Supply ◽  
Power Transmission ◽  
Power Transmission Line ◽  
Electric Transmission ◽  
Traction Network ◽  
Traction Substations ◽  
Traction Power Supply ◽  
Supply Systems ◽  
Traction Power

The article deals with improvement off the efficiency of external and traction power supply systems using for example indicators of traction substations for a real electric transmission line segment of a traction network of 25 kV. The analysis of the functioning of a real section of electrified railways with traction substations, two of which are connected according to the "feeding" scheme is providing in the article. The currents in the wind-ings of traction transformers are calculate for these substations. The proportion of the currents values of the most loaded winding to the two less loaded is 2: 1. The coefficient asymmetry of currents of transformer wind-ings operating on existing traction substations is equal to 1. The results prove a significant currents asymmetry of transformers windings and phases of electric transmission lines which leads to an increasing voltage unbal-ance. New schemes for connecting traction substations for the considered section of electrified railways have been developed in order to improve the quality indicators of electrical energy. New connection schemes for three traction substations, determined according to the requirements for connecting to the external and trac-tion power supply system are presents in the article. The calculation for new schemes of connecting traction substations, similar to the previously considered option, has been performed. The values of winding currents, power transmission line phases and coefficient asymmetry were obtained for new substation connection schemes. The proposed schemes for connecting traction substations provide a decrease in the coefficient asym-metry of the winding currents from 1 to 0.5 and a decrease in the current modulus in the most loaded windings by 1.5 times. New schemes for connecting traction substations reduce the currents of the most loaded windings and phases of the power transmission line, as well as the asymmetry of currents, which ensures an improvement in the efficiency of the external and traction power supply systems of the real traction network.

A Novel Bi-Modal Wave Analysis Approach to Pipelay Installation Analysis

2020 ◽  
Author(s):  
Dan Lee ◽  
Piotr Niesluchowski
Keyword(s):  
Clustered Data ◽  
Computation Time ◽  
Analysis Approach ◽  
Wave Analysis ◽  
Single Wave ◽  
Novel Approach ◽  
Vessel Response ◽  
Wave Heights ◽  
Time Required ◽  
The Impact

Abstract The single wave or uni-modal wave analysis approach to define the installation seastates, based on a single wave with varying directions, wave heights and periods, is a standard approach among the installation contractors. However, in many of the offshore projects, e.g. offshore Trinidad, and Senegal and Mauritania, bi-modal seatates or waves are a common occurrence, but they are not considered in the installation analysis due to the complexity of the analysis and the computation time required to capture two waves, i.e. wind-sea and swell concurrently from different directions. A novel bi-modal wave analysis approach is developed to assess the risk to pipelay installation operations due to the impact of bi-modal waves on the installation vessel, characterised by two peak frequencies of varying directions, wave heights and periods. The approach requires the use of clustered data, based on hindcast wave data over a period of time which can be provided by the Metocean Specialist. A combination of statistical evaluation of the clustered data and vessel response screening is used to identify critical clustered pairs for further installation analysis, and to complement the established single wave analysis and the associated installation seastates. An example is provided in this paper to illustrate the benefits of bi-modal waves consideration, and to demonstrate the use of this novel approach in order to ensure any potential risk is captured so that the pipelay installation operations can be carried out in a safe offshore environment.

Methods for Restricting Maximum Exposure Rate in Computerized Adaptative Testing

Methodology ◽  
2007 ◽  
Vol 3 (1) ◽  
pp. 14-23 ◽  
Author(s):  
Juan Ramon Barrada ◽  
Julio Olea ◽  
Vicente Ponsoda
Keyword(s):  
Measurement Accuracy ◽  
Computerized Adaptive Testing ◽  
Computation Time ◽  
Adaptive Testing ◽  
Exposure Rate ◽  
Control Parameters ◽  
The Impact ◽  
Two Alternatives ◽  
Selection Of ◽  
Maximum Exposure

Abstract. The Sympson-Hetter (1985) method provides a means of controlling maximum exposure rate of items in Computerized Adaptive Testing. Through a series of simulations, control parameters are set that mark the probability of administration of an item on being selected. This method presents two main problems: it requires a long computation time for calculating the parameters and the maximum exposure rate is slightly above the fixed limit. Van der Linden (2003) presented two alternatives which appear to solve both of the problems. The impact of these methods in the measurement accuracy has not been tested yet. We show how these methods over-restrict the exposure of some highly discriminating items and, thus, the accuracy is decreased. It also shown that, when the desired maximum exposure rate is near the minimum possible value, these methods offer an empirical maximum exposure rate clearly above the goal. A new method, based on the initial estimation of the probability of administration and the probability of selection of the items with the restricted method ( Revuelta & Ponsoda, 1998 ), is presented in this paper. It can be used with the Sympson-Hetter method and with the two van der Linden's methods. This option, when used with Sympson-Hetter, speeds the convergence of the control parameters without decreasing the accuracy.

Case Studies of Recent Lightning Troubles in Traction Power Supply System

2013 ◽  
Vol 133 (12) ◽  
pp. 961-966
Author(s):  
Hitoshi Hayashiya ◽  
Kazushi Matsuura ◽  
Norio Koguchi ◽  
Hiroshi Yamamoto ◽  
Tetsuo Fujita
Keyword(s):  
Case Studies ◽  
Power Supply ◽  
Power Supply System ◽  
Supply System ◽  
Traction Power Supply System ◽  
Traction Power Supply ◽  
Traction Power
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