Developments in Traction Transformer

2012 ◽  
Author(s):  
Subhas Sarkar
Keyword(s):  
Short Circuit ◽  
Real Life ◽  
Voltage Regulation ◽  
Essential Elements ◽  
Circuit Testing ◽  
Transit System ◽  
Transit Systems ◽  
Distribution Transformers ◽  
Draft Standard ◽  
Ordinary Power

Mass transit systems are gaining increased attention and popularity in the country. With this increased activity, more and more lines are getting added under public transit systems in more and more cities. One of the essential elements in the transit system is the traction transformer which powers the trains. With the emphasis on reliability, there is also increased awareness of the energy efficiency required of the traction substation equipments and the transformer in particular. Traction transformers are not ordinary power or distribution transformers. They have to meet several special requirements, including parameters like voltage regulation, impedance, commutation, short circuit withstand, operation with rectifiers, harmonic losses, wide fluctuation of load currents depending on the cyclic nature, etc. The reliability criteria are stringent and the traction transformers have to be properly designed, manufactured and tested, including short circuit testing for validation. Use of modern design tools like electric and magnetic field mapping and estimation of forces and stresses are helpful in computing them accurately. With the extensive use of vacuum circuit breakers, the subject of interaction of transformers and breakers have come to the foreground. New standards (like IEEE C57.142) have come into existence, which recommend methods to mitigate such effects. The author of this paper and his team has successfully applied these techniques in real life situations to solve problems. Work is in the final stages for preparation of a standard specifically for Traction Power Rectifier Transformers for transit applications (IEEE draft standard 1653.1) under the IEEE Vehicle Standards Committee.

scholarly journals Core Stress Analysis of Amorphous Alloy Transformer for Rail Transit under Different Working Conditions

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 164
Author(s):  
Jianwei Shao ◽  
Cuidong Xu ◽  
Ka Wai Eric Cheng
Keyword(s):  
Amorphous Alloy ◽  
Working Conditions ◽  
Short Circuit ◽  
Element Model ◽  
Operating Conditions ◽  
Iron Core ◽  
Rail Transit ◽  
Transit System ◽  
The Core ◽  
Distribution Transformers

The rail transit system is a large electric vehicle system that is strongly dependent on the energy technologies of the power system. The use of new energy-saving amorphous alloy transformers can not only reduce the loss of rail transit power, but also help alleviate the power shortage situation and electromagnetic emissions. The application of the transformer in the field of rail transit is limited by the problem that amorphous alloy is prone to debris. this paper studied the stress conditions of amorphous alloy transformer cores under different working conditions and determined that the location where the core is prone to fragmentation, which is the key problem of smoothly integrating amorphous alloy distribution transformers on rail transit power supply systems. In this study, we investigate the changes in the electromagnetic field and stress of the amorphous alloy transformer core under different operating conditions. The finite element model of an amorphous alloy transformer is established and verified. The simulation results of the magnetic field and stress of the core under different working conditions are given. The no-load current and no-load loss are simulated and compared with the actual experimental data to verify practicability of amorphous alloy transformers. The biggest influence on the iron core is the overload state and the maximum value is higher than the core stress during short circuit. The core strain caused by the side-phase short circuit is larger than the middle-phase short circuit.

scholarly journals Flywheel vs. Supercapacitor as Wayside Energy Storage for Electric Rail Transit Systems

Inventions ◽  
2019 ◽  
Vol 4 (4) ◽  
pp. 62
Author(s):  
Mahdiyeh Khodaparastan ◽  
Ahmed Mohamed
Keyword(s):  
Energy Storage ◽  
Energy Saving ◽  
Voltage Regulation ◽  
Appropriate Technology ◽  
Rail Transit ◽  
Peak Demand ◽  
Transit System ◽  
Transit Systems ◽  
Industrial Sectors ◽  
Demand Reduction

Energy storage technologies are developing rapidly, and their application in different industrial sectors is increasing considerably. Electric rail transit systems use energy storage for different applications, including peak demand reduction, voltage regulation, and energy saving through recuperating regenerative braking energy. In this paper, a comprehensive review of supercapacitors and flywheels is presented. Both are compared based on their general characteristics and performances, with a focus on their roles in electric transit systems when used for energy saving, peak demand reduction, and voltage regulation. A cost analysis is also included to provide initial guidelines on the selection of the appropriate technology for a given transit system.

scholarly journals A Dual-Stage Modeling and Optimization Framework for Wayside Energy Storage in Electric Rail Transit Systems

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1614
Author(s):  
Oindrilla Dutta ◽  
Mahmoud Saleh ◽  
Mahdiyeh Khodaparastan ◽  
Ahmed Mohamed
Keyword(s):  
Energy Storage ◽  
Search Space ◽  
Voltage Regulation ◽  
Maximum Energy ◽  
Transit System ◽  
Transit Systems ◽  
Modeling And Optimization ◽  
Optimization Framework ◽  
Dual Stage ◽  
Stage Modeling

In this paper, a dual-stage modeling and optimization framework has been developed to obtain an optimal combination and size of wayside energy storage systems (WESSs) for application in DC rail transportation. Energy storage technologies may consist of a standalone battery, a standalone supercapacitor, a standalone flywheel, or a combination of these. Results from the dual-stage modeling and optimization process have been utilized for deducing an application-specific composition of type and size of the WESSs. These applications consist of different percentages of energy saving due to regenerative braking, voltage regulation, peak demand reduction, estimated payback period, and system resiliency. In the first stage, sizes of the ESSs have been estimated using developed detailed mathematical models, and optimized using the Genetic Algorithm (GA). In the second stage, the respective sizes of ESSs are simulated by developing an all-inclusive model of the transit system, ESS and ESS management system (EMS) in MATLAB/Simulink. The mathematical modeling provides initial recommendations for the sizes from a large search space. However, the dynamic simulation contributes to the optimization by highlighting the transit system constraints and practical limitations of ESSs, which impose bounds on the maximum energy that can be captured from decelerating trains.

Prospective Transient Recovery Voltage Measurement of Short Circuit Testing Circuit by Reverse Current Injection

2019 ◽  
Vol 139 (8) ◽  
pp. 522-526
Author(s):  
Kyoya Nonaka ◽  
Tadashi Koshizuka ◽  
Eiichi Haginomori ◽  
Hisatoshi Ikeda ◽  
Takeshi Shinkai ◽  
...  
Keyword(s):  
Short Circuit ◽  
Reverse Current ◽  
Current Injection ◽  
Voltage Measurement ◽  
Circuit Testing ◽  
Transient Recovery Voltage ◽  
Recovery Voltage

Continuous Approximation Model for Hybrid Flexible Transit Systems with Low Demand Density

2021 ◽  
pp. 036119812199713
Author(s):  
Charalampos Sipetas ◽  
Eric J. Gonzales
Keyword(s):  
Agency Cost ◽  
Optimization Techniques ◽  
Optimization Process ◽  
Analytical Models ◽  
Continuous Approximation ◽  
Flexible Systems ◽  
Transit System ◽  
Transit Systems ◽  
Approximation Techniques ◽  
Service Areas

Flexible transit systems are a way to address challenges associated with conventional fixed route and fully demand responsive systems. Existing studies indicate that such systems are often planned and designed without established guidelines, and optimization techniques are rarely implemented on actual flexible systems. This study presents a hybrid transit system where the degree of flexibility can vary from a fixed route service (with no flexibility) to a fully flexible transit system. Such a system is expected to be beneficial in areas where the best transit solution lies between the fixed route and fully flexible systems. Continuous approximation techniques are implemented to model and optimize the stop spacing on a fixed route corridor, as well as the boundaries of the flexible region in a corridor. Both user and agency costs are considered in the optimization process. A numerical analysis compares various service areas and demand densities using input variables with magnitudes similar to those of real-world case studies. Sensitivity analysis is performed for service headway, percent of demand served curb-to-curb, and user and agency cost weights in the optimization process. The analytical models are evaluated through simulations. The hybrid system proposed here achieves estimated user benefits of up to 35% when compared with fixed route systems, under different case scenarios. Flexible systems are particularly beneficial for serving corridors with low or uncertain demand. This provides value for corridors with low demand density as well as communities in which transit ridership has dropped significantly because of the COVID-19 pandemic.

A Simple Design Approach for Excitation Controller and Power System Stabilizer

2010 ◽  
Author(s):  
G. Fusco ◽  
M. Russo
Keyword(s):  
Power System ◽  
Transient Stability ◽  
Short Circuit ◽  
Design Procedure ◽  
Voltage Regulation ◽  
Operating Conditions ◽  
Power System Stabilizer ◽  
Simple Design ◽  
Wide Range ◽  
System Stabilizer

This paper proposes a simple design procedure to solve the problem of controlling generator transient stability following large disturbances in power systems. A state-feedback excitation controller and power system stabilizer are designed to guarantee robustness against uncertainty in the system parameters. These controllers ensure satisfactory swing damping and quick decay of the voltage regulation error over a wide range of operating conditions. The controller performance is evaluated in a case study in which a three-phase short-circuit fault near the generator terminals in a four-bus power system is simulated.

Accessibility Scenario Analysis of a Hypothetical Future Transit Network: Social Equity Implications of a General Transit Feed Specification–Based Sketch Planning Tool

2017 ◽  
Vol 2671 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Andrew Guthrie ◽  
Yingling Fan ◽  
Kirti Vardhan Das
Keyword(s):  
Planning Process ◽  
Social Equity ◽  
Social Benefit ◽  
Planning Tool ◽  
Transit Planning ◽  
Transit System ◽  
Transit Systems ◽  
Transit Network ◽  
Accessibility Analysis ◽  
Transit Accessibility

Accessibility analysis can have important implications for understanding social equity in transit planning. The emergence and the increasingly broad acceptance of the general transit feed specification (GTFS) format for transit route, stop, and schedule data have revolutionized transit accessibility research by providing researchers with a convenient, publicly available source of data interoperable with common geographic information system (GIS) software. Existing approaches to GTFS-based transit analysis, however, focus on currently operating transit systems. With major transit expansions across the nation and around the world increasing in number and ambition, understanding the accessibility impacts of proposed projects in their early planning stages is crucial to achieving the greatest possible social benefit from these massive public investments. This paper describes the development of a hypothetical transit network based on current GTFS data and proposed 2040 transit improvements for the Twin Cities region of Minneapolis–Saint Paul, Minnesota, as well as its use as a sketch planning tool in exploring the proposed system’s impacts on access to job vacancies from historically disadvantaged areas. This research demonstrates the importance of accessibility analysis in planning a transit system that increases opportunity for marginalized workers and concludes by calling for broader, easier access to accessibility analysis for practitioners and community groups to refine the early stages of the transit planning process and democratize an increasingly crucial transit planning tool.

scholarly journals A NEW AND SUSTAINABLE PKL ELECTRICITY

2021 ◽  
Author(s):  
K. A. Khan ◽  
Shahinul Islam ◽  
M. A. Saime ◽  
S. R. Rasel ◽  
Sazzad Hossain
Keyword(s):  
Rural Areas ◽  
Electricity Generation ◽  
Short Circuit ◽  
Storage System ◽  
Research Work ◽  
Titratable Acidity ◽  
Voltage Regulation ◽  
Open Circuit ◽  
Electricity Production ◽  
Maximum Efficiency

A new method of electricity generation based on Pathor Kuchi Leaf (Genus: Kalanchoe, Section: Bryophyllum) has been developed at the Department of Physics, Jagannath University, Dhaka- 1100, Bangladesh. This electricity generation method has several advantages for smart grid over the conventional electricity production. This sustainable method is likely to generate the employment at particularly in the rural areas of where grid electricity is absent. This research work reports an invention made on Pathor Kuchi Leaf (PKL) electric power plant to enhance the PKL electricity production. The efficiency of the PKl electricity production device, Short Circuit Current ( Isc ), Open circuit Voltage ( Voc ), Temperature effect of the PKL malt, pH of the PKL malt, Titratable acidity of the PKL malt, Generation of PKL electricity, Storage system of the PKL electricity, Particular utilization of PKL electricity, I-V characteristics of the PKL, Classification of PKL, Longevity of PKL malt for PKL electricity generation, Preparation of PKL electric unit cell, module, panel, arrays and the constituent elements of the PKL, Voltage regulation, Internal resistance of the cell and efficiency of the cell have been studied. The chemical reactions of the PKL electrochemical cell have also been studied. In experimental study, it is shown that the maximum efficiency of the PKL electricity production device is ≈ 34%, the pH of the PKL malt is ≈ 4.6(without water), pH of the PKL malt is ≈ 4.8 (with 10% solution), the titratable acidity of the PKL malt is ≈ 0.88%. Most of the results have been tabulated and graphically discussed.

Finite Element Analysis of Rail-End Bolt Hole and Fillet Stress on Bolted Rail Joints

2017 ◽  
Vol 2607 (1) ◽  
pp. 33-42 ◽  
Author(s):  
Kaijun Zhu ◽  
Yu Qian ◽  
J. Riley Edwards ◽  
Bassem O. Andrawes
Keyword(s):  
Finite Element ◽  
Vertical Displacement ◽  
Rail Transit ◽  
Rail Transportation ◽  
Element Analysis ◽  
Transit System ◽  
Transit Systems ◽  
Service Failures ◽  
The University ◽  
Continuously Welded Rail

A rail joint typically is one of the weakest elements of a track superstructure, primarily because of discontinuities in its geometric and mechanical properties and the high-impact loads induced by these discontinuities. The development of continuously welded rail has significantly reduced the number of rail joints, but many bolted joints remain installed in rail transit systems. Because of the unique loading environment of a rail transit system (especially high-frequency, high-repetition loads), defects related to bolted rail joints (e.g., joint bar failures, bolt hole cracks, and cracks in the upper fillet) continue to cause service failures and can pose derailment risks. Recent research in the Rail Transportation and Engineering Center at the University of Illinois at Urbana–Champaign has focused on investigating crack initiation in the bolt hole and fillet areas of bolted rail joints. Stress distribution was investigated at the rail-end bolt hole and upper fillet areas of standard, longer, and thicker joint bars under static loading conditions. Numerical simulations were organized into a comprehensive parametric analysis performed with finite element modeling. Preliminary results indicated that the longer joint bar performed similarly to the standard joint bar but the thicker joint bar reduced rail vertical displacement and rail upper fillet stresses compared with the standard joint bar. However, the thicker joint bar also may generate higher stresses at the rail-end bolt hole. Additionally, joint bar performance was dependent on the rail profile and bolt hole location.

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