scholarly journals Assessment of the Worthwhileness of Efficient Driving in Railway Systems with High-Receptivity Power Supplies

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1836 ◽  
Author(s):  
Alejandro Cunillera ◽  
Adrián Fernández-Rodríguez ◽  
Asunción P. Cucala ◽  
Antonio Fernández-Cardador ◽  
Maria Carmen Falvo
Keyword(s):  
Power Supply ◽  
High Speed ◽  
Energy Savings ◽  
Real Data ◽  
Energy Usage ◽  
Running Time ◽  
Railway Systems ◽  
Ac Power ◽  
Driving Speed ◽  
Regenerative Energy

Eco-driving is one of the most important strategies for significantly reducing the energy consumption of railways with low investments. It consists of designing a way of driving a train to fulfil a target running time, consuming the minimum amount of energy. Most eco-driving energy savings come from the substitution of some braking periods with coasting periods. Nowadays, modern trains can use regenerative braking to recover the kinetic energy during deceleration phases. Therefore, if the receptivity of the railway system to regenerate energy is high, a question arises: is it worth designing eco-driving speed profiles? This paper assesses the energy benefits that eco-driving can provide in different scenarios to answer this question. Eco-driving is obtained by means of a multi-objective particle swarm optimization algorithm, combined with a detailed train simulator, to obtain realistic results. Eco-driving speed profiles are compared with a standard driving that performs the same running time. Real data from Spanish high-speed lines have been used to analyze the results in two case studies. Stretches fed by 1 × 25 kV and 2 × 25 kV AC power supply systems have been considered, as they present high receptivity to regenerate energy. Furthermore, the variations of the two most important factors that affect the regenerative energy usage have been studied: train motors efficiency ratio and catenary resistance. Results indicate that the greater the catenary resistance, the more advantageous eco-driving is. Similarly, the lower the motor efficiency, the greater the energy savings provided by efficient driving. Despite the differences observed in energy savings, the main conclusion is that eco-driving always provides significant energy savings, even in the case of the most receptive power supply network. Therefore, this paper has demonstrated that efforts in improving regenerated energy usage must not neglect the role of eco-driving in railway efficiency.

scholarly journals A partial compensation scheme for MMC-based railway cophase power supply

2020 ◽  
Vol 2 (4) ◽  
pp. 305-317
Author(s):  
Peiliang Sun ◽  
Kang Li ◽  
Chen Xing
Keyword(s):  
Power Factor ◽  
Power Supply ◽  
High Speed ◽  
Current Phase ◽  
Compensation Scheme ◽  
Railway Systems ◽  
Grid Side ◽  
Phase Angles ◽  
Traction Load ◽  
Partial Compensation

Abstract This paper presents a partial compensation scheme for V/v transformer cophase traction power supply in high-speed railway systems. The scheme compensates variable traction load current, and controls the current phase at the secondary side of the V/v transformer for power factor correction and negative sequence current reduction. To achieve this, the grid side current phase angles are optimized while satisfying the grid code on the power factor and voltage unbalance limits. The optimized phase angles are then used to design control references under varying load conditions. The compensation control action is updated regularly based on real-time measurements of the traction load, and the required currents are controlled by a 25-level single-phase back-to-back MMC power conditioner to achieve the compensation target. Static and dynamic load compensation performances are verified based on the simulation studies.

scholarly journals Optimization of High-Speed Train Control Strategy for Traction Energy Saving Using an Improved Genetic Algorithm

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Ruidan Su ◽  
Qianrong Gu ◽  
Tao Wen
Keyword(s):  
Genetic Algorithm ◽  
Energy Consumption ◽  
Control Strategy ◽  
High Speed ◽  
Energy Savings ◽  
Fitness Function ◽  
High Speed Train ◽  
Improved Genetic Algorithm ◽  
Running Time ◽  
Train Control

A parallel multipopulation genetic algorithm (PMPGA) is proposed to optimize the train control strategy, which reduces the energy consumption at a specified running time. The paper considered not only energy consumption, but also running time, security, and riding comfort. Also an actual railway line (Beijing-Shanghai High-Speed Railway) parameter including the slop, tunnel, and curve was applied for simulation. Train traction property and braking property was explored detailed to ensure the accuracy of running. The PMPGA was also compared with the standard genetic algorithm (SGA); the influence of the fitness function representation on the search results was also explored. By running a series of simulations, energy savings were found, both qualitatively and quantitatively, which were affected by applying cursing and coasting running status. The paper compared the PMPGA with the multiobjective fuzzy optimization algorithm and differential evolution based algorithm and showed that PMPGA has achieved better result. The method can be widely applied to related high-speed train.

New Criteria for Estimating Voltage Unbalance Due to Special Connected Transformers in High Speed Railway Systems

2005 ◽  
Vol 4 (1) ◽  
Author(s):  
Wen-Shyan Chu ◽  
Jyh-Cherng Gu ◽  
Bin-Kwie Chen ◽  
San-Yi Lee
Keyword(s):  
Power Supply ◽  
High Speed ◽  
Power Supply System ◽  
Supply System ◽  
Two Dimensional ◽  
High Speed Railway ◽  
New Approach ◽  
Voltage Unbalance ◽  
Railway Systems ◽  
New Criteria

Specially connected transformers can reduce the voltage unbalance in a High Speed Railway (HSR) power supply system. Differently connected transformers reduce unbalance differently. Traditionally, a two-dimensional figure is used to represent the degree of unbalance associated with specially connected transformers. However, such a figure cannot completely express the conditions under which the voltage unbalance factor (VUF) is maximized. This work proposes a new approach to creating figures that represent the VUF of specially connected transformers under different dispatch schedules. Besides helping engineers to estimate voltage unbalance associated with various connected transformers, the analytical results can also provide a valuable reference for train dispatchers of HSR to plan dispatching.

Case study: Prediction and field tests of railway noise and effects of a low-height noise barrier

2020 ◽  
Vol 68 (4) ◽  
pp. 303-314
Author(s):  
Yuna Park ◽  
Hyo-In Koh ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
...  
Keyword(s):  
High Speed ◽  
Field Tests ◽  
Residential Areas ◽  
Railway Systems ◽  
Railway Noise ◽  
Sound Levels ◽  
Noise Barrier ◽  
The Difference ◽  
Reduction Effect ◽  
The Impact

Railway noise is calculated to predict the impact of new or reconstructed railway tracks on nearby residential areas. The results are used to prepare adequate counter- measures, and the calculation results are directly related to the cost of the action plans. The calculated values were used to produce noise maps for each area of inter- est. The Schall 03 2012 is one of the most frequently used methods for the production of noise maps. The latest version was released in 2012 and uses various input para- meters associated with the latest rail vehicles and track systems in Germany. This version has not been sufficiently used in South Korea, and there is a lack of standard guidelines and a precise manual for Korean railway systems. Thus, it is not clear what input parameters will match specific local cases. This study investigates the modeling procedure for Korean railway systems and the differences between calcu- lated railway sound levels and measured values obtained using the Schall 03 2012 model. Depending on the location of sound receivers, the difference between the cal- culated and measured values was within approximately 4 dB for various train types. In the case of high-speed trains, the value was approximately 7 dB. A noise-reducing measure was also modeled. The noise reduction effect of a low-height noise barrier system was predicted and evaluated for operating railway sites within the frame- work of a national research project in Korea. The comparison of calculated and measured values showed differences within 2.5 dB.

Ensuring electrical safety of power supply systems of electrified AC railways for highspeed lines

2018 ◽  
Vol 77 (6) ◽  
pp. 337-346 ◽  
Author(s):  
A. B. Kosarev ◽  
A. V. Barch ◽  
E. N. Rozenberg
Keyword(s):  
Power Supply ◽  
High Speed ◽  
Structural Features ◽  
Electrical Safety ◽  
Safe Operation ◽  
Ballastless Track ◽  
Conventional Structure ◽  
Artificial Earth ◽  
Earth Connection ◽  
Supply Systems

Abstract. High-speed railways are fast-growing and promising type of traffic. In Russia development of high-speed railway service is associated with the solution of a number of problems, including infrastructure. Authors propose to use earth connection of the railway catenary with the help of an artificial earthing switch on currently designed high-speed line Moscow—Kazan for 2×25 kV power supply system. Taking into account requirements for electrical safety conditions for maintenance of the track and earthed catenary supports, paper justifies method for calculating allowable voltages of rail—earth points and supports of catenary. Methods takes into account structural features of ballastless track superstructure used for high-speed lines. It is estimated that the voltages admissible under the electrical safety conditions are random in nature and distributed logarithmically normal. When calculating probability of safe operation, one should take into account random nature of both permissible stresses and those actually occurring on the track. It is estimated that the probability of safe operation in traction networks of sections with ballastless track superstructure does not exceed a similar value in electrified sections with the conventional structure of a ballast prism. Feasibility of using a 2×25 kV earth system using an artificial earth connection is confirmed, recommendations on its use are given. Authors substantiate allowable values of the rail—earth voltage and catenary supports, which practically exclude the occurrence of hazardous situations for personnel maintaining the track in sections with ballastless track superstructure.

Síntesis sencilla de óxido de tungsteno(VI) a partir del filamento de un foco

2011 ◽  
Vol 19 (4) ◽  
pp. 341
Author(s):  
Joel Díaz Reyes ◽  
Aarón Pérez-Benítez ◽  
Valentín Dorantes
Keyword(s):  
Infrared Spectroscopy ◽  
High Temperatures ◽  
Power Supply ◽  
Light Bulb ◽  
Electrochromic Devices ◽  
Tungsten Filament ◽  
Tungsten Oxides ◽  
Ac Power

<span>Tungsten(VI) oxide can be easily synthesized starting from a standard light bulb. The reaction consists in the oxidation at high temperatures (T ≈ 2000 – 3000° C) of a tungsten filament in presence of air; conditions which can be easily achieved by connecting a broken light bulb (but with its intact filament) to an AC-power supply of 110 volts. The vapor of WO3 is condensed into a beaker in a quantity enough to be characterized by infrared spectroscopy. The experiment is very funny, inexpensive and allows to the teacher to link several topics in current chemistry and physics of the tungsten oxides, such as their nomenclature and technological applications (i.e. electrochromic devices, gasochromic sensors, superalloys or as it is used in home: As a “simple” emisor of light!).</span>

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