Energies

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15 pages, 3164 KiB

Open AccessArticle

Energy-Efficient Optimization Method of Urban Rail Train Based on Following Consistency

by Ruxun Xu, Jianjun Meng, Decang Li and Xiaoqiang Chen

Energies 2023, 16(4), 2050; https://doi.org/10.3390/en16042050 - 19 Feb 2023

Cited by 1 | Viewed by 1184

Because of the short distance between stations in urban rail transit, frequent braking of urban rail trains during operation will generate a large amount of regenerative braking energy. Urban rail trains can reduce their actual traction energy consumption using regenerative braking energy. Therefore, [...] Read more.

Because of the short distance between stations in urban rail transit, frequent braking of urban rail trains during operation will generate a large amount of regenerative braking energy. Urban rail trains can reduce their actual traction energy consumption using regenerative braking energy. Therefore, an energy-efficient optimization method for urban rail trains is proposed. By taking the punctuality of trains as the premise, the weighted acceleration of trains is taken as the synergetic variable, the synergetic coefficient is introduced to construct the following consistency model, and its convergence is proved. By analyzing the influencing factors of the following consistency coordination time, an adaptive parameter adjustment strategy is designed to solve the latest secondary traction time and the corresponding maximum speed of the primary traction. In order to save communication resources, the event trigger function is used to construct trigger conditions, and the consistency algorithm is used to update the cooperative controller. The simulation results show that the weighted acceleration of the follower train achieves the following consistency on the premise of ensuring punctuality, and the actual traction energy consumption of the follower train is reduced by 5.73%. The proposed method provides a new strategy for the energy-efficient operation of urban rail trains. Full article

(This article belongs to the Special Issue Studies in the Energy Efficiency and Power Supply for Railway Systems)

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21 pages, 9836 KiB

Open AccessArticle

Modeling and Experimental Analysis of Overvoltage and Inrush Current Characteristics of the Electric Rail Traction Power Supply System

by Jixing Sun, Kaixuan Hu, Yongzhi Fan, Jiyong Liu, Shengchun Yan and Yan Zhang

Energies 2022, 15(24), 9308; https://doi.org/10.3390/en15249308 - 8 Dec 2022

Cited by 4 | Viewed by 1679

Abstract

High-speed EMUs (electric multiple-units) frequently pass through the phase-separation zone during operation. Overvoltage generated during the operation of the vehicle-mounted circuit breaker has a long duration and high waveform steepness, which accelerates the service life of the vehicle-mounted equipment and is likely to [...] Read more.

High-speed EMUs (electric multiple-units) frequently pass through the phase-separation zone during operation. Overvoltage generated during the operation of the vehicle-mounted circuit breaker has a long duration and high waveform steepness, which accelerates the service life of the vehicle-mounted equipment and is likely to cause insulation failures. For the above-mentioned problems, the operating overvoltage characteristics of high-speed EMU were obtained by traction substation-catenary-EMUs system (SCES) analysis and experiments, thus deriving the influences of the closed phase angle and the residual magnetism of the vehicle-mounted transformer on operating overvoltage. The results showed that the voltage phase of the catenary significantly affected the operating overvoltage, and the closed switching overvoltage was small at 0–40°, 140–210° and 320–350°. The voltage on the primary side of the vehicle-mounted transformer was 60.78 kV, with the transient impact of high-frequency oscillation overvoltage of 22.71 kV, and an initial period of oscillation of 0.01 ms. Then, the period became longer, and it took 0.5 ms for the high-frequency oscillation from attenuation to disappearance. Finally, a scheme of series reactance suppression devices was proposed to protect vehicle-mounted voltage transformers. This work is to provide data support for the insulation design and system protection of a traction power supply system. Full article

(This article belongs to the Special Issue Studies in the Energy Efficiency and Power Supply for Railway Systems)

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18 pages, 4697 KiB

Open AccessArticle

Fault Diagnosis Algorithm of Transformer and Circuit Breaker in Traction Power Supply System Based on IoT

by Zhensheng Wu, Zhongli Zhang, Wenlin Wang, Ting Xing and Zhao Xue

Energies 2022, 15(23), 8812; https://doi.org/10.3390/en15238812 - 22 Nov 2022

Cited by 1 | Viewed by 1252

Abstract

Transformers and circuit breakers are essential equipment in traction power supply systems. Once a fault occurs, it will affect the train’s regular operation and even threaten passengers’ personal safety. Therefore, it is essential to diagnose the faults of the transformers and circuit breakers [...] Read more.

Transformers and circuit breakers are essential equipment in traction power supply systems. Once a fault occurs, it will affect the train’s regular operation and even threaten passengers’ personal safety. Therefore, it is essential to diagnose the faults of the transformers and circuit breakers of the traction power supply system. At present, power companies have made many achievements in fault diagnosis of power equipment, but there are still problems with real-time and accuracy. The Internet of Things (IoT) is a technology that connects different types of terminal devices for information exchange and communication to achieve intelligence. It includes data acquisition and transmission, information interaction, processing, and decision-making from bottom to top. It uses sensor terminals to obtain real-time status information on electrical equipment. Moreover, it conducts real-time monitoring and intelligent processing of the equipment status of the traction power supply system. In this paper, the multi-data fusion technology of the IoT combines the real-time information of electrical equipment with fault diagnosis to realize the fault diagnosis of transformers and circuit breakers. First, we built an equipment fault diagnosis system based on the multi-terminal data fusion technology of the IoT. Secondly, the transformer fault diagnosis model is established. We adopt the BP neural network algorithm based on particle swarm optimization (PSO) to realize transformer fault diagnosis and use PSO to optimize the feature subset to improve the diagnosis performance. Finally, the fault diagnosis model of the vacuum circuit breaker is established. We select the current change and time node as typical fault feature quantities and use the PSO–BP neural network algorithm to realize the fault diagnosis of the circuit breaker. Full article

(This article belongs to the Special Issue Studies in the Energy Efficiency and Power Supply for Railway Systems)

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15 pages, 4256 KiB

Open AccessArticle

Propagation Characteristics and Identification of High-Order Harmonics of a Traction Power Supply System

by Miaoxin Jin, Yuehuan Yang, Jiapeng Yang, Mingli Wu, Ganghui Xie and Kejian Song

Energies 2022, 15(15), 5647; https://doi.org/10.3390/en15155647 - 4 Aug 2022

Cited by 2 | Viewed by 1330

Abstract

High-order harmonics in the traction power supply show negative effects on the safe and stable operation of the railway transportation system. There is a fixed resonant frequency in the traction network. When the harmonic current frequency produced by the locomotive matches the resonant [...] Read more.

High-order harmonics in the traction power supply show negative effects on the safe and stable operation of the railway transportation system. There is a fixed resonant frequency in the traction network. When the harmonic current frequency produced by the locomotive matches the resonant frequency of the traction network, it will cause high-frequency resonant overvoltage. The propagation path of the high-order harmonics of the traction load is analyzed based on a V/v wiring traction transformer. The propagation characteristics of high-order harmonics on self-used equipment at 380 V low-voltage side and 27.5 kV high-voltage side are expounded. A simulation model for the low-voltage self-consumption power system is established and the singular value decomposition algorithm is proposed to identify the harmonic impedance. The simulation results show that the proposed method can reduce the error to within 0.1%. Under realistic conditions, the overvoltage caused by high-order harmonics is difficult to identify. To solve this problem, an overvoltage identification algorithm for Electric Multiple Units based on a convolutional neural network is proposed. The ShuffleNet neural network model is then used to identify high-order harmonics overvoltage and other types of overvoltage. The overall accuracy of the proposed classification model can be improved from 97.12% to 98.44%. Better recognition and classification performances can also be achieved. Full article

(This article belongs to the Special Issue Studies in the Energy Efficiency and Power Supply for Railway Systems)

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20 pages, 8864 KiB

Open AccessArticle

Power Quality Management Strategy for High-Speed Railway Traction Power Supply System Based on MMC-RPC

by Teng Li and Yongbin Shi

Energies 2022, 15(14), 5205; https://doi.org/10.3390/en15145205 - 18 Jul 2022

Cited by 7 | Viewed by 1883

Abstract

This paper adopts the Modular Multilevel Converter Type Railway Power Conditioner (MMC-RPC) equipment to effectively manage the power quality of the high-speed railway traction power supply system including the reactive power and negative sequence component. Firstly, the single-phase model of the MMC was [...] Read more.

This paper adopts the Modular Multilevel Converter Type Railway Power Conditioner (MMC-RPC) equipment to effectively manage the power quality of the high-speed railway traction power supply system including the reactive power and negative sequence component. Firstly, the single-phase model of the MMC was established to deduce the working characteristics of the MMC-RPC and its compensation principle for the traction power supply system with the v/v wiring transformer. Secondly, the adaptive VSG control strategy was adopted for the inverter of the MMC-RPC to provide dynamic inertial and damping support for the traction power supply system based on the virtual synchronous generator (VSG) control. Compared with the traditional double closed-loop (DCL) and VSG controls, it has better anti-disturbance and dynamic performance. The root locus analysis of control parameters based on a small signal model shows that VSG control can provide more stability margin. Furthermore, Differential Flatness Control (DFC) was used in the inner-loop controller to ensure the stable control of the inverter and the stability was verified by the Lyapunov stability analysis. For the rectifier of the MMC-RPC, a hierarchical three-level control strategy with system-level control, cluster-group voltage control, and inter-cluster voltage control for keeping the voltage balance was adopted. Finally, simulation results on the Matlab/Simulink platform verified the effectiveness and stability of the joint control applied in the MMC-RPC. Full article

(This article belongs to the Special Issue Studies in the Energy Efficiency and Power Supply for Railway Systems)

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18 pages, 4466 KiB

Open AccessArticle

Traction Load Modeling and Parameter Identification Based on Improved Sparrow Search Algorithm

by Zhensheng Wu, Deling Fan and Fan Zou

Energies 2022, 15(14), 5034; https://doi.org/10.3390/en15145034 - 10 Jul 2022

Cited by 1 | Viewed by 1616

Abstract

In this paper, a traction load model parameter identification method based on the improved sparrow search algorithm (ISSA) is proposed. According to the load characteristics of the AC traction power supply system under transient disturbance, the model structure of the traction load is [...] Read more.

In this paper, a traction load model parameter identification method based on the improved sparrow search algorithm (ISSA) is proposed. According to the load characteristics of the AC traction power supply system under transient disturbance, the model structure of the traction load is equated to the composite load model structure of the static load shunt induction motor’s dynamic load. The traditional sparrow search algorithm is improved to enhance its accuracy and convergence. The generalization ability of the model was tested, and the accuracy of the proposed model was verified. Using the ISSA to determine the load model from the measured data, the results can verify the effectiveness of the ISSA for comprehensive load model parameter identification. Comparing the ISSA with the traditional SSA and PSO algorithms, it shows that the ISSA has better accuracy and convergence. Full article

(This article belongs to the Special Issue Studies in the Energy Efficiency and Power Supply for Railway Systems)

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16 pages, 8639 KiB

Open AccessArticle

Study on Induced Voltage and Circulation Current of Metal Layer in Single-Core Cable of High-Speed Railway Power Transmission Line

by Hao Wang and Zhensheng Wu

Energies 2022, 15(14), 5010; https://doi.org/10.3390/en15145010 - 8 Jul 2022

Cited by 3 | Viewed by 2626

Abstract

The metal shield and metal armor layers of single-core cables on high-speed railroad power penetration lines are usually grounded by common equipment protectors. This grounding method brings a continuous circulating current between the metal shield and metal armor layer compared to the subequipment [...] Read more.

The metal shield and metal armor layers of single-core cables on high-speed railroad power penetration lines are usually grounded by common equipment protectors. This grounding method brings a continuous circulating current between the metal shield and metal armor layer compared to the subequipment protection grounding. In order to quantitatively study the circulating current condition of the through line and its influence on the reliability of the railroad power through line, the induced electric potential and circulating current generation mechanism of the single-core cable of the through line and its influencing factors were firstly analyzed in depth. Then, based on the cross-sectional structure of the single-core cable and the location of the traction network and cable in the roadbed section, a traction power supply model was established and simulated for the interlayer-induced potentials and circulating currents due to the two grounding protection methods under no load, single train operation, and heavy load four-train operation of the line. Finally, three actual sections of the Shanghai–Kunming and Nan–Kunming high-speed railroads in China were selected to collect and analyze the loop flow data with no load and with vehicles passing through, and finally the loop flow law of single-core cable for railroad electric through traffic was derived. The analysis shows that when the metal sheath of a single-core cable is grounded by ordinary equipment, the circulating current generated does not exceed 1% of the core current, which meets the relevant safety standards, but the induced voltage in the case of large loads will exceed 50 V safety voltage. Full article

(This article belongs to the Special Issue Studies in the Energy Efficiency and Power Supply for Railway Systems)

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9 pages, 650 KiB

Open AccessArticle

Timetable Optimization and Trial Test for Regenerative Braking Energy Utilization in Rapid Transit Systems

by Ning Zhao, Zhongbei Tian, Stuart Hillmansen, Lei Chen, Clive Roberts and Shigen Gao

Energies 2022, 15(13), 4879; https://doi.org/10.3390/en15134879 - 2 Jul 2022

Cited by 5 | Viewed by 1679

Abstract

Rapid transit systems play a significant role in supporting rapid social and economic development in large cities all over the world. However, the systems consume a large amount of energy, which brings increasing environmental concerns. A number of energy-saving technologies have been studied [...] Read more.

Rapid transit systems play a significant role in supporting rapid social and economic development in large cities all over the world. However, the systems consume a large amount of energy, which brings increasing environmental concerns. A number of energy-saving technologies have been studied on railways. However, few of the outcomes have been tested and evaluated in practice. This paper presents the development of a timetable optimization and trial test on a metro line to reach the full potential of the train regenerative braking system. To achieve this purpose, a timetable optimization algorithm has been developed, and a trial test of the optimal timetable has been arranged on a metro line for a whole day. In the test, all the trains running in the network were organized to operate in accordance with the optimal timetable. The trial test results indicate that by applying the optimal timetable, the regenerative braking energy utilization can be improved, thereby reducing the overall network energy usage. Full article

(This article belongs to the Special Issue Studies in the Energy Efficiency and Power Supply for Railway Systems)

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17 pages, 72212 KiB

Open AccessArticle

Influence of the Catenary Distributed Parameters on the Resonance Frequencies of Electric Railways Based on Quantitative Calculation and Field Tests

by Qiujiang Liu, Wanqi Zhang, Guotao Cao, Jingwei Liu, Jingjing Ye, Mingli Wu and Shaobing Yang

Energies 2022, 15(10), 3752; https://doi.org/10.3390/en15103752 - 19 May 2022

Cited by 2 | Viewed by 1524

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Studies in the Energy Efficiency and Power Supply for Railway Systems)

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