Metro Traction Power Supply System Research Articles

Research on DC feeder protection of novel metro traction power supply system based on model parameter identification

Research on DC feeder protection of novel metro traction power supply system based on model parameter identification

Modelling and harmonic analysis of metro traction power supply system

The large number of nonlinear loads used in urban metro rail traction grids distorts the voltage and current on the load side, then generates harmonics. The resulting capacitive characteristic harmonics current component provides feedback to the power grid, thus causing additional power losses and equipment damage. To solve this power quality problem, a detailed dynamic simulator of the metro traction power supply system is developed, which includes the corresponding 24-pulse rectifier and low-voltage power distribution system. Based on the established simulator, a study of the harmonic content and characteristics research of the 24-pulse rectifier and low-voltage electricity-consuming equipment are performed. In combination with the digital simulator, we presented and disused the lower-order frequency harmonic currents of the 35kV AC bus exhibiting capacitive characteristics. The results lay a technical foundation for harmonic equivalent impedance calculation and harmonic current suppression of the metro traction power supply system.

Analysis on DC Feeder Protection Technology of Metro Traction Power Supply System

Analysis on DC Feeder Protection Technology of Metro Traction Power Supply System

Energy conscious management for smart metro traction power supply system with 4G communication loop

This paper proposes an intelligent traction power supply system for urban rail transits, employing the wireless 4G modules to establish a communication loop among the trains, the ground bidirectional converters and the top-level energy management system. On this basis, an energy-conscious management system is developed, which obtains the instantaneous power and position of each train, parameters of the traction power supply system, real-time status of the substations and bidirectional converters through the 4G based communication loop to realize the digital reconstruction of the real traction power system for facilitating the ensuing optimizations. As physical executors, the bidirectional converters acquire their optimal DC output voltages from the genetic algorithm and then coordinately achieve the power flow dispatching of the entire metro line, so as to make the metro traction power system have a better power supply quantity and a higher efficiency. The full power scale (6.4 Mega-Watt) experiments conducted in actual Ningbo Metro Line 4 verify that the proposed EMS system is effective in energy-saving.

Design and Health Evaluation of Monitoring Test Platform for Metro Traction Power Supply System

Subway traction power supply system is the energy source of subway operation. The normal operation of subway traction power supply system is directly related to the stable operation and safety of subway. If the subway traction power supply system breaks down, it not only will cause economic losses, but also may cause social disorder. Therefore, it is of great significance to study the traction power supply system of subway to ensure the safe operation of subway. The establishment of a reasonable monitoring and testing platform, the simulation analysis of the traction power supply system, and the regular health assessment can provide a strong guarantee for the safe operation of the subway. This paper aims to design a practical test platform through MATLAB modeling, so as to establish a simulation model of subway traction power supply system, and comprehensively monitor and grasp the health status of subway traction power supply system. This paper quantitatively evaluates the health status of subway traction power supply system, applies the principle of multilayer immunity, establishes the traction power supply system of analytic hierarchy process (AHP), and constructs the immune monitoring system of each layer. This method can provide the health status information of subway traction power supply system, subsystems, and components comprehensively, accurately, and intuitively and determine the subsystems and components that need to be maintained.

A Multiattribute and Multidimensional Based Comprehensive Evaluation Method for New Multipulse Integrated Metro Traction Power Supply System

To improve the comprehensive performance of the metro traction power supply system (MTPSS), a new multipulse integrated metro traction power supply system (MI-MTPSS) is proposed in this article. The configuration and characteristics of MI-MTPSS are introduced, and based on the practical bilateral-ring power supply structure, a series of MTPSS-combinations with different standby equipment have been constructed. Meanwhile, a multiattribute and multidimensional based comprehensive evaluation method is proposed and adopted for evaluating the MTPSS-combinations comprehensively and quantitatively. According to the practical data, the practicability and reliability of the system are verified, and the MI-MTPSS is expected to be used in an industrial application in the future.

Modeling and Analysis of Transformer DC Bias Current Caused by Metro Stray Current

The metro stray current leaked during the subway operation causes the nearby earth surface potential to change, so that the various neutral‐grounded transformers to be at different earth surface potentials, resulting transformer DC bias. In order to analyze the influence of metro stray current on transformer DC bias, the polarization potential monitoring data in metro traction power supply system and neutral point current of nearby transformer were compared, and the positive correlation characteristics between the two were pointed out. By studying the stray current leakage reason in the metro traction power supply system and the circulation path causing transformer DC bias, the mechanism of the transformer DC bias under the subway operating environment was revealed. Based on the discrete model of the stray current distribution, considering the mechanism of stray current on DC bias, the equivalent resistance model of the transformer DC bias caused by metro stray current was built with double‐end power supply environment. Then the calculation formula of transformer neutral point current changing with subway operating conditions was derived, the numerical calculation of DC bias current of transformer caused by metro stray current was realized. The validity of the proposed model was verified by current distribution, electromagnetic field, grounding and soil structure analysis, the simulation results showed that the proposed model can calculate the stray current distribution and the nearby transformer DC bias current with high accuracy, which provided a quantitative analysis method for studying the correlation between metro stray current and transformer DC bias phenomenon. © 2020 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Study on Rail Potential of Metro Traction Power Supply System

Rail over-potential is one of the main problems of DC traction supply system. Firstly, based on the problem of rail over-potential, this paper introduces the comprehensive grounding system of metro substation and the structure of stray current returning ground network. Then, relative research methods and results of rail potential and its distribution are summarized, compared and evaluated. Meanwhile, various protective measures at present are summarized and evaluated according to the influence factors of rail potential. Finally, opinions about the ideas and methods of researching the rail potential of metro are put forward, and the research prospect is prospected.

An Efficient Hybrid AC Metro Power Supply System Integrating PV With Grid

Metro is integral to the urban rail transit with the expansion of the city. Due to the tremendous power consuming of the traction load which is generally considered to be megawatt class, the attendant problems concerning energy-saving and emission-reduction cannot be neglected. An approach wherein the photovoltaic plants are connected into the metro traction power supply system to provide electrical energy is proposed in this paper. Given the deterioration of power quality brought about by PV connection, the photovoltaic inverter adopts output reactive power control method.

Reliability Evaluation of a Metro Traction Substation Based on the Monte Carlo Method

The study of a metro traction power supply system reliability makes a significant contribution to researching on new power supply principles and configuration, and also providing a reference for system design and operation. According to the power supply structure and operation mode of the metro traction substation power supply system, based on the internal equipment, the reliability evaluation model of the traction substation is established by the block processing fault tree. An improved sequential Monte Carlo method is used to realize the quantitative reliability evaluation of the metro traction substation power supply system. The conclusions show that the reliability model and the sequential Monte Carlo simulation method proposed in this paper can obtain rich reliability indexes. Through visual simulation and theoretical calculation, the reliability of the metro traction power supply system can be effectively evaluated.

A Novel Fault Prevention Model for Metro Overhead Contact System

As an indispensable part of metro traction power supply system, the metro overhead contact system (OCS) is complex in composition and has various causes of faults, so its fault prevention is too complicated to be handled by using traditional methods. However, over the last few years, the fault data of metro OCS has been through explosive growth. Consequently, the method of high utility mining, which is capable of pointedly mining fault association rules from historical fault data, is adapted to address the issue. According to the fault association rules, once the precursor of the specified fault occurs, we can immediately conduct preventive maintenance to achieve the purpose of fault prevention. In this paper, we proposed a novel fault prevention model for metro OCS. First, we proposed a concept hierarchical database structure with a detailed encoding method, which can efficiently store the massive fault data and facilitate the subsequent mining. Then an improved algorithm for mining multiple-level top-K high utility fault-sets (MTHU) for metro OCS is proposed. At last, a case study is conducted and the mining result is analyzed to reveal the inner connections between faults. Based on the analysis result, the detailed preventive maintenance suggestions are given to effectively achieve fault prevention for OCS.

Calculation of metro traction power supply considering partial recuperation currents outputted by Rusich-type railway cars

Algorithm of calculation of metro traction power-supply system was considered considering partial recuperation currents output to traction system by modern recuperation rolling stock with asynchronous traction drive and microprocessor-based control system.