Showing papers on "Traction substation published in 2021"

MVDC railway traction power systems, state-of-the art, opportunities, and challenges

Abstract: Advances in voltage-source converters (VSCs), as well as their successful application in VSC-HVDC systems, have motivated growing interests and research in medium-voltage direct current (MVDC) traction power systems (TPSs) for high-speed rail (HSR) applications. As an emerging power-converter-based infrastructure, this study reviewed developments that shape two key evolving pieces of equipment—namely, high-power traction substation (TSS) converters, and power electronic transformers (PETs)—for MVDC TPS as well as prospects for smart grid (SG) applications in the future. It can be deduced that cost-effective and robust high-power TSS converters are available from hybrid modular multilevel converters (MMCs) for enhanced performance and fault-tolerance capability. In addition, silicon carbide (SiC) MMC-based PETs with input-series-output-parallel (ISOP) configuration are present for greater weight/size reduction and efficiency for MVDC rolling stock design. Finally, the implementation of a smart MVDC TPS incorporating a sophisticated railway energy management system (REM-S) based on the smart grid principles is feasible in the future, with numerous benefits. However, there are related challenges, like knowledge gaps on these technologies, the high costs involved, and lack of standardization to overcome to realize widespread future commercial deployment.

A power-quality monitoring and assessment system for high-speed railways based on train-network-data center integration

Abstract: In recent years, with the rapid development of high-speed railways (HSRs), power interruptions or disturbances in traction power supply systems have become increasingly dangerous. However, it is often impossible to detect these faults immediately through single-point monitoring or collecting data after accidents. To coordinate the power quality data of both traction power supply systems (TPSSs) and high-speed trains (HSTs), a monitoring and assessing system is proposed to access the power quality issues on HSRs. By integrating train monitoring, traction substation monitoring and data center, this monitoring system not only realizes the real-time monitoring of operational behaviors for both TPSSs and HSTs, but also conducts a comprehensive assessment of operational quality for train-network systems. Based on a large number of monitoring data, the field measurements show that this real-time monitoring system is effective for monitoring and evaluating a traction-network system.

Robust Energy Management of High-Speed Railway Co-Phase Traction Substation With Uncertain PV Generation and Traction Load

Abstract: Co-phase traction power supply system provides the insights for solving the existing power quality and electrical sectioning issues in high-speed railways, and the flexible control of co-phase traction substation (CTSS) with the integration of photovoltaic (PV) and hybrid energy storage system (HESS) attracts widespread attention. However, the strong volatilities and uncertainties of PV and traction load introduce challenges to the reliable and economic operation of CTSS. In this study, the energy management of CTSS aims at minimizing the operating cost of CTSS by coordinating PV, HESS, power flow controller (PFC) and the energy transactions with the power grid, where the three-phase voltage unbalance constraint is taken into account in particular. Furthermore, to handle the uncertainties of PV and traction load, a two-stage robust optimization model is proposed. The first stage determines the operating status of HESS and energy transaction status with grid, and the second stage aims at finding the optimal scheduling power of CTSS and the worst-case scenario with maximized operating cost of CTSS. A column-and-constraint generation algorithm is employed to solve this robust optimization model, along with efficient linearization approaches for the formulation of mixed-integer linear programming. The proposed methodology is tested with a real high-speed railway line case in China.

A Sequential Decision-Making Process for Optimal Technoeconomic Operation of a Grid-Connected Electrical Traction Substation Integrated With Solar PV and BESS

Abstract: Ensuring the provision of the increasing power consumption and maintaining the power quality (PQ) are considered to be the major challenges for electrical traction substations (TSSs) due to their dynamic characteristics, which render their power demand and electrical behavior to be highly complex. Solar photovoltaics (PVs) and battery energy storage systems (BESS) can be reliable options for integration with the TSSs, the prerequisite, however, is to devise the appropriate approaches for the demand management (DM) and maintaining the PQ of such a system. In this article, a strategy is proposed for the optimal technoeconomic operation of the TSSs using a sequential decision-making process (SDMP). In the first layer, the DM is formulated so that it can address the requirements of the integrated system and the uncertainties. The second layer optimizes the limited capacity of the PV/BESS converters for the mitigation of the unbalances and the reactive power compensation. Moreover, a comprehensive modeling framework incorporating the SDMP is presented that lends itself to use as a robust platform for the realistic modeling of the TSSs, BESSs, and PV systems. The framework is utilized to demonstrate the effectiveness of the proposed SDMP for both the DM and improving the PQ of the TSS, which are validated using different case studies.

Reliability and Life Evaluation of a DC Traction Power Supply System Considering Load Characteristics

Abstract: The traction power supply system is one of the most important parts of a railway system, which is responsible for providing electricity to power the running trains and other operating equipment. The performance of the power supply has a profound impact on the railway system. Therefore, it is necessary to conduct research on the reliability of the power supply system considering traction load and ensure it is highly reliable. This article introduces some reliability-related indexes based on the fault tree analysis (FTA) method and proposes a method to evaluate the system reliability of a dc-electrified railway. The effect of traction load on power supply system reliability is studied based on Institute of Electronics Engineers (IEEE) standards. A dynamic reliability and life evaluation model is built up to evaluate the reliability of traction substation and to develop a plan to reduce the operational risk of the power system. Through analysis of a practical example of the Singapore East–West line, the system reliability and remaining useful life of each traction substation are obtained. The outcome from this study provides guidance for the maintenance and future operation plan of the power system.

The Flexible Smart Traction Power Supply System and Its Hierarchical Energy Management Strategy

Abstract: With the increasing requirements of the railway sector for electrified railways and the development of society, the traction power supply system needs to become more flexible, economic and reliable. The traditional traction power supply system has many problems due to its own topology, such as negative sequence current, load fluctuation, low utilization rate of regenerative braking energy, and inability to use the distributed generation along the railway. In order to solve these problems and make the traction power supply system (TPSS) more flexible, efficient and reliable, a novel TPSS called flexible smart traction power supply system (FSTPSS) is proposed. This traction power supply system consists of AC-DC-AC traction substation and the microgrid along the railway. It can effectively mitigate the problems of negative sequence current, improve regenerative braking energy utilization and distributed generation utilization. A hierarchical energy management strategy is also proposed here, which can effectively improve the operating economy of FSTPSS and reduce the load fluctuation of FSTPSS. And based on the actual load measurement power of a traction substation of China’s Beijing-Shanghai high-speed railway, the proposed energy management strategy has been verified for the economic improvement and load fluctuation reduction of TPSS.

Optimal Sizing and Energy Management of Hybrid Energy Storage System for High-Speed Railway Traction Substation

Abstract: Traction power fluctuations have economic and environmental effects on high-speed railway system (HSRS). The combination of energy storage system (ESS) and HSRS shows a promising potential for utilization of regenerative braking energy and peak shaving and valley filling. This paper studies a hybrid energy storage system (HESS) for traction substation (TS) which integrates super-capacitor (SC) and vanadium redox battery (VRB). According to the characteristics of the traction load under actual operating conditions, an energy management strategy with fixed-period control (FPC) is proposed, which fully leverages the periodicity and regularity of HSRS operation. To achieve the optimal size, economic feasibility is selected as the optimization objective, which is fully assessed in terms of Net Present Value (NPV). The optimization constraints are formulated in which the Discrete Fourier Transform (DFT) is performed for power allocation between SC and VRB. Besides, an improved mutation-based particle swarm optimization (IMBPSO) is proposed to efficiently solve the optimization and enhance convergence performance. Finally, combined with the measured traction load data, the effectiveness of the FPC energy management strategy is verified and the optimal scale of the HESS is provided.

Current Harmonic Analysis for AC Traction Substation with Power Balancer

Abstract: This paper describes results of the harmonic analysis of currents harmonic analysis performed for an advanced AC traction Substation. AC traction substation feeding 25 kV / 50 Hz traction catenary and provide power symmetrization by semiconductor device called electronic balancer. The analysis is concern to currents of electronic balancer part of substation and the grid currents corresponding with quality of taken energy. The harmonic currents components are evaluate with the respect to the switching frequency of IGBTs (250 Hz), modulation technique (PS-PWM) and dead time duration (10 μs), The results are evaluated on the created model of the AC traction substation with multilevel converter topology, having the nominal power of 12.5 MV A.

Operating States of Load Balancer for AC Traction Substation Based on CHB Topology

Abstract: This paper deals with study of operating states for AC traction substation. The selected topology of traction substation is described in paper. The topology suitability is discussed with the respect to industrial component parameters (25kV/50 Hz, substation power 12. 5MVA, 3kV DC-link, switching frequency 250 Hz). The basic theory of power balancing and power quality is documented on phasor diagram and simulation results. The simulation results document selected operation states of electronic balancer based on Cascaded H-bridge converter with PS-PWM.

A Comparative Study of Recent Optimization Methods for Optimal Sizing of a Green Hybrid Traction Power Supply Substation

Abstract: Although there is a premise that electric trains are zero-emission, their source of energy (fossil fuel power plants) pollutes the air in a place far from the consuming area (traction power supply substation). On the other hand, the price of generating electricity from fossil fuel resources has risen in the aftermath of their ever-decreasing sources. These two economic-environmental factors have caused Hybrid Renewable Energy Sources (HRESs) to be introduced as an alternative to fossil fuel ones. This paper proposes the concept of Green Hybrid Traction Power Supply Substation (GHTPS), that is, using renewable energy resources to meet a traction substation. To find the best size of HRES components having a minimum Lifecycle cost; an optimization method is essential. For this reason, a comparative study on the application of recent optimization methods is employed to find the optimum size of the proposed grid-connected PV/wind turbine traction substation. The optimization methods are: the Atom search optimization (ASO), Harris Hawks Optimization (HHO), Coyote Optimization Algorithm (COA), Multi-population Ensemble Differential Evolution (MPEDE), Bird Swarm Algorithm (BSA), Ant Lion Optimizer (ALO), Grey Wolf Optimizer (GWO), Artificial Bee Colony (ABC), Particle Swarm Optimization (PSO), Genetic Algorithm (GA) and HOMER software. Finally, a sensitivity analysis shows that increasing in the grid electricity price and decreasing the wind turbines investment cost could make renewable energies more economically competitive in the future. Besides Net Present Cost (NPC), Cost of Energy (COE), Payback Time (PT), and various emissions are studied, all of which verify the efficiency of the proposed system.

Comparison of Traction Substation Topologies for AC 25kV Electrical Railway

Abstract: The paper is focused on topologies of traction substations for AC railway traction system especially for 25kV, 50Hz (respectively 60Hz). The current progress of power electronic field of study allows to use semiconductor converters as a part of distribution power grid (i.e. for HVDC), for traction issue but also for traction substations. This expansion is related to topologies of TSS, where power electronics are used for symmetrization, compensation, filtration of harmonics of higher order, TSS cooperation, recuperation back to distribution power grid if it is allowed, etc. Conventional transformer topologies used to this day for electrical railway supplies are described in the beginning. The state of the art of TSS, using a power electronic component and the most promising topologies at the same time, is described in the second half of the paper. The main benefit of the paper is comparison of the TSS selected topologies and evaluation of the properties.

A Novel Co-Phase Power Supply System for Electrified Railway Based on V Type Connection Traction Transformer

Abstract: Power quality and neutral section are two technical problems that hinder the development of electrified railway to high-speed and heavy railway. The co-phase power supply technology is one of the best ways to solve these two technical problems. At present, a V type connection traction transformer is widely used in a power frequency single-phase AC traction power supply system, especially in high-speed railway. In this paper, a new type of co-phase power supply system for electrified railway based on V type connection traction transformer is proposed. One single-phase winding in the V type connection traction transformer is used as main power supply channel, and three ports are used as compensation ports. Neutral section is no longer set with traction substation, and the train is continuously powered through. The independent single-phase Static Var Generators (SVGs) are used to compensate the three-phase imbalance caused by single-phase traction load. When necessary, the power factor can be improved at the same time. The principle, structure, control strategy, and capacity configuration of the technical scheme are analyzed in this paper, and the effectiveness of the scheme is verified by using the measured data of electrified railway. The advantage of this scheme lies in the universal applicability of the V type connection traction transformer, and the flexibility of the SVG device.

Synthesis of the transfer function of the voltage controller in an active filter-stabilizer converter

Abstract: It has been established that in order to ensure effective filtration and stabilization of the voltage of DC traction substations, it is advisable to use active filters-stabilizers. The dynamic characteristics of an active filter-stabilizer have been analyzed taking into consideration its discrete properties. It has been shown that the voltage converter in an active filter-stabilizer with bilateral pulse-width modulation for small values of control signal increment is an amplitude-pulse modulator of the second kind. In order to improve the efficiency of using an active filter-stabilizer, which is part of the DC traction substation converter, the task was set to synthesize the transfer function of its converter's voltage controller. When analyzing a closed automatic control system, it was established that the transfer function of the voltage controller, which ensures the implementation of processes of finite duration in the closed automatic control system, includes a proportional part, an integral part, and a differential part. To determine the time constants for the transfer function of the PID-controller, as well as its damping coefficient, a closed automatic control system of the active filter-stabilizer voltage converter was investigated using an apparatus of Z-transformation. The result of synthesizing the transfer function of the voltage controller has established the parameters for the controller's transfer function, which ensure that the process of finite duration is executed in a closed system of automatic control over the converter's output voltage. The transition process in the system with a stepwise input effect of the processes of finite duration has been calculated, which confirmed that the transition process in the system ends after three clock intervals of discreteness. Establishing a transition process that ends over the finite number of discrete intervals, which is determined by the order of the characteristic equation, means that the process has been optimized for performance

Symmetrization Method of AC Traction Substation with Power Balancer

Abstract: The paper describes the symmetrization method of power converter used in topology of AC traction substation with power balancer. This topology provides the three-phase current symmetrization and the reactive power compensation for AC traction substation feeding 25 kV / 50 Hz traction catenary. The described symmetrization method is based on principles of the Steinmetz symmetrizing circuit. The main paper contribution is a derivation and description of the symmetrization equations, which are used for the control algorithm of multilevel semiconductor converters in a delta connected circuit.

Fault-Tolerant Control in a Peak-Power Reduction System of a Traction Substation with Multi-String Battery Energy Storage System

Abstract: This paper introduces the concept of fault-tolerant control (FTC) of a multi-string battery energy storage system (BESS) in the dynamic reduction system of a traction substation load (DROPT). The major task of such a system is to reduce the maximum demand for contracted peak power, averaged for 15 min. The proposed concept, based on a multi-task control algorithm, takes into account: a three-threshold power limitation of the traction substation, two-level reduction of available power of a BESS and a multi-string structure of a BESS. It ensures the continuity of the maximum peak power demand at the contracted level even in the case of damage or disconnection of at least one chain of cells of the battery energy storage (BES) or at least one converter of the power conversion system (PCS). The proposed control strategy has been tested in a model of the system for dynamic reduction of traction substation load with a rated power of 5.5 MW. Two different BESS implementations have been proposed and several possible cases of failure of operations have been investigated. The simulation results have shown that the implementation of a multi-string BESS and an appropriate control algorithm (FTC) may allow for maintenance of the major assumption of DROPT, which is demanded power reduction (from 3.1 MW to 0.75 MW), even with a reduction of the BESS available power by at least 25% and more in the even in fault cases.

High Voltage DC Traction Power Supply for Urban Rail Transit

Abstract: For urban rail transit (URT), high-voltage AC (HVAC) power is generally transmitted from main substation (MS) to traction substations (TS), and then TS utilizes transformers and diode rectifiers to convert AC power to DC traction power. However, the traditional traction power supply (TTPS) shows the limitations in braking energy waste, high rail potential and stray current, etc. So high-voltage DC traction power supply (HDTPS) is proposed in this paper for URT. Both configuration and principle of HDTPS are analyzed, which mainly includes DC main substation (DMS) and DC traction substation (DTS). Then, the comparisons between HDTPS and TTPS on braking energy utilization, rail potential and stray current mitigation are discussed in detail. Finally, the simulation model of HDTPS is built to verify the above theoretical analysis.

Harmonic Distortion Reduction in High Power Systems Supplying AC Electric Railway using SVC

Abstract: This paper deals with the problem of harmonic mitigation solutions in a Vietnam traction substation which supplies a railway electric transportation line. The main studies focus specifically on the order of high harmonic components and total harmonic distortion (THD) of the voltages in electric railway supply to perform 110 kV and 27 kV levels with the influence of one phase system electrified traction. The harmonic distortion factor of the voltage is always less than IEEE 519 recommended limit. In order to keep the harmonic distortion within allowed limits, the proposed filter installation must lead to a significant diminution of the superior order harmonics. In this concrete application, the proposed solution for harmonics mitigation is based on using the static var compensator (SVC). The static var compensator (SVC) installation represents different variants of the filtering compensation solution to reduce harmonic distortion. The simulation is discuses on performed of the ATP version of the electromagnetic transient program (EMTP). The simulation results show that the installation of SVC for higher order harmonics would reduce harmonics levels and harmonic distortion factor to within acceptable limits in the situations.

Complex Design Method of Filtration Station Considering Harmonic Components

Abstract: The paper deals with a new methodology for calculating the filter parameters. The basis is respect for the fact that the real filter current consists of other harmonic components, which filter is tuned. The proposed methodology was used to design filters for traction substation 25 kV/50 Hz. The operation of the locomotives in the AC supply systems of 25 kV/50 Hz leads to a rising of higher order harmonic currents. Due to the 1-phase supply system, these are mainly the 3rd and 5th harmonics. By simulation and subsequent measurement of the proposed traction power station filters the proposed methodology was verified. Thus, the filter design can also be used for filter compensating stations of the standard 3-phase distribution network. The described method presents an optimal filter design without unnecessary oversizing. This fact reduces the size and cost of the filter. It is shown that it is possible to design a filter that meets the requirements for power quality under extreme load and to minimise distortion of line voltage.

Energy Characteristics of the DC Distributed Power Supply Systems

Abstract: Currently the circuit technology of the DC traction power supply system cannot provide the necessary requirements for introduction of high-speed traffic. Numbers of measures and tools have been developed to improve the traction lines that no longer meet current requirements. One of the most promising means for strengthening the traction DC lines is transition to the distributed power supply of the rolling stock. In this article, a comparative analysis was carried out of energy indicators of the classic centralized power system and distributed power systems with use of one aggregate traction substation and with use of the solar generators. That comparative analysis of these systems was performed on a simulation model with the same parameters of the traction line and rolling stock.

Overvoltages Induced in the Supplying Line by an Electric Railway Vehicle

Abstract: The paper focuses on a railway traction system. A railway vehicle, driven by a.c. three-phase asynchronous motors supplied through inverters from a single phase transformer, is connected to it. A brief description of the single phase a.c. (50 Hz, 25 kV) driving system is provided. The traction substation consists in down step voltage transformers supplied from the power system. The single phase traction system, when connected to the three-phase supplying system, introduces non-symmetries and current harmonics. A 50 km line segment from a simple supplying line was considered for simulation of overvoltages at current harmonics. A correct design of the railway vehicle driving system must meet the requirements imposed by the standard EN 50388 relative to its connection to the supplying line. Practical validation concerning overvoltages is discussed.

Adversarial Reconstruction for Outdoors Insulator Anomaly Detection and Recognition in High-Speed Railway Traction Substation

Abstract: As an indispensable part of the high-speed railway traction substation,the outdoors insulator ensures the normal operation of transmission network and defends the stability of transmission line. In order to avoid the serious transmission fault and decrease the economic loss, finding a effective way to find the anomaly regions of insulator is a meaningful issue. Therefore, a method is presented for outdoors insulator anomaly detection and recognition in high-speed railway traction substation based on adversarial reconstruction in this paper. First, the R3Det is employed to fix the position of insulator from the input image of traction substation. At the second stage, the insulator image which located from the first stage is entered into our designed generative adversarial networks to reconstruct input image. In the end, the structural similarity algorithm is adopted to compare the difference between the input image and the generated image to find the anomalous region, then template matching is used for recognition of the anomalous area. Test results on Heishan traction substation show the effective performance of our designed method.

Research on the Construction of Substation Equipment Model Library Based on BIM Three-Dimensional Modeling

Abstract: Substation equipment has a large amount of heterogeneous information during its life cycle. However, when Autodesk Revit is used as the modeling software to build a BIM model of traction substation equipment, due to the limited type of model attribute parameters and parameter grouping methods, the model cannot meet the requirements. Requirements for information integration in the entire life cycle of equipment. Based on this, the thesis uses the MVC model of three-dimensional modeling platform and the technical support of synchronous calculation to propose a BIM-based substation equipment graphics calculation system. Taking the common cable trench, cover plate and foundation earthwork calculation in substation station engineering as an example, the realization method of main technology is explained.

Device for stress balancing on 27_5 kv busbars of adjacent traction substations

Abstract: FIELD: physics.SUBSTANCE: invention relates to power supply line for vehicles. Stress leveling device on 27.5 kV buses of adjacent traction substations comprises single-phase booster transformer, input single-phase transformer, to its secondary winding there connected in series is single-phase rectifier, smoothing filter, single-phase inverter and output filter. Outlet filter is connected to the primary winding of the booster transformer, and its secondary winding is connected to the cut of the feeder of the contact network at the first traction substation. At that, voltage balancing device comprises inverter control unit, comparator unit, units for determination of voltage vector parameters of first and second traction substations, voltage sensors of the first and the second traction substations, the inputs of which are connected to the secondary winding of the measuring transformers of voltage of the first and the second traction substation and units of formation of the reference pulse of the first and the second traction substations, the inputs of which are connected by communication channels to the system of artificial earth satellites.EFFECT: technical result consists in improvement of energy efficiency of traction power supply system.1 cl, 1 dwg

Analysis of the Energy Characteristics of the Traction Substation Rectifier

Abstract: The analysis of the electromagnetic processes of a rectifier unit with a controlled pulse-width modulation with a booster rectifier is carried out. An expression for the power factor of a rectifier unit is obtained by an integral method for determining reactive power. It is shown that the adjustable pulse width modulation parameter has little effect on the power factor. The power factor is greater than with phase control.

Integrated Optimization for Energy-saving Operation in Co-phase TPSS

Abstract: With the increasing scarcity of energy, more and more researchers have begun focus on the field of energy-saving in railway system. A novel topology of traction substation integrated power flow controller (PFC) and hybrid energy storage system (HESS) based on co-phase power supply technology was studied in this paper to increase the utilization rate of regeneration braking energy (RBE) generated by train. And a bi-level optimization model considering the coordination effect of train trajectory optimization and HESS energy scheduling scheme was developed. Several cases studies have been proposed based on certain actual line to verify the effectiveness of this model. The obtained results show that this model effectively improves the utilization rate of RBE and reduces the electricity cost of traction power supply system (TPSS) by 28.02%.

DC traction power substation using eighteen-pulse rectifier transformer system

Abstract: Twelve-pulse rectification system had been widely integrated in today’s DC traction power sub-station (DC-TPSS). This configuration had successfully mitigated low order harmonic distortion. As some research findings had confirmed that the dc voltage and current ripple factors may further minimize by increasing the number of rectification pulses to 18, 24, or 36. This paper had presented a simulation study to investigate the prospect of implementing an eighteen-pulse rectification system in a DC-TPSS. The theory of phase-shifting transformer used to produce an 18-pulse rectifier is presented with simulation verification. Simulation result shows that 3.69% of grid current distortion index is recorded without installing any filters. In addition, the dc voltage and current ripple may also be further reduced for about 30% compared to a conventional twelve-pulse rectification system.

Methodology and Models of Combined Modeling of Electromagnetic Pro-cesses in Electric Traction Systems

Abstract: Purpose. The main purpose of the work is the development of identification models and a new method of modeling electromagnetic processes in electric traction systems with simultaneous consideration of all its subsystems, as well as several feeder zones of the electrified section. Methodology. To achieve this purpose, the methods of mathematical modelling, the basics of the theory of random processes and the methodology of their probabilistic-statistical processing, the methods for solving integral equations and analysis of electric traction circuits in electric traction systems are used. Findings. The requirements to be met by an adequate, stochastic identification model of electric traction devices are established. The solution of Fredholm’s integral correlation equation of the first kind is performed. The analytical expression of the identification dynamic model of the electric locomotive DE–1 is obtained and its adequacy is checked. The methodology of combined modeling of electromagnetic processes in devices and subsystems of electric traction systems is developed and presented tabularly. Originality. For the first time it is proposed to use the pulse transition function as identification models of traction substation and traction network with electric rolling stock in predictive modeling of electromagnetic and electric power processes in electric traction systems. A new method has been developed, a method of complex modeling of electromagnetic and electric power processes in the system of electric traction with simultaneous consideration of all its subsystems, as well as several inter-substation zones of the electrified section. For the first time, a method of partitioning the correlation functions for solving an integral correlation equation has been proposed, which allows defining a pulse transition function as an identification model of any subsystem of an electric traction system. Practical value. The developed identification models and the method of combined modeling make it possible to predict electromagnetic processes simultaneously in all feeder zones of the electrified section of the electric traction system. The obtained identification model of the electric locomotive DE–1 can be adapted with its subsequent use in modeling processes in the traction circuits of electric locomotives of other types. The method of factorization of correlation functions used in solving the Volterra integral correlation equation of the first kind (convolution type) can be adapted to the solution of other integral equations, which describe the processes in electric traction systems.

A Research on Inductance Forcedly Absorbing Current to Reduce Stray Current in Metro

Abstract: The stray current of metro corrodes the buried metal pipe, line and steel structure greatly. To inhibit the flow of stray current into the ground, an inductive force current absorption circuit (IFACC) is analyzed in this paper. It makes the traction current flow back to the traction substation through reflux current wire (RCW) to reduce rail potential, so as to achieve the purpose of inhibiting the stray current leakage. On this basis, the three-layer return flow model of “rail-buried metal-earth” is designed. Based on the circuit mathematical model, we analyzed the working principle of IFACC and the stray current. And The function of IFACC is verified by MATLAB simulation and low voltage experiment. The research results show: it is in the traction power supply system equipped with IFACC that the current flowing through the rail is significantly reduced, and most of the backflow is carried out through the RCW. It is verified that IFACC has a good effect of inhibiting stray current.

Fault distance measurement method for traction network with reinforced line in direct power supply mode

Abstract: The invention discloses a fault distance measurement method for a traction network with a reinforced line in a direct power supply mode, and the method comprises the steps: constructing a data matrixof the fault distance and fault impedance of the traction network under a fault condition according to the short-circuit simulation and test data of the traction network with the reinforced line in the direct power supply mode, and fitting a short-circuit impedance characteristic curve; in combination with the short-circuit impedance curves of the contact line and the reinforced line, the impedance difference measured by the uplink and downlink protection devices during the fault and the fault distance measurement difference of each lead, realizing the judgment of the fault section and the fault line of the traction network and the accurate calculation of the fault distance. The method has the advantages that the problem that the fault sections and lines of the traction network cannot be determined after the reinforced lines are connected in parallel is solved, and accurate judgment of the fault sections and the fault lines in the power supply mode is achieved; accurate calculation ofthe fault distance of the direct power supply mode with the reinforcing line is realized; by adding the technical scheme in a traction substation feeder protection device, hardware upgrading and reconstruction are not needed, a fault distance measuring device does not need to be independently arranged, the cost is low, and implementation is easy.

Определение технического состояния трансформаторов собственных нужд при построении системы мониторинга цифровой тяговой подстанции

Abstract: The article discusses aspects of determining the technical condition of auxiliary transformers when creating a system of monitoring the technical condition of digital traction substation equipment. The technical condition of power equipment is influenced by climatic, operational and technological factors. Modern systems for monitoring the technical condition of power equipment based on measurements on operating equipment ensure its stable operation, signal critical deviations in performance indicators, and evaluate the predicted service life. While making diagnostic measurements of auxiliary transformers, it is proposed to measure the following performance indicators and parameters: load and voltage level (on the HV side); temperature of the upper oil layers; oil level; tank noise and vibration; oil moisture content; the appearance of the main components (integrity check). Analysis of measurement data in determining the technical condition of auxiliary transformers includes a retrospective analysis of changes in test data during maintenance, measurement data in operating mode, analysis of the level and speed of changes of diagnostic data.Technical condition of transformers is assessed and forecasted within the framework of the proposed expert system, which takes into account the data of tests and measurements of diagnostic data and electrical quantities. The considered system of monitoring the technical condition of auxiliary transformers of traction substations is a part of a single equipment condition monitoring system, the construction of which is associated with the project of a digital traction substation. The proposed solutions correspond to the concept of switching to a maintenance system based on the current state, improving the reliability of equipment operation and preventing emergency events.