Search

In a railway traction substation, power electronics devices are used in conjunction with a special transformer of a traction substation to mitigate power quality issues. To study the use of power electronics devices with conventional transformer, this research studies the use of a conventional Delta-star transformer along with power electronics converters. The system forms a co-phase system using single-phase back-to-back converters, which addresses the issue of current unbalance and power factor correction. The control theory derives the value of currents to be drawn from the secondary of traction transformer so as to draw balanced power from the three phases of the grid supply. Accordingly, a control algorithm is developed which calculates the reference converter currents and operates the converters. Validation of control theory is done analytically. Simulation and real-time hardware-in-loop experimentation are performed under different loading conditions. The steady-state and dynamic behavior of the system is studied to validate the proposed control algorithm. The work is presented as a proof of concept. [ABSTRACT FROM AUTHOR]

It has been shown that a three-wire traction power-supply circuit of subway trains increases its energy efficiency by only reconnecting the power lines. The reduction in total electricity consumption by traction substations on a test section of seven traction substations during a model time of 2 h was 2.9%, the reduction in energy losses in the contact and running rails was 6.3%, and the increase in minimum voltage in the traction network was 10–25 V. This indicates the prospects for further study of this system, working out issues of modifying rolling stock to protect against polarity reversal and operation of signaling, centralization, and blocking devices. [ABSTRACT FROM AUTHOR]

The introduction of twelve-pulse rectifiers instead of six-pulse ones at traction substations of urban electric transport leads to an increase in technical and economic indicators, energy savings, a decrease in leakage current. These result in electrical safety of passengers, a trolleybus driver and depot maintenance personnel. Twelve-pulse rectifiers can have a serial or parallel connection of sixpulse bridges. With a parallel circuit, it is necessary to have an equalizing reactor. The implementation of a twelvepulse serial type rectification scheme can be carried out by industrial development by manufacturers of new dry converter transformers with different typical power and new rectifiers (blocks). As part of the new rectifiers, it is necessary to have tablet avalanche valves with coolers based on heat pipes due to their advantages over nonavalanche valves.

Finding the optimal location and power capacity of traction substations is a problem in the design of DC electric power supply systems for trains. The proposed method uses evolutionary multi-objective optimization (EMO) to find the solution. By using two optimization steps: firstly, finding the Pareto optimal solutions with NSGA-ii method, and secondly, selecting from the Pareto optimal solutions by using higher-level information to obtain the best solution. The method is used to optimize 15 kilometer (km) railway power supply systems with three or four traction substations. The load sharing between the traction substations is almost the same as the minimum power capacity. Therefore, the single best solution is obtained, showing that the minimum solution requirements for the location and power capacity of the traction substations are met. [ABSTRACT FROM AUTHOR]

Sites for deployment of energy-storage facilities at traction substations of subway lines or divisions of electric-railway power supply are selected by complex simulation of the traction power-supply system with multifactor analysis of traffic intensity, track profile, storage operation modes, exchange of trains, connection circuits of the traction power-supply system, etc. The calculations, which are iterated for large polygons with various options for deployment of storage facilities, are very time consuming. All traction substations of a subway line or power-supply division cannot be concurrently equipped with energy storage devices due to forbiddingly high costs. However, the choice of the site(s) for the deployment of storage devices should be based on an analysis of the effects on each other of all the electrical facilities along the entire line, these being traction substations and their electric equipment and electric rolling stock. An account for and analysis of the influence on each other of all electrical objects can be performed in the simplest way only using the matrix-topological method of analyzing electrical circuits and generalizing parameters of the electric circuit. A simplified method of rational selection of the site(s) for the deployment of energy-storage facilities on a subway line or a division of traction power supply of electrified railways is described. [ABSTRACT FROM AUTHOR]

Nowadays, nations are moving toward the electrification of the transportation section, and the widespread development of EV charging stations and their infrastructures supplied by the grid would strain the power grid and lead to overload issues in the network. To address this challenge, this paper presents a method for utilizing the braking energy of trains in railway stations to charge EVs located in strategic areas like park-and-ride regions close to railway stations improving energy efficiency and preventing grid overload. To validate the feasibility of the proposed system, a metro substation in Milan city is considered as a case study located in outskirts of the city and contains large number of parking space for vehicles. Three different scenarios are evaluated including DC fast charging station, AC low charging station and collaborative hybrid energy storage based AC charging station as EV charging station type. The results are studied for different EV population number, charging rate and the contractual power grid. Meanwhile, the possibility of proposed system in participating as V2G technology and taking advantage of the EV's batteries to provide ancillary support to accelerating trains is investigated regarding peak shaving objective. The results indicated that the suggested interconnected system operates effectively when a significant quantity of EVs are parked at the station. However, the results revealed that the performance of the proposed system is notably influenced by other factors and a limited number of EVs during the early morning and late evening periods. Overall, this study confirms the feasibility of energy transfer between two types of transportation means in intermodal areas. [ABSTRACT FROM AUTHOR]

Electric power supply system planning is practically an important function of the modern light rail transit system with catenary free operation and rapid charging. Installing a modern dynamic load of the traction power supply system with the local electric distribution network needs to consider its capacity and feeder to support enough and efficiently. In this paper, the design of the electrical power supply system of the pilot project of Nakhon Ratchasima Green Line light rail system with 11.6-km line length and 21 passenger stations operated with catenary-free and powered with an on-board energy storage device has been proposed and planned to replace the old local transportation. The traction power supply of the light rail system drawn power from the MV distribution feeder practically consist of receiving power substation, MV power feeding system power feeder substation, charging power supply and service power supply have been designed provided the configuration circuit. A rapid charge system to delivery high power to fulfill the on-board energy storage is considered to recharge at passenger stations with an overhead conductor or wireless power transfer during a short dwell time. A number of charging station is determined accordingly the capacity of the power substation and its positions. The traction power drawn by a train service round-trip that related to the capacity of the power substation as a charging station has been calculated by the simulation of the train movement. The regenerative braking energy during train operated in braking mode is also considered as a partial charging energy the on-board energy storage device. From the proposed design, the motive energy consumption of each scenario charging formations obtains the maximum charging energy drawn by the train between charging points, the capacity of on-board energy storage devices, maximum charging power and the total charging points.

Integrated subway systems have emerged as a new trend that provides the highest quality service at the lowest investment cost by combining the advantages of the two largest passenger transport capabilities during peak hours. Under the integrated model, designing the traction power supply is much more complex than for other independent systems. This article presents the results of a study on the method of calculating the design load of the power supply for the transport operation of the system. Matlab R2017b/Railway Systems is a reliable software for simulating and analyzing some necessary data, and the research results show the feasibility of the method when applied to the case of asynchronous load on the system. The results meet the power supply design standards according to IEEE P1653.2, EN 50328, and IEC 60146-1 overload allowances for class VI, and voltage standards according to EN 50163, UIC 600, and IEC 60850. [ABSTRACT FROM AUTHOR]

The article presents the results of studies on improving the efficiency of electrical power redundancy systems in power supply systems of railway DC vehicles by improving the technological modes of traction substations. There are presented scientifically based technical solutions of the hardware, a control algorithm of the power reserve system for traction substations with two converter units and a methodology for selecting places for installing automatic power reserve systems to increase the efficiency of the power supply system for railway vehicles. Practical testing of the developed technical and technological solutions has shown the effectiveness of their use in operating conditions.

This paper presents a conception of 3 kV DC traction power system based on distribution sources, as an alternative to traditional traction substation. The system consists of supplying modules (SM) installed along the electrified railway line, the distance between adjacent SMs are much shorter, than between traditional traction substations in 3 kV system. Each SM consists of energy storage system (ESS), and could be charged from adjacent, traditional traction substation via catenary, via medium voltage supplying lines, renewable power sources or by energy recuperation. In the article, the main parameters of the proposed supplying system operation have been compared with parameters of the system with traditional traction substation. For this purpose, in a case study, comparison analysis has been carried out for energy losses in catenary, 15-min peak power demand as well as the cost of the system installation. At the end, the reliability analysis has been carried out for proposed distribution power supply system and for traditional one. [ABSTRACT FROM AUTHOR]

Introduction. The authors analyse the problem of implementing regenerative braking on the AC locomotive with a monophase reversible voltage converter.Materials and methods. The article consided theoretically possible options for the operation of monophase reversible voltage converters during regenerative braking, in which: 1) the reactive component of the electric locomotive current had a capacitive nature, and the operating current of the electric locomotive was ahead of its reactive component; 2) the reactive component of the electric locomotive current had an inductive nature, and the current of the electric locomotive was ahead of its active component. The research demonstrated that the former was only theoretically possible, since the regeneration of current into the contact network was carried out at a very low voltage, significantly less than the lowest voltage on the current collector. The latter was technically feasible in terms of the main harmonic of the electric locomotive current lagged by an angle exceeding of 90 electrical degree, but noticeably smaller than 180 electrical degree. Regenerative braking with a power factor close to unity was possible only theoretically, but in practice a power factor of 0.8–0.9 should be realized. The tangent of the angle between the effective current and its active component was greater (for a certain margin) than the quotient from dividing the active by the inductive resistance of the traction network between the electric locomotive and the traction substation. Moreover, it was necessary to consider the technological reduction of the ohmic resistance in the process of the monophase reversible voltage transducer control (e. g. over the deterioration of contact wire).Results. The article demonstrates the possibility and conditions for the regenerative braking implementation on AC locomotives. Hence, a more advanced electric locomotive current control system with an additional channel for regulating the inductive component of the recuperation current is recommended for development.Discussion and conclusion. An advanced control system stabilizes the current collector voltage and with the channel for regulating the active component of the regeneration current provide for the voltage maintanance at a higher level, determined by the actual electrical parameters of the contact network and the train traffic.

The isolation switch is one of the most important pieces of electrical equipment in traction substation, and its state directly reflects the operation of the power system. However, the realization of automatic isolation switch monitoring based on computer vision still faces three problems, i.e., intra-class diversity, inter-class polymorphism of components, and complex backgrounds. To overcome the issues of isolation switch positioning and states recognition in railway traction substation, we propose a state recognition method of isolation switch in traction substation based on key components detection and geometric ranging. This method is divided into two parts, i.e., ISD-Net for isolation switch detection and geometric ranging for state recognition. Firstly, ISD-Net is proposed to realize isolation switch detection. Secondly, an algorithm based on geometric ranging is designed, which utilizes the coordinate information of key components to realize automatic recognition of isolation switch state. To train the model and evaluate the effectiveness of our method, we established a dataset of isolation switch (called IVIS2021). On IVIS2021, isolation switch detection and state recognition accuracy reach 90.88% and 91.12%, respectively. The experimental results indicated that the proposed method accurately realizes isolation switch detection and state recognition. [ABSTRACT FROM AUTHOR]

The analysis of the problem of innovative transformation of power supply networks of railways made it possible to scientifically substantiate the direction of research related to an optimal strategy for computer monitoring and intellectualization of the processes of power supply of traction substations of railways. Conceptual approaches to the formation of a new model of intellectualization of power supply networks have been developed. Differential models of high organization of synchronous vector measurements are proposed, allowing to determine the comprehensive information content of the primary data. Based on the concept of smart energy, a set of differential models and methods of harmonic and correlation analysis of anomalous and transient processes occurring in power systems has been developed. The REGINA computer system has been designed and manufactured to carry out, in real-time, intelligent monitoring, diagnostics, identification of accidents, optimization of power consumption and expanding the range of market services in managing railway power supply networks. The REGINA system complies with the requirements of ISO 9001: 2015 and the German certification body DOS. Many actual results obtained during the operation of the REGINA on the railways are presented.

Responsible users of auxiliaries of a combined traction substation (CTS) of the subway and the features of their work are considered taking into account the effect of traction load and external disturbances. The criteria to estimate the quality of electrical energy in the supply of users of auxiliaries of the CTS are described. To estimate the quality of electrical energy, the experimental measurements are presented in the power-supply circuits of auxiliaries at two operating CTS with various capacities. The current and voltage oscillograms are given in real time for 24 h. The extremely uneven loading of a three-phase auxiliary system and the instability of voltage levels by phases on buses of a 0.4-kV CTS are qualitatively and quantitatively shown, the asymmetry indicators for positive and negative sequences are calculated. Statistical analysis of the results of experimental measurements showed a discrepancy in the quality of electric energy of the power supply network for the CTS auxiliaries. The means to improve the reliability and quality of electricity with a help of a dc link and use of an energy storage device in the form of a CTS auxiliary battery are suggested. [ABSTRACT FROM AUTHOR]

The main requirements for the traction power-supply system of a subway consist in reliability, continuity, and economic feasibility. Alongside with the development of the subway system, the growth in length, and the commissioning of novel stations and traction substations, those track sections and facilities that have been put into operation a considerable time ago require modernization. To do this, it is necessary to calculate the parameters of the traction power-supply system under modern conditions and to choose correctly all the power elements and equipment. However, a more important issue is connected with choosing the stages of modernization. It is important to keep all the sections of the subway in operation in such a way that modernization does not affect the social and economic aspects of urban life. This paper is devoted to studying the stages of subway modernization in detail from a practical standpoint, involving real functional parameters of the subway traction substations, as well as to the formulation of specific practical recommendations. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Short circuit currents are traditionally calculated in traction ac and dc networks assuming that each of the traction substations has an independent power source. In fact, in most cases a group of traction substations is connected to a single high voltage longitudinal power line that is a component of an external power supply system. Failure to take this into account may lead to errors in calculating distant short circuits reaching several tens of percent, which is entirely impermissible for ensuring reliable functioning of relay protection. Setting up an equivalent circuit for an external electrical supply for calculations of short circuits is a fairly complicated and undesirable procedure, which makes the practical calculations much more complicated. It has been shown that the existing recommendation for the equivalent circuit for a traction substation in a three-phase system of single-phase alternating current with power sources and other components of the system, included in a triangle but not traditionally, in a star, is unjustified and cannot be used for this purpose. A universal equivalent circuit for external electrical supply that takes the features of the system and the connections of inputs for traction substations to a longitudinal electrical supply into account is developed and presented. It is proposed that the resulting resistance of this system be calculated on the basis of known three-phase short-circuit currents at the inlets to two neighboring traction substations. A generalized equivalent circuit for a system of external and traction electrical supply during a short circuit in a contact network for dc and single-phase alternating currents is introduced together with equations for calculating its parameters. [ABSTRACT FROM AUTHOR]

The analysis of the problem of innovative transformation of power supply networks of railways made it possible to scientifically substantiate the direction of research related to an optimal strategy for computer monitoring and intellectualization of the processes of power supply of traction substations of railways. Conceptual approaches to the formation of a new model of intellectualization of power supply networks have been developed. Differential models of high organization of synchronous vector measurements are proposed, allowing to determine the comprehensive information content of the primary data. Based on the concept of smart energy, a set of differential models and methods of harmonic and correlation analysis of anomalous and transient processes occurring in power systems has been developed. The REGINA computer system has been designed and manufactured to carry out, in real-time, intelligent monitoring, diagnostics, identification of accidents, optimization of power consumption and expanding the range of market services in managing railway power supply networks. The REGINA system complies with the requirements of ISO 9001: 2015 and the German certification body DOS. Many actual results obtained during the operation of the REGINA on the railways are presented. [ABSTRACT FROM AUTHOR]

Specific features of operations of auxiliaries of a combined traction substation (CTS) including the effects of traction load are considered. A symbolic circuit of a simulation model of an actual Moscow subway CTS is presented. The main objects of the study—consumers of automobile-engine transformers and lighting and signaling systems—are described, which are taken into account in the simulation of CTS operations that also includes a traction-network segment with trains and an external power-supply system. The instability of voltage on 10- (20)-kV CTS buses and the asymmetry level are shown in qualitative and quantitative terms. Similar oscillograms are also presented for an end consumer—a motor engine—with similar deviations in the electric power quality. The simulation results have been statistically processed. An engineering solution is proposed that consists in using a dc link with energy-storage units to enhance the quality of the power supplied to the CTS' essential auxiliaries. [ABSTRACT FROM AUTHOR]

In the case of a simultaneous operation of multipulse rectification circuits at traction substations of subways, a staged replacement of rectifier units leads to overloads and even to equipment disconnection and failure. The solution to the problem may consist in a change in the secondary voltage of converter transformers. As a rule, for the strictest case, in which one of the rectifiers is a 12-pulse one, and the rest of the transformers are 6-pulse ones, a guaranteed solution to the problem could be provided by a 2.5–5% decrease in the secondary voltage across the converter transformer that feeds the 12-pulse rectifier. In the case of such an approach, the voltage across the busbars of the traction substation remains rated. The change in the secondary voltage is required only for the period of a simultaneous operation of multipulse rectification circuits when modernizing traction substations. At the end of the modernization, when all the rectifiers are of the same type, the secondary voltage across the transformers should be restored to the rated one. In this paper, this issue is considered from a practical point of view on the basis of the real parameters of the functioning of subway traction substations and specific recommendations are given. [ABSTRACT FROM AUTHOR]

Purpose. To develop the method for increasing the efficiency of the equipment’s maintenance and repair system, ensuring necessary level of operational reliability of the equipment, safety and reliability of the electric equipment with minimal expenses on operation. Relevance. Aging of the power equipment in railway power supply systems sharply raised a need for assessment of its states and degree of risk for operation outside rated service life. In critical conditions of technological processes and operational modes of the railways it is necessary to increase the equipment’s operational reliability. The scheduled maintenance and repair system whose main technical and economic criterion is the minimum of equipment’s downtimes on the basis of a rigid regulation of repair cycles, in the conditions of market regulations in the field of repair in many cases does not provide the optimal decisions due to insufficient financing. The solution of this problem is possible by improvement of the maintenance and repair system. Under these conditions the main direction for supporting the operational reliability of power electric equipment on TS is a development of the modern methods based on individual supervision over real changes of technical condition of power equipment. Scientific novelty. In this article the authors proposed an integrated approach, on the basis of which can be developed the effective maintenance and repair system for traction power supply systems. Proposed approach allowed to react quickly to changes of service conditions on traction substations, to control the technical condition of power electric equipment under the conditions of uncertainty, to establish interrelation between quality of service and operational reliability of the equipment, to choose a service strategy on traction substations. Practical importance. The validity of the developed method was confirmed by the results of calculations and practically by choosing the optimal maintenance's option for transformer TDTN-25000/150-70 U1 (ТДТН-25000/150-70 У1) on traction power supply substation.

Overvoltage and overcurrent problems during passing phase-separation and negative sequence current penetration problem are the critical problems in high speed, heavy duty electrified railways, which greatly constrants the safe operation of railway and safety and stability of power system.A novel uninterruptible phase-separation passing and power quality compensation scheme for double-line traction network is proposed in this paper.System configuration, working principle and control strategies are studied.Typical operating modes are designed with the composition of the condition that whether there is locomotive passing neutral section and simulations under various operation modes are carried out in PSCAD.Results show that the proposed scheme can help locomotives from two elirections passing phase-separation without loss of power simultaneously one locomotive passing neutral section to ensure optimal power quality.

The mathematical model is elaborated and analysis of the system is done on the adaptive voltage control and reactive power compensation of AC traction to minimize active losses. Sharp changes in the load shoulder traction substation, which includes a compensating installation, leads to a decrease in the voltage loss in the system to it, and therefore to an increase in its power, which in turn will cause an additional increase in voltage in the traction network. To this voltage does not exceed the permissible, it is necessary to use longitudinal-transverse compensators with adjustable parameters. The purpose of this article is to justify the selection of an algorithm for adaptive voltage regulation and parameters of the reactive power compensator based on continuous measurement of the external power supply system in the simulation of its operation modes, taking into account the influence of the traction power supply system. In particular, it provides for the possibility of regulating the voltage of the traction transformer under load when included in the traction network of longitudinal-transverse compensators installations, taking into account the longitudinal and transverse asymmetry of the power supply system parameters and its real parameters, as well as the non-linear nature of the current-voltage characteristics of the electric rolling stock. In this paper, we will consider in a first approximation a power supply system with a single traction substation with an adjustable transformer equipped with voltage regulation under load, and an adjustable installation of transverse capacitive compensation of compensating installation.

This article analyzes the operating modes of the energy storage. The aim was to conduct laboratory tests in conditions similar to real energy storage and to analyze its basic electrical parameters. A special measuring system has been created for laboratory testing. Real tests took place in the traction substation in Mińsk Mazowiecki, where the energy storage was included in the traction substation system. Based on the laboratory tests carried out and in real conditions it was found that the use of energy storage in the electric traction supply system is justified. It is adapted to work as a device supporting the operation of the traction substation and the section cabin. [ABSTRACT FROM AUTHOR]

Copyright of Electric Power Automation Equipment / Dianli Zidonghua Shebei is the property of Electric Power Automation Equipment Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose. The aim of this work is to develop a mathematical model of the generalized diagnostic indicator of the technical state of traction substations electrical equipment. Methodology. The main tenets of the experiment planning theory, methods of structural-functional and multi-factor analysis, methods of mathematical and numerical modeling have been used to solve the set tasks. Results. To obtain the mathematical model of the generalized diagnostic indicator, a full factorial experiment for DC circuit breaker have been conducted. The plan of the experiment and factors affecting the change of the unit technical condition have been selected. The regression equation in variables coded values and the polynomial mathematical model of the generalized diagnostic indicator of the circuit breaker technical condition have been obtained. On the basis of regression equation analysis the character of influence of circuit breaker diagnostic indicators values on generalized diagnostic indicator changes has been defined. As a result of repeated performances of the full factorial experiment the mathematical models for other types of traction substations power equipment have been obtained. Originality. An improved theoretical approach to the construction of generalized diagnostic indicators mathematical models for main types of traction substations electric equipment with using the methods of experiments planning theory has been suggested. Practical value. The obtained polynomial mathematical models of the generalized diagnostic indicator D can be used for constructing the automated system of monitoring and forecasting of the traction substations equipment technical condition, which allows improving the performance of processing the diagnostic information and ensuring the accuracy of the diagnosis. Analysing and forecasting the electrical equipment technical condition with the using of mathematical models of generalized diagnostic indicator changes process allows constructing the optimal strategy of maintenance and repair based on the actual technical condition of the electrical equipment. This will reduce material and financial costs of maintenance and repair work as well as the equipment downtime caused by planned inspections and repair improving reliability and uptime of electrical equipment.

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.

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.

Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

An approach to designing subway traction power supply facilities with an 825-V traction power system is considered in a general digital model. The continuously increasing passenger traffic in metropolitan cities makes it necessary to build new subway lines and upgrade existing ones, taking into account the compliance with all the standards of ensuring uninterrupted power supply at minimal electric stock (ES) train-to-train spans. The ES is also being upgraded, which includes the commissioning of new-type Moscow cars. To maintain the rates of commissioning new subway lines, the quality of design must be improved and the design process must be relocated to the digital environment. An example digital model (twin) of subway traction power system is exposed, as well as its application to estimating the dynamic behavior of ES. [ABSTRACT FROM AUTHOR]

This paper presents an electrical infrastructure planning method for transit systems that operate with partially grid-connected vehicles incorporating on-board batteries. First, the state-of-the-art of electric transit systems that combine grid-connected and battery-based operation is briefly described. Second, the benefits of combining a grid connection and battery supply in Bus Rapid Transit (BRT) systems are introduced. Finally, the planning method is explained and tested in a BRT route in Medellin, Colombia, using computational simulations in combination with real operational data from electric buses that are currently operating in this transit line. Unlike other methods and approaches for Battery Electric Bus (BEB) infrastructure planning, the proposed technique is system-focused, rather than solely limited to the vehicles. The objective of the technique, from the vehicle’s side, is to assist the planner in the correct sizing of batteries and power train capacity, whereas from the system side the goal is to locate and size the route sections to be electrified. These decision variables are calculated with the objective of minimizing the installed battery and achieve minimum Medium Voltage (MV) network requirements, while meeting all technical and reliability conditions. The method proved to be useful to find a minimum feasible cost solution for partially electrifying a BRT line with In-motion Charging (IMC) technology.

Purpose.The article is aimed to develop the means and methods of forming a plurality of real and potential structural diagrams for zones of energy recovery and different locations of trains for further training neuro-fuzzy networks on the basis of expert solutions and also for the formation of good control. Methodology. Methodology of mathematical and algorithmic constructivism for modeling the structural diagrams of the electric supply system and modes of traction power consumption and the train’s locations in zones of energy recovery was applied. This approach involves the development of constructive-synthesizing structures (CSS) with transformation by specialization, interpretation, specification and implementation. Development CSS provides an extensible definition media, relations and the signature of operations and constructive axiomatic. The most complex and essential part of the axioms is the set formed by the substitution rules defining the process of withdrawal of the corresponding structures. Findings. A specialized and specified CSS, which allows considering all the possibilities and features, that supply power traction systems with modern equipment, stations and trains location was designed. Its feature: the semantic content of the terminal alphabet images of electrical traction network and power consumers with relevant attributes. A special case of the formation of the structural diagram shows the possibilities CSS in relation to this problem. Originality. A new approach to solving the problem of rational use of energy recovery, which consists in application of the methods and means of artificial neural networks, expert systems, fuzzy logic and mathematical and algorithmic constructivism. This paper presents the methods of constructive simulation of a production-distribution of energy recovery zone structure in the system of the DC traction. Practical value. The tasks decision of the rational use of energy recovery can significantly save energy, contribute to the technical re-equipment of a railway transportation of Ukraine through the introduction of modern means and capabilities. The developed model can be used to solve other energy-saving tasks in different systems of electric transport.

Nowadays the issue of electric energy saving in public transport is becoming a key area of interest which is connected both with a growth in environmental awareness of the society and an increase in the prices of fuel and electricity. It can be achieved by improving the usage of regenerative breaking. In 2016 the Przedsiębiorstwo Komunikacji Trolejbusowej (PKT, Trolleybus Transport Company) in Gdynia began practical implementation of Smart Grid solutions within its trolleybus network. These activities constitute an element of the project ELIPTIC, realised by PKT within the scientific research fund Horizon 2020. The first stage of implementing intelligent network solutions was completed in 2016, and further activities are planned for the next few years. This paper presents a review of Smart Grid solutions which can be implemented in urban traction supply systems, describes the PKT experience concerning the implementation of Smart Grid solutions in trolleybus network supply system to date.

Purpose. The purpose of this paper is development of methodology for definition of a quality system of maintenance and repair (M and P) power equipment of traction substations (TS) of electrified railways operating under conditions of uncertainty based on expert information. Methodology. The basic tenets of the theory of fuzzy sets and marks, linguistic and interval estimates of experts were applied to solve this problem. Results. Analysis of the existing diversity of approaches to development of modern methods of improvement of M and P allows us to conclude that the improvement in the quality of the system is achieved by solving individual problems increase the operational reliability of power equipment of traction substations in the following main interrelated areas. There are technical, economic and organizational. The basis of the quality evaluation system is initial data and expertise developed version of the document formalized quality evaluation of electrical equipment of traction substations by experts. The choice of determining the level of Quality service system based on the marks, linguistic and interval estimates of experts, which are reflected in quantitative and / or qualitative form was done. The possible options for expert data presentation and their corresponding quantitative methods of calculating the integral index of quality improvement system maintenance and P of traction substations were described. The methodology and the method of assessing the quality of system maintenance and P of TS allows quickly respond to changing operating conditions of power equipment of traction substations, and to determine the most effective strategies for maintenance of electrical and P TS under conditions of uncertainty functioning distance electricity. Originality. The method of a systematic approach to improve the quality of the system maintenance and P of power equipment of traction substation under conditions of uncertainty based on expert information was further developed. The author offers a number of options at first time. There are version of the document formalized quality evaluation of power equipment of traction substations by experts; expression to define the integral Quality systems maintenance and electrical power P TS, which is absent in the standard system maintenance and P; matrix of quality system with regard to steps (methods) and ways of increasing service quality electrical power control systems. This method makes it possible to conduct an expert assessment of the maintenance system and to predict and select the option rational system of quality improvement and maintenance of power equipment of traction substations considering not only technical but also organizational, legal, financial and economic measures. Practical value. Improvement on electrified railways of Ukraine quality management system maintenance and P TS will improve the efficiency and quality of maintenance of power equipment and provide TA prevent or reduce the severity of possible equipment failures. Based on the relationships matrix components as systems maintenance and electrical power P TP were formed expressions calculating quality indices of integrated systems with directions and stages for specific equipment and systems in general. It was determined that an increase in the quality and maintenance of electrical PR, the rate of change of the measured value at step k during operation is reduced while the standard deviation parameter is also reduced, and the probability of electrical TA increases.

Purpose. The study provides the methods and models development of reducing damages of traction energy systems (TES) at electrified railways of Ukraine. Definition the indicator of preventing damage evaluation TES at electrified railways is necessary. Paper is aimed to search the modern methods and approaches to improve the system of TES monitoring, diagnosis and maintenance. Methodology. To achieve this purpose a study of foreign experience and publications that focus on problem-solving quality of TES using a linguistic approach based on the theory of fuzzy multiple numbers and linguistic variable were done. Findings. In result of research an algorithm to reduce TPS damages which operates under uncertainty was developed. It is found that the solution of this problem is possible by timely detection of actual technical condition of equipment in terms of quality maintenance, diagnostics and update resource of electrical equipment traction substations (TS) power supply TES. The study examined the fuzzy inference scheme, which is based on the use of mechanisms to minimize the area of decision-making. It contributes not only to structural identification in the process of developing a database, but also can significantly improve the efficiency of finding the parameters of fuzzy model, which in turn reduces the efforts that are necessary for the analysis and the design of effective control systems maintenance and repair (M and R) TES. Originality. For the first time the algorithm of reduction the damage of traction energy system of electrified railways of Ukraine was offered. The mathematical model of reduction the damage calculation of TES from TP power equipment failures by improving system maintenance (M and P) was developed. Firstly evaluation index was proposed to prevent the damage of traction energy system. Practical value. The article describes the fuzzy inference scheme, which is based on the use of the mechanism to minimize the area of decision-making and contributes not only to structural identification in the process of developing a database, but also can significantly improve the performance of determining the parameters of fuzzy model. Implementation of this approach comes to the determination of the main stages, features and optimal justification of quantitative and qualitative requirements for system M and R of TS. It will be done with allowable costs for improvements to reduce TPS damage and address the equipment of traction substations in working condition in terms of growth rates and volumes aging (compared to the current speed and volume of updates).

Nowadays the issue of electric energy saving in public transport is becoming a key area of interest which is connected both with a growth in environmental awareness of the society and an increase in the prices of fuel and electricity. It can be achieved by improving the usage of regenerative breaking. In 2016 the Przedsiębiorstwo Komunikacji Trolejbusowej (PKT, Trolleybus Transport Company) in Gdynia began practical implementation of Smart Grid solutions within its trolleybus network. These activities constitute an element of the project ELIPTIC, realised by PKT within the scientific research fund Horizon 2020. The first stage of implementing intelligent network solutions was completed in 2016, and further activities are planned for the next few years. This paper presents a review of Smart Grid solutions which can be implemented in urban traction supply systems, describes the PKT experience concerning the implementation of Smart Grid solutions in trolleybus network supply system to date. [ABSTRACT FROM AUTHOR]

Copyright of Technical Transactions / Czasopismo Techniczne is the property of Sciendo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Two blocks were commissioned of an RZhFA-6500 reactor as part of the two-link smoothing device at the Letnaya traction substation of the Sverdlovsk Railroad. To test the efficiency of the reactor, a forced short circuit experiment was performed without stopping the movement of the electric vehicle over the section, the level of psophometric voltage on the dc buses of the traction substation was measured and an experiment was carried out of a forced short circuit with cessation of movement over the section. During the experiments, oscillograms of transient processes were taken, analysis of which confirmed the efficiency of the new type of reactor in the structure of a two-link filter device. [ABSTRACT FROM AUTHOR]

On August 17th, 2012, a diode rectifier at Nagano Traction Substation was broken. The broken rectifier was dismantled and investigated in detail and, as a result, it was estimated that the overvoltage caused by the lightning flash caused the dielectric breakdown in the rectifier. To confirm the assumption of the broken process, the field measurement at Nagano Traction Substation and FDTD (finite-difference time-domain) calculation analysis at Nagoya Institute of Technology were carried out. As a result, it was indicated that the direct lightning to the elevated bridge over the substation caused the transient overvoltage of the grounding system of the substation and resulted in the breakdown within the rectifier. Because the concrete bridge pier is located adjacent to the substation, the surge voltage from the elevated bridge is able to influence the potential of the substation mesh. In this paper, the investigation process to determine the cause of the trouble will be shown in detail. [ABSTRACT FROM AUTHOR]

• A power flow decoupling algorithm for traction power supply system is proposed. • An identification method of TPSS power supply capacity is introduced. • The performance of the two-phase algorithm is validated by conventional methods. • The proposed method is particularly advantageous in complicated coupling systems. Power flow analysis of traction power supply system (TPSS) is an effective approach to assess supply capacity and power quality, serving the whole process of system design, operation and optimization. The coupling effect between adjacent power supply arms poses challenges for the accurate and efficient solution, especially with the penetration of power converters and energy equipment. This paper proposes a two-phase power flow decoupling algorithm. TPSS is divided into traction substation and two decoupled power supply arms by introducing current ratio coefficients and unit matrices. Specifically, the equivalent voltage source model of traction substation and the modified chain network model of arms are solved by using forward–backward sweep method and LU decomposition method, respectively. Then the TPSS power flow can be obtained by alternative iteration of two solving phases. Simulations verify the proposed algorithm exhibits great compatibility at various operation modes. Additionally, the power supply capacity is mapped to the algorithm convergence. Compared to conventional methods, the algorithm achieves superior performance on accuracy and efficiency. [ABSTRACT FROM AUTHOR]

Purpose. Investigation of the operation of power equipment of traction substations (TS) of Ukrainian electrified railways. The search of the new modern methods and approaches improved monitoring, diagnostics and maintenance of power equipment TS during operation to maintain the required level of reliability of the traction power supply of electrified railway and limit the power equipment accidents TS. Methodology. The study of changes of a technical condition of TSs’ equipment over the last 11 years was done for achieving this goal. This research was done for solving problems of power supply railways with high quality on the base of the reports analysis of the management and power supply of Ukrzaliznytsia. Findings. It was found that on the base of the new methods of maintenance is the risk analysis of old equipment or equipment with some defects (rev servicing equipment for the actual technical condition).Reliable performance of power supply devices has significant impact for solving the problem of safety on the railways of Ukraine. Different kinds of accumulated damage are at the first place before of failures of an electric power supply of electrified railway. The study of main causes of violations from 2002 to 2012 year showed that 80% of the reasons disorders normal operation of the traction power supply over the period constitutes next factors. There are damage to the main power equipment TS; power off the grid; overload and surge; and the impact of weather conditions. The primary power equipment failure of TS are constituted about 43%. Relevant constant monitoring, testing and diagnostics of the equipment with the creation and use of micro-processor smart automated monitoring and diagnosis are topical in the current operating conditions. Originality. The new directions for further improvement of maintenance electrified traction substations for electrified railways were considered. Modern strategies and management techniques and maintenance TS electrified railways of Ukraine were proposed at the first time. This methods aren’t covered in the "Instructions for maintenance and repair of equipment of traction substations, power points and sectioning electrified railways’ IT-0024. The basic problems for implementation of these strategies were identified. Practical value. It was established that system outage under tight central planning and management in the new economy does not provide, in many cases, approval and adoption of effective and optimal solutions in organization and carrying out maintenance. It was investigated that a significant portion of electric power equipment of TS even after normative life maintains its performance under the terms. There are allowable stress regimes, timely testing, diagnosis, maintenance, repair and quality of execution; on the other hand the service life of electrical equipment depends on its residual life.

At present a great attention is paid to increasing of energy efficiency at operated electrified urban transport. Perspective direction for increasing energy efficiency at that type of transport is the application of regenerative braking. For additional increasing of energy efficiency there were suggested the use of capacitive drive on tires of traction substation. One of the main task is the analysis of energy recovery application with drive and without it.These analysis demonstrated that the calculation algorithms don’t allow in the full volume to carry out calculations of amount and cost of energy recovery without drive and with it. That is why we see the current interest to this topic. The purpose of work is to create methods of algorithms calculation for definite amount and cost of consumed, redundant and recovery energy of electrified urban transport due to definite regime of motion on wayside. There is algorithm developed, which allow to calculate amount and cost of consumed, redundant and recovery energy of electrified urban transport on wayside during the installation capacitive drive at traction substation. On the basis of developed algorithm for the definite regime of wagon motion of subway there were fulfilled the example of energy recovery amount and its cost calculation, among them with limited energy intensity drive, when there are 4 trains on wayside simultaneously.

Purpose. At the stage of modernization and reconstruction of electrified railroads in Ukraine one should take into account the innovative development level of all electric supply subjects on the basis of advanced technologies. Determination the ways to increase the power supply reliability of electrified railways and reducing the accidents of the traction substation power equipment (TS). Methodology. For attainment a goal it’s studied the international experience on qualitative power supply of the electrical railways at the basis of the ideology of Smart Grid. It’s conducted a research of the major methods of technical servicing, repairing (TS and R) and diagnostics the traction substation devices of electrified railways. Findings. As a result of research it was concluded that the basis of the new methods of maintenance and repearing is analysis of the risks of operation of the weared equipment or equipment with some defects (maintenance of equipment on the basis of the actual technical condition). It’s also concluded that the conceptual definitions of Smart Grid point to the important role of smart grid technology to the economic development of the electrical system. Significant world experience of maintenance and repairing at the basis of the actual technical state shows the following general assessment of the effectiveness of this method: reducing maintenance costs by 75%, reducing the number of services up to 50%, reduction the number of failures by 70% in the first year. Originality. As a research and improvement result of the maintenance and repairing system of traction substations, the author has proposed the concept of maintenance and repairing intelligent system, monitoring and diagnostic of technical process equipment. The basic components of the system are proposed. It’s proposed a maintenance of the equipment of traction substation at the actual technical state with better resource parameters. In the normative document for maintenance and repairing of the equipment of traction substations, power points and sectioning posts of the electrified railways "CE-0024", this approach for organizing and conducting the maintenance and repairing of the TS is not considered. Practical value. Implementation of this system allows: to increase the main indicators of maintenance and repairing; decrease operating costs of the power equipment by using maintenance and repairing at a basis of the actual technical state; improve the reliability of equipment and the power supply system of TS of electrified railways, obtain economic benefit, and so on.

Purpose. Influence investigation of contact system parameters on current rate of rise during short circuit, and the difference of these parameter values under different connection diagrams of traction motors in the power circuit. Methodology. The mathematical model and method for determining the effect of the contact system parameters, such as inductance and active resistance of the contact wire, on rise speed during the short circuit current were offered. Besides that, it is determined the influence of current speeds on their difference in power circuits of DC electric locomotive in different points of short circuit, different variants of traction electric engines connection and different distances of electric locomotives from the traction substation. The proposed model and method can be used for any type of electric DC locomotive at any point of a short circuit in traction engine circuit. Findings. Qualitative and quantitative influence of contact system parameters on values of current rise speed during short circuit and on the differences value of these parameters with different connection diagram of traction electric engines was established. Originality. The investigation method concerning determination of the influence of contact system parameters on current rise speed in short circuit and on the difference of these parameters on different distances of electric locomotives from traction substation was proposed. Practical value. The results can be used in selection of protective devices of rolling stock power circuits, where the main parameter is the current rise speed during the short circuit.

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In many hub traction power-supply systems (TPSSs), the 27.5 kV busbars in the traction substation (TSS) have supplied several railway lines in a local area for reducing the number of TSSs. However, the multiple railway lines connected to the busbar may affect the resonance behaviors of the entire system. It is therefore necessary to investigate the resonance behaviors under such hub TPSS conditions since the harmonic current collection of all railway lines will aggravate the resonance problem. Thus, resonance-mode assessment and its sensitivity method is adopted for investigating the resonance behaviors of hub TPSS affected by different numbers of connected lines, lengths of supply lines, system capacities, etc. The numerical results of modal sensitivity indices are compared to investigate and quantify the harmonic resonance issue caused by multiple electrical railway lines. In addition, the resonance frequency-shift technique and modal impedance sensitivity index-based method are also employed to mitigate the critical harmonic resonances. The results illustrate that it is effective to analyze resonance issues by adopting the harmonic model and modal methods in this paper. The two types of resonance behaviors (i.e., primary resonance and resonance band) caused from the hub TPSS have been fully investigated, and the resulting harmonic distortion of hub TPSS is suppressed. [ABSTRACT FROM PUBLISHER]