Non-traction Consumers Research Articles

Modeling of double ground fault modes in power supply systems of non-traction consumers of railway transport

THE PURPOSE. Development of digital models to determine the modes of double ground faults in 6-10 kV overhead signaling lines supplying signaling, centralization and automatic blocking facilities.METHODS. To create the models, methods of multiphase modeling of electric power systems were used, based on the use of lattice equivalent circuits from RLCelements connected according to complete graph circuits. For modeling, the industrial software package Fazonord, developed at the Irkutsk State Transport University, was used.RESULTS. The developed models provide correct accounting of all factors influencing the modes of double ground faults, including increased electromagnetic influences of the traction network. In contrast to known approaches, the dynamics of changes in these influences caused by variations in traction loads during train movement are modeled.CONCLUSION. The proposed approach to modeling double ground fault modes is universal and can be used for standard traction power supply systems, as well as promising high-voltage traction networks. The results obtained can be used in practice to configure relay protection devices for overhead signaling lines in order to reliably detect double ground fault modes and take measures to eliminate them. In addition, the modeling methodology presented in the article can be used when selecting measures to improve the reliability of power supply to signaling and automatic blocking facilities that ensure the safety of train traffic, as well as to develop methods and algorithms for determining distances to places of double ground faults in overhead power lines feeding signaling facilities , centralization and autoblocking. The presented results confirmed the effectiveness of the proposed approach for modeling double ground fault modes.

РЕЗОНАНСНЫЕ ЯВЛЕНИЯ В ТРЕХФАЗНЫХ ЛИНИЯХ ЭЛЕКТРОПЕРЕДАЧИ, ПИТАЮЩИХ НЕТЯГОВЫХ ПОТРЕБИТЕЛЕЙ ЖЕЛЕЗНОДОРОЖНОГО ТРАНСПОРТА

The article is devoted to the analysis of the quality of electrical energy in three-phase power supply systems for 10 kV non-traction consumers receiving power from traction substations, taking into account resonance phenomena. Emphasis is placed on high-order harmonics, which negatively affect the operation of modern electrical equipment. The prediction of voltage and current resonances in three-phase power transmission lines feeding the non-traction consumers was carried out on the basis of calculations in MathCAD. SimInTech simulations were performed to study electromagnetic processes, including estimation of the higher voltage harmonics values taking into account resonance phenomena in consumers.

УЛУЧШЕНИЕ КАЧЕСТВА ЭЛЕКТРОЭНЕРГИИ НА ПОДСТАНЦИЯХ, ПОДКЛЮЧЕННЫХ К ЛИНИЯМ «ДВА ПРОВОДА–РЕЛЬС»

A technique for computer simulation of modes of complex traction power supply systems, including lines "two wires - rail" (TWR) is presented. The developed computer models of power transmission lines TWR can be used in the development of measures aimed at improving the energy efficiency and quality of electricity in the power supply systems of non-traction consumers

Quality of electricity in power supply of non-traction consumers of railway transport

The article presents the results of the study of the influence of LED lamps with switching power supplies containing power factor correctors on the quality of electricity in the power supply system of non-traction consumers of railway transport. It is noted that the emission of harmonic components of current by electronic loads can cause deviations in the quality of electricity up to the occurrence of emergency situations due to overloads of low (0.4 kV) and medium (6/10 kV) voltage networks. A non-linear electronic load (LED lamp), although equipped with a power factor corrector, causes the generation of a significant level of current harmonics, which significantly affect the operation of the transformer. As a result, the transformer, calculated taking into account the load factor of 0.7 – 0.8, can not be normally operated in the conditions of using electronic load devices. Mathematical modeling of the correction of the modes of the power supply system with nonlinear single-phase loads is performed, provided that the correction devices made on the basis of several condensers and reactors with nonlinear characteristics are used to balance the modes.

МОДЕЛИРОВАНИЕ АВАРИЙНЫХ РЕЖИМОВ СИСТЕМ ЭЛЕКТРОСНАБЖЕНИЯ НЕТЯГОВЫХ ПОТРЕБИТЕЛЕЙ ЖЕЛЕЗНЫХ ДОРОГ

The influence of sources of reactive power on the quality of electricity on the tires of 
 non-traction consumers who receive power from the two-wire-rail line in the event of a short circuit in
 the contact network is studied. The results show that the use of sources of reactive power contributes 
 to the maintenance of voltage on the substation tires, significantly reducing the coefficient of 
 asymmetry in the reverse sequence.

Complex use of smart grid technology in railway traction networks

The goal is to develop a methodology for modeling electric power supply systems for railways equipped with a complex of devices implemented using smart grid technologies. The results obtained showed that a reliable and high-quality electric power supply for traction of trains and non-traction consumers could be implemented on the basis of the integrated use of Smart Grid active elements, such as a phase converter, an active harmonic conditioner, a controlled reactive power source and a distributed generation plant. On the basis of computer simulation, it has been established that in the absence of reactive power sources, noticeable voltage fluctuations are observed on the 10 kV buses of a non-traction consumer. The asymmetry approaches the limit of normally permissible values; turning off the active filter leads to an increase in the total voltage harmonic distortion up to 16%; in the presence of the whole complex of active devices, high quality of electricity is achieved. The phase number converter is robust and has low sensitivity to parameter setting errors; voltage deviations caused by a limited range of changes in reactive power in its source are short-term and do not exceed values acceptable for practice. Thus, on the basis of Smart Grid technologies, it is possible to implement the connection of distributed generation plants directly to the traction network using a device for transducing the number of phases, formed according to the inverted Steinmetz’s circuit. Elimination of harmonic distortions created by rectifier electric locomotives is carried out by means of an active conditioner of higher harmonics. A controlled reactive power source can be used to maintain voltage levels.

ABOUT THE EXPEDIENCY OF USING ELECTROCHEMICAL STORAGES IN POWER SUPPLY SYSTEMS FOR NON-TRACTION CONSUMERS OF RAILWAYS FROM RENEWABLE ENERGY SOURCES

This paper focuses on the problem of analyzing expediency of using electrochemical storages in power supply systems for non-traction consumers of railways from renewable energy sources (RES). It is quite obvious that RES implementation in any national industry as a proper distributed energy source is too problematic if there is no possibility to accumulate it in good supply. The aim of this paper is to select the most appropriate electrochemical storage device for power systems for non-traction consumers of railways from RES. The methodology of research is based on modern methods of computational mathematics, statistics and information analysis using modern computer technology. Consequently, the analysis helps conclude that batteries are the most preferable for power lines. That especially concerns railway mains with RES use since the batteries have the best power characteristics.

The use of energy routers to improve reliability of power supply to non-traction consumers

The purpose of the studies presented in the article was to determine the effectiveness of the use of energy routers (ER) in railway power supply systems to increase the uninterrupted power supply to non-traction consumers, reduce unbalance and nonsinusoidality, and reduce voltage dips in emergency modes. The research was carried out by means of computer modeling using the Matlab software system based on the developed models of power supply systems (PSS) equipped with ER with energy storage devices. The results obtained show that in standard circuits of PSS for linear consumers with short circuits in the supply network, voltage dips occur, the depth of which reaches 100%. The use of an ER and an energy storage device connected to DC buses allows maintaining voltage at consumer clamps near the nominal value in case of short circuits in the 10 kV feed line and 25 kV overhead contact system. The ER significantly limits the recharge of the short circuit location from the power storage. In addition, on the basis of the ER it is possible to provide the normative quality of electricity considering voltage deviations, asymmetry and harmonic distortions on the 0.4 kV buses of the substation that feeds non-traction consumers.

Prospects of introducing alternative sources of energy on Ukrainian railways

The potential of solar and wind energy was investigated, the existing premises of using the electric power obtained from non-conventional power sources of non-traction consumers for power supply of an electric traction system were analyzed. The influence of solar generation sources connected with the traction substation tires on the stability of non-traction consumers was determined. Possible options of connecting renewable energy sources to the railway power systems were examined. Calculations for determining the number of solar panels for compensating the auxiliary power consumption of the traction substation were made. The modeling of the possibility of implementing alternative energy sources in a traction substation in the PVsyst program was carried out. In Ukraine, the change of conditions for the provision of electricity supply services was caused by the rapid growth and development of renewable energy sources, in connection with which the number of suppliers increased. The question about the possibility of using alternative electricity sources to compensate the auxiliary power consumption of traction substations arises. Therefore, it is relevant to solve the problem of joint work of auxiliary power consumers together with non-traditional energy sources. The auxiliary power consumption of the traction substation include: heating drives and tanks of transformers; cooling down trip coils, relays, control panels, alarm systems, alarm and centralization and blocking devices; heating substation premises, store rooms and shower room. In order to implement alternative energy on the railway, it is necessary to analyze the auxiliary power consumption of the traction substation; to analyze the possibility of placing alternative power sources on the traction substation premises; to investigate how the powering system of the auxiliary power consumption of the traction substation can operate (both directly and in parallel mode).

Комплексное использование технологий Smart Grid в тяговых сетях железных дорог

The purpose of the paper is to develop a methodology for modeling railway power supply systems equipped with a set of devices implemented on the base of smart grid technologies. The research is carried out using the Fazonord software package designed for modeling the modes of railway power supply systems in phase coordinates. The calculation model is implemented for the power supply system of a two-track section with five traction substations. The results obtained show that reliable and high-quality power supply of train traction and non-traction consumers can be ensured on the basis of the integrated use of active Smart Grid elements, such as a phase number converter, active harmonic conditioner, controlled reactive power source, and a distributed generation unit. Computer simulation allows to establish that in the absence of reactive power sources there are noticeable voltage fluctuations on 10 kV buses of non-traction consumers; the asymmetry is approaching the limit of normally acceptable values; disabling of the active filter results in the increase of the total harmonic coefficient of voltages up to 16%; if the entire complex of active devices is available, the high quality of electrical energy is achieved; the phase number converter is robust and features low sensitivity to the errors in parameter setting; voltage deviations caused by the limited variation range of reactive power in the reactive power source are short-term and do not exceed the values acceptable in practice. Thus, on the basis of Smart Grid technologies, distributed generation units can be connected directly to the traction network using a phase number conversion device formed according to the reciprocal Steinmetz circuit. Elimination of harmonic distortions created by rectifier electric locomotives is carried out by means of an active conditioner of higher harmonics. A controlled reactive power source can be used to maintain voltage levels.

Two-Phase Short Circuit in the Power Grid Powered by a Transformer with a Y/Δ-11 Winding Connection

The article describes main provisions and relations for calculating short-circuit currents and phase currents in a three-phase traction transformer with a star-triangle-11 connection of windings, which feeds two single-phase loads in AC traction networks with a nominal voltage of 25 kilovolts. These transformers provide power to the enterprises of the agro-industrial complex located along the railway line. (Research purpose) The research purpose is in substantiating theoretical equations for digital intelligent relay protection in two-phase short circuits. (Materials and methods) It was found that since the sum of instantaneous currents in each phase is zero, each phase of the transformer works independently. We found that this significantly simplifies the task of analyzing processes with a two-phase short circuit. In this case, the problem of calculating short-circuit currents in the traction network can be simplified by reducing it to the calculation of an ordinary electric circuit with three unknown currents. (Results and discussion) The article describes equations for calculating short-circuit resistances for one phase of the transformer when connecting the secondary winding as a star or a triangle. The currents in the phases of the transformer winding at short circuit for the star-triangle-11 and star-star-with-ground schemes are compared. It was found that when calculating short-circuit currents, there is no need to convert the secondary winding of the traction transformer from a triangle to a star. (Conclusions) It was found that the results of the research can be used in the transition of relay protection systems from electromagnetic relays to modern high-speed digital devices, which will increase the operational reliability of power supply systems for traction and non-traction power consumers.

Increasing Power Supply Efficiency for “Two Wire-Rail” Line Consumers

The article is devoted to the problem of non-traction consumers power supply of AC railways. The low efficiency of energy transfer is caused by the design of a non-traction power supply line. The absence of bilateral power is typical for non-traction network 27,5 kV which consist of “two wire-rail” lines. This line is outdated technology, which does not correspond to modern requirements on the power quality, but used on AC railways with three-phase traction transformers. The purpose of the article is to investigate the methods of power supply improvements for non-traction consumers in terms of voltage unbalance, harmonic distortions and energy losses. Connection of the phasing device to delta winding traction transformer for bilateral supplying non-traction customers from network 27,5 kV is suggested in the article. The implementation of a method to increase the efficiency of electricity transmission in the non-traction network power supply allows to reduce power losses from 720 MWh / year to 441 MWh / year, the voltage unbalance from 1,9% to 1,3% and the total harmonic distortion from 8 % to 6 % respectively. Additionally, investment attractiveness of the decision was evaluated. Keywords: non-traction customers, two wire-rail line, phase coordinates, AC railway, power quality

МОДЕЛИРОВАНИЕ РЕЖИМОВ СИСТЕМ ЭЛЕКТРОСНАБЖЕНИЯ НЕТЯГОВЫХ ПОТРЕБИТЕЛЕЙ

The results of computer studies of the modes of power supply systems of nontraction consumers of railways are presented. It is shown that the greatest asymmetry in the reverse sequence and voltage deviations are observed at the substation connected to the two-wire-rail line.

Electromagnetic Effect of an Alternating Current Traction Power Supply System with a High-Voltage Power Cord on Electrical Installations and Networks of Nontraction Consumers

In this paper, we ground a method for calculating switching overvoltages including the discharge of lightning currents into the contact network and into a high-voltage power wire (HVPW) to isolate the contact network in the power supply system with the HVPW. It was established that the protection of outdoor signaling, centralization, and blocking (SCB) devices from switching overvoltages in a power supply system with a high-voltage power wire (PSS HVPW) can be solved by connecting the reinforcement of the support foundations of the contact network to an extended artificial grounding conductor (GC) located under the ground and not connected to the rail track. The use of a GC, along with limitation of pulse overvoltages on the insulation of the contact network supports, solves the problem of ensuring reliable protection of the traction networks from short-circuit currents in the traction network. An algorithm for calculating the voltage of the zero sequence of phase voltages of overhead power lines (OPLs) with an isolated neutral relative to the ground when they are located in the zones of electromagnetic influence of the PSS with the HVPW was developed. Due to the electrical effect of the HVPW voltage, the induced voltage in an OPL is shown to reach values ​​that significantly exceed the levels allowed by regulatory documents. An analysis of the obtained results indicates the feasibility of placing OPL wires on free-standing supports outside the reserved strip. The need for such a solution is also determined by keeping the HVPW voltage from entering the OPL wires, with their possible breakage.

Device for detection of the phase current asymmetry in the three-phase lines of non-traction consumers

electrified railway transport receives power from the power system and operates on a single-phase current, which leads to uneven loading of networks of the traction power supply system. There is a danger of overload and additional losses of active power and electrical energy of three-phase electric motors by reverse sequence currents, therefore, any information obtained about the values (phase currents and voltages) allows carrying out corrective actions for the level of asymmetry. In this paper, discuss the design of the device for detecting the asymmetry of phase currents in three-phase lines is proposed. It is shown that the device can convert the DC current difference and measure three linear currents in a three-wire three-phase circuit.

About technical and economic indicators of wind and photoelectric stations use in the systems of network consumer railway supply systems

Purpose. To analyze the technical and economic indicators of the use of wind and photovoltaic stations in the power supply systems of non-traction consumers of railway power grids. The research methodology is based on modern methods of computational mathematics, statistics and information analysis using modern computer technology. Findings. The authors analyze the current prerequisites for the use of electricity generated from renewable sources (wind and photovoltaic stations) to supply non-traction consumers of railway power grids. The authors note that for reliable power supply to non-traction consumers in the presence of accidental wind flow or intensity of solar radiation, the capacity of wind and photovoltaic plants will need to be significantly overestimated, which leads to a significant increase in capital costs for construction. The paper presents examples of implementation of options for the construction of the above wind and photovoltaic stations for the variable nature of wind speed and intensity of solar radiation for specific regions of Ukraine (Vasylivka, Zaporizhia region). The authors present variants of the basic schemes of wind, solar and combined electric power supply systems for non-traction consumers. Information on technical and economic indicators of the most common domestic photo modules and wind turbines on the Ukrainian market is provided. The originality of the work is reflected in the examples of the introduction of options for the construction of wind and photovoltaic stations for the variable nature of wind speed and intensity of solar radiation for specific regions of Ukraine. Practical implications. The above calculation of the cost of the required number of power sources at wind, solar and combined power plants helps to choose the least expensive option for the introduction of renewable energy sources for non-traction consumers of railway networks. Keywords: renewable energy sources, photovoltaic installation, railway power supply networks, non-traction consumers of railway power grids, electricity production, solar radiation intensity, wind flow rate, capital expenditures.

Features of operation of photovoltaic plants as a supplementary source of electricity for non-traction consumers of railway electric mains

Purpose. To determine the features of operation of photovoltaic stations as а supplementary source of electricity for non-traction consumers of railway power grids. The research methodology is based on modern methods of computational mathematics, statistics and information analysis using modern computer technology. Findings. The authors analyze the current prerequisites for the use of electricity obtained from non-traditional sources (photovoltaic stations) to supply non-traction consumers of railway power grids. The nature of the intensity of solar radiation was clarified due to meteorological observations for 2018, recorded using a SMIR pyranometer from KIRP & ZONEN, which is specially designed to record the flow of solar energy falling on a flat surface from the sun and sky in the wavelength range from 300 to 3000 nanometers (Nm), which has an intelligent interface, in the city of Vasylivka, Zaporizhia region with an interval of minutes. The total number of values was about 25,000. The data obtained are as follows: the lowest intensity of solar radiation during 2018 was 400 W / m2, and the highest - 1000 W / m2. The calculation of the choice of photovoltaic panels type PV-MLV 250 NS with a maximum power of 250 W for the completion of a specific photovoltaic station for installation in the specified region. The authors conclude that in order to provide reliable energy supply to non-traction consumers of railway power grids during the day from autonomous solar power plants, the latter must be provided with electricity (storage batteries) in quantities exceeding the required load by about 1.7 times. The originality is that the use of renewable energy sources in the power supply systems of non-traction consumers of railway transport, in particular photovoltaic installations, is proposed. Practical implications. Introduction of photovoltaic stations as a supplementary source of electricity for non-traction consumers of railway power grids in order to minimize electricity costs. Keywords: renewable energy sources, quality of electric energy, photovoltaic plant, power supply networks of railway transport, non-traction consumers of railway electric networks, electricity production, solar radiation intensity, storage batteries.

Features of operation of wind power stations as an supplementary source of electricity for non-traction consumers of railway electric mains

Purpose. Identify the features of operation of wind farms as an auxiliary supplier of electricity for non-traction consumers of railway networks and analyze the main factors that directly affect the use of wind farms due to the random nature of wind flow and additional factors due to the above conditions in different climates. The research methodology is based on modern methods of computational mathematics, statistics and information analysis using modern computer technology. Findings. The need to use renewable energy sources in the power supply systems of non-traction consumers of railway transport is obvious. Given the constant growth of prices and tariffs for electricity in Ukraine, more and more attention is paid to its savings and the search for the cheapest and most affordable alternative sources. The authors consider issues related to the possibility of using additional generation of electricity in the power supply systems of railway transport through the use of wind turbines, including for non-traction consumers. The analysis of wind flow features in some regions of Ukraine was carried out, and the measurement of wind speed in Zaporizhia and Dnipropetrovsk regions was obtained with the help of a compact wind speed sensor manufactured by Micro-Step-MIS LLC (Russia). The obtained values of wind speed were recorded and stored digitally. The received information of the above device was processed. The authors conclude that in the case of using wind turbines as an additional power source in the networks of non-traction consumers of railway power supply systems it is economically advantageous to connect them directly to these networks and fully use all electricity produced by them, reducing its consumption from this power supply system. The originality is that the use of renewable energy sources in the power supply systems of non-traction consumers of railway transport, in particular wind turbines, is proposed. Practical implications. Introduction of wind power plants as an auxiliary supplier of electricity for non-traction consumers of railway power grids in order to minimize electricity costs. Keywords: renewable energy sources, quality of electric energy, wind power plant, power supply networks of railway transport, non-traction consumers of railway electric networks, electricity production, wind speed.

Experimental wind power and photovoltaic plants as a basis for researching to use renewable energy sources in the power supply systems for non-traction consumers

Purpose. Describe the tools used by the authors for experimental research on the possibilities of using renewable energy sources in the power supply systems of non-traction consumers of railway transport. The methodology of research is based on modern methods of computational mathematics, statistics and information analysis using modern computer technology. Findings. To date, there is no comprehensive approach and specific reasonable measures for the introduction of re-newable energy sources in the energy supply of non-traction consumers. The article presents examples of the introduction of renewable energy sources in the power supply systems of railways abroad. It is noted that when using different renewable energy sources in the power supply systems of non-traction consumers, it is necessary to have a volume of statistical information to determine their technical and economic indicators. The classification of wind power plants with a horizontal axis is given. The schematic diagram and general view of the developed experimental wind power plant are given. The schematic diagram and general view of the developed experimental photovoltaic plant are given. The equipment used for research of wind flow and intensity of solar radiation in places of possible location of wind power or photovoltaic installations is considered. The presented experimental wind power and photovoltaic plants, which serve for a comprehensive study of the possibilities of using wind and solar sources in the power supply systems of non-traction consumers, are generalized and allow to clarify the necessary data for decision making. The originality is the introduction of renewable energy sources in the power supply system of non-traction consumers of railway transport. Practical implications. The use of additional renewable energy sources to supply non-traction consumers minimizes electricity consumption. Keywords: renewable energy sources, quality of electric energy, wind power plant, photovoltaic plant, power supply networks of railway transport, traction and non-traction consumers, electricity production

Effect of distributed generation plants’ automatic controllers on power quality factors

Currently, energy generation industry transition to a new technological platform based on smart electrical energy systems (EES) is underway, with EES equipped with active-adaptive mains. This platform involves a large-scale use of digital devices and significant electrical energy (EE) generation using distributed generation (DG) plants which are to be created by power consumers. These plants can operate as parts of existing grids, or be pooled in network clusters. To implement smart EES, the development of new approaches is required for production, distribution and EE consumption modes management. The article is dedicated to the issues of DG plants application to raise efficiency of non-traction consumers power supply systems. In this case, a special attention was paid to enhancing the electrical energy quality via application of the DG plant which is controlled by concordantly set generator automatic voltage regulator (AVR) and automatic speed governor (ASG). For optimization and harmonization of AVR and ASG settings a method of nonparametric identification of the ‘turbine-generator’ system was used which can be represented as complex activation functions of main channels and crosslinks of regulators and the generator. The study was carried out in Matlab environment on a created railroad power supply system model. The studies conducted helped to detect that application of DG plants with concordantly set AVR and ASG makes it possible to enhance power quality for non-traction consumers and ensure dynamic stability and resilience of railroad line power supply system.