Improving the technology of operating electric locomotives using electric power storage device

The article discussed the questions of the railway transportation organization along the transport corridors passing through the territory of Russia using the innovative locomotives of new generation with the polygon’s structure of the transportation process’ organization. There was carried out an analysis of the railway car standing at the docking stations of the single-phase alternating and direct current. The results of simulation modeling of the transportation process on the railway sections, which have a docking station, are given. There are shown the positive effects of the perfection of the polygon’s exploitation technology of the locomotive fleet due to introduction of the double feed electric locomotives to the transport corridors, manifesting in the cargo delivery’s time reduction due to reduction of the ready train’s standing time at docking stations twice, in comparison with the time during exploitation of the only single-system electric locomotives, and also in increasing of the area’s speed of trains in the all polygon of the heavy trains’ turnover. The usage of the double feed electric locomotives in areas, which contains different kinds of the current, allows increasing the quality parameters of the traction electric rolling stock’s exploitation. There were considered the ways to increase the energy efficiency of the double feed electric locomotives, particularly by applying the electric energy storage unit for connection to the DC link of the electric locomotive’s power circuit. The economic assessment of exploitation of the two-systems electric locomotives was carried out.


Introduction
The railway transport development in the world shows its efficiency and being in demand, especially in the field of the high speed passenger transportation. The Russian railways are in stage of the technological development; this is the infrastructure's modernization, the replacement of the old traction rolling stock's series and the perfection of the organization's system of the trains' movement by transition to the polygon's structure of the transportation process' control and the completion of the conversion's process to the vertical integrated control system. There is continuing the development of the electrified railway's polygon, for which as the basic electric traction system is the alternating current's system with the voltage of 25 kWh. There is realizing a gradual , 0 2019) E3S Web of Conferences https://doi.org/10.1051/e3sconf /2019 ( 110 1100 -2018 10 10 SPbWOSCE 33 33 replacement of the old locomotives' series for innovative locomotives with the asynchronous traction actuator [1]. In the field of the movement's organization there are implementing an automated systems of the energy-optimal timetable [2][3][4][5]. The prospects of the work's perfection of the railway transport in the world tend to the given fields. One of the foreground directions of the freight turnover in Russia, realized by transport corridors between the ports of the Far East and ports of the North-West, Azov-black sea basin of Russia, are the container transportations, the main way of which lies on the electrified Transsiberian railway with the following integration to the international railway project «Eurasia». The export of the essential materials for the Russian economics -ores, ferrous metal is implementing by main railway artery of the country through the areas of the Middle Siberian move, which include in the structure of the transport corridor of the Kuzbass -Centre with the length of 3 824 km ( fig. 1). The realization of the transport corridors for the cargo flow's transit in the direction of East-West is bonded with the cargo delivery's time reduction. For today in RZHD holding there is a need of locomotives for the fast container transportations. On the railway network of Russia there are exploiting the main freight electric locomotive of new DC and AC series, the constructional speed of which is given in the table 1. The specified locomotives' series are intended for the high-weight trains' transportation, and on the areas with the way's mountain profile [6][7][8][9], while the average weight of the container train is about 3 000 t. The reduction of the train's weight leads to the load's reduction on the upper structure of the railway and in perspective to the speed's increase of the freight transportation with the allowed at present maximum speed of movement for the heavy trains from 80 till 140 km/h. The electric rolling stock's energy efficiency depends on many factors, including the train's weight and the way's profile. The specified circumstance leads to the fact, that for the given weight norm more effective is the exploitation of the only one locomotive's series. In a view of the reduction of the train's weight by the container transportations for the energy efficiency' increase of the exploited locomotives of the company "the First locomotive's company» together with the company Bombardier Inc.  The performed calculations allow assessing the exploitation's efficiency of the main electric locomotives of series EV120 on the Middle Siberian move's areas. By the calculation's results there were received the prognosis parameters, which influence the parameters of the transportation process:  the reduction of the trains' downtime; , 0 2019) E3S Web of Conferences https://doi.org/10.1051/e3sconf /2019 ( 110 1100 -2018 10 10 SPbWOSCE 33 33  the reduction of the electric locomotives' downtime and the increase of their daily average run;  the increase of the district speed. The exploitation's efficiency of the double feed locomotive [10] on the railways of the Transsiberian railway and the Middle Siberian move directly depends on the dockings stations' number of the current's types, located on the circulation's polygons of trains. It is necessary to notice, that the realization of the regenerative braking on the double feed locomotive allow increasing substantially the energy efficiency, especially by using the perspective systems of the electric energy's system of accumulation.

The methods of analysis and perfection of the polygon's technology of the transportation process
The effect's estimate of the downtime's reduction in the conditions of the exploitation is performing based on the statistical data of the trains' processing on the dockings stations of the current's kinds. The effect's estimate on the work's example on the station А (the Middle Siberian move of the Transsiberian railway), which was performed with the help of the program "Statistic for Windows Release 8.0" [11], allow receiving the following results for the IVth quarter of the year 2018 in relation to the odd and even directions ( fig. 3, 4 respectively).  The analysis of the received frequency distributions for the movement's amount of 56 pairs of trains per day shows, that the maximal frequency of the observation for the wagon's downtime is observing in the range from 100 up to the 400 wagon hours (the average value from the general downtime is 386 wagon hours) in both movement's directions by the train's structure of 60 -80 wagons. In the specified range of the wagon hours for the train's stopping, which is necessary for the electric locomotive's change for the necessary current's type, the services of the carload economy perform the technological operations: the wagon's inspection, the visual testing of the main breaking's integrity etc. At specified time there are performing the maneuver's operations by the electric locomotives' change and the switching of the point's sections of the contact network's group for the necessary current's type takes about 30 min.
It is necessary to notice, that the train's wagons need the technical inspection every 700 km [20]. For the considering example, the distance from the station of the trains' forming С to the dockings station's current's types A is 160 km. The distance from the station A to the big junction station, where the train's rearrangement or the locomotive brigades' change is 200 km. Therefore, having in the exploitation the two-system electric locomotive, which capable nonstop to pass the docking's station A, it is possible to increase the traction shoulder of the maintenance of the locomotive brigades for 160 km, and to reduce the total train's downtime on the docking's station.
The electric locomotives' downtime at the turnover point is inseparably bonded with the train's downtime. The electric locomotive's timeout of the departure with the train depends on the area's throughput, from the number of the train's pairs per day and for the docking's station, on which the train can pass en route, is determine by formula:  10 10 SPbWOSCE For the determination of the maximal cost of the locomotive it is necessary to use the discounted cash flow, which in turn will reflect the cash inflow and outflow during the process of the locomotive's implementation. The money balance for every period is corrected subject to the leading coefficient [19]. As a calculation's value of the limit price we take net present value (NPV)the accumulated discounted effect for the calculation period период, led to the initial step on the discount norm, from each equation then there will be defined the locomotive's marginal cost. For this we solve the NPV equation, equated the left part to zero, and estimated the all the cash inflow and outflow for a year:  10 10 SPbWOSCE 33 33

Results
The simulation modeling's results were received for the following source data. It was accepted, that the electric locomotive's service life is 40 years, the discount rate is 0,13. The calculations are performed for the different electric locomotive's payback periods for the specified marginal cost [12].
With the help of the program Simulink of matrix system MatLab, there was built a simulation model of trains' movement on the Middle Siberian move's areas subject to the integration to the exploitation of the main two-systems electric locomotives of series EV120. As a docking's station by modeling there was taken the above considered station А.
During the simulation modeling of the trains' processing with the exploited locomotives' series and electric locomotive's series EV120 there were received the following results:  the average time of the trains' downtime of the long trains was reduced twice up to 207,42 wagon hours in the odd and even directions of movement;  the electric locomotives' downtime on the docking's station was reduced up to the timeout of the departure with the train, equal the average value for the electric locomotives' park of series 2EV120 was 23 min, against to 52 min by the exploitation of the only single-systems electric locomotives, the daily average locomotive's run was increased from 446 up to 683 km;  the average value of the local speed of the trains' movement on the examined area was increased from 49,6 km/h up to 57,2 km/h. As an activity of the energy efficiency's increase of the double feed locomotives is the using of the electric energy storage' systems, allowing increasing the energy parameters of the electric rolling stock and the electric traction system [13][14][15][16], particularly, reducing the load of the power equipment and the heating of the current carrying parts in the electric traction system, increasing the work's reliability of the locomotive's equipment, in some cases, increasing the bandwidth and the transportation capacity of the area [17].
The feature of the main two-systems electric locomotive of series EV120 is the presence of the free space on board, intended for the generating set [18], allowing the electric locomotive autonomously to maneuver on the station's traction ways. There exists a technological possibility of the setting instead of the generator of the hybrid electric energy storage. The using of the electric energy storage on board allows aligning the graph of the locomotive's electric load, increasing of the using's efficiency of the regeneration's electric energy and the safety of the electric power supply of the asynchronous traction electric engines and the engines of own needs. The supply of the double feed electric locomotive's asynchronous traction electric engines is performing through the DC link, to which are connected the voltage's DC-AC converters, providing the works of the traction electric engines and the system's engines of own needs [18]. The availability of the DC link allows using the advantages of the electric energy storage' system by the locomotive's work with the DC and AC. The variant of the hybrid electric energy storage's connection in the power circuit of the asynchronous AC electric engines is given on the fig. 5. By the disconnected valves 1 and 2 the storage's discharge is performed for the asynchronous system's engines NS by the reduction of the voltage's level on the DC link to the specified level. The transformers' work of DCV is performed accordingly to the characteristics of the electrochemical and capacitive modules. By achievement of the maximal voltage on the hybrid storage, the device moves to the standby mode or to the discharge mode, depending of the work mode of the electric rolling stock and the energy parameters' values.
The expediency of the implementation of the main double feed electric locomotive of series EV120 with the electric energy storage is performed for the cost's range, depending of the locomotive's complete set and the technical characteristics of the onboard electric energy storage. By the minimal locomotive's cost (50 mln. rub.) the payback is 13 years of the exploitation's beginning and further it grows with the growth of the locomotive's cost ( fig. 6).

Conclusions
The reduction of the trains and electric locomotives' downtime on the docking's stations of the current's kinds on account of the double feed electric locomotives' use allow increasing the daily average run of the electric locomotives and the local speed positively affects the graph of the trains' movement. The use in the double feed electric locomotive's energy installation of the hybrid electric energy storage allow increasing the electric locomotive's energy efficiency, the reliability of the own needs' electric power supply and providing the graph's smoothing of the train's electric load. The offered scheme of the electric locomotive's energy installation is intended for the realization of the driven charge and discharge's modes of the hybrid storage in depending of the voltage's level on the locomotive's engines, the change's speed of the capacity of the traction electric engines and own needs, the capacity transferring to the traction network, separately for theдля electrochemical and capacitive module of the electric energy storage, the control's opportunity of the direction of the storage's capacity in the charge mode on the SN of the electric rolling stock or the total load together with the load of the ТEE.