TO THE EFFICIENCY OF ELECTRIC LOCOMOTIVES ON A HILLY SECTION OF THE RAILWAY

ABSTRACT

The results of studies on the justification of the kinematic parameters of the movement of freight trains with different masses of the composition and energy indicators of the transportation operation of 3VL80^S electric locomotives without stops on a virtual hilly section of the railway are presented. These parameters and indicators were obtained in the form of tabular data and regression equations designed to determine them on virtual and identical real hilly sections of the railway, which are recommended for implementation in practice by specialists of the locomotive complex of the Uzbek railways.

АННОТАЦИЯ

Представлены результаты исследований по обоснованию кинематических параметров движения грузовых поездов с разной массой состава и энергетических показателей перевозочной работы электровозов 3ВЛ80^С без остановок на виртуальном холмистом участке железной дороги. Указанные параметры и показатели получены в виде табличных данных и уравнений регрессий, предназначенных для их определения на виртуальных и, идентичных им, реальных холмистых участках железной дороги, которые рекомендуются для реализации на практике специалистами локомотивного комплекса узбекских железных дорог.

Keywords: investigation, result, the freight train, the electric locomotive, railway track, parameter, the stage, analysis, the station, time, speed, hilly, virtual.

Ключевые слова: исследование, результат, грузовой поезд, электровоз, железнодорожный путь, параметр, разъезд, анализ, станция, время, скорость, холмистый, виртуальный.

Introduction

Recently, a noticeable increase in the total length of the electrified sections of the Uzbek railways and the replenishment of the locomotive fleet of "O'zbekiston temir yo'llari" JSC with new electric locomotives of Chinese and Russian production determine the priority direction in the development of electric traction.

The foregoing undoubtedly contributes to an increase in the efficiency of the use of the electric locomotive part of the locomotive fleet of the railway industry in Uzbekistan. Despite this, the demand for electric locomotives of the VL80^S series in a three-section design remains quite high. Indeed [1], now 3VL80S electric locomotives carry out about fifty-nine percent of the total volume of rail transportation of goods on sections of Uzbek railways of different degrees of complexity (difficulty).

Therefore, research on the effectiveness of the use of these electric locomotives in operating conditions on real and virtual sections of railways of various degrees of

complexity is timely and relevant.

Tasks and methods of research

The main performance indicators of electric traction locomotives are the kinematic parameters of the movement of a freight train (speed and travel time of the train in the studied section in different modes of operation of the power plant) and the energy efficiency parameters of the indicated locomotives themselves in terms of the total (total) and specific consumption of electric energy for train traction in quantitative and monetary terms.

The present research continues the work [2-4] and concerns electric traction locomotives, with the help of which the technology for the movement of freight trains on a virtual hilly section of the railway is organized. Purpose - to substantiate the main kinematic parameters of the movement of freight trains and indicators of the transportation work of 3VL80S electric locomotives, to study the influence of real conditions for the organization of rail transportation of goods on these indicators when moving without stopping at separate points.

To implement the formulated research goal, the authors use the algorithm [4] and the methodology [5] for performing traction calculation, the initial data [2] about the studied freight electric locomotive 3VL80^S and the virtual hilly section of the railway, the object and subject of research.

The object of study is freight trains with different weights and a constant number of train axles, three-section mainline (train) freight electric locomotives of the 3VL80^S series and a straightened track profile of a virtual hilly section of the railway.

The subject of the study is the main kinematic parameters of the movement of freight trains when moving without stops at an intermediate station and the energy efficiency indicators of the studied 3VL80^S electric locomotives in quantitative and monetary terms on the accepted (given) virtual section of the railway.

Results and analysis of the study

A series of traction calculations was performed on a virtual hilly section of the railway in three variants when driving freight trains weighing in the range of 2500 -

3500 tons with a change by ∆Q = 500 tons and with a constant number of axles m = 200 without stopping at the intermediate and final stations.

The numerical values of the kinematic parameters of the movement of freight trains for each stage of the virtual hilly section of the railway in various modes of operation of the power energy systems of 3VL80^S electric locomotives without stops at the intermediate and final stations in the implementation of rail transportation of different types, types, structure and content of goods are given in table. 1.

Table 1.

Distribution of the travel time of a freight train by hauls on a virtual hilly section of the railway, 3VL80^S electric locomotives

In table. 2 shows the parameters of energy efficiency indicators of the use of three-section main (train) freight electric locomotives 3VL80^S on a virtual hilly section of the railway when moving without stops at an intermediate separate point in quantitative and monetary terms, taking into account different conditions for organizing the transportation work of these locomotives. Index (sign) asterisk * - cash costs (cost of electricity) including value added tax (VAT).

Evaluation and analysis of the efficiency of the transportation work of three-section main (train) freight electric locomotives 3VL80^S on a given, virtual, hilly section of the railway were carried out by comparing the numerical values of the above kinematic and energy parameters with similar values of a unified freight train.

Table 2.

Indicators of the transportation work of 3VL80^S electric locomotives on a virtual hilly section of the railway track

Analysis of the research results [2-4] and the data in table. 1 in relation to a unified freight train with a train mass Q₂ = 3000 tons and a constant number m = 200 axles in the train shows the following.

1. The average total train travel time is 0.517 h, a decrease in train mass by ∆Q = 500 t leads to a decrease in the total train travel time by 2.43 percent, and with an increase in train mass by ∆Q = 500 t, an increase in this time by 3.88 percent.
2. Technical speed of the train with a similar change the mass of the composition tends to increase and decrease within the same limits, and, on average, it is equal to 88.75 km / h.
3. The average train travel time for acceleration - deceleration is 0.0341 h, a decrease in the mass of the train by ∆Q = 500t leads to a decrease in the time for deceleration by 3.55 percent, and the time for acceleration remains unchanged with an increase in the mass of the train by ∆Q = 500t the time of the train to accelerate - deceleration increases by 3.88 percent.
4. The total and specific average consumption of electric energy for train traction is 2630.26 kWh and 19.25 Wh/t km, respectively. The total and specific average costs of electric energy correspond, respectively, to 228937,3 soums and 5024.76 soums - excluding VAT and 274599 soums and 5989.5 soums - including VAT.
5. An increase in the mass of the composition by ∆Q = 500 tons contributes to an increase in the total consumption of electricity by 7.62 percent, however, the specific consumption of electricity in this case decreases by 7.76 percent, and a decrease in the mass of the composition by ∆Q = 500t provides a reduction in the total and an increase in the specific consumption of electricity, respectively, by 4.35 and 14.80 percent.
6. Reducing the mass of the composition by ∆Q = 500t leads to a decrease in the total and specific cost by an average of 11.21 percent, and with an increase in the mass of the composition by ∆Q = 500t, these indicators increase by an average of 10.24 percent.
7. Reducing the mass of the train by ∆Q = 500t leads to a decrease and an increase in the use of traction modes [7], as well as idling and braking [5], respectively, by 0.8 percent, and with an increase in the mass of the composition by ∆Q = 500 tons, on the contrary, there is an increase and decrease in these indicators by 1.53 percent.
8. The travel time of the train in the idling and braking mode, as well as in the traction mode, varies, respectively, from 0.168 h to 0.192 h and from 0.334 h to 0.324 h. With an increase in the mass of the train by ∆Q = 500t, there is a decrease in the travel time of the train in the idling and braking modes, as well as its increase in the traction mode, respectively, by 0.015 h and 0.005 h. The travel time of the train in the idling and braking mode increases, and in the traction mode it decreases by 0.008 h and 0.004 h, respectively, with a decrease by ∆Q = 500 tons of the mass of the train.

Using the standard program of the Microsoft Office Excel series, regression equations (analytical expressions) were obtained to calculate the parameters of the main indicators of the transportation work of 3VL80^S electric locomotives on a virtual hilly section of the railway track for any i-th mass Q of a freight train. In formulas (1) - (10), a sufficient value of the approximation reliability is R² = 1.0 (the necessary reliability condition is R²≥0.8), and the sign (index) asterisk * - taking into account value added tax (VAT), and the value Q_i = 1,2,3 is a factor (indicator) of the traction calculation option.

Technical speed of the train V_т, km/h

V_т = – 0,555Q² - 0,555Q + 92,45                                        (1)

Total train travel time t_x, min

t_x = 0,225Q² – 0,075Q + 29,86                                           (2)

Train travel time in traction mode t_т, min

t_т = 0,025Q² + 0,175Q + 19,85                                      (3)

Train running time at idle and braking modes t_хх,т, min

t_хх,т = 0,2Q² - 0,1Q + 10,0                                         (4)

Total electricity consumption per trip A, kWh

А = -47,795,6Q² + 441,93Q +1969,4                                (5)

Specific electricity consumption per trip a, Wh/tkm gross

а = -0,12Q² – 0,9Q + 21,61                                           (6)

Total cash costs of С_Э, sum

С_Э = -4160,5Q² + 38467Q + 171420                         (7)

Total cash costs С*_Э including VAT, som/km

С*_Э=-4990,5Q²+46140Q+205609                                 (8)

Reduced monetary costs of с_Э, som/km

с_Э = -35,15Q² + 671,55Q + 3845,7                                   (9)

Reduced cash costs ce* including VAT, som/km

с_э*=-108,7Q²+1005,1Q+4479,6                                 (10)

The analysis of the given regression equations shows that the dynamics of the parameters mentioned above, depending on the change in the mass of the freight train, is described by a polynomial of the second degree.

In the course of the research, various conditions for organizing the movement of freight trains with different masses of trains were studied, regression equations were obtained and the numerical values of the parameters of the main indicators of transportation work and the energy efficiency of using 3VL80^S electric locomotives on a given virtual hilly section of the railway track were substantiated, the analysis of the results of which shows the following:

• when organizing railway transportation of various goods, movement with varying and non-constant speed coexist only in cases of braking (stopping), starting and accelerating, and uniform movement of a freight train is exclusively dominant;
• the consumption of electrical energy spent on the movement of freight trains by 3VL80^S electric locomotives directly depends on the operating time of power plants (systems) under current, the reduction of which will lead to a decrease in the mechanical operation of the mentioned electric locomotives, and as a result, will reduce the consumption of electric energy;
• an increase in the volume of transportation work by 3VL80^S electric locomotives contributes to an increase in the efficiency of using these electric locomotives in operating conditions, regardless of the type of cargo being transported and the type of freight train traffic.

Conclusion

The authors substantiated the kinematic parameters of the movement of freight trains and the parameters of the energy efficiency indicators of 3VL80S electric locomotives, and obtained regression equations to determine the main indicators of the transportation work of the studied locomotives of electric traction  on virtual and identical to them, of real hilly sections of the railway when organizing freight traffic without stopping along the way rolling stock.

In addition, the research results obtained by the authors are recommended for implementation in the practice of the work of drivers - instructors in heat engineering and specialists of the operation shop of locomotive depots of the Uzbek railway network with a hilly track profile, on which the movement of freight trains is realized by electric traction locomotives.

Reference:

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