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The article discusses the solution of problems related to the development of a simulation model of a DC traction substation designed to evaluate energy and other performance indicators, including electricity quality indicators. The development of a simulation model makes it possible to evaluate the effectiveness of technical measures that can be used at traction substations to solve problems of improving the quality of rectified voltage, reducing non-sinusoidal busbars for their own needs, regulating the voltage on substation tires, and a number of others. Currently, the urgent tasks in the field of non-traction power supply include reducing the non-sinusoidal voltage on the busbars of alarm, centralization and blocking consumers who are sensitive to high voltage harmonics. The simulation was performed for one of the most common circuit solutions, characterized by the fact that a twelve-pulse rectification circuit of a sequential type is used at the substation. The proposed model was developed in the SimInTech software environment and allows you to evaluate the performance of a substation for various circuit states using switches inserted into the circuit. The simulation results are given for a symmetric system of sinusoidal voltages. The simulation results are compared with the results obtained on the basis of an experimental assessment of electricity quality indicators for one of the operating DC traction substations. The above measurement results at a traction substation with twelve-pulse rectifiers of a sequential type were performed synchronously for two pairs of inputs of 0.4 and 10 kV of the traction substation. A comparison of the simulation results shows the adequacy of the developed model and the equipment characteristics used in it, which makes it possible to use it to solve a number of other tasks.

One of the ways to increase the capacity of railways is to use long-distance freight trains with a distributed traction system. In order to reduce the influence of the human factor, it is advisable to use automatic speed control systems on the locomotives of such trains, that take into account the transients occurring in the train. Determination of the longitudinal forces that occur in the train can be carried out by using either a reference mathematical model of the train, or pre-calculated dependencies of these forces on the parameters of the train movement. The second method allows you to simplify the structure and improve the performance of automatic control systems.

Nowadays a frequency-controlled externally excited synchronous motor intensively uses in highly automated high-power electric drives. Earlier there were less reliable and more carefully maintained electromechanical direct current systems in these applications. At the same time, setting up of the closed-loop automatic control systems with subordinate regulation of the synchronous machines is the more difficult task. This is because a synchronous machine is a more complex control object. The purpose of this work is a comparative analysis of transients. In this case, saturation is taken into account according to the magnetic flux in the air gap. The coordinates of the machine are regulated by two different automatic control systems. The first system is typical, which uses field-oriented control of the magnetic field of the stator, the second system is upgraded, it selects the law of control of the magnetic field depending on the static load. Special attention in the current article is paid to the method of accounting for the saturation of the magnetic system of the motor and the construction of a mathematical and simulation model convenient. This article substantiates the feasibility of synthesizing more complex automatic control systems are ones with variable structure. The choice of the magnetic field control law in such systems avoids the negative effect of saturation of the machine's magnetic system on the quality of transients. The models presented in the current work can be used in the design of real controlled synchronous electric drives operating under high loads.