Том 90, № 6 (2019)

According to the analysis of domestic railroad automation and telemechanics (RRATM) systems, they are in no way inferior to their foreign counterparts in terms of such basic criteria as safety, reliability, functional capabilities, service life, and procurement and operation cost. This is confirmed in this paper by the characteristics of modern Russian railroad automation systems, as well as by the examples of their exportation to railroad in other countries. To consolidate achieved positions and ensure further progress, it is necessary to consider the latest global trends in the field of creating railroad automation equipment, the main areas of which are—creation of integrated multilevel control systems;—broader use of modern digital radio communication equipment in information management systems;—ensuring reliable cybersecurity of developed RRATM systems;—development of modular systems with flexible architecture;—standardization of requirements on developed equipment and their harmonization with worldwide requirements and standards;—creation of multilevel integrated systems of deep internal and external diagnostics; and—switching to life cycle contracts for maintaining RRATM systems, which will reduce the cost and improve the quality of maintenance.

When operating power autotransformers that have become widely used in networks of 110 kV and higher, it is often necessary to deal with open-phase modes caused by disconnections of one or two phases in the case of short circuits or in the case of single-phase repairs. This leads to asymmetry of the voltage of autotransformers, which affects the quality of power supply to consumers. For the autotransformer itself, an open-phase operation can be dangerous with respect to overloading of individual windings. The presence of an electrical connection between high and medium voltage causes the specifics in the analysis of their operating modes. In addition, while the theoretical analysis and the general approach to the calculation of asymmetrical modes of two-winding transformers are currently considered in sufficient detail, the task of analyzing the asymmetrical operating modes of three-winding autotransformers remains important. An approach to the calculation of autotransformer and combined asymmetrical operating modes of power autotransformers has been developed on the basis of the method of symmetrical components. The proposed model and obtained analytical expressions allow one to determine the currents and voltages of the phase windings of the autotransformer in a variety of asymmetrical modes of operation on the basis of a unified approach.

Different technologies for manufacturing the rotors of reluctance electrical machines with anisotropic rotor magnetic conductance—with longitudinal batching of the pole packages of the rotor and transverse batching of the rotor package with special cutouts—are analyzed. It is shown that the energy efficiency of reluctance machine with longitudinal batching of the rotor pole package significantly excels the energy efficiency of reluctance machine with transverse batching of the rotor pole package. The equivalent circuit of the magnetic circuit of reluctance electric machine with anisotropic magnetic conductance of the rotor with longitudinal batching of the rotor pole package is presented. The equations of magnetic fields in the zone of longitudinal and transverse magnetic conductance are written. Based on the proposed equivalent circuit, differential equations are derived, the solutions of which generate the functions of transverse magnetic flux depending on the angular coordinate of the machine, the anisotropic magnetic conductance of two-pole rotor of which is achieved by its longitudinal batching. The distribution of magnetic voltage between stator and rotor along the air gap is defined. The obtained analytical relations make it possible to determine the longitudinal and transverse magnetic conductance of the machine. The experimental studies of determination of magnetic conductances according to the presented procedure confirm the theoretical computations. The absolute error in determining the magnetic conductances by derived analytical relations and physical simulation does not exceed 7%.

When analyzing the powerful pulsed electromagnets used in seismic sources, it is necessary to take into account the current displacement in conductors of the winding. In this paper, the possibility of determining theoretically the time dependence of winding resistance using the Field factor, Maxwell software, and equations of electrodynamics to calculate the time constant of field penetration into a conductor in the case of current jump has been analyzed. The small duration of leading current edge in the winding of an electromagnet allows these equations to be used.

The increased requirements to high-speed travelling-wave relay protective systems of high- and extra-high-voltage transmission lines are imposed for ensuring high reliability of interaction of protection algorithms and fault-phase selection detectors of single-phase automatic reclosings for the purpose of ensuring the necessary conditions for the maximum use of advantages of these protective systems. The discussion covers travelling-wave relay protection device operation principles, together with the fault-phase selection detector, in which the comparison of magnitudes of phase fault currents (voltages) of the transmission lines average in absolute values takes place. Criteria for selecting the response and return time of the travelling-wave protection directional elements and the fault-phase selection detectors are developed that allow improving the efficiency of operation of protection in the single-phase automatic reclosing cycle. It is shown that the response times of the fault-phase selection detector and the directional elements should be commensurate and the devices themselves should have the ability to detect not only the occurrence of a short circuit, but also the short circuit’s transition to more complex modes in the single-phase automatic reclosing cycle. In the open-phase mode of transmission line operation, the reset time of protection can be significantly reduced compared to the previously selected values due to the fact that the decay constants of the free periodic component are 30–50 ms and decrease with the component frequency and increase in transient resistance at the point of a short circuit.