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Abstract. Smart power grids provide efficient control of power flows or other grid variables, such as voltages or short circuit currents. Most essential the control has become, if the consumers are electrical systems of high power capacity. These systems are able to reconfigure the grid structure for emergency situations. The developed algorithm is intended for carrying out operational calculations of short-circuits modes in electrical grids of voltage 0,4kV to 220kV. In the calculation the following methods have been used: methods of node voltages, method of superposition and method of branch expansion to form the node voltage matrix according to the graphs theory. In the software the short circuit inflow from all electrical motors and nodes with generalized load is taken into account as opposed to other algorithms. The calculated circuit can have up to 700 nodes; there is ability to decrease number of branches and nodes and to form the calculative model of the grid part. Calculation algorithm of the short circuit currents is implemented as a sequence of software calculations. Software of systems and grids, in which short circuits are altered, allows carrying out operational calculations of the short circuit modes to adjust settings of relays protection devices, to check electrical equipment and to replace it, to choose optimal operational circuits. Actuality of the calculations is caused by need of the software implementation to maintain, upgrade and design the electrical grids of enterprises that have their own power plants.

The paper presents the results of paleomagnetic and rock magnetic studies of rocks from the mafic dikes of the Sergeevka terrane that intruded the basement rocks. Currently, they are widespread in coastal outcrops of the eastern part of the Peter the Great Bay of the Sea of Japan between Anna and Priboinaya bays in the south of Primorsky Krai. Structural information allows us to conclude that dikes of both the eastern (Srednyaya Bay-Priboinaya Bay) and the western (Anna Bay-Cape De Livron) clusters intruded from the igneous centers of the same strike. Rocks of the dikes have undergone significant secondary alterations. Inverse magnetic fabric in the dikes is the result of high-temperature decomposition and granulation of primary titanomagnetites during postmagmatic deformations and metamorphism, traces of which are clearly visible in the microscopic and microprobe study of secondary alteration products. All this testifies to a significant secondary change in the rocks of the dikes after their intrusion. This is the secondary heating of the dikes above a temperature of 600 °C, that is, above the Curie point of magnetite (578 °C). The nature of the isolated high-temperature NRM component of the dikes is not primary, but secondary, that is, metachronous. The paleomagnetic data constrained the time of the metamorphic event leading to the remagnetization of mafic dikes of the Sergeevka terrane to ca. 250 Ma. The calculated paleolatitude of the Sergeevka terrane at the time of acquisition of the metachronous NRM component by mafic dikes (21.8 ± 4.2° N) is consistent with the paleolatitudes of the northeastern edge of the North China Craton at the Late Permian/Early Triassic boundary.

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In the paper the optimization of the control loops of the variable frequency induction motor drive for the feed screw of a flame reactor has been carried out to obtain required dynamic characteristics of the electric drive for known parameters of the plant. Simulation studies of basic control loops (current, flux-linkage and speed) are performed and dynamic parameters of control quality are presented. Results of the studies show that the obtained parameters meet requirements of the workflow and the modern variable-frequency drive based on induction motor can be implemented for actuating the feed screw of flame reactor. It should also be mentioned that transients quality factors in speed loop with input filter are better than without it.