The paper provides investigation results of magnetizing current inrushes in three-phase transformer during one-phase switching. Numerical experiments have been carried out with the help of a mathematical model developed on the basis of the second dissipation theory. It is shown that a magnetizing current inrush in the phase to be switched with absence of a residual induction exceeds an analogous inrush values by 1.4…1.6-fold in the case of simultaneous switching of all three phases.

During the last decade a general trend is observed among power engineering companies towards the deregulation of production activity. This social and political movement causes revaluation of reliability control of electric network system policy at Joint-Stock Company «Lenenergo», elaboration and development of methods and means for solution of integrated problems involving the whole process from putting into operation till equipment writing off.

The paper considers properties of electrets and electret structures. The developed method of electric power synthesis on the basis of electret structures is given in the paper. This method makes it possible to obtain significant values of current and capacity in the output circuit.

The paper reveals that while loading transformers from idle running till nominal value it is preferable to apply transformers with less power losses in steel because total losses of active power in the indicated range are less than in transformers with larger losses in steel.

The paper contains relationships determining input resistances and gains from any i-x terminal pairs of a homogeneous ladder circuit. These relationships are expressed in parameters of one four-terminal network.

Development of automatic designing system for power supply of industrial enterprises is considered in the paper. Its complete structure and principle of operation are determined and established. Modern graphical interface and data scheme are developed, software is completely realized. Methodology and software correspond to the requirements of the up-to-date designing, describe a general algorithm of program process and also reveals properties of automatic designing system objects. Automatic designing system is based on module principle while using object-orientated programming. Automatic designing system makes it possible to carry out consistently designing calculations of power supply system and select the required equipment with subsequent output of all calculations in the form of explanatory note. Automatic designing system can be applied by designing organizations under conditions of actual designing.

Optoelectronic sparking analyzer provides the possibility to realize a number of algorithms that permit to convert indicated light signals containing information on number of sparkings in the measuring cycle and their intensity divided in ten classes. The paper presents the selected sparking indices converted with the help of a computer and these indices make it possible to evaluate sparking level of separate commutator sectors by calculating average values in the whole measuring cycle of brush-commutator contact in dc machines. The paper also contains limiting values of the presented indices. 

The paper considers a construction method of arithmetically frequency symmetric band-pass filter on the basis of frequency conversion that results in scheme function with comprehensive coefficients. Methodology of its realization with the help of a digital filter is proposed in the paper.

It is obtained an approximate solution of the second main boundary problem of heat conduction theory (Neyman’s problem) for Laplasse equation in an individual circle. A uniform estimation of approximate formula error makes it possible to conduct calculations with the given accuracy.

The three-dimensional mathematical model for numerical modeling of stressed and deformed state of ingots that move with a constant speed in a furnace with step heating and given number of temperature zones is proposed in the paper. The paper presents results of computer calculations pertaining to temperature stresses of an ingot that moves with a constant speed in furnaces with six temperature zones.

The paper provides a methodology and measurement results of pressure impulses and tangential stresses initiated on a flat wall while burning a gas mixture 2H₂ + O₂ in a chamber installed above horizontal surface. Pressure and tangential stress distribution along the surface length at various distances to the chamber with its various gas mixture filling is revealed in the paper. 

The paper considers various aspects pertaining to determination of main technical characteristics of water-development projects of water-power stations. Technical and economical characteristics of overflow dams at the Grodno water-power station are compared in the paper.

The paper contains results of model investigations of two-tier overflow dam which is included in composition of the Grodno water-power station and presents methodology for calculation of pool integration behind two-tier dam which has been developed at the water-development and power engineering department. This methodology makes it possible to determine rate coefficient and compressed depth. In addition to this the paper gives technical and economical comparison of various designs of overflow dams at the Grodno water-power station, analyzes their cost and on the basis of this comparative analysis it is recommended to construct a two-pier dam. 

The paper considers dependences of electric power supply cost on transferred power and reveals conditions of economical efficiency of electric power transmission in power system.