A methodology has been developed to take account of repeated earth connection of a zero wire while making calculation of modes and losses in 0.38 kV and using method of nodal potentials that permits to refine operating conditions of a zero wire. It has been shown that an account of a repeated earth connection of a zero wire exerts an influence on parameters of a mode and power loss in the 0.38 kV network and in this case an influencing force is in direct proportion to unsymmetry degrees of load phase currents and is in inverse proportion to resistance of earthing devices and rods

The paper is devoted to the development of measuring device to register dynamic processes of electromagnetic irradiation during the treatment of materials with energy of explosion. Standard units to register main parameters of the explosion do not allow predict and control results of the process. So, to overcome disadvantages of former control units a new one has been developed applying Hall’s sensors. The device developed allows effectively register of the inductive component of the electromagnetic irradiation in wide range of temperature for many shot-time processes.

Provision of quality indices is of great importance for motor drive in the case of parametric and external disturbances. The purpose of the paper is to make synthesis of a scalar control system of asynchronous motor drive that ensures the required quality indices in the specified range of parameter changes of a linearized electric motor model. Expressions have been obtained that make it possible to estimate change limits of main linear model parameters

The paper considers a structure of a closed loop system with dynamical output feedback and its derivative. A simulation has been executed for a calculative linear system and for a system with a simulating model of an asynchronous short-circuited electric motor at various laws of frequency control.

The method provides the required dynamic indices at parametric and external disturbances occurring in the limited area.

The paper considers a principle for determination of a short circuit type which is used in the mathematical model of adaptive micro-processing protection with the purpose to improve sensitivity. As a result of a calculative experiment dependences ΔI(t) for various short circuit types (three- and two-phase short circuits) have been obtained at a number of points of the investigated power network. These dependences make it possible to determine a numerical value of ΔI coefficient. A comparative analysis has been made to study an operation of adaptive and non-adaptive microprocessing protections in the case of asymmetric damages of the investigated power network just in the same points.

The paper reveals principles for development and operation of soft-hardware complex which is designed to control transformer substations of industrial enterprisers. Purpose of soft-hardware components of the complex is considered in the paper.

Development and application of such complex allow to increase an efficiency of power transformer resource and decrease electric power losses in the elements of power-supply system at industrial enterprisers.

The paper considers one variant for increasing fast-operation of a frequency synthesizer with a small step of an output grid that is a realization of an equivalent fractional division factor with the help of a digital counter synthesizer (DCS). Analysis of static synthesizer parameters has been executed at a number of DCS controlling variants.

On the basis of statistic data analysis it has been established that nearly 10 % of fires that oc­curred in the dwelling sector of the Republic of Belarus in 2006 are related with emergency regime of electric equipment, electric devices and power networks. The paper contains results of experimental comparative investigations concerning operation of fuses for 25 A current and automatic thread fuses for nominal 25 A current.

The investigations have shown that fuses do not ensure protection of power networks in a dwelling in 40 % of executed tests. Replacement of these fuses for automatic thread ones permits to reduce a number of fires in a dwelling sector and, first of all, in the rural area.

The paper considers an accumulated experience concerning investigation of heat exchange and thermal modes of ring furnaces applied for heating simulation. Physical and mathematical model and methodology for theoretical investigation of round billet heating in the ring furnace are proposed in the paper.

Thermal power stations of small capacity in the Belarus power system are sources of heat supply in the heat supply systems of some cities or urban districts with 100% electric power generation using heat consumption. Presently it is necessary to find optimum technical solutions concerning their reconstruction.

On the basis of thermodynamic analysis the paper considers a complex approach to heat-and-power engineering system applied for polyester thread production. As a result of this analysis a structure of power supply required for heat engineering are clearly observed and its main system shortcomings are revealed as well.