The paper contains analysis of advantages and disadvantages of existing differential protection terminals of power reducing transformers. The paper shows that there are good reasons to develop microprocessor protection of power reducing transformer which contains required functions and settings and which is based on Belarusian principles of relay protection system construction. The paper presents functional structure of microprocessor terminal of power reducing transformer which is developed.

 

The paper contains values of torque magnification ratio while shifting vertical loads due to horizontal wind forces affecting on supports of overhead transmission lines of 35 kV and higher. These values pertain to various types of unified reinforced concrete conic and cylindrical supports while changing climatic conditions. The values make it possible to exclude rather complicated calculations in respect of support deflection in the case when there is uncertainty in initial data.

Methodology for sparking control in generator brush contact has been developed on the basis of the proposed fuzzy diagnostic model for ad.c.starter-generator and complex processing of diagnostic data. The paper provides investigation results, namely: dependence of voltage parameters  in an external generator circuit on collector sparking intensity.

The paper considers a problem pertaining to synthesis and qualitative assessment of a harmonic voltage composition of multiple uniform PWM pulses generated by step builder functions. Analytical expressions for PWM pulse parameters a_i and t_i have been obtained and they can be used for software-based formation of the given PWM, determination of  U_п^*  -amplitude of  n-harmonic voltage in pulse-width regulation and AC motor operation simulation

The paper considers a dynamic model for locomotive electric drive with four asynchronous traction motors and their stator windings are serially connected. A mathematical model for motors being fed by one autonomous inverter has been developed in the paper. Serial connection makes it possible to increase a value of the total supply voltage. An analysis of the developed model shows that currents consumed by motors with their serial connection are lower in case of their parallel operation.  Direct and frequency start-up curves are given on the basis of the developed model.

The paper considers an effect of ZrO₂ content in 20%Co/xZrO₂∙(100 – x)SiO₂ (x = 0, 10, 15, 25, 30, 40 and 100 mass percent) catalyst carriers on their catalytic properties. Temperature programmed desorption of NH₃ has made it possible to determine relations between their acid and catalytic properties. The paper reveals the TPD spectrum is the result of 4 overlapping peaks originating during NH₃ desorption from the respective groups of acid sites. Total acidity of samples and contribution of separate acid site groups into the given acidity have been have been determined in the paper. The paper contains graphical dependences of a various-type acid site number on  content of zirconium oxide in the carrier. Correlations between change in various-type acid site number and catalytic process parameters (CO conversion, C₅+ hydrocarbon output and  C₅+ isoparaffin output) have been found in the paper. The paper shows that the highest values of CO conversion and C₅+ hydrocarbon output correspond to maximum number of acid sites, and that number accounts for a peak of desorbed ammonia at T_max = 122 °C, while the lowest isoparaffin output corresponds to minimum number of acid sites, which characterizes a peak of desorbed ammonia at T_max = 224–257 °C.

 

The paper considers problems arising in case of burning local-type fuels in pilot boilers with spreader stokers. Some solutions and proposals permitting to increase efficiency of fuel-burning units are given in the paper.

Movement of  viscous fluid with relaxing viscous stresses under influence of external sources of impulse and energy has been theoretically studied in the paper. The paper contains solutions of two problems, namely: non-isothermal Couett flow with lateral pressure gradient and  coordinately periodic flow. Intermittency of two-type resistances characterized by different temperature properties has been detected in the paper. The paper reveals relations between coordinately non-uniform properties of a vortex field with extreme properties of an entropy production.

The paper contains an analytical analysis of the present situation and prospects of further development of power engineering industry inVietnamup to 2030.

 

The paper presents a long-term programme for power engineering development in Germany and its specific features, namely: development of power generation on the basis of renewable sources, consistent decommissioning of Nuclear Power Plants, reduction in energy consumption due to higher efficiency of its usage, reduction in greenhouse gas emissions.