ELECTRICAL POWER ENGINEERING
The paper considers longitudinal and lateral compensation of a.c. power line parameters. It is shown that controlled and shunt reactor creates controlled longitudinal compensation.
The paper studies one of the principles used for execution of adaptive micro-processor current directional protection of a line against inter-phase short circuits. This principle makes it possible to decrease a number of measuring elements of protection current and increase protection-ability while preserving high speed of response.
An algorithm has been developed to form a matrix for balancing a state of monotonous circuits. It is shown that proper numbers of asymmetric matrix for balancing states of a monotonous circuit are real ones.
The paper contains the results obtained with the help of accepted methods.
It is noted that there are no points with minimum of total power losses due to character of their component changes.
Analysis of the Over-Voltage Limiter (OVL) influence on electromagnetic high-frequency over-voltages at commutations with isolators of unloaded sections of wires and possibility of application of a frequency-dependent resistor in case of necessity to facilitate OVL operation conditions is provided in the paper.
It is shown that it is necessary to take into account characteristics of OVL by IEEE circuit and its modifications at computer modeling of high-frequency over-voltages.
НEAT POWER ENGINEERING
The paper presents results of the investigations pertaining to operation of a GM-50-14/250 boiler with a contact economizer. It is shown how a contact economizer influences on fuel saving and reduction of nitrogen oxide effluents.
The developed measuring methods make it possible to investigate mechanisms and kinetics of radiation drying processes of multi-layer materials having special properties.
It is possible to consider a hydraulic calculation technique of distributing gas-systems as a combination of factors that influence on the cost of construction and maintenance of gas-distributing system. The paper contains proposal of a new specification of economic distribution of calculated pressure differential in the system sections; optimum initial flow distribution from the point of view of reliability and economy and taking into account linkage of system rings.
The program of hydraulic calculation of low-pressure distributing gas-systems has been developed. While calculating combined systems consisting of steel and polyethylene gas lines reduction in discounted expenses constitutes up to 4 %.
The paper considers methods for determination of gas-expansion and generator unit indices when they are applied at a thermal power station. It is shown, that while relating the effect of additional power-and-heat generation output due to heat taking-off from steam turbines to gas-expansion and generator unit to the operation of this unit a specific fuel consumption of power supply from gas-expansion and generator unit can be lower than fuel equivalent of kilowatt-hour.
The paper considers and provides methodology for calculation of maximum over speeding value of a turbine rotor in the case when we face the failure of all its protective systems. It is presented a derivation of main equations required for making the calculation and the paper also cites results of their practical application at an industrial TRB (Turbine of the Republic of Belarus) turbine while constructing its protective control systems.
HYDRAULIC POWER ENGINEERING
A mathematical model of a steady circulating motion of fluid in a pre-screen zone of the committed well is constructed. Its screen is parted not only by horizontal partitions but also by vertical packers into a series of blowing and sucking quadrants. The proposed mathematical model allows to determine pressure and speed of fluid during circulation in any point of pre-screen well zone with constant and changed permeability. Theoretical and experimental investigations of circulating fluid motion with various permeability of pre-screen well zone are given in the paper. As a result of it, it has been ascertained that pressure on quadrant boundaries is equal to zero and an angular component of a velocity vector reaches a maximum value. A radial component of the velocity vector reaches its maximum value in the center of a quadrant. Good convergence of the results of mathematical and physical simulation testifies about the possibility to use mathematical model for determination of design parameters of a circulating regeneration quadrant device.
ISSN 2414-0341 (Online)
