Frequency-independent methods for receipt of input signal amplitudes in microprocessor protection of an electrical installation in the aggregate with earlier analyzed digital filters are considered in the paper. The paper contains comparative analysis and specified characteristics have been obtained.

The influence of modem firequency converters with uncontrolled rectifiers on the supply network is investigated in this paper. The developed mathematical model permits us to analyze rectifier input currents with symmetrical and asymmetrical supply networks and in discontinuous operational mode. Results of modeling in case of asymmetrical supply network are shown in the form of mains current curves and current spectrum of one phase.

The paper shows that reliability calculation of a power-supply system using a non-parametric method allows to distinguish highly reliable schemes at indefinite initial data and availability of own generating sources availability at an industrial enterprise. It has been determined that connection of an electric power station generator to an intemal power-supply system and provision of full enterprise capacity lead to increase of the scheme reliability by two and more fold. Higher reliability is ensured by operation of the generator on bus bars of lower voltages, namely, 0.38 or 6 kV.

Mathematical expressions have been obtained that allow to determine a number of transformers being operated either in parallel or separately for a common load and ensuring minimum power losses. An electrical load exists in the case of an unequal load of reciprocally reserved transformers. In order to reduce power losses it is expediently to change the number of operating transformers. It has been found out that a value of the load depends on the rate of transformer utilization at the initial mode. In case of load decrease timely transformer trip reduces consumption of active and reactive power as well. Consequently, such trip increases power factor of a consumer load.

It has been shown that minimum losses in active power of a power transformer do not correspond to its maximum efficiency. For a transformer being operated there are no so called «zones of its economical operation». In this case strictly specified value of active power losses corresponds to a particular current of the winding.

The paper considers a method for accuracy improvement of automatic control systems with break-up control laws. The method presupposes asymmetrizing of a structure or parameters of a non-linear regulator proportionally to destabilizing effects. Some variants of such asymmetrizing with usage of so-called ‘quick’ automatic oscillatory motions for compensation of slow errow components are given in the paper.

Application efficiency of various absorption laser spectroscopy methods for determination of gas component concentration in boiler smoke gases has been studied in the paper, O₂ and CO absorption spectra have been analyzed, optimum absorption lines in near IR spectral range (about 0.76 µm for O₂ and 1.56 µm for CO) have been selected and graphical dependences of intensity and half-width of the selected lines on the investigated medium temperature and pressure have been shown. Processes of monitoring CO and O₂ content in boiler smoke gases while using basic laser spectroscopy methods have been simulated and measuring errors have been analyzed. It has been found out that in order to decrease methodical errors of concentration measuring it is necessary to take into account the investigated medium temperature and pressure. The paper shows that the least errors of continuous CO and O₂ concentration monitoring at the presence of variations in dissipative losses have been ensured by the modified correlation method though its threshold sensitivity is less than integral and correlation ones.

The paper contains analysis of heat exchange investigations while boiling hydrocarbon fuel. The obtained data are within the limits of the S.S. Kutateladze dependence proposed in 1939. Heat exchange at non-stationary heat release has not been investigated. The data for hydrocarbon fuel with respect to critical density of heat flow are not available even for stationary conditions.

A mathematical model has been proposed for ecological monitoring of a boiler unit. This model makes it possible to obtain maximum decrease in effluents at minimum reduction in economical operational efficiency of the boiler unit.

The paper contains results of the investigations pertaining to specific volume and composition of neutral and acid portions of the used reclaiming solution of H-cationic filters used in a chemical desalting plant. The filters operate in accordance with small run-off technology and they are applied for regeneration of Na-cationic filter and acidification of limed water for replenishment of a heating system.

A method has been developed for calculation of final temperature while taking into account heat losses at the region of a heat exchanger to be designed in accordance with “pipe in pipe” principle. In addition to conventional scheme for two heat-exchanging flows the paper considers a heat-exchange case of three flows that are moving along ring channels relative to each other by П and Z schemes. The given calculative method has made the basis for the development and investigation of operational modes of the pipeline with one and two ring channels.

Prospects of the technical solution of the developments to be planned have been confirmed by the results of the investigations and calculations that were carried out with the help of a special computer program

The paper presents results of the experimental research that studies influence of geometric characteristics of conic electrodes on electrolyzer productivity.

Methodology and calculation example are given in the paper