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ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations

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No 5 (2012)

ELECTRICAL POWER ENGINEERING

5-11 701
Abstract

The paper considers methodology for creation of software complex while using Fortran software modules and DELPHI object programming system. Software complex is designed for investigation of line operational modes of 6–10 (35) kW with supply on one side and remote inter-phase short circuits.

 

11-17 622
Abstract

The paper considers two schemes of the urban distributive electric network for supply of the second and third category consumers for whom indicators of reliability have been determined.

As for a network scheme of the 2nd category it has been determined that while installing low-oil and vacuum switches at a distributive point the most remote transformer substation has the highest non-availability  factor which is higher of the corresponding non-availability  factor of the nearest transformer substation by 1,21–1,23 fold  accordingly.

As for a network scheme of the 3rd category consumers it has been obtained the data that reliability of consumers receiving supply from bus-bars of transformer substations with 0,38 kW voltage changes  significantly (by 1,2–1,9-fold) while changing a breakpoint of the network with 10 kW voltage.

18-24 1623
Abstract

A conceptual model for a computer aided design and engineering system has been developed in the paper. The paper presents basic automation process principles including a graphical representation   network and calculation results, convenient user interface, automatic mode calculation, selection of transformer rated power and cross-section area of wires. The developed algorithm and program make it possible to save time and improve quality of project implementation.

25-34 735
Abstract

The paper proposes a mathematical model for thermal processes that permits to calculate non-stationary thermal processes of core insulation and surface of a single-core power cable in real-time mode. The model presents the cable as four thermal homogeneous bodies: core, basic insulation, protective sheath and internal environment. Thermal processes between homogeneous bodies are described by a system of four differential equations. The paper contains a proposal to solve this system of equations with the help of a thermal equivalent circuit and the Laplace transform. All design ratios for thermal parameters and algorithm for calculating temperature of core insulation and temperature of power cable surface. These algorithms can be added in the software of microprocessor devices. The paper contains results of experimental investigations and reveals that an absolute error of the mathematical model does not exceed 3ºС.

35-43 1551
Abstract

The paper considers problems pertaining to selection of non-restorable continuously reserved discrete control and management systems of electric and heat and power processes. Two problems concerning system optimization on the basis of the following criteria – their reliability and cost have been solved in the paper.

 

43-50 924
Abstract

The paper presents an analysis of existing vibration diagnostics methods. In order to evaluate an efficiency of method application the following criteria have been proposed: volume of input data required for establishing diagnosis, data content, software and hardware level, execution time for vibration diagnostics. According to the mentioned criteria a classification of vibration diagnostics methods for determination of their advantages and disadvantages, search for their development and improvement has been presented in paper. The paper contains a comparative estimation of methods in accordance with the proposed  criteria. According to this estimation the most efficient methods are a spectral analysis and spectral analysis of the vibration signal envelope.

52-56 1568
Abstract

The paper substantiates the necessity  and expediency that instead of instantaneous values it is recommended to use mean values of the current components in the discrete range in order to improve the controllability and observability of the electric drive system. Rather simple measuring devices for electric drive current components have been proposed for analogous and digital control systems. The devices provide high accuracy and quick measurement of current components.

57-66 1743
Abstract
The paper analyzes the existing calculation methods for load characteristics of an asynchronous generator with a capacitive excitation. The improved calculation method for static characteristics of the  asynchronous generator working on a dynamic active-inductive load has been given in the paper. The methodology takes into account frequency of the generated voltage.

НEAT POWER ENGINEERING

67-70 638
Abstract

The paper presents dependences required for calculation of heat and energy  for building operation within the period of its functioning and mean specific power of heat loss.

70-75 1659
Abstract

The paper considers existing systems of smoke removal from heat-generating plants of various heat power. Advantages and disadvantages of every system are specified in the paper. The paper analyzes properties of fiberglass smoke stacks.

76-82 713
Abstract

The paper considers a method for joint numerical analysis of cycle parameters and heatex-change equipment of steam-compression heat transformer contour that takes into account a non-stationary operational mode and irreversible losses in devices and pipeline contour. The method has been realized in the form of the software package and can be used while making design or selection of a heat transformer with due account of a coolant and actual equipment being included in its structure.

The paper presents investigation results revealing influence of pressure loss in an evaporator and a condenser from the side of the coolant caused by a friction and local resistance on power efficiency of the heat transformer which is operating in the mode of refrigerating and heating installation and a thermal pump. Actually obtained operational parameters of the thermal pump in the nominal and off-design operatinal modes depend on the structure of the concrete contour equipment.

83-86 614
Abstract

The paper presents a selected method for drying high wet bulk products with uniform distribution of a drying product in inter-grain space of a compact fixed layer. In order to implement the selected drying method it is recommended to apply a device with inner receptacle having a channel  whose cross-section is decreasing along movement of a  thermal flow.   Specific feature of the accepted drying device design is that the process is carried out in continuous mode: temperature and  heated air velocity along the height and width of the drying chamber are unchangeable due to design of heat supply channel located inside of netted receptacle. An analytical expression has been derived in order to  calculate resistance to movement of thermal flow – heated air – in a compact fixed layer of product mass.



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ISSN 1029-7448 (Print)
ISSN 2414-0341 (Online)