Energy Losses in Electrical Networks

2022 ◽  
pp. 384-393
Author(s):  
A. F. Burkov ◽  
V. V. Mikhanoshin ◽  
Nguen Van Kha
Keyword(s):  
Energy Losses ◽  
Electrical Networks

scholarly journals Calculations, norming and reducing of electrical energy losses in city electrical networks

2019 ◽  
Vol 21 (3) ◽  
pp. 46-54
Author(s):  
A. V. Lykin ◽  
E. A. Utkin
Keyword(s):  
High Voltage ◽  
Power Transmission ◽  
Low Voltage ◽  
Demand Curve ◽  
Electrical Energy ◽  
Electrical Network ◽  
Energy Losses ◽  
Capital Investments ◽  
Electrical Networks

The article considers the feasibility of changing the structure of a distribution electrical network by transferring points of electricity transformation as close to consumers as possible. This approach is based on installation of pole-mounted transformer substations (PMTS) near consumer groups and changes the topology of the electrical network. At the same time, for groups of consumers, the configuration of sections of the low-voltage network, including service drops, changes. The efficiency of approaching transformer substations to consumers was estimated by the reduction in electrical energy losses due to the expansion of the high-voltage network. The calculation of electrical losses was carried out according to twenty-four hour consumer demand curve. To estimate the power losses in each section of the electrical network of high and low voltage, the calculated expressions were obtained. For the considered example, the electrical energy losses in the whole network with a modified topology is reduced by about two times, while in a high-voltage network with the same transmitted power, the losses are reduced to a practically insignificant level, and in installed PMTS transformers they increase mainly due to the rise in total idle losses. The payback period of additional capital investments in option with modified topology will be significantly greater if payback is assessed only by saving losses cost. Consequently, the determination of the feasibility of applying this approach should be carried out taking into account such factors as increasing the reliability of electricity supply, improving the quality of electricity, and increasing the power transmission capacity of the main part of electrical network.

scholarly journals Optimization of Electrical Networks Modes on Transformation Coefficients of Transformers

2020 ◽  
Vol 216 ◽  
pp. 01095
Author(s):  
Tulkin Gayibov ◽  
Sherkhon Latipov ◽  
Davron Abdurashidov
Keyword(s):  
Minimum Energy ◽  
Energy Losses ◽  
Electrical Networks ◽  
Electric Networks ◽  
The World ◽  
Distribution Of Power ◽  
Technological Constraints ◽  
Transmission And Distribution ◽  
Minimum Costs

Optimization of modes of electrical networks provides for the determination of rational values of reactive powers of controlled sources, voltages of reference nodes and transformation coefficients of adjustable loop transformers, at which the minimum costs associated with the production, transmission and distribution of electricity are ensured and all the specified operating and technological constraints are met. As a result of a lot of work performed by specialists from all over the world on the development of methods and algorithms for optimization the modes of electrical networks, at present, the methods for optimization of reactive powers and voltages of nodes are quite developed. At the same time, the algorithms for optimization of transformation coefficients of transformers, taking into account the provision of permissible voltage levels and minimum energy losses in closed electric networks by ensuring the optimal distribution of power flows in them, requires corresponding improvement. In this regard, this work proposes a new algorithm for optimization of modes of electrical networks on transformation coefficients of adjustable loop transformers. The results of researched the effectiveness of the proposed algorithm are presented.

scholarly journals DEVELOPMENT PROSPECTS OF EXTERNAL POWER SUPPLY ELECTRICAL NETWORKS OF TRACTION SUBSTATIONS

2020 ◽  
Vol 1 (154) ◽  
pp. 8-15
Author(s):  
I. Domanskyi ◽  
О. Kozlova
Keyword(s):  
Power Supply ◽  
Electrical Equipment ◽  
Energy Losses ◽  
Electric Transport ◽  
Electrical Networks ◽  
Traction Substations ◽  
External Power ◽  
Traction Power Supply ◽  
Traction Power ◽  
External Power Supply

In the paper on the basis of the analysis of classical power schemes traction substations of railways and urban electric transport conceptual directions of development of electric networks of external power supply of traction substations in the conditions of market economy and normative requirements of the electric power industry of Ukraine are developed, which allow to provide energy saving modes of their operation. Based on system analysis of domestic and foreign traction power supply systems of railways and electric transport of large cities, the concept of their development is substantiated and proposed by increasing the supply voltage of traction substations and minimizing capacity upflows and energy losses, which provides resource and energy savings. It is suggested that the investment programs of the structures that are part of Corporation «Ukrzaliznytsia» and the municipal services be synchronized according to their technological indicators, as well as according to the criteria of energy efficiency and quality of energy supply with similar investment programs of external energy. For reduction of energy losses, it is proposed: realization of rational schedule of train movement and deep high voltage inputs with the prospect of transition to own 110 kV distribution networks, modernization and equipping of modern rolling stock electrical equipment and infrastructure of the main and perspective directions of the railways. The need to expand tram and trolleybus lines and modernize power supply devices in terms of resource conservation requires new technologies for the design, construction and operation of the facilities of municipal enterprise «Miskelektrotransservice». Such technologies have been implemented by the «DAK-Energetika» enterprise in the manufacture of modern electrical equipment of municipal enterprise «Miskelektrotransservice» TS. The most important tasks are the improvement of stationary and mobile substations and other linear facilities of traction power supply by completing functional modular blocks with modern switchgear with digital relay protection and diagnostics of traction networks; local and remote control of switchgear devices, as well as switch diagnostics and self-diagnosis. Keywords: external power supply, traction substations, electrical networks, power systems operation modes.

scholarly journals Algorithms for estimating equivalent resistances of in-plant electrical networks

2021 ◽  
Vol 23 (4) ◽  
pp. 3-13
Author(s):  
E. Yu. Abdullazyanov ◽  
E. I. Gracheva ◽  
A. N. Gorlov ◽  
Z. M. Shakurova ◽  
T. V. Tabachnikova ◽  
...  
Keyword(s):  
Electric Power ◽  
Reference Values ◽  
Power Supply ◽  
Electrical Energy ◽  
Energy Losses ◽  
Equivalent Resistance ◽  
Electrical Networks ◽  
Contact Devices ◽  
Power Point ◽  
Plant Power

THE PURPOSE. Investigation of the degree of influence of the characteristics of in- plant electrical networks on the reliability of the results in the algorithms for estimating equivalent resistances. METHODS. When solving this problem, a study of the radial power supply scheme of the tool shop section was carried out with the calculation and modeling of equivalent and reference values of the circuit resistances. Algorithms and methods for estimating the values of equivalent resistances have been developed, taking into account the main technical characteristics of in-plant networks.RESULTS. The data of calculations of the equivalent resistance values of the circuits with an assessment of the heating factor of the conductors and the resistance factor of the contact devices are analyzed. The proportions of the influence of the resistances of the contact equipment and lines, taking into account the number of electric power receivers connected to the power point, on the value of the equivalent resistances of the circuit are revealed. CONCLUSION. The article develops algorithms for estimating the values of equivalent resistances of in-plant power supply circuits. Nomograms are presented that take into account the number and length of the circuit lines with the allocation of the zone of accounting for the resistances of contact equipment in the equivalent resistances of the circuits. The obtained algorithms and results are recommended to be used to clarify the amount of power and electrical energy losses in the intra- factory networks, which will increase the reliability of calculations.

scholarly journals Exact minimization of the energy losses and the CO2 emissions in isolated DC distribution networks using PV sources

DYNA ◽  
2021 ◽  
Vol 88 (217) ◽  
pp. 178-184
Author(s):  
Alexander Molina ◽  
Oscar Danilo Montoya ◽  
Walter Gil-González
Keyword(s):  
Mathematical Formulation ◽  
Main Idea ◽  
Distribution Networks ◽  
Global Optimum ◽  
Mixed Integer ◽  
Energy Losses ◽  
Electrical Networks ◽  
Convex Model ◽  
Daily Energy ◽  
Minlp Model

This paper addresses the optimal location and sizing of photovoltaic (PV) sources in isolated direct current (DC) electrical networks, considering time-varying load and renewable generation curves. The mathematical formulation of this problem corresponds to mixed-integer nonlinear programming (MINLP), which is reformulated via mixed-integer convex optimization: This ensures the global optimum solving the resulting optimization model via branch & bound and interior-point methods. The main idea of including PV sources in the DC grid is to minimize the daily energy losses and greenhouse emissions produced by diesel generators in isolated areas. The GAMS package is employed to solve the MINLP model, using mixed and integer variables; also, the CVX and MOSEK solvers are used to obtain solutions from the proposed mixed-integer convex model in the MATLAB. Numerical results demonstrate important reductions in the daily energy losses and the harmful gas emissions when PV sources are optimally integrated into DC grid.

scholarly journals On the Efficiency in Electrical Networks with AC and DC Operation Technologies: A Comparative Study at the Distribution Stage

Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1352 ◽  
Author(s):  
Oscar Danilo Montoya ◽  
Federico Martin Serra ◽  
Cristian Hernan De Angelo
Keyword(s):  
Power Distribution ◽  
Urban Areas ◽  
Optimal Power Flow ◽  
Low Voltage ◽  
Mathematical Formulation ◽  
Distribution Networks ◽  
Voltage Regulation ◽  
Numerical Results ◽  
Energy Losses ◽  
Electrical Networks

This research deals with the efficiency comparison between AC and DC distribution networks that can provide electricity to rural and urban areas from the point of view of grid energy losses and greenhouse gas emissions impact. Configurations for medium- and low-voltage networks are analyzed via optimal power flow analysis by adding voltage regulation and devices capabilities sources in the mathematical formulation. Renewable energy resources such as wind and photovoltaic are considered using typical daily generation curves. Batteries are formulated with a linear representation taking into account operative bounds suggested by manufacturers. Numerical results in two electrical networks with 0.24 kV and 12.66 kV (with radial and meshed configurations) are performed with constant power loads at all the nodes. These simulations confirm that power distribution with DC technology is more efficient regarding energy losses, voltage profiles and greenhouse emissions than its AC counterpart. All the numerical results are tested in the General Algebraic Modeling System widely known as GAMS.

New Aspects in the Design of Electron Optical Magnification Systems

1972 ◽  
Vol 30 ◽  
pp. 606-607
Author(s):  
Willem H.J. Andersen
Keyword(s):  
Electron Microscope ◽  
Imaging System ◽  
Chromatic Aberration ◽  
Research Tool ◽  
Energy Losses ◽  
Objective Lens ◽  
Theoretical Limit ◽  
Optical Magnification ◽  
Chromatic Aberrations ◽  
High Degree

Electron microscope design, and particularly the design of the imaging system, has reached a high degree of perfection. Present objective lenses perform up to their theoretical limit, while the whole imaging system, consisting of three or four lenses, provides very wide ranges of magnification and diffraction camera length with virtually no distortion of the image. Evolution of the electron microscope in to a routine research tool in which objects of steadily increasing thickness are investigated, has made it necessary for the designer to pay special attention to the chromatic aberrations of the magnification system (as distinct from the chromatic aberration of the objective lens). These chromatic aberrations cause edge un-sharpness of the image due to electrons which have suffered energy losses in the object.There exist two kinds of chromatic aberration of the magnification system; the chromatic change of magnification, characterized by the coefficient Cm, and the chromatic change of rotation given by Cp.

Localization of DNA in chromatin using ESI and osmium ammine staining

1990 ◽  
Vol 48 (3) ◽  
pp. 116-117
Author(s):  
C.L. Woodcock ◽  
R.A. Horowitz ◽  
D. P. Bazett-Jones ◽  
A.L. Olins
Keyword(s):  
Spectroscopic Imaging ◽  
Energy Losses ◽  
Electron Spectroscopic Imaging ◽  
Feulgen Reaction ◽  
Specific Location ◽  
Eukaryotic Nucleus ◽  
Chromatin Fibers ◽  
Patiria Miniata ◽  
Model Structures

In the eukaryotic nucleus, DNA is packaged into nucleosomes, and the nucleosome chain folded into ‘30nm’ chromatin fibers. A number of different model structures, each with a specific location of nucleosomal and linker DNA have been proposed for the arrangment of nucleosomes within the fiber. We are exploring two strategies for testing the models by localizing DNA within chromatin: electron spectroscopic imaging (ESI) of phosphorus atoms, and osmium ammine (OSAM) staining, a method based on the DNA-specific Feulgen reaction.Sperm were obtained from Patiria miniata (starfish), fixed in 2% GA in 150mM NaCl, 15mM HEPES pH 8.0, and embedded In Lowiciyl K11M at -55C. For OSAM staining, sections 100nm to 150nm thick were treated as described, and stereo pairs recorded at 40,000x and 100KV using a Philips CM10 TEM. (The new osmium ammine-B stain is available from Polysciences Inc). Uranyl-lead (U-Pb) staining was as described. ESI was carried out on unstained, very thin (<30 nm) beveled sections at 80KV using a Zeiss EM902. Images were recorded at 20,000x and 30,000x with median energy losses of 110eV, 120eV and 160eV, and a window of 20eV.

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