scholarly journals Increasing the Sensitivity of Protections in Electrical Networks up to 1 kV by Using Microprocessor and Semiconductor Release Tripping Devices

2021 ◽  
Vol 64 (5) ◽  
pp. 393-407
Author(s):  
A. Yu. Kapustsinski ◽  
S. N. Kаnstantsinava
Keyword(s):  
Comparative Analysis ◽  
Electric Power ◽  
Cross Section ◽  
Electrical Networks ◽  
Circuit Breakers ◽  
Electric Networks ◽  
Positive Effects ◽  
Protective Devices ◽  
The Cross ◽  
Negative Phenomena

The paper deals with the problem of increasing the efficiency of the functioning of electric networks up to 1 kV, namely, the possibility of increasing the sensitivity of protections in networks up to 1 kV, which helps to reduce the protection response currents and, accordingly, reduce the cross-section of cable and wire products. The topicality of this problem is shown and the research tasks are defined. Much attention is paid to the concept of selectivity; attention is also paid to the concepts of full and partial selectivity. “Which protective devices can be considered selective?” is a question that is considered and worked out in sufficient depth in the paper. The negative phenomena that occur when ensuring the selectivity of protections in networks up to 1 kV are systematized and described in detail. Based on a comparative analysis of the parameters of circuit breakers with release tripping devices of various types, a solution to this problem is proposed by using circuit breakers with microprocessor and semiconductor release tripping devices. Additional advantages of microprocessor-based circuit breakers are considered and indicated, as well as their disadvantages are indicated, too. The main expected positive effects from the use of circuit breakers with microprocessor release tripping devices are listed, taking into account the fact that this type of circuit breakers is considered as a complex of devices replaced by it. The article can be recommended to employees of electric power specialties working with networks up to 1 kV.

scholarly journals ON THE MANAGEMENT OF URBAN ELECTRIC NETWORKS IN THE CONDITIONS OF THE SMART GRID

2018 ◽  
Vol 61 (1) ◽  
pp. 15-27 ◽  
Author(s):  
M. А. Fursanov ◽  
A. A. Zalotoy
Keyword(s):  
Smart Grid ◽  
Electric Power ◽  
Power Transmission ◽  
Electrical Networks ◽  
Electric Networks ◽  
Urban Networks ◽  
Theoretical Criterion ◽  
Active Power Losses ◽  
And Control ◽  
The City

The issues of prospective operation of the city electric networks in the conditions of the MART GRID, which will be quite different as compared to the traditional understanding and approaches, are under consideration. This requires the selection and application of appropriate analytical criteria and approaches to assessment, analysis and control of the networks. With this regard the following criteria are recommended: in a particular case – the optimal (minimal) technological electric power consumption (losses), while in general – economically reasonable (minimal) cost value of electric power transmission. It should be also borne in mind that contemporary urban networks are actively saturated with distributed sources of small generation that have radically changed the structure of electrical networks; therefore, account for such sources is an absolutely necessary objective of management regimes of urban electric networks, both traditional and in associated with the SMART GRID. A case of the analysis and control of urban electric 10 kV networks with distributed small sources of generation has been developed and presented according to the theoretical criterion of minimum relative active power losses in the circuit as a control case. The conducted research makes it possible to determine the magnitude of the tolerance network mode from the point of the theoretical minimum. 

Poverty in the Dolnośląskie Voivodship

2016 ◽  
Vol 61 (6) ◽  
pp. 70-85
Author(s):  
Agata Girul
Keyword(s):  
Comparative Analysis ◽  
Cross Section ◽  
Objective Assessment ◽  
Subjective Assessment ◽  
Poverty Level ◽  
The Cross

The article presents selected aspects of economic poverty in the Dolnośląskie Voivodship on the background of the country and other voivodships, as well as in the cross-section of the Dolnośląskie powiats in 2013, as compared to 2010. The comparative analysis of poverty level by powiats was presented by means of taxonomic synthetic measure based on a set of three selected diagnostic indicators. A complement to the objective assessment of poverty in the Dolnośląskie Voivodship was a presentation of results of subjective assessment of material situation of households in the voivodships’ cross-section.

scholarly journals Specificity of strength calculation for glued-in steel rods in LVL with unidirectional veneer

2018 ◽  
Vol 2 (51) ◽  
pp. 196-201
Author(s):  
Andrii Bidakov ◽  
Evhenyi Raspopov ◽  
Oksana Pustovoitova
Keyword(s):  
Comparative Analysis ◽  
Failure Mode ◽  
Cross Section ◽  
Joint Strength ◽  
Design Method ◽  
Strength Calculation ◽  
Test Results ◽  
Rigid Connection ◽  
The Cross ◽  
Made In

Design of joints of LVL elements with glued-in steel rods and metal connectors is considered as semi-rigid connection and requires taking of account the compliance. A comparative analysis of the test results of the beams with a metal connector and glued-in steel rods as well as solid beams is made in the paper. Design method of glued-in rods in LVL is proposed and taken into account failure mode. It allows reducing the distance between the axes of the rods as well as the distance from the rod axіs to the edges in the cross section of the beam and increasing the joint strength.

Place Selection of Sectionalizing Units in 0.38 kV Power Networks

2021 ◽  
Vol 10 (4) ◽  
pp. 35-52
Author(s):  
Alina Vinogradova ◽  
Alexander Vinogradov ◽  
Alexey N. Vasilyev ◽  
Alexey Dorokhov ◽  
Vadim Bolshev ◽  
...  
Keyword(s):  
Cross Section ◽  
Calculated Data ◽  
Power Line ◽  
Maximum Distance ◽  
Power Lines ◽  
Power Networks ◽  
Protective Devices ◽  
The Cross ◽  
Selection Of

In the paper there is the developed methodology for selecting the installation places and number of sectionalizing units which allows solving the problem according to the criterion of providing the necessary sensitivity of the protective devices installed on the line input. The obtained expression allows calculating the maximum distance to the installation place of a sectionalizing unit. It also allows determining the need to install a sectionalizing unit in a power line. If a sectionalizing unit is installed to protect an outgoing line, the technique can also be used taking into account the adjustment of the original calculated data. The developed methodology for determining the installation place of a sectionalizing unit can be used for other purposes. For example, it allows selecting the cross section of power lines in terms of the protection sensitivity when designing power lines or when reconstructing them.

Mathematical models for determining limit operating modes in electrical networks with distributed generation plants

2020 ◽  
pp. 17-36
Author(s):  
Yuri Bulatov ◽  
◽  
Andrey Kryukov ◽  
Aleksandr Cherepanov ◽  
◽  
...  
Keyword(s):  
Power Systems ◽  
Low Power ◽  
Electric Power ◽  
Distributed Generation ◽  
Renewable Energy Sources ◽  
Distribution Networks ◽  
Electric Power System ◽  
Electrical Networks ◽  
Operating Modes ◽  
Positive Effects

Decentralization of electricity generation based on distributed generation plants is an important segment of the new technology platform for the power industry. On the basis of this approach, significant positive effects can be obtained, which consist in reducing financial costs of energy supply, increasing the uninterrupted power supply, improving the quality of electricity and stimulating the use of renewable energy sources. Effective use of distributed generation in electric power systems requires the development of methods and tools that provide coordinated management of normal, emergency and post-emergency modes. Of particular relevance is the problem of determining the limit operating modes of networks, at the nodal points of which relatively low power generators are connected. In some situations, for example, when using small hydraulic stations, groups of such generators can be located at significant distances for 6-10-20 kV distribution networks from consumption centers. In this case there will be a noticeable limitation of the regions of static aperiodic stability. The article presents the results of developments aimed at implementing methods for determining the limit operating modes by static aperiodic stability in networks with distributed generation plants. The proposed approach is based on the limit modes equations which provide the formation of effective algorithms for the operational finding of points belonging to the boundaries of stability regions. The results of the construction of the indicated areas for a 6 kV electric network with distributed generation plants based on low-power hydraulic stations are presented. Additionally, the transient processes in the studied electric power system were simulated in the Matlab system for various space points of the controlled mode parameters.

scholarly journals ENERGY CHARACTERISTICS OF PHASE REGULATING DEVICE BASED ON “STAR” CIRCUIT

2021 ◽  
Vol 28 (3) ◽  
pp. 71-79
Author(s):  
Lev Kalinin ◽  
◽  
Dmitrii Zaitsev ◽  
Mihai Tirsu ◽  
Irina Golub ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Smart Grid ◽  
Electric Power ◽  
Electric Power Industry ◽  
Power Industry ◽  
Phase Shifting ◽  
Electrical Networks ◽  
Energy Characteristics ◽  
Electric Grids ◽  
Technical Solutions

The electric power industry development mean increases the electric grids flexibility through the use of various devices type (FACTS) controlled by means of power electronics and being an element of the Smart Grid. This type of device includes a phaseshifting transformer (PST), which redistributes power flows in the branches of electrical networks. In connection with the relevance of this topic, new technical solutions appear that implement similar functions, which entails the need for a comparative analysis of such developments in order to optimize the energy characteristics of this kind of equipment. The aim of the work is to develop schematic version of the PST made according to the "star" scheme and analyze its operation in typical modes. During the study, the energy characteristics of the device were determined. The possibility of reducing the typical power of the phase-shifting device due to the use of capacitive compensation is analyzed.

scholarly journals EXPERIMENTAL STUDY OF THE POSSIBILITY TO SINGLE OUT THE MODE OF SINGLE-PHASE CLOSURE TO THE GROUND IN THE CIRCUIT 6– 10 kV BY THE INTELLIGENCE SYSTEM OF ELECTRICITY METERING

2020 ◽  
pp. 5-15
Author(s):  
Ainur F. Abdullazyanov ◽  
Alexander I. Fedotov ◽  
Marat N. Khabibullin ◽  
Linar I. Abdullin ◽  
Georgii V. Vagapov
Keyword(s):  
Power Systems ◽  
Electric Power ◽  
Distribution Systems ◽  
Single Phase ◽  
Electric Power Systems ◽  
Electricity Supply ◽  
Electrical Networks ◽  
Electric Networks ◽  
Emergency Situations ◽  
Diagnostic Signs

The problem of increasing the reliability of electricity supply is relevant at the current stage of electric power systems development both in the territory of the Russian Federation and in foreign electric power systems. One of the ways to improve the reliability of electricity supply is to prevent the development of emergency situations on overhead power transmission lines as the most important components of electric power systems, which is confirmed by a substantial number of annual domestic and foreign publications. Preventing the development of emergency situations is largely facilitated by early detecting the signs of emergency modes onset in the functioning of all voltage classes’ electric networks. At the same time, the development of intelligence systems for technical and commercial electricity metering opens up new opportunities for monitoring numerous parameters of different operational modes of electrical networks, including those of 6-10-35 kV voltage with isolated neutral operation mode. Numerous works of author’s teams are devoted to the theoretical analysis of the possibility to early detect the diagnostic signs of emergency signals. However, existing publications do not always present the results of field experimental studies in existing electrical networks on the subject under consideration, which demonstrates some discrepancy between theoretical provisions and the possibility of their practical implementation. The present article attempts to assess the possibility of practical implementing the part of theoretical provisions on early detection of diagnostic signs for emergency regimes and, as a result, increase reliability of electricity supply. At the same time, the article presents the results of the field study the basis of which were used to open up current possibilities of early detecting the diagnostic signs of emergency regimes on the example of individual singling out higher harmonic components of currents and voltages, including when using already existing intelligence electricity metering systems installed in the existing electrical distribution systems with the voltage of 10 kV. At the same time, the article demonstrates implementability and further development of online monitoring of emergency modes in electric networks functioning on the example of identifying a single-phase ground fault, which makes it possible to significantly reduce the costs of temporary and material resources when localizing the single-phase closure zone.

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