scholarly journals The Proposal of a New Tool for Condition Assessment of Medium Voltage Power Cable Lines

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4116
Author(s):  
Krzysztof Siodla ◽  
Aleksandra Rakowska ◽  
Slawomir Noske
Keyword(s):  
Research Work ◽  
Technical Condition ◽  
Power Cable ◽  
Investment Planning ◽  
Medium Voltage ◽  
Cable Network ◽  
Rate Analysis ◽  
Cable Lines ◽  
The Individual ◽  
Service Data

A medium voltage (MV) cable network is a substantial component of the distribution network. Present management of this grid segment is mainly based on the failure rate analysis, i.e., a rise in the number and kind of faults on the actual line means that its technical condition is getting worse. The efficiency of the power system is low and additional costs of repair works, supply interruption, difficulties in the investment planning and operation and maintenance works are necessary. The aim of the R&D works done in the realised project is to implement the management of the MV cable network based on the estimated condition of the individual cable line, obtained from diagnostic measurements. The diagnostic investigations of the cable lines are the reference. Many years of research work have led to the development of the Health Index based on diagnostic, technical and service data.

scholarly journals Experimental tests of PVD AlCrN-coated planer knives on planing Scots pine (Pinus sylvestris L.) under industrial conditions

2021 ◽  
Author(s):  
Krzysztof Nadolny ◽  
Wojciech Kapłonek ◽  
Marzena Sutowska ◽  
Paweł Sutowski ◽  
Piotr Myśliński ◽  
...  
Keyword(s):  
Research Work ◽  
Experimental Tests ◽  
Technical Condition ◽  
Cutting Edge ◽  
Raw Material ◽  
Edge Condition ◽  
Wear Area ◽  
Pine Wood ◽  
Wood Processing ◽  
Machining Operations

AbstractRaw pine wood processing and especially its mechanical processing constitute a significant share among technological operations leading to obtaining a finished product. Stable implementation of machining operations, ensuring long-term repeatable processing results depends on many factors, such as quality and invariability of raw material, technical condition of technological equipment, adopted parameters of work, qualifications and experience of operators, as well as preparation and properties of the machining tools used. It seems that the greatest potential in the search for opportunities to increase the efficiency of machining operations has the modification of machining tools used in it. This paper presents the results of research work aimed at determining how the life of cutting tools used in planing operations of wet pine wood is affected by the application of chromium aluminum nitride (AlCrN) coating to planar industrial planing knives in the process of physical vapour deposition. For this purpose operational tests were carried out under production conditions in a medium-sized wood processing company. The study compares the effective working time, rounding radius, the profile along the knife (size of worn edge displacement, wear area of the cutting edge), selected texture parameters of the planar industrial planing knife rake face and visual analyses of cutting edge condition of AlCrN-coated planar knives and unmodified ones. The obtained experimental results showed the possibility of increasing the life of AlCrN-coated knives up to 154% compared to the results obtained with uncoated ones. The proposed modification of the operational features of the knives does not involve any changes in the technological process of planing, does not require any interference with the machining station nor its parameters, therefore enabling rapid and easy implementation into industrial practice.

scholarly journals Thermal Analysis of the Medium Voltage Cable

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4164
Author(s):  
Tomasz Szczegielniak ◽  
Dariusz Kusiak ◽  
Paweł Jabłoński
Keyword(s):  
Temperature Distribution ◽  
Analytical Method ◽  
Good Accuracy ◽  
Proximity Effects ◽  
Electrical Performance ◽  
Power Cables ◽  
Power Losses ◽  
Transmission Networks ◽  
Medium Voltage ◽  
Cable Lines

The use of high voltage power cables in distribution and transmission networks is still increasing. As a result, the research on the electrical performance of cable lines is still up to date. In the paper, an analytical method of determining the power losses and the temperature distribution in the medium voltage cable was proposed. The main feature of the method is direct including the skin and proximity effects. Then the Joule law is used to express the power losses in the conductor and screen, and the Fourier-Kirchhoff equation is applied to find out the temperature distribution in the cable. The research was focused on a cable with isolated screen and return current in the screen taken into account. The proposed method was tested by using the commercial COMSOL software(5.6/COMSOL AB, Stockholm, Sweden) as well as by carrying out laboratory measurements. Furthermore, the results obtained via the proposed method were compared with those given in literature. The differences between the temperature values calculated by the analytical method, numerical computations and obtained experimentally do not exceed 10%. The proposed analytical method is suitable in prediction the temperature of the power cables with good accuracy.

Examination of State of the Cable Insulation by the Return Voltage

2018 ◽  
Vol 19 (6) ◽  
Author(s):  
Dmitry Semenov ◽  
Anna Sidorova ◽  
Pavel Romanov ◽  
Aleksey Kuvshinov
Keyword(s):  
Residual Life ◽  
Technical Condition ◽  
Actual State ◽  
Power Cables ◽  
Insulation Resistance ◽  
Cable Lines ◽  
P Factor ◽  
Paper Insulation ◽  
New System

Abstract The relevance of the study is conditioned by the need to determine the state and residual life duration of high-voltage cable lines to identify faulty and maintainable cables. The aim of the article is to determine a reliable scientifically grounded criterion for assessment of insulation characteristics of the cables in use and to perform a comparative analysis of the results obtained by the traditional method of diagnosing insulation with the results of a new method of assessment by the return voltage. In this regard, the article deals with the issues related to the testing of cables having oil-impregnated paper insulation, as well as with the issue of switching from planned replacement of cables to assessment of their actual state and period of residual life. The authors propose to use the method of examining the cables by the return voltage using the device for testing electrical insulation “UDEI-1” developed at the department of Electrification and Automation of the Nizhny Novgorod State University of Engineering and Economics. The article presents the results of measuring the return voltage of three cables that operated under different conditions. The cables had different technical state. The analysis of the estimation of the residual life of cables by the return voltage was carried out using such criteria as the PIRV polarization index, the LIRV electrical conductivity index, and the P-factor. The P-factor is the physical criterion demonstrating the aging of paper-oil insulation by the shape of the return voltage curve. It represents such characteristics of insulation aging as moistening. To compare the results of testing the cables by the return voltage with the conventional methods of diagnostics and to determine the actual technical condition of power cables, the authors applied the method of spatiotemporal reflectometry and the method of measuring insulation resistance with the determination of such indicators of state as insulation resistance normalized per one kilometer, absorption coefficient, and polarization index. The results of this article confirm that the return voltage gives a qualitative assessment of the state and degree of aging of cables with impregnated paper insulation. The authors proposed a new system for evaluation of cable condition by weighting coefficients. In this approach, the determination of residual life of cables with impregnated paper insulation is based on the values of the return voltage. Application of the new system gives opportunity to improve reliability of the power lines. Recommendations for the further operation of the studied cables are given. The materials of the article are of practical value for carrying out complex assessment of the technical condition of power cables by the return voltage and can be useful for drawing up a schedule for replacement or repair of cable lines depending on their actual state.

scholarly journals Vibrations attenuation of a system excited by unbalance and the ground movement by an impact element

2016 ◽  
Vol 1 (2) ◽  
pp. 603-616 ◽  
Author(s):  
Marek Lampart ◽  
Jaroslav Zapoměl
Keyword(s):  
Differential Equations ◽  
Research Work ◽  
Computational Procedure ◽  
Ground Movement ◽  
Frequency Interval ◽  
Nonlinear Behaviour ◽  
Helical Springs ◽  
Impact Element ◽  
The Individual ◽  
The Impact

AbstractThis paper concentrates on the vibrations attenuation of a rotor driven by a DC motor and its frame flexibly coupled with a baseplate by linear cylindrical helical springs and damped by an element that can work either in inertia or impact regime. The system oscillation is governed by three mutually coupled second-order ordinary differential equations. The nonlinear behaviour occurs if the impact regime is adjusted. The damping element operating in inertia mode reduces efficiently the oscillations amplitude only in a narrow frequency interval. In contrast, the damping device working in impact regime attenuates vibrations of the rotor frame in a wider range of the excitation frequencies and it can be easily extended if the clearances between the rotor casing and the damping element are controlled. The development of a computational procedure for investigation of vibration of a flexibly supported rotor and for its attenuation by the inertia and impact dampers; learning more on efficiency of the individual damping regimes; finding possibilities of extension of the frequency intervals of applicability of the damping device; and obtaining more information on the character of the vibration induced by impacts are the main contributions of this research work.

Student scientific circle as a form of tutor’s support

2020 ◽  
Vol 22 (4) ◽  
pp. 220-227
Author(s):  
V. I. Odin
Keyword(s):  
Soviet Union ◽  
Human Life ◽  
Rapid Development ◽  
Research Work ◽  
Modern Science ◽  
Activity Level ◽  
Imperial Russia ◽  
Scientific Circle ◽  
The Individual ◽  
Active Implementation

The concept of a student scientific circle as a form of tutor training is presented. The history of the circle movement in Russian universities of imperial Russia is analyzed, starting with the circle organized by Professor Schwartz in 1781 and continued in the Soviet Union. The data on the state support of students research work in the post-war period, including state documents of title and measures of financial support, are presented. The traditional student scientific circle is a circle of those wishing to educate themselves in addition to the planned curriculum, by conducting their own research and publishing the results. As a result, an activity-level specialist is formed from a graduate of the circle. In contrast to the traditional one, the tutor-type training circle forms the circle member as a future specialist not only at the activity level, but also at the project and, preferably, conceptual levels. Methodologically, the task of a tutor-type training circle is not only to teach the circle members the practical skills of conducting scientific research, but, first of all, in personalized work to achieve anthropological goals, to create a reasonable, creative, effective personality who can create, plan and design. In the conditions of the rapid development of modern science, the construction of the future is proceeding at a rapid pace and is associated with the active implementation of the results of scientific experiments in all aspects of human life, which requires active suppression of everyday consciousness. At the same time, due to the risk of a landslide dehumanization, the circle member, as a scientist, needs to lay down humanitarian values that define the individual as a person who shares the ideals of goodness and justice. Thus, the student scientific circle is a system in which a new generation of honest and effective scientists and high class specialists is formed under the guidance of a tutor.

Personal Knowledge Management by the Knowledge Citizen

2010 ◽  
pp. 131-140
Author(s):  
América Martínez Sánchez
Keyword(s):  
Knowledge Management ◽  
Building Block ◽  
Research Work ◽  
Individual Performance ◽  
Individual Development ◽  
Personal Knowledge ◽  
Strong Impact ◽  
Personal Knowledge Management ◽  
Knowledge Based ◽  
The Individual

The discipline of Personal Knowledge Management (PKM) is depicted in this chapter as a dimension that has been implicitly present within the scope and evolution of the Knowledge Management (KM) movement. Moreover, it is recognized as the dimension that brought forth Knowledge-based Development (KBD) schemes at organizational and societal levels. Hence, this piece of research work aims to develop parallel paths between Knowledge Management moments and generations and the PKM movement. KM will be depicted as a reference framework for a state-of-the-art review of PKM. A number of PKM authors and models are identified and categorized within the KM key moments and generations according to their characteristics and core statements. Moreover, this chapter shows a glimpse of the knowledge citizen’s PKM as an aspect with strong impact on his/her competencies profile; which in turn drives his/her influence and value-adding capacity within knowledge-based schemes at organizational and societal levels. In this sense, the competencies profile of the knowledge citizen is of essence. Competencies are understood as the individual performance of the knowledge citizen interacting with others in a given value context. The chapter concludes with some considerations on the individual development that enables PKM to become a key element in the knowledge citizen’s profile, such as the building block or living cell that triggers Knowledge-based Development at organizational and societal levels.

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