• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 29
  • 22
  • 10
  • 10
  • 8
  • 2
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 96
  • 96
  • 22
  • 21
  • 20
  • 17
  • 16
  • 16
  • 15
  • 13
  • 13
  • 12
  • 11
  • 11
  • 10
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Simulace dějů v elektrických přístrojích / Simulation of phenomena in switchgears

Daševič, Ladislav January 2009 (has links)
Aim of the thesis is to explain the issue of forces acting in circuit breaker caused by magnetic fields induced by short-circuit current. This thesis is focused on force affecting in concrete system of a circuit breaker. The given circuit breaker is made by OEZ Letohrad, the type Modeion BD250. In the thesis the way of creating 3-D model is shown for the purpose of creating numeric simulation by ANSYS 11. The next approach of the thesis is the description of applicating the results for DC and AC current calculations. The noted calculation is made in the programme MATLAB 6.5. The solutions are mentioned at calculations both in the graphic form and numeric specifications. Visualisation was made by using GIF graphic system animation. The individual pictures processing was done in the programme UNLEAD GIF ANIMATOR 5.
92

Posouzení možnosti provozu zdrojů v dané oblasti při nestandardních provozních stavech sítě VN / Evaluation of nonstandard operation possibilities of power sources in MV network

Čáslava, Jiří January 2012 (has links)
This Master's thesis deals with solution of nonstandard operation connection of E.ON's 22kV distribution network in given area, considering the possibilities of operating dispersed electric power sources currently available, as well as possible power sources connected to the distribution network in the future and its potential operation limitation. A part of this paper is a description of calculation methods used for network evaluation in steady state, with emphasis on linear calculations used by E-Vlivy program, in which the operational possibilities are simulated. Therefore, a description of this program is also included. Suggested operation possibilities correspond with E.ON's valid distribution network operation rules. The outcome of this paper will serve to E.ON's 22kV network's controllers as materials for network operating in nonstandard operation states.
93

Kontejnerové NN/VN rozvodny / Containerized Low-Voltage/ Middle-Voltage Substations

Marcol, Michal January 2013 (has links)
As it is already apparent from a title of my work, I will be engaged in proposal of container VN/NN distributor using components from company ABB. This work will be after final making also used by company ABB to simplify procedure of proposal of any kind of container distributor. In my labor I will be generally deal with individual products, which will after that be used in distributor. Next I will be engaged in particular making of distributor, which should be made. The distributor will be designed for a separate part of the transformer and for a transformer as a unit, which is not separated from substation.
94

Výpočet tepelného pole rozvaděče UniGear 500R / Calculation of heat and force field UniGear ZS1

Mokrý, Lukáš January 2015 (has links)
The aim of my work is to describe high-voltage switchgear type UniGear 500R, which is part of UniGear switchgears family. I will focus on heating issue of one 500R unit and its parts during operation. Maximum values of this heating is limited by standards and can´t be exceed to ensure safe and reliable operation. That is why the heating tests are necessary part of designing and developing switchgears. Calculation will be made by two different ways. First is classic one-pole heating net method and second is numerical simulation in Solidworks flow simulation program. Except the theoretical description there will be presented also used 3D model and explanation of both method, used to calculation and simulation. Last point of this work is measuring of this type of switchgear and getting real data. The main point there is to compare measured values with values calculated and decide if is possible to simulate tests with appropriate accuracy. Then would be also possible to substitute the real test in laboratory, which costs many thousand crowns and takes lots hours of time. This work is collaborated with EJF division of ABB Company, where I am employed. Heating issues in this company is always on process, because of developing and improving of their products. So this work could be helpful in this field. ABB provides all materials needed, especially technical catalogues, 3D model and final values from laboratory measuring. Support from college faculty is mainly in study consultations and proposing of calculations making. In the end of work will be make final comparison and evaluation of achieved results.
95

Rekonstrukce elektrické části vytloukacího roštu / Reconstruction of discharging shakeout machine electric installation

Bednář, Vojtěch January 2016 (has links)
This Diploma work is concerned with the design of project documentation for discharging shakeout machine electric installation. This work continues in the Semestral project 2 in which the background of a new machine was made. Then, this work deals with the replacement of a switch room with required devices including the design of a new connecting cables and power streams. In the first part, the work deals with the control part of the device and the design of control and signal cables including the product documentation of the device. In the second part, the work deals with the proposal of building electro installation in which a new lighting and its use is described. The last part focuses on the coordination during the realization of a suggested device. In this part, all problems coming from the particular working procedures including a proposal of possible solutions are described. According to the project documentation and following realization, the documentation of final concept reflecting the real status of the device is described.
96

遮断器用油圧操作装置の動作時間安定化に関する研究 / シャダンキヨウ ユアツ ソウサ ソウチ ノ ドウサ ジカン アンテイカ ニカンスル ケンキュウ

山下 透, Tohru Yamashita 02 March 2017 (has links)
電力用遮断器の油圧操作装置において,油圧回路内の気泡が操作装置の動作に及ぼす悪影響を解消するために,新しい油圧回路方式である常時高圧安定回路方式を提案し,油圧回路内の流れおよび可動部の定式化と解析および実測を行った.本方式の動作特性と動作安定性,ピストンの制動特性,複数の油圧操作装置の駆動特性について検討し,本方式が有効かつ安定的に機能することを確認した.以上により,油圧操作装置の動作時間安定化技術を開発することができた. / We proposed and studied a hydraulic operation stabilizing system for a hydraulic operating device of a circuit breaker to eliminate the influence of air bubbles created in hydraulic fluid. We formulated the flow of hydraulic circuit and the motion of moving parts, which were numerically simulated and experimentally confirmed. We confirmed that this stabilizing system functioned effectively and stably through the investigation: operation characteristics and stability of the stabilizing system, braking characteristics of a piston-dashpot system and operation characteristics of two hydraulic operating devices. Based on the results, we could perform an engineering development for stabilizing operation time of the hydraulic operating device. / 博士(工学) / Doctor of Philosophy in Engineering / 同志社大学 / Doshisha University

Page generated in 0.0492 seconds