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Evaluation of a switching device behaviour during short-circuit current
Fendrych, Martin ; Dostál, Lukáš (referee) ; Valenta, Jiří (advisor)
At work, I focused on the principle of electric arc extinction in low voltage devices. I particularly focused on the issue of magnetic switches. Next, I processed by the theory site issue of contact system in magnetic switches. In the practical part of my work, I was testing modular low voltage circuit breaker type of 2B and 10B. Testing was carried out in the laboratory of switchgear. I observed the movement of the contact and electric arc, which was burned between them and conductor wall. Observation was recorded by using a high-speed camera and an oscilloscope. Of acquired waveforms, I evaluated the dynamics of contacts, electric arc length and the value of the arc voltage for different moments.
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Usage of high-speed camera in the area of switching arc
Samohejl, Matěj ; Bušov, Bohuslav (referee) ; Valenta, Jiří (advisor)
This bachelor´s thesis is focused on optimizing recording of electrical switching arc in magnetic switches by high-speed camera. Measurements were performed on the circuit breaker 10B without removed side case, which was subsequently cowled by neutral density filter. The voltage and current of the circuit breaker contacts were acquired by measuring system of the Laboratory of switching arc diagnostics. The energy source was motor-generator with a nominal power 16 MVA and test bench consisting of a capacitors and inductors, which have been tuned to the resonance frequency of 50 Hz. Evaluation of the measurements was taken with regard to the brightness distribution levels of the record. Results showed that the mean brightness value varies on the square of the current passing through. For proper localization of the arc, it is necessary to appropriately set the camera exposure. The main problem usually is to darken the scene enough. It was found that it is necessary to take into account that brightness level change depends nonlinear on the exposure offset. The thesis gives a proposal to determine the exposure shift of the record. The possibility of usage high-speed camera to determine the temperature distribution in the arc using the brightness equiintensities was also designed. There are mentioned suggestions how to improve recording of the arc in circuit breakers, especially in the arrangement of the optical parts.
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Current distribution and heat losses in the low voltage circuit breakers
Musil, Pavel ; Janda, Marcel (referee) ; Makki, Zbyněk (advisor)
The work is focused on the calculation of decomposing the current and the thermal loss in circuit breakers of low voltage. In the work´s first half, there is a summary of the most frequently used circuit breaker elements with a focus on their constructional layout. The biggest attention is devoted to the circuit breaker marked LPN-16B by the company OEZ. A model of the under current trajectory of this specific element is created in a program Inventor on which the following calculation of decomposing the current and thermal loss was accomplished in a program Ansys. The obtained results are assessed in the conclusion of this work.
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Calculation of electrodynamic forces in 630 A circuit breaker
Staněk, Pavel ; Bušov, Bohuslav (referee) ; Valenta, Jiří (advisor)
The aim of this thesis is to simulate the action of electrodynamic forces on current carrying path and a movable contact of the circuit breaker OEZ Modeion BH 630NE. For the calculation there is used the simulation program Ansys Maxwell. The first part is devoted to theoretical analysis of electromagnetic forces on a conductor in a magnetic field. Further I discuss the constructional design of the circuit breaker itself, especially the current path and the contact mechanism. In the next part there is (with using program Autodesk Inventor) created a simplified 3D model of the current path including an arc chamber. With program Ansys Maxwell then there is performed simulation of the acting of forces in each mode. This is magnetostatic and transient analysis for symmetrical and asymmetrical flow of the fault current. In conclusion the results obtained are evaluated and processed in the tabular way.
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Experimental verification of properties of circuit breaker quenching chamber
Kadrnka, Petr ; Vávra, Zdeněk (referee) ; Valenta, Jiří (advisor)
The circuit breakers are able to switch on and off automatically either the short circuit currents up to the limits of their breaking capacity. While the disconnection of the contacts in the switching devices are generated by the arc then it is needed to put it out quickly. A manner of the arcing in the electrical switching devices is influenced by several different factors. It must be taken into account the dynamics of a plasma, a current flowing in the electrodes, a flowing stream in a plasma and a magnetic field generated by a flowing current. This paper is devoted to describe the manner of the arcing in the arc chamber. The experiments carried out in an experimental way attempt to explain, specify and thoroughly comprehend the movements and the characteristics of the arc in a metal arc and in a metal enclosure circuit breaker.
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Testing of Control and Logic Functions of Feeder Terminal
Kaplanová, Klára ; Paar, Martin (referee) ; Orságová, Jaroslava (advisor)
This work occupies itself with an analysis of operational manipulations in the feeder terminal of the distribution system and it considers the configuration of its apparatus equipment with the following configuration of the logical operations for controlling the apparatus in the feeder terminal. Further, this work occupies itself with switching high voltage equipment, their qualities and distribution, with their electrically driven mechanism, including the method of their control. Moreover, the work is aimed at the configuration of the logical operation with the aid of the Boole functions for controlling the feeder terminal apparatus within the CAP 505 software, and at its following testing on the REF 543 terminal from the ABB Company. The aim of the work is theoretical analysis of controlling and operational manipulations in a high voltage distribution system, the following creation and registration of the blocking conditions as well as with their use to create a functional configuration of the feeder terminal of the distribution system and its testing on the demonstration panel which is set with the REF 543 terminal and with further apparatus equipment that simulates the complete high voltage distributor. In the factory configuration the simulation is carried out by the LOGO! module from the Siemens Company. Therefore, our further aim is to design and subsequently to connect the feeder terminal so that the controlling and signaling panel elements could be connected directly to inputs and outputs of REF 543 terminal and could so enable its controlling and checking of the operation conditions. The main aim of the work is to elaborate a detailed description of the functional configuration creation as well as the following REF 543 terminal adjustment for testing the blocking conditions.
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Electrical installation in family home
Pokorný, Marek ; Bátora, Branislav (referee) ; Macháček, Jan (advisor)
The goal of this bachelor paper with the topic " Electrical installation in family home" is to describe laws and public notices that relate to an electrical setting; relevant norms and conditions for a connection to a distribution network (low tension service lines); ways of connections and its location. Furthermore, this paper describes operational conditions, external effects, dimensioning, cabel lodgements and protection (its ways, principles, security and conductor). In a separate chapter low tensinon switch-boards distribution and its instrumentation is covered. Another sphere of this bachelor paper is the field of illumination and lamps. The following chapter deals with sorts of electrical setting (classic, intelligent), low-tension electrical setting (PC distributions), fire and safty electrical setting and audit report elaboration. A practical sample of a electrical installation in family home is shown at the end of this paper
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Calculation of electrodynamic forces in 250 A circuit breaker
Görig, Michal ; Dohnal, Petr (referee) ; Valenta, Jiří (advisor)
This master’s thesis deals with the calculation of electrodynamic forces breaker BD250NE305. Main tasks in this semester project is to study the theoretical analysis of individual parts specified breakers. Processing theoretical analysis of these forces. Creating a 3D model current path and sheets quenching chamber single phase circuit breaker in Autodesk Inventor Professional 2012. Another challenge is the subsequent export the model into the simulation program ANSYS Maxwell. After simulation, the specified conditions must be processed and the results of the present work is to evaluate.
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Calculation of heat and force field UniGear ZS1
Mokrý, Lukáš ; ABB, Drahomír Tůma, (referee) ; Dohnal, Petr (advisor)
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.
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