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AC current sensors
Hašpica, Štěpán ; Huták, Petr (referee) ; Patočka, Miroslav (advisor)
Aim of the bachelor's thesis is to anylize chosen types of AC current sensors with focus on design of one chosen type. Sensoring of AC current can be done for instance by current measuring transformator, Hall's sond or Rogowski coil. These ways and types of sensors are disscussed in chapter no. 2. But main focus of thesis is in finding one definite algorithm for current meassuring transformator. New possible way in design is in-depth disscussed in chapter no. 3. Current meassuring transformator, or other types of sensors finds great application in area of power energetics and electronic engineering.
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Power supply for acquisition and communication subsystem of a current transformer
Beran, Tomáš ; Král, Jan (referee) ; Kubíček, Michal (advisor)
This bachelor thesis is focused on designing a power supply for measuring part and communication part of a device, which is supposed to analyze current waveforms on high voltage lines. The power supply consists of a current transformer, control electronics, and accumulation elements. The thesis analyzes the current waveforms on high voltage lines to get an overview of input data so that the right current transformer can be chosen. A working principle of these transformers is described, as well as the options for accumulation elements. Power supply requirements for the power supply are determined as well. The next part of the thesis summarises this theoretical knowledge and applies it to the schematic design. This is followed by a description of the schematic with an included description of function blocks. Additional adjustments that would improve the power supply's properties might be mentioned. This will be followed by designing a PCB layout. The final part includes the manufacturing process and determination of parameters like power, efficiency, etc. In the manufacturing process, the PCB will be printed, soldered, and evaluated on an electrical test. The electrical test inspects the functionality of the designed power supply by simulating real-life scenarios of high voltage lines. At last, an impact of the power supply on the measuring system will be analyzed.
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Primary testing of the protection relays
Macek, Vratislav ; Topolánek, David (referee) ; Toman, Petr (advisor)
The main subject of this bachelor’s thesis is the creation of laboratory task on the issue of primary injection testing of the protection relays. The thesis is made up of two parts: theoretical and practical. In theoretical part there are information concerning the issue of protecting. One of them the meaning and relay function, requirements applicable on them, failure states, which may arise on the device operation, description of instrument transformers and methods of testing relays. In practical part is created laboratory task on the issue of primary injection testing of overcurrent relay, of which will demonstrate the influence of load current transformer to its function. In task are used Overcurrent and Earth-fault protection REJ 525A and measuring instrument Omicron CPC 100.
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LOSSES IN MEDIUM VOLTAGE CURRENT TRANSFORMERS
Bajánková, Denisa ; Langerová, Petra (referee) ; Baumgartnerová, Alena (advisor)
Tato bakalářská práce umožňuje nahlédnout do problematiky ztrát u přístrojových transformátorů proudu vysokého napětí. Přístrojové transformátory proudu představují velmi důležitou součást elektrických zařízení, slouží k transformování měřených proudů na standardní hodnoty, které měřicí a jistící přístroje mohou zpracovat. Je důležité, aby tyto proudy byly převáděny s co nejvyšší přesností. Teoretická část práce se zaměřuje na popis přístrojových transformátorů proudu a analýzu jednotlivých ztrát u transformátoru. Praktická část je obsažena v deváté kapitole, má za cíl ověřit teoretické poznatky práce a popisuje laboratorní měření.
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Extensible measurement socket placement optimalization with respect to the higher number of conductors
Šindler, Matěj ; Čepička, Martin (referee) ; Wasserbauer, Vojtěch (advisor)
In opening, this bachelor thesis is describing structure and basic block description of UniGear switchgear manufactured by ABB company. Then this thesis focus on current and voltage transformers and sensors often used in this type of switchgear. Main part of this thesis is dedicated to evolution and description of connector, used in connection solution of withdrawable metering unit with low-voltage compartment. Next part states the main requirements for new connector, that will replace current connector in future solution. In following part there is a list of different options for new connector with their biggest strengths and weaknesses pointed out. Then there is list of alternative placements for new connector. In final part is chosen and described new connector and its placement. This solution is valuated and backed up by created 3D models.
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Comparison of Instrument Transformer and Sensor Applications in Feeder Terminal REF 542plus
Hrycík, Tomáš ; Majer, Karol (referee) ; Orságová, Jaroslava (advisor)
The aim of this Master´s thesis is use of instrument transformers and sensors on field of industry protection. We will compare current and voltage transformers, current sensor – based on Rogowski coil, voltage sensor – based on voltage divider. By this measure devices, we can monitoring values of analog quantities in medium voltage switchgear. It is impossible to compare, measure and analyze without this measure devices. There is protection terminal REF542plus, which can compile this values. The REF542plus ability are measuring, monitoring, remote control and protection. First, we will discuss about theory of sensors and convential instrument transformers and analysis of analog signal. We will compare analog input channel on sensor´s analog module and transformer´s analog module. There are few differences between type of analog modules. For analog signal analysis are important frequency filters and Analog/ Digital Convertor (sigma-delta). We will describe functions and options of REF542plus. In practical part of this project, we will test protection functions of protection terminal. First, protection terminal will be connected to sensors. Second protection terminal will be connected to transformers. For testing we chose Earth-fault directional protection and differential protection. We will make only secondary tests. That´s mean, input analog quantities to REF542plus will be simulated by tester. In all we will verify quality of protection. We will focus on lower settings of protection and we will inject protection by low current. Objectives are testing of trip characteristics and measuring of trip time.
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Design of instrument transformers for digital protection relays
Souček, Jan ; Matuška, Marcel (referee) ; Toman, Petr (advisor)
Master’s thesis is concerned with instrument transformers, which are used in conjunction with numerical protection relays. Therefore mainly with protective transformers of class P and transformers dimensioned for transient effects, which are important e.g. for fast differential or distance protections. The introduction includes fundamental notions, quantities and equations, which refers to instrumental current and voltage transformers. Below are mentioned connection diagrams of these transformers applied to specific electrical network types and faults, of which identification is required. These diagrams and faults are supplied with math equations and eventually with phasor diagrams. Noted informations corresponds to the present standards. Task of the next part is to compile requirements for dimensioning of current transformers, which imposes digital protections from ABB, AREVA and Siemens companies. These requirements, which mostly defines the minimal accuracy limit factor or the knee-point voltage of current transformer, are specified for individual protection terminals, eventually for specific protective functions. Part of the thesis is computer program developed as macro in the Microsoft Office Excel program via Visual Basic for Applications programming language. Program uses equations noted in this work and it can be used for quick dimensioning of current transformers for protective terminals from manufactures mentioned above.
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Design of switching-mode regulated power supply
Zelinková, Lenka ; Kováč,, Michal (referee) ; Brančík, Lubomír (advisor)
The thesis addresses the conceptual design and implementation of the switched-mode power supply having the adjustable dc voltage output up to 25V and current output up to 15A. The half-bridge topology is used for this supply. Design features and quantities are simulated in PSpice and Micro-Cap simulation tools. The thesis covers the simulation results, assembly data and the results measured on the implemented functional sample.
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Current Transformers and Current Sensors Confrontation
Popek, Jiří ; Bok, Jaromír (referee) ; Topolánek, David (advisor)
Current transformers and current sensors are devices which are mostly used for current measurement in high voltage systems. This devices transform measured currents to range which are workable for measurement and protection devices. Current transformers have been using for current measurement since electric system was built. Current sensors are using for measurement after applying digital devices in their secondary circuits. Theoretical part includes fourth and fifth chapter. These chapters contain construction analysis and characteristic points for both devices. Practical part is in chapter six. This chapter consists results from laboratory measurement. Results are used for verification with theoretical part of the thesis. Accuracy class in nominal range and progress for measurement error in overcurrent range was verified for tested devices. Conclusion of this thesis comparing properties and summarises results from laboratory measurement.
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AC and DC current sensors
Zimek, Alois ; Huták, Petr (referee) ; Patočka, Miroslav (advisor)
The aim of this master’s thesis is to focus on analysis of a current transformer with feedback correction of measuring error, make an AC current sensor and verify its qualities experimentally. The measuring scale of this transformer is I = 0 to 100A, f = 50Hz.
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