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Current sensor with digitized output signal
Hanuš, Ivan ; Vágner, Martin (referee) ; Havránek, Zdeněk (advisor)
The objective of this thesis is to describe principles of measuring of alternating current in low voltage power supply network with Rogowski coil and to study details of requirements for electronic current sensor with digital output. Furthermore to study the current solution of digitalization of output signal from Rogowski coil and to determine metrological characteristics of the digitalization module for processing the signal from the Rogowski coil as current sensor and to design a concept of an electronic current sensor unit with Rogowski coil and the digitalization module with the expected optical output. The theoretical part deals with the measurement of current using Rogowski coil, its characteristics and advantages compared to conventional current transformers. Further in the thesis there are specified the requirements for current sensor. The practical part deals with the design of digitalization module consisting of a pair of AD converters, a microcontroller and output circuits. Furthermore, the thesis deals with digital signal processing of signal from Rogowski coil. Furthermore, the thesis describes firmware for microcontroller and PC application. The result of thesis is functional circuit of electronic current sensor that processes signal from Rogowski coil and converts it to digital form.
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Current sensor with digitized output signal
Poruban, Milan ; Klusáček, Stanislav (referee) ; Havránek, Zdeněk (advisor)
The main aim of this thesis is to describe principles of measuring of alternating current in low voltage power supply networks with Rogowski coil and study in detail the requirements for electronic current transformer with digital output. Farther confirm the basic parameters of Rogowski coil as an current sensor and creating its alternate electric model. Theoretical part deals issue of measuring alternating current with Rogowski coil, its properties, characteristics, construction and advantages over conventional current transformers of alternating current. There are also listed requirements for alternating current transformers and requirements for their digital output. A/D converters are also discussed. Practical part deals with measuring of parameters of Rogowski coil and creating its alternate electric model. Furthermore, the design and implementation of the input circuit for a pair of A/D converters, which represents a measurement card from NI. Data from the measuring card is processed by the program LabVIEW. The outcome of this thesis is a functional circuit that provides an analog signal pre-processing of Rogowski coils represented by installed PCB designed for 18-bit AD7690 converter and technology demonstrator, which processes the digitized signal from the measuring card.
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Universal control unit for life test of motors
Ševčík, Šimon ; Macháň, Ladislav (referee) ; Musil, Vladislav (advisor)
This thesis describes theway of BPM motors control and its use in life testing. Firstly it describes the properties of motors and their differences. Secondly it describes possibilities of motor control and their need for life testing. Finally it describes proposal of the universal control unit, types of controling, programming part and technical documentations.
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Current sensing with Hall-effect sensors
Štindl, Daniel ; Kovář, Jan (referee) ; Šotner, Roman (advisor)
This master's thesis deals with integrated Hall-effect current sensors. The thesis contains summary of manufacturers of current sensors suitable for low current measurement and comparison of their important parameters. Next objective of the thesis is a design of test board used for evaluation of temperature depedent accuracy of several sensors simultaneously. The device can be connected with PC through USB interface for saving measured values or automated control with other instruments.
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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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Device for diagnostic of induction machine
Buln, Tom ; Janda, Marcel (referee) ; Huzlk, Rostislav (advisor)
The aim of the thesis is to study the problems of induction motors, which belong among the most widespread and used machines. Due to their expansion, it is advisable to start the fault monitoring to prevent any more damage and losses. It can be used for condition monitoring different types of methods, which are variety technically and costly demanding to implement. It is used the method of measurement using stator currents in this thesis, because these currents are already monitored and it is easy to create devices for a more detailed analysis. The whole monitoring is carried out using products from National Instruments. The program of monitoring is created in graphical setting of LabVIEW. The analysis is conducted by calculating the Fast Fourier transform of the time signal. The result is the frequency spectrum, which contains frequency peaks and some of these peaks represent failure. The test data are collected with a DAQ device and then the same data are used for creating a methodology for evaluating online analysis and it is subsequently implemented into CompactRIO.
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Switching supply source 5,5kV/4,3kW with silicon-carbide semiconductors
Gabriel, Petr ; Patočka, Miroslav (referee) ; Vorel, Pavel (advisor)
This thesis is about to introduce the development of switched power supply with output voltage of 5,5 kV and power of 4,3 kW. This thesis directly follows the outputs of two previous semester projects. Main task is about to finish the development of remaining printed circuit boards and perform launching of all parts of developed power supply. Next necessary task is about to assemble a functional prototype of the supply using the developed parts, performing a series of measurement supply’s parameters and creating of technical documentation of mechanical part. There are all stages of supply’s development included in this thesis. From the first part, that describes various types of converters, through the design of all the supply’s parts, to final implementation of functional prototype. There are the results of measurement supply’s parameters at the end of this thesis.
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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 digital optical output
Kubáč, Stanislav ; Beneš, Petr (referee) ; Klusáček, Stanislav (advisor)
This work descibes general principles of measuring the alternating current and voltage using conventional and unconventional sensors.This work shows specific parmeters conected with principles of the measurement, advantages and disadvantages of individual measuring procedures, types of output signals, precisions, limitations, ways of power and so on. Part of the work is to find optimal measurement procedure, which can be aplicated to practical measuring of alternating currents and voltage. Main part of the work concerns the realisation of optimal method of measuring alternating current.
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