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Development of new types of composites for concrete rehabilitation with increased protection reinforcement
Taranza, Luboš ; Durica,, Tibor (referee) ; Dohnálek,, Pavel (referee) ; Bydžovský, Jiří (referee) ; Drochytka, Rostislav (advisor)
Around the world there is a great number of reinforced concrete structures, who´s life cycle, for which they were designed, is significantly shortened due to action of various aggressive environments, or due to defects created during the construction process. (i.e. insufficient steel reinforcement cover depth). One of the most common causes of problems in reinforced concrete structures is corrosion of steel reinforcement. It is necessary to repair structures degraded in this fashion and return them to their original state. We made a unique polymercement concrete repair system was developed with value added. Corrosion inhibitors, including the newly developed, are implemented into its polymercement matrix, which significantly limit the corrosive processes in all new materials. The principle of proposed solution is application of repair system on a corrosion damaged structure, and then the active substances in the repair material will penetrate into substrate concrete and protect corroded steel reinforcement. Another value added is the application of recycled raw materials into the proposed materials, which has indisputable environmental effect and simultaneously allows for improvement of some properties of the repair materials. Further was developed a new method for detecting corrosion inhibitors in concrete.
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Replacement of electromechanical protections in TNS Vraňany
Čechová, Karolína ; Šiler, Michal (referee) ; Orságová, Jaroslava (advisor)
The reconstruction of the traction substation Vraňany currently involves only the replacement of power oil transformers. The main reason for their replacement is the fact that the power transformers have already exceeded their designed lifecycle. According to an investor requirement, only the transformer replacement is considered, however, a new system of protection is not included. Even though the fault-free operation of power transformers is closely related to ensuring a reliable and safe electric power supply. The main aim of the thesis is to design a new system of protection for power transformers to replace the present one. In the theoretical part of the thesis is described the current state of the traction substation along with a calculation of short circuit current ratios and their comparison with the new ones considering the installation of the new power transformers. In the next part are inspected instrument current transformers if they comply with the requirements for the new protection system. The practical part of the thesis focuses on the selection of protection relay, calculation of the primary setting for selected protection functions, and subsequently conducting their functional tests. In conclusion, the economic part of the planned investment is estimated.
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MV Overhead Line Protections and their Coordination with Autoreclosers
Šoustal, Petr ; Skala, Petr (referee) ; Orságová, Jaroslava (advisor)
The aim of this Master’s Thesis is to describe protections for overhead lines in distribution networks. Here are described requirements for the protection and the basic protections. Protections are divided according to their protective function. For each protection is given its use and its power plans. It is stated in the work setting of protection in the real network. On this network is simulated place with short-circuit and described the action of protection. The work also deals with the coordination of protection with automatic circuit breakers. This chapter shows that, given the selectivity is not possible to deploy two or more reclosers (remotely-operated switches) to the core network management. The next chapter describes two representatives reclosers available on the Czech market OSM 27 and GVR 27. Chapter describes and compares their performance characteristics. Conclusion the work includes a proposal protected the lead in incorporating automatic circuit breakers (remotely operated circuit breakers and reclosers). The proposal is based on two different levels of annual number of interruptions and duration of annual general interruption of electricity supply. For these levels the company EGÚ Brno, a.s. proposed several variants of the use of remote-controlled in terms of reducing the cost of the penalty. Our task was to choose a variant that would be applicable in the real network. Reducing costs is feasible only in the limits Ln = 6 failures / year and Lt = 720 min / year, where the selected option No. 4. The limits Ln = 8 failures / year and Lt = 1,080 min / year, not in the real network may no option in terms of selectivity.
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Compact inverter for BLDC motor
Nevřivý, Tomáš ; Červinka, Dalibor (referee) ; Procházka, Petr (advisor)
The work describes the design and implementation of compact inverter for brushless DC motor, which have mechanical power 600 W and rated torque 1.6 Nm. Motor is designed for DC link voltage with value 300 V. The focus is placed on the cost and simplicity. On this basis, the inverter is designed for uses single purpose power and control circuit. The power part is solved using a circuit FSBB15CH60C. The circuit is placed on a separate board of power electronics. Cooling of the power circuit is performed by the surface structure of BLDC motor. Control of the inverter ensures circuits LB11696V and NE566. The both circuits are placed on separate board of control electronics. Circuit LB11696V contains a control algorithm, as well as protections, which are necessary for safe operation of the inverter. Power supply of electronics is performed using step-down converter from MYRRA company.
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Design of Protection Relays for MV Distribution Grid
Sochor, Tomáš ; Bukvišová, Zuzana (referee) ; Toman, Petr (advisor)
The master´s thesis deals with the design of medium voltage power line protection and the calculation of reliability indicators. First, it deals with the possibilities of power system operation. Subsequently, it divides the networks according to the grounding of the transformer node and the switching elements and devices occurring in the MV distribution network are mentioned. It presents the basic classification of power line protection and its use, especially it focuses on overhead and cable MV power lines. It also discusses the reliability of the power supply and lists the basic reliability indicators and their possible calculation. The practical part describes the changes in the considered area of the distribution network, where the reconstruction of the power line VN872 and a new way of powering the village Drnholec will take place. The impact of this change on the reliability of the supplied energy is also calculated. Furthermore, the protection of the power line is designed and the correctness of its setting is then verified on the model in the PSS Sincal software.
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Amplifier with Speaker Protection
Přibyl, Libor ; Schimmel, Jiří (referee) ; Kubánek, David (advisor)
The present work deals with the issue of speaker damage due to large displacement of the membrane at low frequencies. The main focus is the design and construction of the circuit to protect the speakers from this type of damage and the subsequent measurement of its parameters. The thesis includes theoretical predictions for the optimal design and implementation of the circuit. The work includes complete construction of equipment, including power supply and auxiliary circuits.
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Protection for Generator Unbalance
Kuba, Petr ; Paar, Martin (referee) ; Orságová, Jaroslava (advisor)
The thesis deals with the problem of unbalance in generators and discusses various means of generator protection against the effects caused by this abnormal working condition. The general importance of the problem is described in the introductory part of this work. The theoretical section of the thesis contains an analysis of procedures applied to solve different types of unbalance by the help of the method of symmetrical components. As a central aspect of the topic, the causes of unbalance are examined. This investigation is realized together with a close insight into the diverse possibilities of unbalance reduction and, importantly, in respect the effects of negative sequence current on a generator and its components. The principles of generator protection against unbalance are described at the end of this section. In its practical part, this work deals with the procedure of protection setting and testing. The applied protection is an actual component of the REM 543 machine terminal as made by the ABB company. In order to facilitate the testing of the protection, we used the TZO3 electrical protection testing device provided by the EGÚ Brno, a. s. company. A summary of the most important information and measurement results can be found in the final part of the thesis.
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The use of optical fibers in potentially explosive atmospheres
Mafka, Martin ; Münster, Petr (referee) ; Filka, Miloslav (advisor)
The main object of semestral’s thesis was show familiarize with using optical networks in explosive areas. The thesis is divided into several basic thematic areas, in which we describe the divison by environmental threats hazards, types of protections optical systems, types of testing and verification of optical systems and ignition hazard assessment. The last chapter illustrates the method and procedure, which will be used in the practical part.
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Field test of feeder protection ABB REF615 using an experimental model of 22kV distribution system
Váhala, Václav ; Orságová, Jaroslava (referee) ; Topolánek, David (advisor)
The main purpose of the bachelor thesis is to describe, preset and verify function of digital protection ABB REF615. The thesis is focused on detailed description from the protection function and hardware configurations point of view. The thesis also informs about parameters of experimental model of medium voltage distribution network. This model was used for operation testing of selected protection functions. First of tested function was admittance earth fault protection respectively conductance protection. This conductance principle is based on admittance protection function where only real part of zero sequence admittance is evaluated. Intermittent earth fault, phase directional over-current protection and circuit breaker failure protection were tested next. Evaluation of all test results is subject of the final part of the thesis.
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