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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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The effect of disperzed generation on power quality
Kružík, Martin ; Orságová, Jaroslava (referee) ; Drápela, Jiří (advisor)
This MASTER`S THESIS engages in connecting with dispersed generation into electrical network and their influence on power quality. This thesis sets out to make up simple dynamic model of Wind power station and model of simple network. At this model I would like to simulate influence its working on voltage’s characteristics in addition place. Besides this is necessary calculate voltage’s characteristics according present methods – factory energy rules [PNE]. And these results compare with results of simulation
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Safe Uninterruptable Power Supply of Power Station Internal Consuption
Tomášek, Petr ; Přidal, Petr (referee) ; Orságová, Jaroslava (advisor)
This thesis examines issues connected to safe uninterruptible power supplies. The term safe uninterruptible power supply is used for an aggregate of devices providing power for appliances that participate in safe rapid shutdown of a power plant in case power from a usual source fails. The thesis is divided into two parts – theoretical and practical. Theoretical part deals with possibilities and ways of realizing an aggregation of safe uninterruptible power supply. Various devices that can appear in the section of a safe uninterruptible power supply are listed and each device is characterized. Appliances that can be provided for by the sources of safe uninterruptible power supply are mentioned as well. These appliances are listed in accordance with ČSN standard nr. 381120. The theoretical part concludes with new trends in realization of safe uninterruptible power supplies. One of these sources is a clean source technology that can also be implemented in various ways. Practical part contains a suggestion of a safe uninterruptible power supply for particular steam power plant. This suggested safe uninterruptible power supply consists of rectifiers, batteries, inverters and a dieselgenerator. Calculated parameters of each device at the conclusion of the practical part are followed by a diagram of the suggested section of safe uninterruptible power supply.
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Dimensioning of Earthing System in HV Switchgear
Buršík, Roman ; Matuška, Marcel (referee) ; Orságová, Jaroslava (advisor)
My master's thesis is focused on grounding of HV switchgear. The aim of this work is to create a computer program intended for dimensioning of earthing networks. The earthing networks are the most convenient alternative in term of effective grounding and distribution of ponential. They are based on latiny a flat conductor network cables and connection of appliance parts to network. Introduction of the thesis is dedicated to explanation of grounding theory and to description of requirements essential for properly designed earthing system (dimensioning of earthing system). Following chapter brings description of computer program algorithm testing propriety of an assigned earthing network for a particular switchgear. The chapter also contains description of an user interface and explanation of all features, included in the program. Last part provides presentation of program utilization to particular numerical assignment.
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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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Project of Outgoing Transformer Unit for the Photovoltaic Power Station
Hanák, Miroslav ; Procházka, Aleš (referee) ; Orságová, Jaroslava (advisor)
This master’s thesis engages in project of outgoing transformer unit for the photovoltaic power station. It describes project and its design documentation what conducts to practising of construction. It has compared investing to more expansive transformer what has lower loss. It describes charges of operation’s transformer in twenty years. It leads project of cable low voltage. It compares whether is better to use aluminium or cupric cables. Project is led with respect for investment costs and minimum of operation loss.
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Model for the Cable Thermal Characteristic Calculation
Starý, Zdeněk ; Drápela, Jiří (referee) ; Orságová, Jaroslava (advisor)
The result of this assignment is the Model for the Cable Thermal Characteristic Calculation. Firstly, there is a prepared overview that is focused on the essential ideas of cable technology. The following part describes the simple possibilities of passaging the heat. Secondly,the physical essence of warming cables as well as the possibility to discover the methods how to calculate the warming cables are also mentioned in this task.There is an opportunity to find the methods for calculating the warming cables as well. The model was verificationed in the conclusion of my assignment. The measurement was done and the empirical results were compared with the results that were achieved by modeling.
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Project of Earthing System in 110/22 kV Transfornmation Station
Pavlík, Ludvík ; Procházka, Aleš (referee) ; Orságová, Jaroslava (advisor)
This Thesis is concerned with the concept of grounding of 110/22 kV transformer station. The aim of the Thesis is to create a ground network for grounding a specified outdoor substation. This 110 kV outdoor substation is formed according to H-scheme and encircles a wide area. In additon to this, an earth potential has to be distributed as equally as possible within the whole area of the substation. The most convenient alternative from the point of view of effective grounding and distribution of potential is a grid network. Therefore, the grid network is the means of grounding which I have chosen as a solution for this issue. In this solution, flat conductor network cables are used to cover the whole substation, with ground rods placed at the points of intersection. Parts of appliance can be then connected to this existing network, thus creating several parallel channels which provide grounding with low resistance. The network is made of common steel zinc-coated stip, size 30 x 4 mm. When proposing a concept of grounding and adjustment of ground electrodes, we have to take account of grounding requirements, stated according to ČSN standards. The proposed earthing system was created in appropriate size in order to meet all these grounding requirements. These requirements are also mentioned and described in a theoretical part of the Thesis. Second part of the Thesis consists of proposed concept of the grounding itself, together with calculated parameters. The grounding has to be carried out according to both safety regulations and electrical appliance requirements. The issue of grounding substations of power system is resolved by the ČSN standards 33 3201 (“Elektrické instalace nad AC 1kV”), 33 2000-4-41 (“Elektrická zařízení – Ochrana před úrazem elektrickým proudem”) and 33 2000-5-54 (“Elektrická zařízení – Výběr a stavba elektrických zařízení – Uzemnění a ochranné vodiče”) and by the PNE company standards 33 0000-4 (“Příklady výpočtů uzemňovacích soustav v distribuční a přenosové soustavě dodavatele elektřiny”) and 33 0000-1 (“Ochrana před úrazem elektrickým proudem v distribuční soustavě dodavatele elektřiny”). These standards apply to creating a concept of grounding and grounding of new, reconstructed or expanded electrical substations of power system.
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Conventional and Unconventional Solving of 123 kV Outdoor Switchgears
Petrucha, Lukáš ; Pisarčík, Tomáš (referee) ; Orságová, Jaroslava (advisor)
This graduation theses shows some of possible versions of outdoor switchgears with very high voltage, especially on the level 123 kV both concerning own complement of classic outdoor switchgears with devices as are overvoltages limiter, disconnecting switchgears, circuit breakers, etc., and compact connections. In the introduction of my theses there are explained basic ideas and theories of switchgears and described main devices and equipments which create classic (from equipment setting point of view) outdoor switchgears of very high voltage. Subsequently it describes possible ways of linking-up of these devices in the complex of switchgears themselves according to possible dispositions arranged and busbars systems. The same focus is dedicated to new, non-classic (non-standard solution in terms of devices solution), compact solving of outdoor very high voltage modules either by air isolated or by means of enclosed technology with gas SF6 which represent innovative solving first of all from reduction of built up area point of view which is very important from economic point of view especially during constructions of new switchgears. In the end of my theses there are mentioned also brief evaluations of producers and economics for development and operation of individual technologies. I used for my work materials of companies CEZ, a. s., Siemens, a. s. and Abb, a.s.
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