|
|
Analysis of Static and Dynamic Stresses the Existing 110 kV Substation for Short Circuit Strength Increasing
Balák, Dušan ; Škapa, Milan (referee) ; Orságová, Jaroslava (advisor)
This thesis is concerned with static and dynamic stress calculation of busbar and wire conductors in HV and EHV substations according to standards ČSN EN 60865-1 ed. 2 and ČSN EN 50341-1 ed. 2. Calculations are done in program made in MS Excel with consideration to corporate regulations of energetics. In introduction is described the construction of HV substations and methodical step-by-step computation. Practical evaluation is applied to the substation R110 kV Dluhonice, where has to be checked up sufficient short-circuit resistance because of short-circuit strength increasing. At the end is analysed the influence of the spring structure constant on short-circuit strength forces in substation. Highly significant utility is the founded program for HV substations designations.
|
|
|
Comparison of Instrument Transformers and Current Sensors with Respect to the Function of Differential Protection
Rajchman, Zbyněk ; Topolánek, David (referee) ; Orságová, Jaroslava (advisor)
Current transformers and current sensors are devices which are mostly used for current measurement in high voltage systems. These devices transform measured currents to range which are workable for measurement and protection devices. Theoretical part includes from third to seventh chapter. These chapters contain construction analysis and characteristic points for both device and problems of protecting the transformer with differential protection. Practical part includes from eighth to tenth chapter. This chapter consists results from laboratory measurement. Results are used for verification with theoretical part of the thesis. Conclusion of this thesis comparing properties and summarises results from laboratory measurement.
|
|
|
The Protection System Working on Output of Electronic Sensor System Measuring Current and Voltage
Bajánek, Tomáš ; Jiřičková,, Jana (referee) ; Janíček, František (referee) ; Orságová, Jaroslava (advisor)
At present, there is a widespread use of alternative measurement technologies in electrical networks that include current and voltage sensors. Their use is closely related to the use of IEC 61850-9-2 for data transfer of measured values within the substation for the purpose of protection and measurement. The use of sensors and communication standard IEC 61850 together with high-speed Ethernet will simplify the concept of the arrangement of protection terminals in substations and enable the development of a new protection system based on central protection. The dissertation is focused on protection algorithms, which use the SV according to IEC 61850-9-2, and their implementation into the central protection model. Thesis describes development in the field of protection of substations and the currently available solutions using IEC 61850-9-2 and the principle of central protection. Thesis explains algorithms for selected protection functions - overcurrent protection, negative sequence overcurrent protection, logic busbar protection and differential protection. Further, thesis deals with the programming of protection function algorithms in LabView development environment in the form of a central protection model. The model processes data from a process bus according to IEC 61850-9-2 and sends a GOOSE message over Ethernet in the event of a failure. To verify the correct function of the programmed protection algorithms, a testing procedure was developed using OMICRON 256plus, the current sensor and the merging unit. The results of the testing of the central protection model and the proposed algorithms were compared with the results of testing the currently used protections. At the end, the thesis deals with the assessment of the benefits of central protection for protecting substations and the possibility of further utilization of the central protection model. The thesis highlights a new way of protecting the electrification system using digital data from MU transferred via the process bus described in IEC 61850-9-2.
|
|
|
2D and 3D Simulation of Electric Fields of MV Source
Kováč, Martin ; Hruška, Ivan (referee) ; Orságová, Jaroslava (advisor)
In the master´s thesis author deals with simulations of electromagnetic fields and their applications in the electric practice at the design of electromagnetic devices. The first part of thesis deals with 3 electromagnetic field simulation softwares, their comparison and selection of the best software for the practical part of the thesis. The second part contains the practical applications of electrostatic and electromagnetic field simulation of HT power supply.
|
|
|
Analysis of Frequency Measurement and RoCoF in Simulation Programs
Koudelka, Jan ; Máslo, Karel (referee) ; Orságová, Jaroslava (advisor)
The thesis deals with the issue of measurement of frequency and its derivative (RoCoF) in simulation software. The aim of the thesis was to compare results obtained in three different pieces of software (PSS/E, PSCAD, MODES). 2 disturbances were simulated in a grid model IEEE 39 bus system and values of frequency and generator speed were assessed. The results obtained in different software are diverse. This is influenced by method of modelling of synchronous generator and algorithm of calculation of frequency. Findings are important for future investigation of power system transients in simulation software and also point to potencial incorrect assassement of frequency in protective relays.
|
|
|
Increasing of reliability of power supply from the Jasenie hydropower plant to Železiarně Podbrezová
Budovec, Michal ; Čerňan, Jozef (referee) ; Orságová, Jaroslava (advisor)
This thesis deals with operation of the Jasenie hydroelectric power plant, which supplies electricity to Železiarne Podbrezová Inc. This thesis describes actual operation, devices and equipment in all substations. The second chapter briefly describes company’s history and activities of the company. The next chapter mentions an overview of the sources of own electricity production. The fourth chapter in detail deals with actual situation of the hydroelectric power plant operation, describes devices and equipment in all substations. It also outlines what measures should be taken to increase the reliability of electricity supply. Next part deals with replacing insulators on the 22 kV line. Sixth chapter is focused on protection this line by multifunctional protection relay and data transfer from HC Jasenie to the building of power engineering. In the next step is designed a backup transformer with bus control for thermal and dynamic effects of the short-circuit current. The last chapter is focused on surge protection in HC Jasenie as well as in the area of Stary závod substation. The results and benefits of this work are summarized in the conclusion. The attachment contains schemes of substations and overall overview scheme, which are used for better understanding of this problem.
|
|
|
Operational Evaluation of the Small Photovoltaic Power Plants Connected to the LV network
Černý, Jaroslav ; Mastný, Petr (referee) ; Orságová, Jaroslava (advisor)
The objective of this thesis is to perform practical measurements of two small photovoltaic power plants, compare the received results with a theoretical calculation, and evaluate how the two differ from each other. Measured data are divided into three groups. The first group evaluates an overall electric power production in the individual months and compares it with the theoretical presumption that is instrumental to a return of investment calculation. The second group shows us a development of electric power production during characteristic days. We can compare how an ideal day from the FVE production point of view looks like, in other words a sunny and clear-sky day, with the opposite case when it is cloudy and raining all day long. Another extreme is a rapid growth or a performance drop, which can happen in a pho-tovoltaic power plant and a time period when this situation can arise. The third group contains statistic data from the electric power production. They are processed in the form of histograms and polygons of production that graphically illustrate production decomposition into the individual months. These data can be instrumental to a decision making about the form of purchase, whether it is economical for us to use the so called green bonus or not.
|
|
|
Direct load angle measurement on the laboratory generator unit
Dvořáček, Jiří ; Bukvišová, Zuzana (referee) ; Orságová, Jaroslava (advisor)
Synchronous generators are the most used machines for production of electricity. Therefore it is critical to use various methods for checking operating parameters. One of the worst faults is falling out of synchronism which can even lead to machine damage. Main objective of bachelor thesis is to design a method for load angle measurement using available laboratory equipment and to calculate saturated synchronous reactances using load angle. Load angle is measured using incremental sensor and output voltage waveform.
|
|
|
Structure of Surge Arresters and Their Application in Power System
Strapko, Miroslav ; Novotný, Jan (referee) ; Orságová, Jaroslava (advisor)
This work deals with internal and external protection against surge phenomena occurring in the power system. Describes the atmospheric and the operating overvoltage. The main objective is to theoretically describe the issue of protection - surge arresters, which are used for different voltage levels from the view of parameters, use and construction. The last part shows the calculation of a sufficient gap between the devices of external protection against lightning - a safe isolating distance, the calculation of a protective distance of surge arresters and practical choice of overvoltage limiters for high-voltage transformer.
|
|
|
Calculation of characteristic values of the earth fault in MV network.
Písařovic, Antonín ; Orságová, Jaroslava (referee) ; Toman, Petr (advisor)
In the bachelor thesis author deals with the earth fault in MV network. In the theoretical part of thesis there are identified existing faults occuring on power lines. The pivotal point of thesis is the analysis of the earth fault in network with ineffectively earthead node. In the parctical part author calculates the total capacity of specific network and according to the obtained results he proposes the suitable arc suppresion coil to reduce the earth current.
|
guest ::
