This master’s thesis deals with the design of electric switchgear for low voltage, which will serve for presentation purposes. The switchgear is analogy of the modular system MNS 3.0, which includes the latest equipment of ABB Ltd. that is currently available on the market. Switchgears of this type are widely used in industry primarily for controlling motor units. For this reason, in the switchgear there are located motor starters in various performances, as well as distribution modules. In addition, the switchgear has an automatic transfer switch function in case of failure of one of the power supplies. The complete documentation of the switchgear is processed in the professional software EPLAN Electric P8 with use of the 3D software EPLAN Pro Panel for modelling device compartments. The final part of the thesis is the calculation of the maximum cable lengths that a potential customer can connect to the switchgear. In addition, an analysis of the power and control circuits was carried out for voltage drop calculations, as well as the effect of these voltage drops and capacitance of long control cables on the actuation of contactors.

This diploma thesis discusses two major topics. The first one is the control size of the voltage in LV networks in regard to the increase in distributed generation concered to renewable energy sources. The study contains a review focused on the current state of low voltagegrid followed by a proposal for the solution of the oncoming state. The solution is identified as a deploying OLTC distribution transformer. In the case of more complex topology is deployed a series voltage transformer. Both methods are part of the Smart Grid. The thesis also analyzes the issue of the data measurement and data transmission. The second part of the thesis consists of the description of selected control strategies and their simulations. The design of individual system elements in the PSCAD is described. From these elements, a test network was constructed and tested the individual simulation scenarios.

This thesis is focused on Radiation damage of samples in low-voltage transmission electron microscopy. In thesis is general description of transmission electron microscopy and their important parts. There is described how samples are damaged by primary electron beam and how samples for transmission electron microscopy are prepared and which degradation occurs from the point of view materials of sample and time dose of electrons from primary electron beam.

In this master thesis the new possibilities of software Autodesk Inventor Professional 2008 are described. Autodesk Inventor is a system for 3D machine engineering containing tools for 3D modeling, information management, cooperation and technical support. Autodesk Inventor Professional 2008 has a lot of new possibilities and improvements compared to the previous version. This Master thesis contains also description of the circuit breaker BD250N and its utilization in the distribution of low voltage. In enclosed CD the model animation of circuit breaker with description of modeling process can be found. The Autodesk Inventor Professional 2008 is used for this master’s thesis – English version.

This master’s thesis is concerned with the proposal of new locality electrification. There are 59 detached houses. The thesis is divided into theoretical part and computational part. In the theoretical part, there are all documents necessary for the successful proposal of the electrification. In the computational part is drafted distribution substation, high voltage power cable, proposal of low voltage power cables and protection. Each part is made for two versions (for the degree of electrification A and for the degree of electrification C) and recorded in cadastral maps. The proposal of distribution substation and high voltage power cable is made by traditional method - all calculations are processed by the designer. Low-voltage power cables and protection are implemented in a computer program Sichr (version 11.01) OEZ company.

This paper deals with possible ways of voltage regulation. Theoretical part includes a search of published methods and the available voltage regulators. Acquired theoretical knowledge has been applied in the development of mathematical models of two selected controllers applied to the testing network. The result of this work is a summary of the outcomes of dynamic simulations with two selected regulators at various locations in testing network. Comparing the results of dynamic simulation for two selected states was chosen the most appropriate regulator and its optimal location in testing network.

This master’s thesis deals with realization of fault recorder designed for a distribution transformer station. In theoretical part is created research about operation of distribution transformer stations and about analytic methods, which gives bases for fault detection in power network. The practical part consists of design and realization of fault recorder in LabVIEW interface using CompactDAQ measurement platform. Purpose of this recorder is monitoring and recording of voltage and current waveforms on secondary side of transformer station during the fault in high voltage network. Principle of fault detection is primarily based on level monitoring of voltage negative symmetrical component. Fault recorder has been successively optimized and the final version is presented in this thesis. At the end functionality of designed system is evaluated on simulated fault in a model of high voltage network.

The future operation of public low voltage networks has to consider increased decentralised generation using photovoltaic systems for residential application. For utilities it is necessary to determine the maximum permissible installed power of residential photovoltaic systems in sections of the low-voltage network. For this purpose a method based on modelling low-voltage network structures, occurring loads and insolation situations is presented and demonstrated. The maximum permissible installed power of residential photovoltaic systems is fundamentally determined by the structure of the settlement of the affected low-voltage network section. By modifying the generator model the method can be applied too for other types of decentralized generators in the low-voltage network such as fuel cell systems. / Für den Betrieb des öffentlichen Niederspannungsnetzes in Wohnsiedlungsgebieten ist zukünftig mit einem verstärkten Einsatz dezentraler photovoltaischer Energiewandlungsanlagen zu rechnen. Für Netzbetreiber ist es erforderlich, die maximal zulässige Netzanschlussleistung derartiger Anlagen für Niederspannungs-Netzbezirke zu bestimmen. Dazu wird ein Verfahren auf der Grundlage der Modellierung der Struktur von Netzbezirken, der dort auftretenden Belastungen und Einstrahlungssituationen vorgestellt und demonstriert. Die maximal zulässige Netzanschlussleistung dezentraler photovoltaischer Energiewandlungsanlagen wird wesentlich durch die Siedlungsstruktur des betreffenden Niederspannungs-Netzbezirkes bestimmt. Durch Modifikation des Erzeugermodelles kann das Verfahren auch für andere dezentrale Kleinerzeuger im Niederspannungsnetz angewandt werden.

I denna rapport utreds hur systemdesignen av lågspänningsfördelningen för järnvägen kan kostnadseffektiviseras. I dagsläget har det utarbetats en norm kring systemdesignen som tenderar att efterbildas från år till år vilket har medfört brist på innovation inom området. Syftet med arbetet var att designa två typstationer med signalställverken M11 respektive M95, där placering samt nominell storlek av UPS:er skulle fastställas för att tillhandahålla en kostnadseffektiv lösning. Dessutom skulle kablage dimensioneras för typstationerna samt se över möjligheten att ersätta UPS:er med likriktarsystem. Stationerna baserades på två redan existerande driftplatser, Fagersta C (M11) och Skänninge (M95). Slutligen skulle olika energilagringsalternativ för UPS-system jämföras för att tillhandahålla det lämpligaste alternativet. Genom simuleringar och beräkningar i bland annat datorprogrammet El-Vis har lågspänningsfördelningen dimensionerats för typstationerna. Arbetet visar på att ett distribuerat UPS-system är att föredra ur ett ekonomiskt perspektiv gentemot ett centraliserat UPS-system. Vidare har det konstaterats att likriktarsystemet Rectiverter kan ersätta UPS:er samt att ackumulatorer är det mest passande energilagringsalternativet. / This report identifies how the system design of low voltage power distribution of the railway can be more cost effective. In the current situation there is a norm on the system design that tends to be replicated each year. This has brought a lack of innovation in the field. The purpose of the thesis was to come up with two model stations with the interlocking system M11 respectively M95, where the positioning and nominal size of the UPS:s would be determined to provide a cost effective solution. Furthermore, the cable dimensioning of the model stations was computed as well as the possibility of replacing UPS-systems with rectifier-systems. The model stations were based on two already existing operating sites, Fagersta C (M11) and Skänninge (M95). Lastly, different energy storage alternatives for UPS-systems were compared to acquire the most appropriate choice. Through simulations and calculations in, inter alia, the computer program El-Vis, the low voltage power distribution was dimensioned for the model stations. The thesis shows that a distributed UPS-system is preferred in an economical point of view compared to a centralized UPS-system. Furthermore, the thesis establishes that the rectifier system Rectiverter can replace UPS:s. It also states that accumulators are the most suitable alternative for energy storage.

Les mutations observées sur le système électrique (production décentralisée, véhicules électriques, stockage, micro réseau...) font émerger des problématiques d'ordres économiques et techniques dans la gestion de ce dernier. Parmi eux, l'impact sur les niveaux de tension et de courant de neutre des réseaux de distribution. Le but de cette thèse est d'étudier des modèles probabilistes pour estimer ces impacts. L'incertitude sur la puissance PV produite et sur l'utilisation des VEs implique la nécessité de développer des modèles probabilistes de consommation et de production d'électricité. Deux modèles différents de production et de consommation ont été étudiés : L'un basé sur l'approximation de données historiques par une densité de probabilité, l'autre reposant sur la répartition des données en groupes définis par un profil type et une probabilité d'occurrence. Des techniques de load flow probabilistes ont été étudiées dans cette thèse pour prendre en compte l'effet intermittente de la production PV et l'incertitude sur la consommation. Une technique basée sur la méthode de simulation Monte Carlo, une deuxième basée sur l'approximation PEM et une dernière basée sur l'utilisation du clustering appelée méthode pseudo Monte Carlo. Après avoir comparé la pertinence des méthodes sur deux réseaux test, la méthode pseudo Monte Carlo est appliquée, pour son gain en temps de simulation et son adaptabilité, dans un cas d'application qui porte sur l'estimation de la probabilité de dépassement des limites du courant de neutre en fonction du déséquilibre de production PV installée. / The current changes on the electrical system bring out economic and technical issues in the management of the latter. Among these issues, the impact of distributed generation and VEs on the technical constraints of the distribution network. The aim of this thesis is to study probabilistic models to estimate the impacts of photovoltaic production and electrical vehicles on medium and low voltage distribution networks. Two different probabilistic models of production and consumption were studied : one based on the fitting of historical data by one probability density function, the other one based on the data clustered in groups defined by a standard profile and a probability of occurrence. Three probabilistic load flow technics have been studied in this thesis. The first is based on the Monte Carlo simulation method, the second is based on the PEM approximation method and the last, based on the use of clustering, is called pseudo Monte Carlo method.