Search

This article presents the general information about the opportunities for utilization of renewable energy resources for electrical energy generation in the Czech Republic and the forecast to 2010. There are several types of power generators that can be used in a power system. In the near future approximately 8 % of electricity produced in the Czech Republic should be generated from (new unconventional and innovative energy resources) distributed generation.

In photovoltaic systems economic wiring can results in remarkable savings. A technique so far used in electrical systems of buildings and factories is the power bus with piercing contacts. A flat cable - the so called power bus - is installed as one single cable run. The electrical connections are carried out via plugs and sockets, which are clamped onto the flat cable. The electrical connection of the cores is done by piercing contacts. Multi core cables are used to reduce installation costs. With the application to photovoltaic systems the thermal overload limit is off special interest.

This paper deals with achievements of wind technology and evolution of commercial wind technology. Next it deals with a challenge of wind technologies and running up to commercial technology. In this paper are described wind turbine vertical-axis, or "egg-beater" style, and horizontal-axis (propeller-style) machines.

The daylighting and the artificial lighting is a part of environment. The lighting plays an important role in life of everyone of us. We know that it is not possible fully replace daylighting by artificial lighting. The amount of daylight is important mainly in areas with permanent stay of people and it influences the choice of parameters and functions of system of artificial lighting. That`s why I focus on the relations between daylighting and artificial lighting in my report. Owing to these relations I evaluate influences causing an optimal using of artificial lighting. Finally, I state here the influence of using of lighting sources in lighting on environment and ecological aspects used for the production and the liquidation of light sources.

Recently the range of types and the number of units of power electronic systems and other equipments causing harmonics and interharmonics rise sharply. This paper describes how and why harmonics and interharmonics are generated, how their presence affects the electrical system and equipment and how to minimise these effects. The relations between the renewable energy sources and harmonic - interharmonic polution are mentioned.

The future vision for hydrogen is that it will be cost-effectively produced from renewable energy sources and made available for widespread use as an energy carrier and a fuel. Biomass has the potential to accelerate the realisation of hydrogen as a major fuel of the future. The article describes the relevant technologies that convert biomass to hydrogen.

This article deals with utilisation of renewable energy sources with orientation on their benefits and handicaps. Possibilities of distributed generation and utilisation of the renewable energy sources are also mentioned. Actual conditions of these sources within the European Union are analysed, and their external costs are compared with the external costs of conventional energy sources. The continual development of the renewable energy sources utilisation is emphasised.

Dieser Eintrag beschreibt die Problematik von Doppelerdschlüssen in einem Mittelspannungsnetzen. Es wurde eine Messung an einem Notzmodell mit eingebauter Distanzschutz durchgefürt, und der Eintrag enhält beschreibung und die Ergebnisse von der Modelation.

The quality of input data is essential at designing systems for combined heat and power production. Because of relatively high investment coasts, it is needed to select a suitable electrical adn/or thermal output, so that the system´s yearly utilization ratio is as high as possible. The design should also take into account the maximum and minimum heat and power demand of an object to be supplied. In real conditions, it is very often quite uneasy to obtain precise data of heat and power consumption (like daily load profile) of consumers, usually only monthly or yearly consumption of heat and power is known. This paper tries to assess the impact of data quality on the accuracy of resulting design of a cogeneration system. It shows how even low-quality data can be processed and rearranged in order to gain pretty reliable results.

Power engineering is the oldest and most traditional of the various areas within electrical engineering, yet no other facet of modern technology is currently undergoing a more dramatic revolution in both technology and industry structure. One of the more impressive areas of technical improvement over the past twenty years has been the emergence of powerful and practical numerical optimization methods for power-system engineering and operation, methods that ensure that the very best electrical and financial performance can be atained. The value contibuted by optimization use in power systems is considerable, both in terms of economics, but also in terms of operational reliability and security. Systems run with optimization-based monitoring and control react better to both expected patterns in power demand and equipment availability and unexpected events such as storm damage and sudden equipment failure.

This paper deals with the intelligent building installation system and integration DALI interface (Digital Adressable Lighting Interface) in a higher-ranking building management system such as the European Installation Bus (EIB). This combination opens up a whole new range of options to designers for the intelligent interconnection of various systems and save energy.

This paper deals with the connection of distributed resources. It is divided into two parts. The first is devoted to renewable energy resources. The review of these resources will help to determine if they could reduce the global warming and if they could play a significant role in electricity generation over the course of a decade. The second part deals with problems of blackouts, overcurrent coordination and voltage sags in distributed generating systems.

This article deals with possibility of biomass utilization and methods of its processing. Further deals with a heating power and characteristic of each biomass fuel. Sources of biomass fuels and their power potential are described. At the end are described two power plants, which represent two most frequent utilizations of biomass energy.

The document describes influence of basic meteorological value to proposition of photovoltaic arrays. Results from 3 years long measurements on demonstration system are displayed in supporting figures and tables. Next part features experiences gained during installation and trial run of 20 kWp photovoltaic system installed on the roof of new building of Faculty of Electroengineering in Pilsen. Time distributions of electrical values containing information about interactions between supply network and monitored system are presented in figures and resolved.

The paper entitled “Classification and calculation of electric energy losses in distribution networks” deals with the problem of the losses division for an operative calculation in distribution companies.

The developed software for the short-circuit analysis is intended for the students of the power engineering study programme offered by the University of West Bohemia. The program is based on the method of symmetrical components. The power system elements are modelled by equivalent p-circuits. The software was developed in Borland Delphi. The results are recorded into text files and also displayed graphically as the phase vector diagrams that are suitable for teaching purposes.