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This paper is focused on the description of phenomenon called "floating water bridge" and several experiments in our high voltage laboratory which are joined with this phenomenon. Water bridges bring some new knowledge in chemistry, electrochemistry, lighting technology and high voltage field. In this paper we will be dedicated space for describing the properties of water bridges in the...
Laboratory testing of high voltage tested objects often leads to creation of discharges. Discharges are generated by breakdowns or flashovers outer insulation of the tested objects. These discharges generate emission in the IR, UV and also in the spectrum of light. The spectrum and intensity of radiation is dependent on the duration and level of passing current discharge. The shape, density and the...
The article describes UGR measurement with luminance analyzer and discusses overall impact of background luminance on the calculation result. Background luminance, defined as 2π, causes a problem if the luminance is on the periphery of the visual field. Another complication is that the position index is defined only for the upper half of the view. This causes a complication in glare measurements of...
The paper describes a new approach to the analysis of lighting systems, namely the lighting environment in general, with focus on luminance contrast mapping. Using the modern measuring equipment based on luminance analyzer units it is possible to transmit the obtained data from luminance maps to contrast maps. The current methods of determining contrast are too simple and can be applied only to a...
High voltage capacitors are widely used in middle and high voltage laboratories and testing rooms. Capacitors are used for measurement of voltage in the form of voltage dividers. Injection and blocking capacitors are placed in the galvanic systems of partial discharges. And high voltage capacitors are also used in the high voltage as the part of laboratory bridge circuits. Common characteristics of...
This paper focuses on development of negative sequence relay model that is processing IEC 61850-9-2 Sampled Values. The detection of negative sequence current and fast, reliable operation of protection relay is useful for power system components. This paper describes negative sequence relay model programmed in LabView that was tested with software tools developed at Brno University of Technology....
Sampled Values transferred via process bus according to IEC 61850 are used for protection functions in substation. Nowadays a lot of researchers are dealing with their processing and using them for protection algorithms. There are some software tools that could be used for their processing. This paper is focused on package of software tools developed at Brno University of Technology and they allow...
Article describes the design of lighting in growth chamber with low energy consumption. For this purpose we created a special luminaire that allows during different phases of plant life, regulate the spectrum of emitted energy and thereby effectively utilize light without wasting electricity. It is also important light intensity for proper growth of plants, respectively incident radiation. The paper...
The parameters of luminaires for the phytotron and growth chambers have some characteristics different from conventional luminaires. Example could be the different requirements for spectral distribution, thermal management and requirements for irradiation of plants. This paper deals with the complex description of these requirements on luminaires and they properties, supported by its own laboratory...
Nowadays is increasingly used process bus for communication of equipments in substations. In addition to signaling various statuses of device using GOOSE messages it is possible to transmit measured values, which can be used for diagnostic of system or other advanced functions. Transmission of such values via Ethernet is well defined in protocol IEC 61850-9-2. Paper introduces a tool designed for...
This paper deals with the description of the behavior of water at lightning impulses. The electric potential distribution in water at lightning impulses is simulated for the calculation of the safe distance. There are not hazardous conditions to human body at distances greater than the safe distance. The examples are swimming pools or water where people are bathing. In these simulations is considered...
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