ISSN 1805-3386

April 6, 2020


2018 No.1

Analysis of Influence on the Grid of Input Part of Special Power Source 113 kW / 1 kA DC

Fořt, J., Pittermann, M.

This paper compares some variants of power circuit configurations for a special power DC source 110 V / 1 kA. The requirement for the source was to ensure minimum ripple of the output current and reduced EMC-disturbance generated from this DC-source to the supply network and to other surrounding equipments.


Keywords: power quality, static power converter, 12-pulse rectifier, higher order harmonics.


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Comparison of Si and SiC based Power Converter Module of 150 kVA for Power System Applications

Štěpánek, J., Streit, L., Komrska, T.

The paper deals with the comparison of power semiconductors based on Si and SiC in application of power converters for power systems. These are single-phase voltage-source bridge inverters with nominal power of 150 kVA. Power converters are designed to operate under both active power and reactive power. Mechanical design of the converters is ready for interchange the power semiconductor modules and assess the operation with both, Si and SiC technology.


Keywords: Si semiconductors, SiC semiconductors, single-phase voltage-source inverter, power converter.


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Physical Analysis of Low-dynamic Magnetic Field Impact on Human Tissue

Richter, A., Ferková, Ž., Bittner, V.

This article makes an effort to explain physical aspects of low-dynamic magnetic field in the human tissue. The principles of electromagnetic induction in the muscle tissue as a typical example of parts of human body are briefly presented. The problems are indicated by modelling. One of the goals is to warn about different distribution of magnetic field in parts of body caused by metal implants. Another analyse introduces physical and energy differences among individual types of power sources of magnetic field and their dynamic behaviour.


Keywords: Low-dynamic magnetic field, electromagnetic induction, human tissue, metal human implant, magneto-therapy, 3D modelling of electromagnetic field.


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The Issue of Shunting of the Affected Phase in Compensated Medium Voltage Networks

Cimbolinec, I., Švec, J., Hubený, J.

Permanently increasing size of the capacitive currents in medium voltage networks becomes a limiting factor in their operation. This negative trend is manifested especially in the mixed networks, where the proportion of cable gradually increases in comparison with the overhead medium voltage lines. The residual currents in the one-pole insulation faults in the medium voltage system, in insulation fault site are continually increasing. Large investment funds are necessary for full elimination of the fault currents, while other known ways used in the partial elimination of the size of the fault currents have some technical limitations. In this article, the positive and negative sides of the method “Shunting of the affected phase in compensated medium voltage networks” are then evaluated.


Keywords: shunting-method, rehabilitation of the affected phase, CI paradox.


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