Výpočty zkratových poměrů v průmyslové síti

Abstract

The aim of this thesis is calculation of the short-circuit condition of power network in Australian underground mine. Because the short-circuit currents can cause a lot of problems in power network, it is necessary to evaluate the maximum and minimum values of these currents. Based on these values the devices must be dimensioned and insured. For successful understanding of these problems it is needed to clarify the type of faults, their creation, size and time-characteristics. In the thesis there are relations required for the calculation the short circuit currents, the impedance of cables and devices that are part of the network. Software Daisy Bizon Projektant 4.42 is used for calculation of the short-circuit conditions. The results are compared with the software Power Factory 11, which has been successfully used for calculation of short-circuit ratios by IEC 60909. Thesis gives description how does software Daisy Bizon Projektant 4.42 work. Given the extensive features of the program, the description focuses only to short-circuit calculation and the elements, which are part of underground power network. In accordance to results of the software, I checked fusing and selectivity of switching stations.