Kouhsari - Amir Kabir Technical Univ.London Polytechnic
Motamed - Amir Kabir Technical Univ.London Polytechnic

calculation of short circuit currents f or todays power system is a complex analysis because of the mixture of sources contributing currents to the faults, especially in the industrial plants. In a typical. modern industrial system the basic Sources of fault currents are the utility the in-plant generation, and synchronous and induction motors . These sources contribute additional exponentially decaying currents which make fault current magnitude at various locations time dependent. A number of international standards are provided to consider the decay of the ac and dc components of the fault current. All the standard methodo logies are for good reasons, chosen to give conservative design a and also on the use of experimental factors . advances in the computer technology have made it possible to produce short circuit analysis programs with more rigorous dynamic solutions .The paper examines the differences between recommendation o f the standards and dynamic short circuit currents by comparing for a specific industrial power system .