This final thesis describes causes and consequences of short circuits in electric power system with emphasis on the importance of calculating short circuit currents. The goal was to demonstrate short circuit study using standard IEC 60909 on the chosen model. First, system model was constructed and its parameters were set. Then, after calculation of all impedances in the system, the parameters of Thevenin’s equivalent at the short circuit were calculated. Finally, the short circuit currents were calculated in case of single phase to ground fault and balanced three phase fault. Calculations were performed for two cases, one than includes shunt impedances and loads, and one neglecting the shunt impedances and loads