Analysis of voltage dips in power system - case of study

The knowledge about the occurrence of voltage dips in a network can be obtained through the use of power quality monitors or by means of prediction methods. For assessment of the number of voltage dips, the method of fault positions could be used. The method was applied to a real 110 kV grid. The common software for short-circuit analysis was used for calculation of remaining voltage in the network during the faults. All fault types were taken into account. The expected number of dips and distribution of remaining voltage in the chosen substation, and the exposed areas for this substation are calculated. The results were compared with the outcome of the voltage dip monitoring. Although the comparison shows a good correspondence, the accuracy of assessment could be very influenced by accuracy of the failure statistics.