Values of short-circuit duration and dynamie forces during short-circuits in the EHV substations: simulation-based investigations

Presented question is the continuation of investigations concerning the short-circuit duration’s estimation in the short-circuit effect calculations using the probabilistic method. In the paper, the developed simulation model of the short circuit duration under the disturbing conditions just in the distribution substation is presented. The model development was based on the analysis of operation of the automatic power protections EAZ and circuit-breakers in the EHV substations during short-circuits. The results of simulation investigations aiming to estimate the frequency of occurrence of the defined short-circuit duration are reported. The calculations have been carried out for different configurations of the EAZ system. For selected spans in the 220 kV substation, probabilistic analysis of dynamic forces accompanying the in-substation faults has been carried out. Also, the way of the short-circuit duration’s estimation when calculating the dynamic effects of the fault current flow basing on an assumed risk value has been proposed.