Research on optimal scheme of decreasing short circuit level for local power network

Since breaking transmission lines has thousands of combinations for large power grid, it´s difficult to find the best combination to decrease short circuit level in a short time. Sensitivity relationship between transmission line outage and impedance change is aquatinted firstly in this paper, then preliminary combination schemes of transmission line outage is selected according to the sensitivity. Index values of factors including constraint condition, power supply reliability and other factors that mainly affect system stability are given using the fuzzy comprehensive evaluation. Finally, the optimal scheme can be determined from maximum priority. The rapidity of the proposed method is verified by the simulation of short-circuit current exceeding limit of 220 kV buses of Area Power Grid.