An optimization method of long-time process in cascading failure

To reduce the loss of large-scale fault in cascading failure, an optimization method based on risk index of breaking path is presented. Compared with the assessment methods, the method treated risk value as a risk function to the line expansion coefficients; the line expansion program was changed into an interior point optimization program. In a IEEE-30 node network example, the risk of the optimization program was lower than the expansion program of the classic model. The result of the present work implied that the method can give a lower-risk program with the constraint of a certain total capacity.