This paper presents a practical/analytical multi-stage transmission expansion planning approach to mitigate the impacts of cascading failure. It combines forward pseudo-dynamic planning strategy with the proposed analytical method to identify the most critical transmission line according to its impacts on initiating and propagation of the cascading failure throughout power system. The proposed methodology decomposes the planning time horizon into several years or stages. In each stage, an identification method, based on multi decision-making vulnerable index, is applied to optimally assign the location of the new transmission line for strengthening the transmission network. Using an adaptive threshold, another decision is made about repetition of the proposed identification method in each stage with new topology or going to the next stage. The IEEE 9-, IEEE 39-, and IEEE 118-bus test systems are investigated for the efficacy of the proposed method. The simulation results demonstrate that the proposed scheme is able to find the optimal solution in the form of one or more line(s) at each round of calculation; the solution that leads to optimal mitigation against cascading failure.
