Cascade-risk-informed transmission expansion planning of AC electric power systems

Latest standards for transmission system planning require investigation of the performance during the simultaneous loss of two elements and an assessment of the risk of cascading outages. Consequently, transmission system expansion must also be supported by in-depth security analyses. In this study, we propose a risk-informed transmission expansion planning method. At the core of the method is an AC based cascading failure model that simulates the power system responses after contingencies. The method aims to provide an optimal expansion plan striking the balance between the cost of expansion and the risk of systemic failures. Addressing this challenge requires a simulation based multi-objective optimization, which we tackle using a meta-heuristic algorithm. The tool developed for transmission expansion planning is applied to the IEEE 118-bus system and compared with state-of-the-art transmission expansion approaches. Remarkably, the proposed TEP procedure produces solutions that improve system security at comparable expansion costs.