Transmission expansion planning for power grids considering resilience enhancement

During recent decades, blackout accidents caused by cascading failures worldwide raised concerns of power grid operators and researchers about enhancing power grid resilience to withstand disruptions. As an effective approach to identifying critical components and quantitatively measuring transmission networks' weaknesses, vulnerability assessment (VA) is instrumental for power grid resilience enhancement. This paper proposes a transmission expansion planning (TEP) model incorporating the VA to improve the resilience of the grid planning scheme. Firstly, a structural vulnerability index (SVI) and an operative vulnerability index (OVI) are introduced for the VA of buses. The affinity propagation clustering technique is adopted to reduce the dimension of the large masses of SVI/OVI data. In particular, considering that the vulnerability of a power grid largely depends on the most vulnerable components rather than the rest, the overall vulnerability is evaluated through both the mean and equilibrium value of the clustered SVI/OVI data. In order to integrate expert opinions and objective factors of the clustered SVI/OVI data, the analytic hierarchy process (AHP)-entropy method is adopted to design the weights in the overall VA for a TEP scheme. Finally, as an inverse problem of the overall VA for a TEP scheme, a multi-objective TEP optimization model is proposed, which minimizes the overall vulnerability as one of the objectives for enhancing power grid resilience. Case studies based on the IEEE 39-bus system and two practical TEP cases in central and southwestern China demonstrate the effectiveness of the proposed overall VA method and the TEP optimization model, which can help planners make a trade-off between economic investments and resilience enhancement.