Optimal Planning of SNOP Considering Natural Disaster

Although Soft Normally Open Point (SNOP) shows its strong capability to control load transfer and regulate network voltage profile in a distribution network, considerations of the high investment costs of these special electric devices are quite limited. This paper proposes an optimal sizing and siting method for an SNOP that considers the costs and benefits of an SNOP in a distribution network. Firstly, the operation scenario of the distribution network is generated under time-series multiple scenarios during the entire period of the life cycle of an SNOP. Based on the restrictions of SNOP and system operation states that have been generated, the influence of different installation positions and SNOP capacities on the power loss is quantitatively analyzed. Secondly, the relationship between the cost of an SNOP and the capacity is analyzed. Furthermore, to make SNOP more profitable, a practical algorithm is designed for the scanning of the possible formations of islands that can be restored by an SNOP when disasters happen. In the end of the paper, the capacity and the location of an SNOP are optimized considering the balance between the benefit of energy-loss reduction in daily operations and the investment costs of the SNOP. From case study, it is validated that implementing only one SNOP in the distribution network is both optimal and practical in most simulation cases due to the restrictions of the extremely high costs, and this may greatly simplify the complexity of the optimal planning problem for the SNOP in a distribution network.