Robust optimization model of flexible distribution network considering source-load uncertainty

Abstract

The increase in renewable energy permeability and the electrical load uncertainty aggravates the fluctuation of power flow and bus voltage magnitudes of the distribution network (DN). Then, the fluctuation threatens system security and makes increasing difficulties in DN regulation. However, the widespread utilities of power electronic technology promote rapid developments in flexible distribution networks, thereby providing certain opportunities to treat the open question. Therefore, this study proposes a robust optimization model of flexible distribution network allowing for system security and economy. Firstly, a optimal power flow (OPF) model of flexible distribution network with various active management strategies is derived and constructed by taking the minimum loss and voltage offset as the objective function. The model is linearized and relaxed to convex problem by a second-order cone. Then, the robust OPF model of flexible distribution network is established considering the uncertainty of load and renewable energy. Finally, a relaxation-based co-evolution algorithm is proposed to solve the model. The modified IEEE 33 bus system and PG&E 69 bus system are involved for case studies, in which the calculation results under various scenarios are compared. Consequently, the effectiveness and practicability of proposed model to locate and cope with the worst situation is demonstrated.