Optimal Planning of Battery Storage for Flexible HVDC Network with Pumped Storage Hydropower Plants

With the development of energy storage technology, battery energy storage system (BESS) and pumped storage hydropower plants (PSHP) with variable-speed units are promising technologies to provide flexibility for the power system with increasing renewable power generation. This paper proposes an approach for optimal siting and sizing of BESS to further promote the renewable energy accommodation and reduce the total investment and operation cost in a flexible high voltage direct current (HVDC) network with a PSHP. To consider the uncertainties of renewable energy generation and load at the planning stage, typical scenarios are generated by the K-means clustering method. Thereafter, the BESS planning problem is formulated as an optimization problem considering the typical scenarios. Then, the optimization problem is relaxed into a mixed-integer second-order cone programming (MISOCP) model. The proposed method is applied to calculate the optimal BESS allocation scheme for the 4-bus flexible HVDC network in North, China. Sensitivity analysis is performed to investigate the influence of the BESS cost and the electricity price on the optimal planning results.