Nodal frequency-constrained energy storage planning via hybrid data-model driven methods

Cross-regional high voltage direct current (HVDC) systems bring remarkable renewable power injections to the receiver side of power grids. However, HVDC failures result in large disturbances to receivers and cause critical frequency security problems. High renewable energy penetration also reduces the system inertia and damping coefficients. Thus, some nodal frequency nadirs may be much lower than those calculated by the center-of-inertia (COI) and may trigger low-frequency protection. Energy storage is a promising solution for frequency-related problems. In this study, we build an energy storage planning model considering both COI and nodal frequency security constraints. The energy storage capacities and locations are determined in the planning scheme based on year-round operations. First, we carry out a year-round COI-frequency-constrained unit commitment to obtain comprehensive operation modes. Next, we propose a hybrid data-model driven approach to generate nodal frequency security constraints for extensive operation modes effectively. Finally, we achieve optimal energy storage planning with both COI and nodal frequency constraints. Case studies on a modified RTS-79 test system and a 1089-bus power system in practical in Jiangsu, China, verify the effectiveness of the proposed methods.