Abstract: To address insufficient flexibility in power grid dispatch with high-penetration renewable energy, taking the 500 MW/2 000 MW·h independent energy storage station project at the source side of a 500 kV substation as engineering background and a 30-bus regional transmission network as the simulation case study object, a multi-objective optimal allocation model for energy storage plants is established considering time-series characteristics and uncertainty. Taking system total cost minimization, net load peak-valley difference minimization, and renewable energy accommodation rate maximization as core optimization objectives, a coordinated control strategy for energy storage systems in day-ahead, intraday and real-time multi-scale dispatch is proposed. The frequency support effect of energy storage is verified through frequency disturbance simulation. The results show that optimally allocated energy storage plants can effectively reduce net load peak-valley difference, improve renewable energy accommodation, and provide fast active power support under frequency disturbance. The proposed method, validated on a simplified simulation system, provides theoretical support and method reference for energy storage planning and dispatch decisions in actual engineering projects.