Degradation-Aware Real-Time Power Allocation Approach for Heterogeneous BESS

With growing hybrid configurations and phased deployments, rising heterogeneity in battery energy storage system (BESS) challenges the cost-minimization power allocation due to the difficulty in accurately quantifying realtime degradation cost. To address this, we propose a dual energy distribution model which stores the cycle information related to SoC trajectories within the energy distribution, tackling the problem to seek the full cycle for current action with past operation. A real-time degradation cost calculation formulation is presented to analytically express nonlinear degradation over a continuous action space, without requiring historical SoC backtracking or the rainflow simulation. A real-time power allocation algorithm is designed based on dual energy distribution ranking. Unlike traditional rainflowbased online methods that rely on estimating the marginal degradation cost of infinitesimal actions, our approach allocates power based on the degradation cost evaluated across the entire power range of each battery. Numerical tests and comparison are done for heterogeneous BESS response to frequency regulation service, the results show our method reduces daily degradation costs by 12% to 31% compared to conventional strategies, and with fast solving speed of each response within milliseconds.