Coordinated central-local control strategy for voltage management in PV-integrated distribution networks considering energy storage degradation

Abstract

In PV-integrated distribution networks, there is increasing interest in developing cost-effective voltage control strategies that utilize PV inverters and battery energy storage systems (BESS). However, energy storage often plays a secondary role in mitigating the inherent uncertainty of PV generation, and the associated maintenance and replacement costs of batteries due to improper scheduling are frequently overlooked. To address this issue, this paper proposes a coordinated central-local control strategy for voltage management in PV-integrated distribution networks, incorporating the cycle life degradation of energy storage. In the proposed strategy, the central controller formulates a multi-stage Wasserstein-based distributionally robust optimization problem based on the requirements of the distribution system operator (DSO). In the local hierarchy, each PV inverter adjusts reactive power output via the control curves improved by the central controller to manage rapid PV fluctuations. Additionally, battery replacement costs are allocated per discharge/charge cycle and incorporated into voltage control costs to assess the impact of short-term scheduling on long-term battery degradation. Simulation results show that the proposed strategy achieves the global optimal decision according to the required robustness and economy in the central hierarchy, while ensuring appropriate scheduling of BESS and minimizing the impact of scheduling on battery lifespan. Furthermore, the proposed strategy can effectively reduce voltage deviations caused by PV fluctuations.