Research on Line Loss Reduction in Distribution Networks Integrated with PV and Energy Storage Systems

With the large-scale integration of photovoltaic (PV) systems and energy storage systems (ESS) into distribution networks, traditional line loss control methods face significant challenges due to the intermittent characteristics and spatial-temporal variability of renewable energy. To address these issues, this paper proposes a novel line loss reduction strategy based on coordinated PV-ESS operation and multi-time scale optimization. Firstly, a comprehensive line loss model that incorporates three-phase imbalance, transformer loss, and conductor loss is developed. Then, an Attention-LSTM based prediction model is established to accurately forecast PV output and load demand, providing essential boundary conditions for optimization. A hierarchical multi-time scale optimization framework consisting of second-level, minute-level, and hour-level coordination is designed. This framework employs an improved multi-objective particle swarm optimization (IMOPSO) algorithm to effectively balance short-term voltage fluctuations and long-term energy redistribution. Case studies demonstrate that the proposed approach significantly reduces line losses, enhances voltage stability, and improves resource utilization efficiency in distribution networks with high penetration of renewables.