The integration of distributed photovoltaic power into the distribution network is leading to changes in the components, organizational structure, and production operation mode of the network. This evolution is resulting in a multi-layered, multi-looped, and multi-faceted system. One of the challenges that arise from this integration is power loss caused by various factors. To effectively reduce network losses, it is necessary to consider all the influences comprehensively. Currently, the decision-making process for loss reduction only focuses on single-factor optimization, which has limitations. To overcome this limitation, this paper declares a dynamic combination optimization model aiming to solve the loss reduction problem considering distributed photovoltaic and energy storage. This model takes into account three-phase imbalance, energy storage devices, and distributed photovoltaic power output. The proposed approach utilizes a dynamic combination optimization method that includes both switch cost and network loss cost in the objective function. To demonstrate its effectiveness, the approach is applied to a modified IEEE 34 nodes system through example analysis. The model system analysis considers factors such as capacity and equivalent access position of distributed photovoltaic power generation units, charge-discharge efficiency and capacity of energy storage devices, and reactive power compensation device capacity in relation to network losses. The results from the example analysis validate the correctness and effectiveness of the adopted distribution network combination optimization method. These results also provide decision-making support for loss reduction strategies, ultimately enhancing the economic performance of distribution networks.