Abstract: Battery energy storage equipment has the characteristics of controllability and modularity, and can be widely used in distribution network systems. By adjusting the connection position of energy storage equipment in the substation area, observing the changes in line loss in the substation area, it can be concluded that when the energy storage equipment is connected to the photovoltaic side, power generation is basically absorbed on site, achieving loss reduction; The energy storage equipment is connected to the distribution transformer side, and the power supply radius of photovoltaic charging for energy storage is too large, resulting in increased line loss. Connecting energy storage equipment at a reasonable location in the distribution network has the practical effect of reducing line loss rate and can bring benefits to power grid enterprises.