Research on DC Photovoltaic and Energy Storage Aggregation System for Railway Station Loads

The power consumption demand of railway station loads fluctuates greatly, and there are extremely high requirements for power supply reliability. When traditional AC power transmission integrates photovoltaic and energy storage systems, it faces problems such as phase mismatch and frequency synchronization. On the other hand, DC power features a large power-supply radius, low line losses, and can provide stable and reliable power supply, which meets the stringent requirements of station loads. It also facilitates the aggregation of photovoltaic and energy storage systems and optimizes the railway's energy structure. First, this paper studies the network architecture of DC aggregation of photovoltaic and energy storage systems, and proposes a reasonable DC wiring form and grounding form. Second, the concept of DC load distance is introduced, and the equivalent method of distributed load transplantation is proposed. On this basis, the possible DC voltage levels without the integration of photovoltaic and energy storage systems are determined according to the Guidelines for Medium-and Low-Voltage DC Power Distribution. Finally, the influence of the integration of photovoltaic and energy storage systems on the DC voltage is analyzed through Simulink simulation, and the DC voltage level after the integration of photovoltaic and energy storage systems into the railway through line is determined.