Grounding Operation Analysis of Low Voltage Direct Current Supply and Utilization System

With the large-scale integration of the distributed photovoltaic (PV) power generation system and power-electronic-device-based loads such as electric vehicles and data centers. The low voltage direct current supply and utilization system (LVDCSUS) has received much attention from academics and industry in recent years. However, the initial research has not been conducted in the LVDCSUS, including but not limited to operation modes, control strategy, protection, grounding mode. As one of the most important factors in the operation, reliability, and protection configuration of LVDCSUS, the choosing of the grounding mode in the LVDCSUS may influence the transient characteristics of the connecting point of the energy storage and PV generation system, which will determine the operating stability of the LVDCSUS. To provide a guideline to future LVDCSUS grounding mode chosen in different operation conditions, in this paper, the transient characteristics of the DC bus, energy storage port and photovoltaic power supply port of the symmetrical monopole system after the monopole ground fault of the DC bus are analyzed, and the influence of the grounding fault on the power generation and energy storage module operation of the low-voltage DC system is discussed. The research can provide reference for the selection of grounding mode and the configuration of fault protection in the LVDCSUS.