中文摘要：

针对民用低压直流供电系统的接地型式和电气安全问题，分析基于直流微网、电压平衡器的直流双极供电系统的接地故障参数，利用Matlab／Simulink软件构建DC±190V系统进行验证。在此基础上，讨论各接地型式的供电连续性、电击防护性能与保护设备要求。与传统交流220V供电系统的对比表明：低压直流供电系统在电气安全方面有较明显的优势；直流TT系统在配备剩余电流保护器的情况下，其供电连续性和电气安全性能可以得到很好兼顾，相较直流IT和直流TN系统而言，更适合作为该类含有电压平衡器的直流双极供电系统的接地型式。并给出了保证其电气安全的接地电阻取值范围及保护装置技术要求。

英文摘要：

For the civil low voltage DC distribution systems, selecting a suitable grounding type and improving electrical security is of significance. Using the DC bipolar distribution system based on DC micro-girds and voltage balancer as the research subject, this paper presented the grounding fault parameters and validated them with the aid of Matlab/Simulink software. On this basis, this paper discussed the power supply continuity, protection property against electric shock and protection requirement for each grounding type. It indicates that, compared with the traditional AC 220 V distribution system, the low voltage DC distribution system has a significant advantage in terms of electrical security. In addition, the power supply continuity and the electrical security of the DC TT system equipped with residual current device （RCD） can be improved as well, which is more suitable for this bipolar distribution system with voltage balancer than IT or TN system. Finally, the allowed range values of the grounding resistors and technical requirements are given to ensure the electrical security.