【摘要】 为了确定适合微电网的接地方式,分析总结了微电网中三类可能的接地方式(TN,TN,IT)的主要特点。并以ICCS/NTUA微电网标准模型为例,基于微电源的简化等效模型,在PSCAD/EMTDC中建立各种不同接地方式下的微电网仿真模型。比较研究了在并网模式和孤网模式下不同接地方式对微电网故障特性及其继电保护的影响。仿真分析结果表明TN-C-S方式下的故障电流足够大,能够及时地启动过电流保护装置,且设备接触电压比较低,能为低压用户的安全提供更可靠的保证,是最适合微电网的接地方式。更多还原

【Abstract】 In order to determine the suitable earthing system for micro-grid, firstly, this paper analyzes the main features of the three possible earthing ways (TN, TN, IT) for micro-grid. Secondly, the equivalent simplified models of the ICCS/NTUA micro-grid benchmark under a variety of different earthing system are established in the PSCAD/EMTDC environment. Then, the fault current distribution characteristic of micro-grid under different earthing systems is studied in connected mode and islanded mode, respectively. Finally, the impact of different earthing systems on micro-grid protection is also analyzed. It can be found that the TN-C-S earthing system has large fault current which can start over-current protection devices immediately, and relatively lower equipment touch voltage can provide a more reliable security guarantee for the low voltage users. Therefore, the TN-C-S earthing system is the most suitable earthing system for the micro-grid.更多还原