含多分布式电源的小电阻接地系统单相接地故障特征分析

经小电阻接地方式配电网系统的单相接地故障特征会受到类型不一的并网分布式电源(distributed generation, DG)所采用的接地方式影响。针对此问题，结合对称分量法，首先建立了含有多个、不同类型、不同接地方式并网DG的配电网单相接地故障分析模型。然后对系统单相接地故障点电流和线路的三序电流进行了分析。最后，利用Matlab/Simulink搭建单相接地故障仿真模型，验证了对故障电流特征分析的正确性。结果表明，并网DG为不接地方式时对系统故障特征影响最小。这为并网DG的种类和并网变压器接地方式的选择提供一定的理论依据。

Analysis of single-phase grounding fault characteristics of low resistance grounding systemwith multi-distributed power supply

The single-phase grounding fault characteristics of the distribution network system via low resistance grounding mode will be affected by the grounding mode adopted by different types of grid-connected DGs. Aiming at the problem, combined with the symmetrical component method, a single-phase grounding fault analysis model of distribution network with multiple grid-connected DGs having different types and grounding modes is established first. The single-phase grounding fault point current of the system and the three-sequence current of the line are analyzed afterwards. Finally, the simulation model of single-phase ground fault is built by Matlab/Simulink, which verifies the correctness of the analysis of fault current characteristics. The results show that the grid-connected DG being ungrounded has the least impact on the system fault characteristics. This provides a theoretical basis for the selection of the type of grid-connected DG and the grounding mode of the grid-connected transformer.