为了合理划分微电网拓扑结构，精准判定各种微电网故障情况下的故障区域，提出一种四维坐标系下并网型光伏微电网故障区域判定技术。令微电网拓扑结构为坐标图，设备节点为坐标点，以坐标点间最小欧式距离最大化，平均最近邻坐标点数量最小化为划分依据，通过球填充四维坐标点集的集合划分方法，划分微电网拓扑结构，获取微电网划分区域；以各划分区域为节点，断路器为边，通过图论算法构建微电网故障数学模型，依据故障前后功率变化量和区域故障电流方向，建立故障区域判定矩阵，实现故障区域判定。试验证明：该技术可有效划分微电网拓扑结构，划分后可有效提升微电网信号传输效果；在出现多重故障、两相故障与系统侧故障情况下，该技术均可精准判定故障区域。

In order to reasonably divide the microgrid topology and accurately determine the fault area under various microgrid faults, a fault area determination technology of grid connected photovoltaic microgrid in 4D coordinate system is proposed. The microgrid topology is taken as a constellation diagram and the equipment nodes are selected as constellation points. On the basis of maximizing the minimum Euclidean distance between constellation points and minimizing the number of average nearest neighbor constellation points, using the set division method of ball filling 4D constellation point set to divide the microgrid topology and obtain the microgrid division area. Taking each divided area as the node and the circuit breaker as the edge, the microgrid fault mathematical model is constructed by graph theory algorithm. According to the power change before and after the fault and the direction of regional fault current, the fault area judgment matrix is established to realize the fault area judgment. The experiments show that this technology can effectively divide the microgrid topology and improve the signal transmission effect of microgrid. In case of multiple faults, twophase faults and system side faults, the technology can accurately determine the fault area.