中文摘要：

根据分布式电源（distributed generation，DG）等效电路模型及相量图，推导了故障时刻分布式电源对并网点电压支撑作用的原理，揭示了电压支撑效果与电网阻抗比及DG渗透率之间的关系。据此，提出了故障时刻根据电网阻抗比分配DG输出有功和无功来支撑并网点电压的方法。仿真算例结果验证了所提方法的有效性。

英文摘要：

Based on equivalent circuit model of distributed generation （DG） and phasor diagram, the principle of supporting effect of DG on voltage of grid-connection point at the moment of fault occurrence is derived, and the relations among the voltage supporting effect, the R/X ratio of equivalent impedance and the penetration level of DG are revealed. On this basis, a method to inject active and reactive output of DG into power grid according to the R/X ratio of equivalent impedance to support the voltage of grid-connection point at the moment of fault occurrence is proposed. The effectiveness of the proposed method is validated by simulation results.