低频减载被认为是当电力系统发生频率严重下降事故时所能采取的最后一项补救措施．针对配电系统中的低频减载问题，文中提出了计及分布式电源和负荷静态特性的最优低频减载策略．该策略以频率及频率变化率为执行依据，并由几个基本轮和一个特殊轮组成． 在基本轮中，按反馈控制律分轮次快速切除负荷，以保证频率摆脱紧急状态．而在特殊轮中，则优化分布式电源的出力和调整部分负荷，以保证频率恢复到安全状态并使系统运行参数最优．最后，以修改的IEEE 37 节点配电系统为例来验证所提出的最优低频减载策略的有效性．

The under-frequency load shedding ( UFLS) is considered as the last effective remedial measure against a severe frequency decline of a power system.Aiming at this issue,an optimal UFLS strategy considering distributed generator ( DGs) and load static characteristics is proposed based on the frequency and its change rate. This strategy consists of several basic rounds and a special round. In the basic rounds,the system emergency can be alleviated by quickly shedding some loads runs by runs according to the feedback control law. In the special round,by optimizing the output power of DGs and adjusting some loads,the system security can be regained and the corresponding ope-rating parameters can be optimized. Finally,the effectiveness of the proposed optimal UFLS strategy is verified with the modified IEEE 37-node test feeder as an example.