基于时变通用生成函数的孤岛运行模式下微电网可靠性评估

并网型微电网进入孤岛运行模式后,其未来短期运行的供电可靠性具有时变性。为此,提出基于时变通用生成函数(TVUGF)的可靠性评估方法。采用马尔可夫—TVUGF模型求取预测风速状态概率及微电网系统时变状态概率,得到分布式电源出力TVUGF模型;考虑微电网计划解列和孤岛切负荷策略,对每个系统状态进行分类故障影响分析,建立微电网可靠性TVUGF模型,进而得出微电网负荷点和系统可靠性指标。考虑到TVUGF运算中需计算的状态数较多,提出TVUGF运算的合并同类项和状态重新划分法,以减少计算量,提高计算速度。采用所述方法对典型低压微电网系统进行可靠性评估,评估结果及分析验证了该方法的正确性和有效性。

Reliability Evaluation of Microgrid in Islanded Operation Mode Based on TVUGF

After grid-connected microgrid entry into islanded operation mode, the reliability in its future short-term run is variable with time. A reliability evaluation method based on the time-varying universal generating function (TVUGF) is proposed. The state probabilities of forecast wind and time-varying state probabilities of microgrid system are obtained based on Markov-TVUGF model. And TVUGF models of distributed generator output power are obtained as well. Further, the classified fault impact is analyzed for each system state, to develop the microgrid reliability TVUGF model. And microgrid load points and system reliability indices are obtained. With planned microgrid splitting and island load shedding strategy taken into account, the microgrid reliability model based on TVUGF is developed. And, in consideration of the large number of states to be calculated in TVUGF operation, the method of merger of similar items and re-division of states is proposed to reduce the amount of calculation and improve computing speed. The proposed method is successfully applied in reliability evaluation for a typical low-voltage microgrid. This work is supported by National High Technology Research and Development Program of China (863 Program) (No. 2012AA050217).