中文摘要：

研究了并网型光伏发电系统对配电网可靠性的影响。分析了光伏发电系统（PVS）的元件失效模式及其对PVS输出功率的影响，建立了元件故障阶数考虑至三阶时PVS的可靠性模型；将光照资源的不确定性和PVS的元件随机停运相组合，得出PVS输出功率的概率模型。基于配电网可靠性评估的故障扩散法推导出孤岛内负荷点的可靠性指标计算公式。通过算例探讨了光伏发电系统对配电网可靠性的影响，计算结果表明光伏发电系统接人配电网能有效改善配电网供电可靠性。

英文摘要：

The effect of grid-connected photovohaic system on the reliability of distribution network is researched. Firstly, by analyzing PVS component failure modes and their impacts on PVS output power, the reliability model of PVS is built. Then the probability model of PVS output power is presented by considering both illumination uncertain- ty and PVS component random faults. And the analytical formulas to calculate reliability indices of the load points in- side the intentional islands are deduced based on fault spread for distribution network reliability evaluation. The appli- cation of the presented reliability evaluation model is studied using a typical example to show the practicality and va- lidity of the proposed approach.