光伏发电是目前很具潜力的发电形式之一，但光照强度的波动和间歇特性使得对含光伏发电的系统进行准确可靠性评估较为困难。分析了光伏发电系统(PVS)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。根据孤岛外配电网元件故障对孤岛负荷可靠性的影响，定义了修复域、隔离域和零域的概念及其分层思想，有效计及了断路器/熔断器拒动影响。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入配电网能有效改善配电网供电可靠性。

Photovoltaic power generation is considered to be one of the most promising power generation forms. It is difficult to accurately assess the reliability of the photovoltaic system (PVS) for the volatility and intermittent of the light intensity. 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 uncertainty and PVS component random faults. According to the influence of components random faults outside the intentional islands on the reliability of load points inside the intentional islands, the concepts of repair zone, isolation zone and zero zone are defined. Furthermore, by considering the fail-operation of breaker and fuse, the concept for zone hierarchy is proposed, and the analytical formulas to calculate reliability indices of the load points inside the intentional islands are deduced. The application of the presented reliability evaluation model is clarified using a typical example to show the practicality and validity of the proposed approach.

国家自然科学基金资助项目(50977094，50607021)；重庆市自然科学基金资助项目(CSTC，2011BB6047)；国家高技术研究发展计划(863计划)资助项目(2011AA05A107) ;输配电装备及系统安全与新技术国家重点实验室自主研究项目(2007 DA10512711208)