To properly set the guaranteed quality of service for different distribution system operators (DSOs), the regulator has to determine the influence of extreme events on the annual reliability indices and predict the reliability of these events. In this paper, the spatial correlation of lightning storms and annual reliability indices for different DSOs are determined. The correlation is calculated using the global annual reliability and lightning data aggregated from individual DSOs. Using Gaussian and t copula, the joint distribution of individual reliability indices (SAIFI and SAIDI) and lightning density for different DSOs and geographical regions has been determined. After the distribution fitting, it is possible to calculate the risk of not attaining the guaranteed quality of service for every individual DSO on condition that the lightning activity does not surpass the required level. The methodology is tested by using 7 year's period real operational data from 27 Serbian distribution utilities.

为了适当地为不同的配电系统运营商（DSO）设置保证的服务质量，监管机构必须确定极端事件对年度可靠性指标的影响，并预测这些事件的可靠性。本文确定了不同DSO的雷暴空间相关性和年度可靠性指标。使用各个DSO汇总的全球年度可靠性和闪电数据计算相关性。使用高斯和tcopula，确定了不同DSO和地理区域的各个可靠性指标（SAIFI和SAIDI）和闪电密度的联合分布。进行配电拟合后，可以在雷电活动未超过要求水平的情况下，为每个DSO计算未达到保证的服务质量的风险。通过使用来自27个塞尔维亚配电公司的7年期实际运营数据对方法进行了测试。