线损和线损率是反映配电网运行的重要指标，降低配电网线损对电能的有效利用及配电网经济运行均有着重要意义。为了更好地发现对配电网降损效果较明显的降损措施以及为科学制定线损目标提供依据，本文研究了配电网的极限线损分析指标及降损措施的优化步骤。 本文提出了极限线损分析指标，并在此基础上提出一种基于极限线损率和极限降损率指标的配电网降损措施优化步骤。根据提出的综合极限线损率指标是否能满足目标线损率要求，将降损措施优化步骤分为基本降损措施优化步骤和基于负荷转移的进一步降损措施优化步骤；对于基本降损措施优化考虑了在降损改造经费宽松和紧张两种情况下的优化步骤。以上述算法为核心，基于MATLAB编制了配电网极限线损分析及降损措施优化程序，采用算例对提出的极限线损分析指标和降损措施优化步骤以及编制的应用程序进行了测试和分析。 结果表明：提出的一系列极限线损分析指标能够反映各种降损措施对配电网的降损效果以及具备的降损潜力；提出的基于极限线损率和极限降损率指标的优化步骤，能够得出满足线损率要求的配电网降损优化措施；所研制的应用软件达到线损分析及获得满意降损措施的预期要求。

Line loss and line loss rate are important comprehensive economic and technical indexes to reflect the distribution network operation. Reduce line loss has great significance to the effective use of electric power and the economic operation of distribution network. To help the identification of the key loss reduction to reduce line loss and to establish the goal of losses reduction scientifically, a family of loss limitation analysis index and steps of loss reduction optimal planning method are investigated in this thesis. This paper presents the limitation line loss analysis indexes, a loss reduction optimal planning method is put forward, which is based on the proposed loss indexes and loss reduction indexes. According to the proposed total line loss limitation index whether can meet the goal line loss rate requirements, steps of loss reduction optimal planning method is divided into two categories: One is steps of basic loss reduction optimal planning method, the other is steps of basic loss reduction optimal planning method. For steps of basic loss reduction optimal planning method is considered in either case with cost or not. On the basis of above approaches, the program of loss limitation index and the loss reduction optimal planning method is developed based on MATLAB. Examples are put forward to illustrate the proposed approaches. It is shown that the suggested indexes can identify the extent of the influence of an individual element on line losses and the potential of loss reduction. It is also shown that the proposed planning method can obtain the satisfied loss reduction scheme. The software can meet expected requirement of the line loss analysis and loss reduction.