本文为 2021-01-28 所做讲座的文稿，以电力计算相关基础知识为主要内容，是对“电力系统基础”讲座的补充。（注：文稿内容仅包括知识点，多数不含详细解释。） This post is the presented script of the lecture given on 2021-01-28, containing the basic knowledge on power systems calculations, is the supplements to the lecture “Fundamentals of electrical power systems”. (Note: The script only contains the key points, most of which are not explained in detail.)