摘   要
随着我国国民经济的快速增长，用电已成为制约我国经济发展的重要因素,而且随着负荷密度迅速增长，对电能的质量和可靠性都提出了更高的要求，但是由于许多变电站建站时间较早，站内配电装置陈旧，跟不上经济及用电发展的要求，因此对变电站的改造和设计成为首要解决的问题。
本文第一章主要阐述了变电站的发展现状以及中里变电站的基本情况。第二章为负荷计算和主变压器的选择。首先运用需用系数法计算出该变电站的负荷大小，然后以此为依据，并结合发展趋势和经济技术性确定主变压器。第三章阐述了电气主接线的设计，根据进出线、负荷的性质等因素综合确定电气主接线的形式。先确定每一级电压下的基本接线形式，最后确定整个变电站可靠的、经济的电气主接线形式。第四章为短路电流计算。明确短路电流计算的目的，确定了短路电流计算点，并做出等值电路图，从而进行标幺值的换算。同一点的短路电流计算包括：三相短路电流、冲击短路电流。第五章为电气设备的选择与校验。主要内容有母线、进出线、断路器、隔离开关、以及电流和电压互感器的选择等。一般是按正常条件选择，按短路电流校验。第六章介绍了配电装置。结合中里变电站的实际情况，确定中里变电站配电装置的形式。
关键词：负荷计算  变压器选择  短路电流计算  电气设备

Abstract
Along with the fast growth of our country national economy, electricity has become the check and supervision important factor of the economic development. and along with the quick growth of the burden density, the circumstance all put forward the higher request to the quantity and credibility of the electric power, but because the years of many transformer substations is very early, station inside go together with the electricity device are so old that can not keep up with the economy and the request of using electrity, the reformation and designs of the transformer substation has become the problem that need to be resolved.
This text chapter 1 mainly elaborated the development of present condition of the transformer substation and basic circumstance of the transformer substation of Zhongli.Chapter 2 computes for the burden and the choice of the main transformer. Working out the burden size of the transformer substation with the