摘要:本设计是一个小型火力发电厂电气部分的设计，针对一个发电厂电气部分设计而言，电气主接线在发电厂电气设计中扮演着重要的角色，因为主接线的确定对整个电力系统的运行以及发电厂、变电所运行的可靠性、灵活性和经济性有着密切的关联。同时，电气主接线的设计对选择各种电气设备的型号也至关重要，电气设备的合理选择能确保各种继电保护得以实现，从而保证电网的安全运行。

　　　本次设计主要是针对一个新建小型凝汽式火力发电厂，主要装设1台QF-25-2型发电机和1台QFQ-50-2型发电机，所发出的额定电压都为10.5KV,规定出线回路数为4回，输送的距离分别为：25km、50km、75km、100km。此次设计的主要内容是给定一份原始资料，然后通过分析原始资料，对主变压器进行选择，最终设计出相对较为合理的电气主接线连接方式。然后根据电气主接线进行相应的短路电流的计算、各种电气设备的选择与校验，同时对发电机、变压器、输电线路做出相应的继电保护及对整个电厂采取防雷保护的初步设计，最后根据自己的设计画出与之相对应的主接线图。

关键词：电气主接线；电气设备；继电保护；防雷保护

Abstract:This is a design of the electric parts to small coal-fired power plants , according to this part, the main electrical wiring plays an important role in electrical design, because the determine of main wiring are closely related to the operation of the power system and reliability, flexibility and economy in power plants, substation operation. At the same time, it is the also important for main electrical wiring design to choose the type of electrical equipment, the reasonable selection of electrical equipment can ensure all kinds of relay protection can be realized, so as to ensure the safe operation of the power grid.

　　　This design is mainly aimed at a new small condensing coal-fired power plants, mainly installed a generator QF-25-type 2 and a generator QFQ-50-type 2, rated voltage is 10.5 KV, loop number is four which was ruled, the transmission distance respectively is: 25 km, 50 km and 75 km and 100 km. The main content of the design is given a raw material, and then I analyze the original material and choice main transformer, and design a relatively reasonable the main electrical wiring connection. Then I make the corresponding the calculation of short-circuit current according to the main electrical wiring, and chose and checkout if all kinds of electrical equipment is reasonable, at the same time, I protect the generator, transformer, transmission line accordingly and make the preliminary design of lightning protection for the whole power plant. Finally, I draw the corresponding main hookup accordingly to my own design.

Key words:  The main electrical wiring；electric equipment；relay protection；lightning protectio