化工厂35KV总降压变电所设计

摘要变电站是电力系统的重要组成部分，它直接影响整个电力系统的安全与经济运行，是联系发电厂和用户的中间环节，起着变换和分配电能的作用。

电气主接线是发电厂变电所的主要环节，电气主接线的拟定直接关系着全厂（所）电气设备的选择、配电装置的布置、继电保护和自动装置的确定，是变电站电气部分投资大小的决定性因素。

本次设计建设一座35kV降压变电站，首先，根据主接线的经济可靠、运行灵活的要求选择各个电压等级的接线方式，在技术方面和经济方面进行比较，选取灵活的最优接线方式并以CAD辅助设计软件绘制它接线图。

其次进行短路电流计算，根据各短路点计算出各点短路稳态电流和短路冲击电流，从三相短路计算中得到当短路发生在各电压等级的工作母线时，其短路稳态电流和冲击电流的值。

最后，根据各电压等级的额定电压和最大持续工作电流进行设备选择，然后进行校验并计算出系统的负载、负荷电流以及短路电流的数据用来选择供电设备，并且注意系统的接地、防雷以及常见故障的排除等。

关键词: 工厂供电；降压变电；CAD软件AbstractSubstation is an important part of power system.It directly affects the entire power system security and economic operation of power plants and the user is linked intermediate links,play a role in transformation and distribution of electric energy.Electrical power plant substation main connection is the main link,preparation of main power is directly related to the entire plant (the) selection of electrical equipment, power distribution equipment layout, relay protection and automatic devices to determine, Is part of the investment size of the electrical substation decisive factor.The design of the construction of a 35kV step-down substation,first, according to the main terminal of the economic and reliable operation and flexible asked to select various voltage levels of connection mode,technical and economic aspects in the comparison, select a flexible manner and the optimal connection to CAD-aided design software to draw its wiring diagram.The simulation of short circuit current calculation,points calculated according to the points short circuit current and short-circuit steady-state impact of current,when calculated from the three-phase short circuit occurs while the work in the bus voltage,steady state short circuit current and impact of its current value.Finally, according to the voltage level of the rated voltage and maximum continuous operating current to equipment selection,then check and calculate the system load,load current, and short-circuit current of the data used to select power supply equipment,and attention to system grounding, lightning protection and the exclusion of other common failures.Keywords: Power feed system，Factory electricity supply，Electric automation technology目录摘要 (I)Abstract (II)目录 (III)1 绪论............................................................................................................................... - 1 -1.1 工厂供电的意义.................................................................................................... - 1 -1.2 工厂供电的原则.................................................................................................... - 1 -1.3 原始资料................................................................................................................ - 2 -2 工厂变电所的选择........................................................................................................... - 4 -2.1主变选择................................................................................................................. - 4 -2.1.1 供电方案论证............................................................................................. - 4 -2.1.2 主变压器的选择......................................................................................... - 4 -2.2短路电流计算....................................................................................................... - 15 -2.2.1 短路的种类及原因................................................................................... - 15 -2.2.2短路电流的计算........................................................................................ - 16 -2.3电气设备选择....................................................................................................... - 21 -2.3.1电气设备选择的一般条件........................................................................ - 21 -2.3.2 各种电气设备的选择............................................................................... - 23 -2.4 本变电所高低压电气设备的选择...................................................................... - 27 -2.4.1 高压35kV侧设备选择............................................................................ - 27 -2.4.2 中压10kV侧设备选择............................................................................ - 28 -2.4.3 低压0.4kV侧设备选择........................................................................... - 28 -3 主接线设计..................................................................................................................... - 30 -3.1 主接线的设计原则和要求.................................................................................. - 30 -3.1.1 电气主接线的设计原则........................................................................... - 30 -3.1.2设计主接线的基本要求............................................................................ - 31 -3.2 主接线的设计步骤.............................................................................................. - 32 -3.3 基本接线型式...................................................................................................... - 33 -3.3.1单母线接线................................................................................................ - 33 -3.3.2 单母线分段接线....................................................................................... - 33 -3.3.3双母线接线................................................................................................ - 33 -3.3.4双母线分段接线........................................................................................ - 34 -3.3.5桥形接线.................................................................................................... - 34 -3.4 主接线初步设计方案.......................................................................................... - 35 -4 继电保护配置................................................................................................................. - 37 -4.1 继电保护的任务.................................................................................................. - 37 -4.2 继电保护装置...................................................................................................... - 37 -4.3 主变压器保护...................................................................................................... - 37 -4.4 35kV进线线路保护............................................................................................. - 38 -5 降压变电所防雷与接地装置的设计............................................................................. - 39 -5.1变电所的防雷保护............................................................................................... - 39 -5.1.1 直接防雷保护........................................................................................... - 39 -5.1.2 雷电侵入波的防护................................................................................... - 39 -5.2 变电所公共接地装置的设计............................................................................ - 39 -5.2.1接地电阻的要求........................................................................................ - 39 -5.2.2接地装置的设计........................................................................................ - 40 -结论............................................................................................................................. - 41 -致谢..................................................................................................... 错误!未定义书签。