变压器风冷控制系统设计(附CAD电气控制系统图,PLC梯形图)(论文说明书15000字,CAD图1张)
摘 要
在变电所中, 大型电力变压器一般均采用强迫油循环风冷式冷却方式。目前这种冷却方式在国内大部分为继电器控制。这种控制模式存在控制回路复杂、接点接线多、可靠性低、故障率高、控制误差大,而且风冷控制系统长年在户外连续运行, 工作环境恶劣等问题，所以提出并设计了基于PLC的变压器风冷控制系统装置。装置以西门子S7-200(CPU226)型PLC作为控制器构建了变压器风冷控制系统；系统是以变压器的顶层油温为被控量，提出了根据给定温度，系统中的三台风机通过与PLC连接能够自动投切，实现对变压器油温控制的负反馈控制策略。本设计主要包括系统的控制主回路，元器件选型和上位机组态软件的设计；整个系统具有通信及远方监视、信息显示、故障报警等功能。
这种装置具有可靠性高、控制精确、抗干扰能力强、功能强大、智能化，并能延长风机寿命的优点，极大的简化了系统接线，提高了装置本身的可靠性；完善了对风机的保护和控制，满足了大型变压器风冷控制装置智能化控制的要求。
关键词：变压器 可编程序控制器 风冷控制系统 PID
The design of control system of air-cooled transformer
Abstract
In substation, the main transformer oil generally adopt forced air-cooled cooling way . At present , this cooling method in most of the domestic relay control . This kind of control mode has a lot of problems .such as the complicated control circuit，complex contact wiring ,low reliability, high fault rate，large control error, Cooling control system for continuous operation in outdoor , its working conditions is poor. So the transformer wind cooling control system apparatus is proposed and designed based on PLC. The device use Siemens S7-200 PLC(CPU226)as controller, construct the cooling control system for transformer；the transformer temperature as the control system’s controlled variable，according to a given temperature , the cooling automatically switching by the negative feedback control method. Beside this，the device has other functions such as，communication and remote surveillance，fault locating，information display．In the system ，Three fans can be connected to the PLC via automatic switching, transformer oil temperature control to achieve negative feedback control methods. This design mainly includes the main loop of the control system, components selection and upper unit configuration software design。The design also has the communication and the distance monitoring, information display, fault alarm functions.
The device has the advantages of high reliability, precise control, strong anti-interference ability, powerful, intelligent, and can extend the life of the cooler group, greatly simplifies system wiring and improve the reliability of the device itself . Improve the protection and control of the cooler and the requirements of the intelligent control for large capacity transformer cooling device are satisfied．
Key Words: transformer；PLC；cooling control system；PID
目 录
摘要 I
ABSTRACT II
第一章 绪论 1
1.1选题背景及其意义 1
1.2变压器风冷国内外研究现状 2
1.3本文主要工作 3
第二章 变压器风冷控制装置的设计方案 4
2.1变压器风冷控制的方法和策略 4
2.2变压器的发热及冷却原理 6
2.3变压器油温自动控制方法及其流程图 6
第三章 变压器风冷控制系统设计中各设备选型 9
3.1风机的选型 10
3.2低压电器器件选型 12
3.3扩展模块EM235型号选择 17
第四章 风冷控制装置的硬件设计 18
4.1 PLC逻辑控制回路的原理及接线 18
4.2 装置电气连接 19
第五章 软件设计 23
5.1 STEP-7 软件介绍 23
5.2 MCGS组态软件简介 23
5.3 触摸屏人机交互功能实现 26
第六章 总结与展望 28
致谢 29
参考文献 30
附录：变压器风冷控制PLC编程 31
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