【作者】 粟迟；

【导师】 王少荣；

【作者基本信息】 华中科技大学 ， 电力系统及其自动化， 2007， 硕士

【摘要】 接地网是电力系统中的一个必要环节。而接地网埋在地下,土壤环境对其的腐蚀作用不可避免。腐蚀严重时,接地网中的接地体和接地线会变细甚至断裂,使接地电阻升高,电气设备“失地”。这种情况下,很容易发生事故危害电网运行和人身安全。因此,接地网防腐保护是保证电力系统正常工作和安全运行的一项重要措施。阴极保护是埋地金属防腐的一种有效方法,包括牺牲阳极法和强制电流法。牺牲阳极法已广泛应用于电力系统接地网的防腐工程中,而强制电流法在接地网防腐中的应用还处于起步阶段。基于这种状况,本文提出了一种以强制电流法为主要防腐手段的接地网阴极保护系统方案。其核心工作包括设计一种适用于电力系统接地网的阴极保护电源——SF-200-2型恒电位仪,以及由该恒电位仪为远端设备构成的接地网阴极保护监控系统。SF-200-2型恒电位仪由主电路和控制电路组成。主电路采用单相桥式相控整流、LC滤波。控制电路是以AT89C51为主控芯片的嵌入式系统。整个阴极保护系统采用CAN总线技术实现底层网络,而上层数据通信由电力系统数据网完成。调试实验结果表明:所设计的恒电位仪有很高的控制精度和抗干扰能力,并且操作方便,而整个接地网阴极保护系统的设计则更是有利于提高电力系统防腐工程的防腐水平和自动化程度。更多还原

【Abstract】 Grounding grids, a fundamental part in power system, is very vulnerable to the corrosion damage caused by soil. When corrosion is severe, grounding device including grounding wire and grounding conductor may quickly get thinner or even broken, which could force the grounding resistance to increase and make those grounded equipments become inadequate grounded. In this situation, incidents might easily occur, endangering the power system and personnel. Therefore, anticorrosion of grounding grids is of great significance.Cathodic protection is an effectual way of protecting buried metal structure from corrosion. It consists of two methods: sacrificial anode and impressed current. The former has already been widely used in grounding grids anticorrosion project in power system, while the latter’s application in grounding grids is still underway.A scheme of grounding-grid cathodic protection system using the method of impressed current is discussed in this dissertation. Two aspects of the design are a cathodic protection power source ( SF-200-2 potentiostat ) and a network for centralized supervisal and control in which potentiostats are RTUs.SF-200-2 potentiostat is composed of the host circuit and the control circuit. The host circuit adopts a single-phase semicontrol rectifier and an LC filter, while the control circuit is an embedded system using an AT89C51 singlechip as the main controller. The cathodic protection system contains bottom networks based on CAN bus and upper networks making use of SPDnet.Conclusions reached from testing experiments are that SF-200-2 potentiostat performs well because of its high precision, stability and convenience, while the cathodic protection system could promote the automation degree of the grounding-grid anticorrosion project.更多还原