变电站接地网研究及故障诊断分析(毕业论文).docx

变电站接地网研究及故障诊断分析摘要电力系统的接地网是维护电力系统安全可靠运行、保障运行人员和电气设备安全的重要措施。构成接地网的导体埋在地下，常因施工时焊接不良及漏焊、土壤的腐蚀、接地短路电流电动力作用等原因，导致地网导体及接地引线的腐蚀，甚至断裂，使地网的电气连接性能变坏、接地电阻增高。为了保证和提高电网设备工作的可靠性、安全性，电网接地技术的应用是必不可少的。电力系统接地网的一个非常重要的指标就是接地电阻，对接地电阻的测量将是判别接地网好坏的一个重要标准。显然接地网的测量手段和方法也是十分重要的。本文结合工作实际，对接地网测量技术进行了较系统的研究。论文首先对接地网测量所采用的方法进行了分析和归纳，对每种不同的方法进行了比较分析，也对接地的几个常用概念做了说明，对测量接地电阻的基本原理进行了阐述。电力系统接地网接地电阻这个指标是反映了地网总体水平，但是如果某一个支路电阻增大或支路导体腐蚀断裂，接地电阻将很难反映出来。现有判断地网腐蚀及断点的常用方法就是“停电抽样开挖”的办法，往往带有很大的盲目和实际操作上的困难，并且在接地工程竣工后对施工中的地网漏焊和虚焊也缺少有效的检查验收手段。本文将在电力系统正常运行的情况下，对如何确定变电站接地网的故障（包括断点及腐蚀）位置的准确、可靠和简单的诊断进行理论分析。通过接地网各引线间电气参数的测量值来确定地网的断点及腐蚀情况。本文建立了一个能准确反映地网各段导体电阻值和地网接地引线间电气参数之间关系的数学模型。地网各段导体电阻值和地网接地引线间电气参数之间的数学关系是一个非线性关系，必需采用迭代方法进行求解，模拟系统仿真结果表明了方法的有效性。关键字：接地网接地电阻测量故障诊断 Research on the Substation Grounding System and Analysis of the Fault Diagnosis ABSTRACT Grounding systems used in electric power systems are important means to keep a secure and reliable operation of the power systems, and ensure safety of operating personnel and electrical equipments. Conductors that form a grounding system are buried underground. The poor quality welding work or failure to conduct welding work in the course of construction, soil corrosion, electrodynamics effects of ground short-circuit current, etc. may lead to corrosion, or even break, of grounding system conductors and grounding wires, resulting in bad electrical interconnection of the grounding systems, and increasing of electrical resistance to ground. In order to secure and enhance reliability and safety of work related to power system equipment, grounding technology for the power system are quite necessary. Electrical resistance to ground is a very important indicator for grounding systems in the power systems, and measurement of resistance to ground is an important criterion adopted to determine whether a grounding system is good or bad. As a result, means and methodologies for resistance measurement of grounding systems are important re