【作者】 翟运娟；

【导师】 潘贞存； 高厚磊；

【作者基本信息】 山东大学 ， 电力系统及其自动化， 2009， 硕士

【摘要】 与输电系统采用中性点直接接地方式不同,中低压配电系统中性点多采用不接地、经消弧线圈或电阻的接地方式,称为中心点非有效接地系统,即小电流接地系统。小电流接地系统发生单相接地故障后,三相线电压依然对称,可持续运行1-2小时。但非故障相对地电压升高为原来的3^1/2倍,长期运行可能会损坏其绝缘,引起进一步故障。因此,必须尽快确定故障线路和故障点。但由于小电流接地系统中发生单相接地故障后故障特征不明显,因此小电流单相接地故障的检测成为电力系统的一大难题。近年来,随着数字信号处理技术的发展,小电流接地选线技术取得了很大进步,有些选线装置选线精度能够达到90%以上。但小电流单相接地故障的定位还没有得到很好的解决,配电线路虽然不像输电线路那么长,但分支较多,覆盖区域广,定位难度较大。此外,随着配电系统规模不断扩大,供电容量也在不断增加,用户对供电质量提出更高的要求,这就要求具备有效的手段对单相接地故障进行准确、快速的定位。目前提出的多种定位方法或现场应用效果不理想,或自动化程度不高。信号注入法是在实际中运用的比较成熟有效的方法之一,传统基于信号注入的定位方法虽能较准确地定位,但在自动化程度、容错性及装置性能等方面还存在很多问题,有待进一步完善。本文在分析信号注入法基本原理的基础上,提出并构建了配电网单相接地故障自动定位系统,实现了单相接地故障的自动、准确定位。针对传统信号注入法定位自动化程度低的问题,开发了配电系统自动定位软件系统,该系统以VS.NET为开发平台,引入了SQL Sever数据库系统,其中网络模型的建立参考了IEC61970-CIM 301公共信息模型建模标准,采用了面向对象的编程设计思想;网络拓扑分析在对配电系统网络划分区域的基础上引入了广度优先的搜索算法,简单有效的实现了整个网络拓扑的分析;自动定位算法根据远方信号探测装置位置间的关系,增加了信号探测装置信息补偿算法,有效的解决了当故障信息不准确、不完整时仍然能够准确定位故障的难题。同时为保证远方探测装置和上位机软件系统间可靠的通信,实现配电网单相接地故障准确定位,本系统采用了以GPRS数据通信为主,GSM短消息为辅的通信方式,并开发了相应的通信功能模块。本文研究的单相接地故障自动定位系统在现场实验的过程中取得了良好的效果,完全可以实现配电网单相接地故障的自动、准确定位。更多还原

【Abstract】 While neutral points of transmission system is usually directly earthed, distribution system adopts neutral point unearthed mode or neutral point earthed via arc-suppression coil, which is known as non-solidly earthed network. When single-phase to earth fault occurs in a non-solidly earthed network, the three phase line to line voltages are still symmetric, and the network can keep on running for one to two hours. But the non-faulted phase voltage would increase to 3^1/2 times of original voltage, which would lead to more serious phase-to-phase fault. So it is necessary to detect faulted line and fault location as soon as possible. However, after fault occurs, since no short-circuit loop is formed, the fault current is too. small to detect, so detection of single phase to ground fault in distribution networks is one of the hot interests in the area of power systems.Recently, with the development of Digital Signal Processing, the faulted line selection technique has got great progress, but fault location is still an issue which has to be solved. So far, a variety of proposed location methods have not been applied in practice, or have a low degree of automation. Signal-injection method is one of the most useful methods to locate fault point. This method can locate the fault point accurately, but there are still a lot of problems that remain to be further improved, such as the degree of automation, fault tolerance and performance of devices.Based on the analysis of injection-method principle, this paper built distribution network single phase to ground fault location system, which has obtained good effect in locating single phase fault. In the system, to solve the problem of low automation lever, distribution system location software was developed, using VS.NET as platform, and adopted SQL sever database. The network model construction referred to IEC 61970 -CIM 301 public information modeling standard, and adopted the object-oriented programming design thought. On the basis of partition of distribution system, network topology introduced the breadth-first search algorithm. This method can achieve the entire network topology analysis, simply and effectively. According to position of remote signal detector, automatic locating algorithm added information compensation algorithm. This algorithm finally solves the difficulty of accurate locating when detectors’ information is inaccurate or incomplete.Communication between remote detectors and PC software system is another key to locate fault point. Means of communication in this paper add GPRS communication mode on the base of the traditional GSM short message. The developed automatic location system has achieved good results in the field experiment. It can locate single phase ground fault point, automatically and accurately.更多还原