【作者】 张慧芬；

【导师】 潘贞存；

【作者基本信息】 山东大学 ， 电力系统及其自动化， 2006， 博士

【摘要】 我国中低压配电网中性点广泛采用小电流接地方式，这种接地方式具有供电可靠性高的优点。但发生单相接地故障后，由于故障电流微弱、电弧不稳定等原因，单相接地故障选线和故障定位问题长期以来没有得到很好地解决，至今许多变电站仍然使用人工拉路方法查找故障线路和目测法寻找故障点。本论文重点研究配电网单相接地故障选线及故障定位问题。 为充分利用故障信息，本文提出用粗糙集理论综合多种单一选线判据，把反映故障稳态分量的判据、暂态分量的判据和利用外加诊断信号的判据有机融合。该方法以信息表和决策表为主要工具。各单一选线判据从原始故障数据中提取出各自需要的故障特征量并离散化。以变电站母线所带出线为研究论域，各单一选线判据为条件属性，离散化的各故障特征量为条件属性值，形成故障信息表，并对其进行论域缩减，利用决策规则形成决策表，从决策表的决策属性中找到综合选线结果。整个过程只需采集到的原始故障数据，不需要先验知识和工作人员的干预，就可以给出选线结果。仿真验证了综合选线的优越性。 本文从现场应用的角度提出了与零序电压和零序电流极性无关的基于零序电流投影值的选线方法。该方法以母线零序电压所在直线为参考轴，所有馈线的基波零序电流在参考轴上投影。对中性点经消弧线圈接地系统和中性点经电阻接地系统，各馈线零序电流向参考轴投影；对于中性点不接地系统，将所有馈线的零序电流旋转90°后，再向参考轴投影。不管零序电压和各馈线零序电流的极性如何，总有故障线路零序电流的投影数值最大。通过仿真验证了该方法的正确性。该选线方法作为综合选线判据中反映故障稳态特征的判据。 根据小波变换后的近似系数以及其提供的时域信息，本文提出了基于零序电流暂态极大值的选线判据。定义了特征时刻和零序电压特征值的概念，在特征时刻故障线路和非故障线路零序电流的符号相反，若所有线路电流的符号都相同，则认为母线故障。对于只有2条出线的系统，可以采用零序电流暂态极大值和零序电压特征值极性比较的方法。本文选用db4小波对原始信号进行4层分解。通过仿真验证了该方法的正确性。该选线方法作为综合选线判据中反映故障暂态特征的判据。更多还原

【Abstract】 In China, the non-solidly earthed neutral is widely used in distribution system. It has the virtue of proving power supply’s reliability. But faulted feeder selection and fault location are not solved when single-phase to earth fault occurs due to weak current and unstable fault arc. To date utilities still use manual switching to identify an earthed feeder and eyeballing to locate the fault point in the absence of a more reliable detection method. So, this paper studies faulted feeder selection and fault location in distribution system.To make the best use of fault information, synthesizing many kinds of fault selection criteria based Rough sets theory is proposed. The criteria based steady state component, transient component and additional diagnosis signal are integrated on the validity. The main tools of the method are information table and decision table. The fault characteristic quantity with each selection method is extracted from the original data and discretized. To get the fault information table, we should make the feeders on the busbar as universe, make the selection criteria as condition attributes and make the discrete fault characteristic quantity as attribute value. Then we should reduce the universe, form the decision table by decision rules, and find the faulted feeder from the decision attribute of the decision table. In the whole process, only the original fault data is needed. The faulted feeder can be identified without experiences and human work. The simulation has proved its advantage.In terms of practice, the paper provides the selection method based projection value of zero-sequence current, which has nothing to do with polarities of zero-sequence voltage and zero-sequence currents. This method makes the line of zero-sequence voltage as reference axis. The fundamental zero-sequence current of each feeder projects on the reference axis. To Peterson Coil neutral system and resistance neutral system, zero-sequence current of each feeder projects on the axis directly. To theungrounded neutral system, phase of the zero-sequence current shift 90°, then project on the axis. No matter how the polarities of zero-sequence voltage and zero-sequence更多还原