【作者】 谢芝东；

【导师】 孙鸣；

【作者基本信息】 合肥工业大学 ， 电力系统及其自动化， 2007， 硕士

【摘要】 我国6-66KV配电网多数采用小电流接地运行方式，这种接地方式具有提高供电可靠性等优点。但发生单相永久性接地后，故障选线和故障定位问题长期以来没有得到很好的解决。本文首先回顾了现有的各种小电流接地系统单相接地故障选线原理和方案，指出了目前选线原理所存在的缺陷和弊端。采用了基于模型参数识别原理的小电流接地系统单相接地故障选线和故障定位的一种新方法。针对一个简单的具有多条出线的中性点不接地系统发生单相接地故障时，对每一条线路建立其非故障的下的零序参数数学模型，利用零序电流、电压数据求解模型零序电容和零序电感在最小二乘意义下的参数估计值，依据得到的线路对地电容判断实际发生的故障是否符合所建立的模型，从而判断出故障线路，再依据得到的该线路零序电感进一步判断出故障点的位置。通过EMTP进行故障仿真研究，验证该方法正确、有效，耐过渡电阻能力强。根据上述方案，同时借助实验室现有条件，设计了一套小电流接地系统单相接地故障选线及定位装置，详细介绍了装置的软硬件结构设计及控制流程。更多还原

【Abstract】 The non-effectively grounded system is used in the distribution net of 6-66kV. It has the virtue of proving power supply’s reliability. But fault selection and fault location are not solved when single-phase permanent grounded fault appears. Through reviewing of the existing theories on fault line selection systematically, it points out the defects and drawbacks of those in this paper. It proposed a new approach to the single-phase-to-earth fault selection and fault location based on the model parameter identification method in the non-effectively neutral system.When single-phase earth-fault appears we establishes mathematical model of the zero sequence equivalence networks for every line under non-fault, then established corresponding differential equation on unknown variable of line parameters. The model parameter estimation of least square can be solved by the zero sequence voltage and the current of real-time gathered. According to the line zero sequence capacitance value to the ground and the zero sequence inductance from the fault point to the bus, the fault line can be selected and the location of fault can be measured. This principle has been verified via the EMTP simulator, and it is correct and reliable.We design a suit of equipment of fault line selection and fault location according to this project .The device’s hardware and software is explained in detail.更多还原