【作者】 潘永刚；

【导师】 杨以涵；

【作者基本信息】 华北电力大学（北京） ， 电力系统及其自动化， 2003， 硕士

【摘要】 中性点采用小电流接地是中低配电网一种典型的接地方式，这种接地方式具有有利于提高供电可靠性等许多优点。但由于单相接地电流非常小，干扰影响严重，所以小电流接地电网单相接地故障选线保护是一大技术难题，很久以来没有得到圆满解决。本论文从改进小电流选线装置的调试和检测手段出发，研究解决小电流接地系统电网单相接地故障选线保护问题，主要内容如下：描述了小电流接地系统正常运行和单相接地故障运行情况的原理和特征，分析影响小电流接地选线的因素，归纳出小电流接地选线的主要困难。以真实反映这些因素和困难为目标，作为小电流接地选线装置调试和检测系统应该达到的要求。提出了建立小电流接地选线物理模拟实验系统解决小电流接地选线装置调试和检测问题的方法。针对小电流接地选线问题解决不好的现状，本设计从选线装置的检测和调试手段出发，列举了现在科研开发和工业生产过程中普遍采用的调试和检测手段，分析其原理、特点和局限性，结合小电流选线特征，提出了建立模拟实验系统的新方案。论文的主体部分介绍了实验系统的结构、特点和作用，以及作为实验系统补充的小电流接地选线仿真测试装置的方案。本实验系统的核心设备是10kV电网模型，并配备有相关的实验设备，如保护、测量、分析仪器等，另外，模拟实验系统还包括小电流接地系统的单相接地故障模拟，实验系统的安全规程等内容。物理模拟实验系统电压、电流、阻抗、故障时间都实现了与实际系统的1：1模拟，最大限度地再现了小电流接地系统的单相接地故障。对比实验系统的实验数据与某地区变电站小电流接地系统单相接地故障录波数据，反应实验系统对实际故障特征的揭示的充分性和准确性，论证了模拟实验系统的模拟是真实有效的，符合小电流接地选线的要求。同时，也比较了其他调试检测手段的数据，证明具有明显的局限性。实验系统不仅是我们认识10kV系统运行规律和各种接地故障本质的平台，也是我们理论开发和技术改进的基础和依据。小电流接地选线课题研究组的每一项成果都来源于实验系统提供的丰富的知识和信息。通过实验系统，澄清了对小电流接地系统运行规律和接地故障机理的认识，为选线的研究做好了理论准备；通过实验系统实现了对一些选线方法的客观评价和有效域的发掘；通过实验系统实现了连续判断等选线理论和方法的创新，实现了新型自动调谐消弧线圈方案的首创等。本设计提出了建立小电流接地选线仿真测试装置的思想，并提出了装置的方案。<WP=3>模拟实验系统调试检测效果好，但是却不方便移动，且如果实验多次重复又会使设备老化，绝缘水平降低，出现击穿等问题。仿真测试装置是一种利用软件建立模型，反应实验系统和现场运行和故障规律，通过单片机模拟输出的方案。本设计提供了仿真测试装置的方案：用数学建模的方法，参照实验室的物理模型、实验数据和通过故障录波得到的现场数据，建立计算机可以表达的数学模型，用高级语言编写程序。通过人机交互，设定各种实验所需要的初始条件及故障方式。然后进行计算，得到故障电压和电流数据。利用计算机并口，将数据输出，接收端为单片机器件，对数字信号进行转换和放大，得到与实验结果相对应的电压和电流模拟数据再输出给选线设备。物理模拟实验系统为小电流接地选线的研究和开发创造了一个故障再现的平台，揭开了以往选线失败之谜，推进了小电流接地选线的发展。仿真测试装置具有模拟实验系统故障再现的真实性，而更加灵活、方便，是实验系统的重要补充。更多还原

【Abstract】 Due to the multifold advantages as improving reliability, neutral small current earth represents a typical scheme in MV and LV power distribution networks. But because the phase to earth fault current is tiny whereas the interference is relatively heavy, fault line detection has become a troublesome problem, which hasn’t been settled satisfactorily for long time.This thesis sets out from ameliorating debugging and testing methods of the fault line detection equipments to devote to solving the problem mentioned above. The principal contents are as follows:The principium and characteristic of neutral small current earthed power system normal running state and single-phase-to-earth fault running state are presented in this thesis, elements that influence fault line detection are educed, and the main difficulties of fault line detection are concluded. This thesis takes the aim reflecting these elements and difficulties truly as the essential desire of the fault line detection equipments debugging and testing systems.A method is proposed to solve fault line detection equipments debugging and testing problems to establish small current fault line detection physical simulative experimental system. Aiming at the actuality that neutral small current earthed fault line detection problems are poorly solved, this thesis comes from the methods of fault line detection equipment debugging and testing, analyzes the principium, features and deficiency, combines with the fault line detection points, proposed the scheme of establishing the neutral small current earthed fault line detection physical simulative experimental system.The main body of the thesis describes the structure, features and effects of the simulative experimental system. It also introduces an assisted scheme of developing a simulating test equipment.The skeleton of the experimental system is the model of a 10kV electrical grid, including all the correlative experimental equipments, such as protection, measuring and analyzing equipments and so on. Further, it also involves the single-phrase-to-ground fault simulation and the experimental system security regulations. The voltage, current, impedance and time of the experimental system have all achieved 1:1 simulation to the actual power system. Fault reproduction is achieved as veridical as possible.A contrast is made between the fault data from experimental system and a certain power station. The sufficiency and verity of the experimental system simulation are<WP=5>proved. The experimental system accords with the need of fault line detection equipments debugging and testing. Data also reveal the obvious deficiency of other methods.The experimental system is not only the foundation to understand the 10kV grids running properties and fault essences, but also the base and tools of theory exploitation and technology improvement. Every achievement in our research team comes from the experimental system, including the clarification of acquaintance, the realization of estimate for several fault line detection theories and exploitation of efficiency range, as well as the invention of new theories and equipments.An idea of develop a simulating test equipment is shaped and comes to scheme. It can move easily and repeat debugging and testing at will. It has a longer life and less maintenance work. It is an essential assist for the experimental system.The scheme of the equipment: Take advantage of mathematics modeling to analyze and manage physical model, fault data of experiment system or field, then establish a computer model, and form a program. Fault mode is chosen through dialogue with the computer. Fault voltage and current are calculated automatically and transmitted to single-chip controller. Signal transformed and disposed in the single-chip controller that is homologous to the power system can be received.The physical simulative experimental system creates groundwork for neutral small current earthed fault line detection equipments research and development, and reveals the reason更多还原