基于工频分量的输电线路单端故障测距算法研究

发布时间：2018-03-29 12:48

本文选题：工频分量　切入点：单端故障测距　出处：《山东理工大学》2016年硕士论文

【摘要】：输电线路是整个电力系统不可或缺的重要一环,它肩负着输送电能的重要任务,同时由于输电线路长期暴露在自然环境中,导致其很容易发生短路故障。当故障发生后,准确及时的对故障点进行定位,就成为了需要特别关注的问题。快速准确的定位故障点,不仅能节省一定的人力物力,而且对整个电力系统的安全稳定及经济运行有着十分积极的作用。本文采用基于工频分量的单端测距原理,对输电线路发生各种类型的短路故障进行分析。同时对故障发生后稳定时间窗进行分析,提出一种针对时间窗自动选取的算法,以提高利用工频测距原理的测距精度。力求为采用工频分量测距原理的微机保护装置时间窗的快速准确选取提供参考。本文的研究内容主要有以下几点:1.详细分析基于工频分量的单端故障测距方法在集中参数模型和分布参数模型中的基本原理,针对线路中发生的各类短路故障,总结相应测距原理下的故障距离通用表达式,并分析影响测距精度的原因。2.针对故障后稳定时间窗选取这一问题,提出一种利用故障相电流的差值对时间窗进行自动提取的算法。通过将故障相电流做差值处理,突出故障过渡状态,并利用门槛值剔除故障过渡阶段,求出稳定时间窗。同时对故障测距过程中故障类型的判断、故障分量的提取及测距原理等环节进行算法设计。3.利用仿真软件PSCAD分别搭建输电线路几何参数模型和分布参数模型,对线路发生单相接地短路及两相短路故障进行仿真。结合仿真波形,借助MATLAB软件对所提时间窗自动选取算法进行验证。分别利用基于集中参数模型的单端测距原理与基于分布参数模型的单端测距原理对故障点进行定位,分析所得测距结果,对比两种测距原理的精度。本文提出的针对故障发生后稳定时间窗的自动提取算法,能对故障稳态进行快速准确的定位,利用所求时间窗,能准确获取故障后电压电流的工频分量。
[Abstract]:Transmission line is an indispensable and important part of the whole power system. It shoulders the important task of transmitting electric energy. At the same time, because the transmission line is exposed to the natural environment for a long time, it is prone to short circuit fault. Accurate and timely location of fault points has become a problem that needs special attention. Fast and accurate locating fault points can not only save some manpower and material resources, Moreover, it plays an active role in the safety, stability and economic operation of the whole power system. In this paper, the principle of single terminal ranging based on power frequency component is adopted. This paper analyzes all kinds of short-circuit faults in transmission lines, analyzes the stable time window after the fault occurs, and puts forward an algorithm for automatically selecting the time window. In order to improve the ranging accuracy of using the principle of power frequency ranging, this paper tries to provide a reference for the fast and accurate selection of the time window of the microcomputer protection device based on the principle of power frequency component ranging. The main research contents of this paper are as follows: 1. The basic principle of single end fault location method based on power frequency component in centralized parameter model and distributed parameter model is analyzed. In view of all kinds of short circuit faults occurring in the line, the general expression of fault distance under the corresponding location principle is summarized, and the reasons that affect the location accuracy are analyzed. 2. Aiming at the problem of selecting the stable time window after the fault, This paper presents an algorithm to extract the time window automatically by using the difference value of the fault phase current. By dealing with the difference value of the fault phase current, the transient state of the fault is highlighted, and the fault transition stage is eliminated by using the threshold value. At the same time, the algorithm design of fault type, fault component extraction and location principle in fault location process is carried out. 3. The geometric parameter model and distributed parameter model of transmission line are built using simulation software PSCAD, respectively. The fault of single-phase grounding and two-phase short circuit is simulated. The algorithm of automatic selection of time window is verified by MATLAB software. The fault point is located by using the principle of single end location based on centralized parameter model and the principle of single end location based on distributed parameter model, and the result of fault location is analyzed. Comparing the accuracy of the two principles, this paper presents an automatic extraction algorithm for the stable time window after the fault occurs, which can locate the steady state of the fault quickly and accurately, and use the time window. The power frequency component of voltage and current after fault can be accurately obtained.
【学位授予单位】：山东理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM75

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