基于单端行波的配电网单相接地故障测距方法研究

发布时间：2018-05-16 00:30

本文选题：暂态行波 + 故障测距　；参考：《中国矿业大学》2017年硕士论文

【摘要】：输配电线路作为电网骨架,对社会经济有着重大影响。为了保证线路故障后电能安全稳定地输送,应快速准确地确定故障点位置以便及时排除故障、恢复供电,由于我国配电网主要采用小电流接地系统,因此对小电流接地系统单相接地故障测距的研究有重大意义。配电网结构复杂,分支较多,相比双端法,单端测距更具优势,因此本文以单端测距法作为基础原理进行研究。本文分析了单相接地故障时暂态行波的特征,通过相模变换获取了行波的线模分量和零模分量。线模分量较稳定,通常用作测距,然而零模分量中同样包含故障信息,充分利用其特性可进一步提高故障测距结果的准确性。通过分析零模分量的传输特性可知,零模分量高频部分波速比低频更高,但衰减也更大,因此不同频带下的初始波速与反射波速有较大差异。零模分量波速随故障距离增加而单调降低,因此反射波波速必小于初始波速。基于此特征可实现零模波速的估算,选取某一频带,该频带下的波速较为稳定,零模初始波速与零模第一次反射波速最为接近,可将该频带的反射波速作为初始波速实现测距。由于波速存在衰减,基于模量传输时差的测距方法仍有一定误差,因此可将其结果作为初步故障距离实现进一步测距。利用初始故障距离小于实际故障距离这一特征减小波头的搜寻范围,通过故障点反射波头与对端母线反射波头到达时间的特定关系同时确认两个波头,将对应时间带入测距公式得到更精确的故障距离。
[Abstract]:Transmission and distribution lines, as the backbone of the grid, have a great impact on the social economy. In order to ensure the safe and stable transmission of electric energy after line failure, the location of fault point should be determined quickly and accurately in order to troubleshoot the fault in time and restore the power supply. Since the distribution network of our country mainly adopts the small current grounding system, Therefore, it is of great significance to study the single-phase grounding fault location of low-current grounding system. The structure of distribution network is complex and there are many branches. Compared with two-terminal method, single-terminal ranging has more advantages. Therefore, the single-terminal ranging method is used as the basic principle in this paper. In this paper, the characteristics of transient traveling wave in single-phase grounding fault are analyzed, and the linear mode component and zero mode component of traveling wave are obtained by phase mode transformation. The linear mode component is more stable and is usually used for fault location. However, the zero-mode component also contains fault information, so the accuracy of fault location results can be further improved by making full use of its characteristics. By analyzing the transmission characteristics of the zero mode component, it can be seen that the high frequency partial wave velocity of the zero mode component is higher than that of the low frequency band, but the attenuation is also greater, so the initial wave velocity and the reflection wave velocity are different from each other in different frequency bands. The zero mode component wave velocity decreases monotonously with the increase of fault distance, so the reflected wave velocity must be less than the initial wave velocity. Based on this characteristic, the zero mode wave velocity can be estimated, and the wave velocity in a certain frequency band is relatively stable. The initial wave velocity of zero mode is the most close to the first reflected wave velocity of zero mode, and the reflected wave velocity of this frequency band can be used as the initial wave velocity to realize ranging. Due to the attenuation of wave velocity, there are still some errors in the ranging method based on Modulus transmission time difference, so the result can be used as the initial fault distance to realize the further location. By using the feature that the initial fault distance is smaller than the actual fault distance, the search range of the wave head is reduced, and the two wave heads are confirmed simultaneously by the specific relationship between the arrival time of the fault point reflection wave head and the opposite end bus reflection wave head. A more accurate fault distance is obtained by bringing the corresponding time into the range finding formula.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM755

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