利用配电自动化系统实现单相接地故障定位的研究
http://www.tabobo.cn/soft/20/233/2007/556315010284.html摘 要
故障定位是配电自动化的重要功能之一，由于单相接地故障是配电网中最常见的故障，研究单相接地故障定位方法对于减小停电范围、缩短停电时间及提高供电可靠性具有重要意义。
我国中低压配电网一般都采用中性点非直接接地方式，即中性点不接地或者经消弧线圈接地方式，单相接地故障时故障定位面临的主要困难是：工频故障电流微弱与电弧不稳定，为此本文分析了小电流接地系统发生单相接地故障时电气量中暂态分量的特性，利用现有配电网自动化系统的设备条件，着重解决单相接地故障定位中的故障区段定位和故障点定位两个问题，本文的主要研究工作如下：
1．针对故障区段定位问题，提出一种综合区段定位方法。该方法综合了两种具体的区段定位方法：基于特征频带的暂态零序电流方向比较法和零序电流有功分量幅值比较法，前者提取首容性频带内暂态零序电流分量用于电流流向比较，适用于中性点经消弧线圈接地系统的强故障与中性点不接地系统的所有故障；后者通过比较各个检测点处零序电流有功分量大小选择故障区段，适用于中性点经消弧线圈接地系统发生弱故障的情况。综合区段定位方法适合于各种故障类型，具有很高的灵敏度和准确性。
2．针对故障点定位问题，提出一种参数辨识法。该方法采用集中参数的配网模型，在此模型基础上建立了单相接地故障的故障点定位时域方程，并利用暂态时域信息通过最小二乘优化算法来辨识出故障点位置。该方法更充分地利用了单相接地故障时的暂态故障信息。
3．最后，提出了利用现有的配电自动化系统设备解决故障定位的实现方案：首先利用综合区段定位方法进行故障区段定位，然后在故障区段内应用参数辨识法进行故障点定位。
4．仿真结果验证了以上方法的有效性和方案的可实现性。
关 键 词：中性点非直接接地系统；暂态电流分量；故障区段定位；故障点定位；参数辨识
论文类型：应用研究
ABSTRACT
Fault Location is an important function of the distribution automation system. Because single phase grounding fault is the most frequently happened fault in distribution system, location of such fault is crucial to reduce outage area, shorten outage time, and thus upgrade the reliability.
In China, the non-solid earthed neutral, i.e. isolated or Petersen coil compensated neutral, is widely adopted in middle and low voltage distribution network. The most challenging problem encountered in locating single phase grounding fault is that the fault current is extremely weak and the fault arc is unstable too. In this thesis, the characteristics of the transient currents in single phase earthed distribution network with non-solid earthed neutral are analyzed, and the major focuses are on fault section location accurate fault location on the basis of the present situation of distribution automation system. The major contributions are as follows:
1. In this thesis, an integrated fault section locating method is proposed. The proposed method integrates two fault section locating method: the method comparing the direction of transient ground mode current component in specific frequency band, and the method comparing the amplitude of active component in low frequency band. The former, which uses the transient ground mode current component signals in the first capacitive band to compare the current directions, is suitable for obvious fault in compensated networks and all kinds of fault in isolated networks. The latter, which locates the fault section by comparing the amplitude of active component of the zero sequence current, is suitable for weak fault in compensated networks. The integrated method is suitable for all kinds of fault and has high sensitivity and accuracy.
2. In this thesis, a method for accurate fault locating is proposed. The method employs the faulted phase network and zero-sequence network as the fault location model, constructe location equations based on this model. The accurate fault location is identified using transient electric component . Transient fault component are more effectively used.
3. Finally, A integrated method for both fault section locating and accurate fault locating is realized in distribution automation system: firstly fault section is determined using integrated fault section locating method; secondly accurate fault position is determined using Parameter Identification method.
4. Simulation experiments with EMTP and data processing with MATLAB verified the proposed method.
KEY WORDS: Non-solid earthed neutral networks; Transient current component; Fault section location; Accurate fault location; Parameters Identification
TYPE OF THESIS: Applied Research
目 录
1 绪论 1
1.1 课题背景及研究意义 1
1.1.1 单相接地故障的危害及其研究意义 1
1.1.2 配电自动化现状及其处理模式 2
1.2 单相接地故障定位的研究现状分析 3
1.2.1 监测定位法 4
1.2.2 故障分析法 5
1.2.3 信号注入法 7
1.3 本文的主要研究工作 8
2 小电流接地系统单相接地故障的特性分析 9
2.1 引言 9
2.2故障零序电流分量分析 9
2.2.1 单相接地故障时稳态零序电流分量特征 9
2.2.2 零序电流暂态分量分析 11
2.3 区段的暂态零序电流特性分析 16
2.3.1 配电系统的结构 16
2.3.2 区段定位中的特征频带概念 17
2.3.3 特征频带上下限的确定 19
2.3.4 特征频带内暂态零序电流的分布特点 21
3 配电网中故障区段定位的综合区段定位方法 23
3.1 基于暂态零序特征电流分量方向的方法 23
3.1.1 暂态零序电流的分布特点 23
3.1.2 基本原理 23
3.1.3 故障区段判别方法 24
3.1.4 实现算法 26
3.1.5 算法评价与适用条件 26
3.2 零序电流有功分量幅值比较的方法 27
3.2.1 算法原理 27
3.2.2 有功分量幅值算法实现 27
3.2.3 故障区段具体判别方法 27
3.2.4 算法评价及适用条件 28
3.3 综合区段定位方法的实现 28
3.4 EMTP仿真研究 29
3.4.1 EMTP仿真模型的建立 29
3.4.2 仿真实验及分析 31
3.5 小结 35
4 配电网中故障点定位的参数辨识法 36
4.1 引言 36
4.2 参数辨识的理论基础 36
4.2.1 参数辨识的基本概念 36
4.2.2 最小二乘优化算法的基本原理 37
4.3 故障点定位的参数辨识法 38
4.3.1 算法方程 38
4.3.2 该算法在测距中应用的分析 40
4.3.3 算法中使用的数学方法 41
4.4 EMTP仿真研究 43
4.4.1 仿真系统及参数 43
4.4.2 仿真条件 43
4.4.3 仿真实验结果及分析 44
4.5 本章小结 45
5 利用配电自动化系统实现故障定位的总体方案 47
5.1 实现故障定位的技术基础 47
5.2 单相接地故障点定位总体方案的流程 48
5.2.1 启动模块和永久性故障判断模块 48
5.2.2 故障相判别模块 48
5.2.3 总体方案的基本流程 49
5.3 故障定位总体方案的例证 50
6 结论 54
致 谢 55
参考文献 56
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