小電流接地系統單相接地故障選線方法的分析研究

論文編號:ZD1438  論文字數:35952,頁數:67

論文題目：小電流接地系統單相接地故障選線方法的分析研究
摘 要
 故障定位是配電自動化的重要功能之一，由于單相接地故障是配電網中最常見的故障，研究單相接地故障定位方法對于減小停電范圍、縮短停電時間及提高供電可靠性具有重要意義。
 我國中低壓配電網一般都采用中性點非直接接地方式，即中性點不接地或者經消弧線圈接地方式，單相接地故障時故障定位面臨的主要困難是：工頻故障電流微弱與電弧不穩定，為此本文分析了小電流接地系統發生單相接地故障時電氣量中暫態分量的特性，利用現有配電網自動化系統的設備條件，著重解決單相接地故障定位中的故障區段定位和故障點定位兩個問題，本文的主要研究工作如下：
 1．針對故障區段定位問題，提出一種綜合區段定位方法。該方法綜合了兩種具體的區段定位方法：基于特征頻帶的暫態零序電流方向比較法和零序電流有功分量幅值比較法，前者提取首容性頻帶內暫態零序電流分量用于電流流向比較，適用于中性點經消弧線圈接地系統的強故障與中性點不接地系統的所有故障；后者通過比較各個檢測點處零序電流有功分量大小選擇故障區段，適用于中性點經消弧線圈接地系統發生弱故障的情況。綜合區段定位方法適合于各種故障類型，具有很高的靈敏度和準確性。
 2．針對故障點定位問題，提出一種參數辨識法。該方法采用集中參數的配網模型，在此模型基礎上建立了單相接地故障的故障點定位時域方程，并利用暫態時域信息通過最小二乘優化算法來辨識出故障點位置。該方法更充分地利用了單相接地故障時的暫態故障信息。
 3．最后，提出了利用現有的配電自動化系統設備解決故障定位的實現方案：首先利用綜合區段定位方法進行故障區段定位，然后在故障區段內應用參數辨識法進行故障點定位。
 4．仿真結果驗證了以上方法的有效性和方案的可實現性。

關 鍵 詞：中性點非直接接地系統；小電流接地系統；故障區段定位；故障點定位；參數辨識
論文類型：應用研究

Title: Undercurrent earth system single-phase earth fault route selection method analytical study
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; Neutral un-effectual grounded system; Fault section location; Accurate fault location; Parameters Identification
TYPE OF THESIS: Applied Research

目  錄
1 緒論 1
1.1 課題背景及研究意義 1
1.1.1 單相接地故障的危害及其研究意義 1
1.1.2 配電自動化現狀及其處理模式 2
1.2 單相接地故障定位的研究現狀分析 3
1.2.1 監測定位法 4
1.2.2 故障分析法 5
1.2.3 信號注入法 7
1.3 本文的主要研究工作 8
2 小電流接地系統單相接地故障的特性分析 9
2.1 引言 9
2.2故障零序電流分量分析 9
2.2.1 單相接地故障時穩態零序電流分量特征 9
2.2.2 零序電流暫態分量分析 11
2.3 區段的暫態零序電流特性分析 16
2.3.1 配電系統的結構 16
2.3.2 區段定位中的特征頻帶概念 17
2.3.3 特征頻帶上下限的確定 19
2.3.4 特征頻帶內暫態零序電流的分布特點 21
3 配電網中故障區段定位的綜合區段定位方法 23
3.1 基于暫態零序特征電流分量方向的方法 23
3.1.1 暫態零序電流的分布特點 23
3.1.2 基本原理 23
3.1.3 故障區段判別方法 24
3.1.4 實現算法 26
3.1.5 算法評價與適用條件 26
3.2 零序電流有功分量幅值比較的方法 27
3.2.1 算法原理 27
3.2.2 有功分量幅值算法實現 27
3.2.3 故障區段具體判別方法 27
3.2.4 算法評價及適用條件 28
3.3 綜合區段定位方法的實現 28
3.4 EMTP仿真研究 29
3.4.1 EMTP仿真模型的建立 29
3.4.2 仿真實驗及分析 31
3.5 小結 35
4 配電網中故障點定位的參數辨識法 36
4.1 引言 36
4.2 參數辨識的理論基礎 36
4.2.1 參數辨識的基本概念 36
4.2.2 最小二乘優化算法的基本原理 37
4.3 故障點定位的參數辨識法 38
4.3.1 算法方程 38
4.3.2 該算法在測距中應用的分析 40
4.3.3 算法中使用的數學方法 41
4.4 EMTP仿真研究 43
4.4.1 仿真系統及參數 43
4.4.2 仿真條件 43
    4.4.3 EMTP仿真理論分析和驗算……………………………………………………44
4.4.4 仿真實驗結果及分析 44
 4.5本章小結…………………………………………………………………………..46
 5 利用配電自動化系統實現故障定位的總體方案 47
5.1 實現故障定位的技術基礎 47
5.2 單相接地故障點定位總體方案的流程 48
5.2.1 啟動模塊和永久性故障判斷模塊 48
5.2.2 故障相判別模塊 48
5.2.3 總體方案的基本流程 49
5.3 故障定位總體方案的例證 50
6 結論 54
致    謝 55
參考文獻 56