10kV輸電線接地故障仿真平臺

電氣自動化論文編號:ZD788  論文字數:17444,頁數:53  有開題報告和任務書

 目    錄
1 第一章緒論 1
1.1 課題背景 1
1.2 電力配電網故障概述 1
1.3 10kV輸電線在電力系統中的應用 2
1.4 國外研究現狀 2
1.5 本章小結 3
2 第二章中性點不接地系統 5
2.1 電力系統的各種接地方式介紹 5
2.1.1 中性點直接接地 5
2.1.2 中性點不接地 6
2.1.3 經消弧線圈接地方式 6
2.1.4 中性點經電阻接地方式 7
2.2 各種接地方式的應用情況 8
2.3 中性點不接地系統構成 9
2.3.1 中性點不接地系統的優缺點 9
2.3.2 中性點不接地系統正常運行時的對地電容電流 10
2.3.3 中性點不接地系統單相故障的特征分析 12
2.4 電力系統中的諧波 19
2.4.1 電力系統中諧波的來源 19
2.4.2 諧波的危害 19
2.5 本章小結 21
3 第三章小電流接地系統單相接地故障仿真 23
3.1 仿真工具的選擇 23
3.1.1 仿真工具的比較 23
3.1.2 MATLAB的認知 26
3.2 仿真實驗系統 28
3.2.1 各元件的MATLAB建模 28
3.3 基于MATLAB的小電流接地系統模型 32
3.4 仿真參數設置 32
3.5 故障仿真 33
3.5.1 單相接地故障的仿真理論基礎驗證 34
3.5.2 過渡電阻的大小和零序電流的關系 38
3.5.3 故障位置對電壓電流的影響 41
3.6 本章小結 44
4 結束語 45
4.1 全文結論： 45
5 參考文獻 47
6 致謝 51

中文摘要

 在我國低壓配電網大都采用中性點不接地方式運行，在分支繁多、接線復雜的樹狀配電網中，單相接地故障是發生機率最高的一種故障。雖然發生單相接地故障，但線路的線電壓不變，對負荷連續供電沒有多大影響，所以規程允許中性點不接地系統在發生單相接地故障后繼續運行1～2 h，不必立即跳閘。但是單相接地后，其他兩相非故障相電壓升高倍，尤其是弧光引起的過電壓極易造成兩相或三相短路事故，長時間弧光電流引起局部過熱，則可能導致架空線路燒毀，所以應迅速查找并排除接地點，提高系統的供電可靠性。由于單相接地故障情況復雜，接地電流小，給單相接地故障的探測帶來了很大的難度。
 本文詳細介紹了中性點不接地系統的特點，利用MATLAB構建一個10kV的中性點不接地的配電系統，進行故障仿真實驗，并對各種故障情況作了大量的仿真，充分研究了10kV接地故障的各種特點,因此，本文所得的結論對與中性點不接地系統發生單相接地短路的監測和故障排除具有重要的參考價值。
關鍵詞：單相接地故障，中性點不接地系統，故障相，MATLAB仿真軟件

Abstract

 Neutral non-effectively grounded systems and resonant grounded systems are widely adopted in power distribution networks in China, and the phase-to-earth fault happens most frequently in power distribution networks. Since the line voltage is still symmetrical under fault conditions, the systems can keep operating for one or two hours. However long-time earthing operation will result in two-point, more seriously, multipoint earthing fault as well as ground arcing fault caused over voltage. It will destroy the systematic safe operation. Thus how to detect the fault line quickly and accurately is an important issue in power system protective relaying, which has not been solved completely.
 This article introduced in detail the neutral point earth system characteristic, does not construct the electrical power distribution system using MATLAB which 10kV the neutral point does not earth, carries on the breakdown simulation experiment, and has made the massive simulations to each kind of breakdown situation, has fully studied 10kV earth fault each kind of characteristic, therefore, the this article obtained conclusion to does not have the monitor and the trouble shooting with the neutral point earth system which the single-phase earth short-circuits has the important reference value.
Key words：Single-phase earth fault, neutral point earth system, breakdown, MATLAB simulation software