基于小波變換的電力電纜故障檢測研究

電氣工程論文編號:DQ181   論文字數:23208,頁數:50

目錄
摘 要 I
Abstract II
目錄 III
1  緒論 1
2  電力電纜故障分類 4
2.1 電纜的組成結構 4
2.2 形成電纜故障的原因分類 4
2.2.1 機械損傷 4
2.3  電力電纜故障分類 6
2.3.1 按電纜的組成材料分類（物理屬性） 6
2.3.2 按電纜故障發生的原因分類 8
2.3.3 按電纜的結構特性分類 9
2.3.4 按電纜故障發生的部位分類 9
2.3.5 按故障外表特性或人的直覺性分類 10
2.3.6 按電纜損壞程度分類 10
2.3.7 按電纜的耐壓等級分類 11
3  常見故障檢測方法 12
 3.1 電纜故障點的粗測 12
3.1.1 直流電橋法測量短路和接地故障 12
3.1.2 脈沖反射法測量電纜故障 16
3.2 電纜故障點的精測(定點) 19
3.2.1 聲測法 19
4  小波分析理論 24
4.1 小波變換的基本概念 24
4.1.1 基本小波 24
4.1.2 小波基函數 25
4.1.3 連續小波變換 25
4.1.4 離散小波變換 26
4.2 常用小波函數 26
4.2.1 Haar小波 27
4.2.2 Daubechies(dbN)小波 28
4.2.3 Coiflet(coifN)小波 28
4.2.4  Symlets(symN)小波 29
4.2.5 Mexican Hat(mexh)小波 30
4.2.6 Meyer小波 30
4.3 MATLAB算法 30
4.4 小波變換模極大值與奇異性檢測 32
5  基于小波分析的電纜故障在線定位檢測的設計與仿真 35
5.1 基于小波的電纜故障在線定位系統描述 35
5.1.1 小波分析在輸電線路奇異點檢測中的應用 35
5.2 電纜故障在線定位系統仿真 36
5.2.1 建立電纜故障系統模型 36
5.2.2 電纜斷路故障仿真模型 37
5.2.3 斷路故障的數據分析計算 37
5.2.4 電纜短路故障仿真模型 39
5.2.5 短路故障的數據分析計算 40
6  總 結 43
致 謝 44
參考文獻： 45

摘 要
 隨著國民經濟的快速發展，我國電力工業得到了迅猛發展。電網規模越來越龐大，城市配電網絡結構日益復雜完善，電力電纜的應用日益增多，電力電纜故障也相應增多。而輸電線路電壓等級和輸送容量的逐步提高使得輸電線路故障對社會經濟生活造成的影響和損失也越來越大。因此如何盡快探測故障點距離，尤其是如何快速準確地找出電纜故障點并盡快修復，對配電網運行維護人員來講是一項頗為艱辛的任務。目前，線路保護己經進入微機保護時代，而小波變換作為新型的更有效的數學分析工具，己在電力系統中得到應用。
 本文將采用小波變換快速算法對電力系統中故障信號進行分析、判斷。仿真結果表明，這種算法能夠準確及時判斷故障，符合工程實時性的要求。和傳統方法相比：利用了小波的帶通濾波性質，減少了信號損失，簡化了檢測系統硬件電路。此方法實現容易，信號分析效果好。
 
 
關鍵詞：小波分析、電力電纜、故障波形、檢測波形

Abstract
With the rapid development of the national economy, our national power industry also has been developing fast. The larger the size of the grid, the more complex and advanced the power distribution network, the larger the application of power cable, the more the power cable fault. The gradually improvement of the voltage classification of transmission line and the transmission capacity leads to greater influence and loss to the social and economic life caused by transmission line fault. Consequently, how to detect the point of fault as soon as possible, especially how to identify exactly and quickly repair the cable fault, is a rather difficult task for the operation maintenance personnel of power supply. At present, the railway protection is approaching into the microcomputer protection era, while wavelet transform, as the innovative and the most effective mathematical analysis tool, has been widely applied in the power system.
This thesis is adopting the wavelet transform fast algorithm to analyze and judge the fault signal of power system. The emulation results show that this formula can judge and locate the fault precisely and timely, which conforms to the requirements of real-time project. Compare with traditional methods, this method uses the band-pass filter qualification of the wavelet, and decreases the signal loss, simplifies electrical circuit of detecting hardware system. This method is easy to accomplish and boasts a great effect of signal analysis.

Keywords：wavelet analysis、 power cables、fault waveform、the waveform detection