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華北電力大學(xué)本科畢業(yè)設(shè)計(jì)(論文) 6 2 輸電線路故障測距方法 按采用的線路模型,定位原理,測量設(shè)備的不同,高壓輸電線故障定位原理和方法可大致分為阻抗法、故障分析法和行波法 [7]。 2) 分析輸電線路模型和數(shù)字濾波算法,從各種濾波算法中得出適合于工頻雙端電氣量測距的濾波算法。 綜上所述,輸電線路測距裝置的發(fā)展,對(duì)適應(yīng)現(xiàn)代電力系統(tǒng)精確故障測距算法的研究具有非常重要的意義和工程實(shí)用價(jià)值。電網(wǎng)故障信息系統(tǒng)的建立,不僅可以大大地提高整個(gè)電網(wǎng)的自動(dòng)化水平,更能加強(qiáng)對(duì)事故的分析處 理能力。除此之外,它還可以自動(dòng)的完成故障測距等錄波后必要的計(jì)算環(huán)節(jié),實(shí)現(xiàn)故障測距數(shù)字化、表格化。早期需要故障錄波裝,人們用都是機(jī)械型的光線故障錄波器。 但是微機(jī)故障測距技術(shù)出現(xiàn)的時(shí)間并不長,無論是在理論上還是在實(shí)際應(yīng)用中都有許多不足之處。七十年代以來,隨著計(jì)算機(jī)技術(shù)在我國電力行業(yè)中的應(yīng)用,特別是微機(jī)保護(hù)裝置的開發(fā)和大量投運(yùn) ,為高壓輸電線路故障測距的研究注入了新的活力,加速了故障測距的實(shí)用化進(jìn)程。 受科技和生產(chǎn)力發(fā)展水平的限制,所以早期的故障測距裝置測距精度不高,并且需要非常豐富的實(shí)際操作經(jīng)驗(yàn)才能做出判斷。 輸電線路故障測距技術(shù)的發(fā)展 長期以來,對(duì)于故障定位也就是故障測距問題的研究一直受到學(xué)術(shù)界和電力工業(yè)部門的重視。如果裝置能夠同時(shí)監(jiān)視多條線路,無疑還會(huì)進(jìn)一步提高其性能價(jià)格比。另 一方面,如果測距誤差太大,也可以說測距結(jié)果不可靠。 5)線路不對(duì)稱。一些算法要涉及到線路兩端系統(tǒng)的綜合阻抗,但是電力系統(tǒng)的實(shí)際運(yùn)行方式在不斷變化,所以給定的系統(tǒng)阻抗很難和故障時(shí)的實(shí)際情況一致,這就會(huì)給測距裝置帶來誤差。主要是指硬件引起的誤差和軟件中數(shù)學(xué)模型和算法的誤差。相對(duì)誤差以被測線路的全長的百分比表示,例如 2%, %等。裝置應(yīng)能測定永久性也能測定瞬時(shí)性故障。但對(duì)輸電線路對(duì)外物放電的小電流電弧故障,則過渡電阻將很大,有幾十歐姆甚至幾百歐姆。根據(jù)電弧情況可以把短路故障分為兩種。輸電線路故障不外乎是絕緣擊穿和雷擊造成的。單相短路接地故障的幾率最大,占輸電線路故障總數(shù)的 80%左右,其次是兩相短路接地故障。 輸電線路故障 輸電線路故障 類型 輸電線路的故障大致分為兩類:橫向故障和縱向故障。故障測距裝置又稱為故障定位裝置,是一種測定故障點(diǎn)位置的自動(dòng)裝置。永久性故障排除時(shí)間的長短會(huì)直接影響到輸電線路的供電和電力系統(tǒng)的安全穩(wěn)定運(yùn)行,排除的時(shí)間越長,則停電所造成的損失會(huì)越大,對(duì)電力系統(tǒng)安全穩(wěn)定運(yùn)行的影響也越大。因此,在線路故障后迅速準(zhǔn)確地把故障點(diǎn)找到,不僅對(duì)及時(shí)修復(fù)線 路和保證可靠供電,而且對(duì)電力系統(tǒng)安全穩(wěn)定和經(jīng)濟(jì)運(yùn)行都有十分重要的作用。 關(guān)鍵詞: 輸電線路;故障測距方法 ;雙端測距算法; MATLAB/simulink 仿真 華北電力大學(xué)本科畢業(yè)設(shè)計(jì)(論文) II TRANSMISSION LINE OF SINGLEPHASE GROUNDING FAULT LOCATION ALGORITHMS Abstract As an important elements of power system, transmission line is the lifeblood of the power system. So, precise fault location method for transmission line plays a very important role in ensuring security, stability and economic operation of power system. Yet, it is a plex and dynamic system for power system itself, and long and heavy transmission line systems are often running in the critical stable state based on some economic benefits. When some disturbances or faults occured, a variety of plex and dynamic process will inevitably exist in transmission line system. The article first introduces the basic principles of a variety of methods ranging and ranging method is divided into various existing traveling wave, singleended and doubleended ranging ranging three categories, then the various algorithms by category theory and application conditions were analyzed, pared and discussed. Then focused on a singleloop algorithm for twoterminal electrical quantities ranging study, pared to the conventional algorithm the algorithm proposed real part equal solutions for fault ponent reuse distance calculations, so that the load can be eliminated currents, and the ranging precision is almost free from transition resistance, fault type and other factors. Finally, the simulation of the fullwave and fullwave Fourier algorithm differential Fourier algorithm are pared, and finally e to a fullwave Fourier algorithm differential filtering effect is better, ranging results more precise. And correspond to different transition resistance, the actual measured fault distance less, indicating that the transition resistance ranging little impact. Keywords: Transmission line。 文章首先介紹了各種測距方法的基本原理,并將現(xiàn)有的各種測距方法分為行波測距、單端測距和雙端測距三類,然后逐 類對(duì)各種算法的理論基礎(chǔ)和應(yīng)用條件進(jìn)行了分析、對(duì)比和討論。然而,電力系統(tǒng)本身是一個(gè)復(fù)雜的動(dòng)態(tài)系統(tǒng),基于經(jīng)濟(jì)因素考慮,長距離、重負(fù)荷的輸電系統(tǒng)常常運(yùn)行在臨界穩(wěn)定的狀態(tài)下,當(dāng)系統(tǒng)發(fā)生擾動(dòng)、故障等情況時(shí)會(huì)不可避免地存在各種復(fù)雜多樣的動(dòng)態(tài)過程。 而 對(duì)應(yīng)于不同的過渡電阻,實(shí)際測量到的故障距離相差不大,說明過渡電阻對(duì)于測距影響不大。 MATLAB / simulink simulation 華北電力大學(xué)本科畢業(yè)設(shè)計(jì)(論文) 目錄 摘要 ........................................................................ I Abstract ................................................................... II 1 緒論 ...................................................................... 1 故障測距定位的意義和作用 ................................................ 1 輸電線路故障 ............................................................ 1 輸電線路故障類型 ...................................................... 1 輸電線路故障對(duì)測距裝置的基本要求 ...................................... 2 輸電線路故障測距技術(shù)的發(fā)展 .............................................. 3 本文主要研究內(nèi)容 ........................................................ 4 2 輸電線路故障測距方法 ...................................................... 6 阻抗法 .................................................................. 6 行波法 .................................................................. 6 故障分析法 .............................................................. 7 利用單端電氣量法測距 .................................................. 8 利用雙端電氣量法測距 ................................................. 10 智能化測距方法 ......................................................... 12 各類測距方法的比較 ..................................................... 12 本章小結(jié) ............................................................... 13 3 線路模型的建立與信號(hào)提取 ................................................. 14 輸電線路常見數(shù)學(xué)模型 ................................................... 14 RL 模型 ............................................................. 14 π 型或 T 型模型 ...................................................... 15 分布參數(shù)模型 ......................................................... 16 數(shù)字濾波算法 ........................................................... 17 全波傅氏算法 ......................................................... 18 全波差分傅氏算法 ..................................................... 18 帶通濾波 ............................................................. 19 最小二乘濾波算法 ..................................................... 20 本章小結(jié) ............................................................... 20 4 單回線雙端電氣量故障測距算法 ............................................. 22 算 法原理 ............................................................... 22 相模變換 ............................................................... 24 正序故障分量的提取 ..................................................... 25 華北電力大學(xué)本科畢業(yè)設(shè)計(jì)(論文) 算例仿真與對(duì)比分析 ..................................................... 26 算法仿真流程 .........................................