【正文】
主要的難點(diǎn)有: ①行波信號(hào)的采樣與存儲(chǔ);②故障電流采集的觸發(fā);③行波波頭到達(dá)時(shí)間的獲取。由行波反射、折射理論可知,暫態(tài)初始行波與故障點(diǎn)反射波極性相同,而對(duì)端母線反射波與這兩者極性相反 [30] ,且對(duì)側(cè)母線反射波極性與本側(cè)母線反射波極性相同 [31],可上海交通大學(xué)碩士學(xué)位論文 致謝根據(jù)檢測(cè)到的行波極性來(lái)判斷故障點(diǎn)的真?zhèn)?。?lián)立兩個(gè)檢測(cè)點(diǎn)的時(shí)間信息即可求出故障點(diǎn)X 的位置。為便于分析各個(gè)行波的順序,記檢測(cè)點(diǎn)依次檢測(cè)到的行波與第一個(gè)行波的時(shí)間差為 ( =0,1,2…n) , =0。XY 1M 1 M 21ft2ft1bt2bt3btY 21bt1ft2ft2bt3btf3f圖26 非金屬性接地故障網(wǎng)格圖上海交通大學(xué)碩士學(xué)位論文 致謝Fig26 The trellis of nonmetal grounding fault在Y2處,由圖25可以此求出各個(gè)行波到達(dá)檢測(cè)點(diǎn)Y2的時(shí)刻,及各個(gè)行波到達(dá)檢測(cè)點(diǎn)的時(shí)間與第一個(gè)行波的時(shí)間差其表達(dá)式分別如式(215) 、式(216)所示, (215)123123()//()/ffbtYXvLtvtYX?????????? (216)1231230()/4/()/ffbtLvtXYv?????????式中 為線路總長(zhǎng)度, 為電流行波波速。在不同的檢測(cè)點(diǎn)故障行波及其反射波和折射波到達(dá)檢測(cè)點(diǎn)的時(shí)間是不一樣的,記前向行波經(jīng)反射或者折射后依次到達(dá)檢測(cè)點(diǎn)的時(shí)間為 、1ft… ,記反向行波經(jīng)反射或者折射后依次到達(dá)檢測(cè)點(diǎn)的時(shí)間為 、 … 。本裝置采用的是分布式故障測(cè)距方法,對(duì)于故障電流行波的檢測(cè)本裝置采用多點(diǎn)分布式檢測(cè)方法,由安裝在輸電線路上的監(jiān)測(cè)裝置檢測(cè)導(dǎo)線故障電流行波傳輸時(shí)間實(shí)現(xiàn)。同理,可以得到電流行波的折射和反射系數(shù)為: (214)22121qifi uqZ?????????? 行波的衰減與變形行波在理想的無(wú)損線路上傳播時(shí),能量不會(huì)散失,電壓波與電流波之間的關(guān)系由波阻決定,波不會(huì)衰減和變形。0C由于分裂導(dǎo)線和電纜的 較小和 較大,故波阻抗較小,約為 1050 左右。 為導(dǎo)線的半徑(m) ; 為真空磁導(dǎo)率(hr0?H/m)。其中電壓 是在空間的位置 以速度 向 x 軸()fuxvt?()qixvt?()fixvt?()quxvt?的正方向運(yùn)動(dòng)的電壓波,我們稱為前行電壓波, 表示一以速度 向 x 軸負(fù)方f?v向運(yùn)動(dòng)的電壓波,稱為反行電壓波。上海交通大學(xué)碩士學(xué)位論文 致謝第二章 分布式故障定位裝置的理論基礎(chǔ) 行波的基本理論在高壓長(zhǎng)距離輸電線路中,同一瞬間沿線的電壓、電流都不相同,傳統(tǒng)的集中參數(shù)模型無(wú)法進(jìn)行分析,因此必須將線路作為分布參數(shù)處理。將近年來(lái)的一系列新技術(shù)結(jié)合行波定位法提出了新型輸電線路故障定位裝置的設(shè)計(jì)方案。C. 雙端定位法需要采用 GPS 等同步裝置來(lái)同步采樣時(shí)間,成本較高,不僅存在同步誤差,而且 GPS 失步或者時(shí)鐘信號(hào)消失、啟動(dòng)失敗等原因也會(huì)導(dǎo)致定位失敗 [26]。則故障距離為:fnuNTvL 。由于行波傳輸過程中衰減較大,使得故障點(diǎn)反射行波波頭的辨識(shí)變得復(fù)雜,從而可能導(dǎo)致定位失敗。這兩種方法在行波測(cè)距法發(fā)展的早期得到過應(yīng)用,但投資較大。雙端阻抗測(cè)距算法有很多,一般可以分為兩類,一是基于兩端同步采樣數(shù)據(jù)的算法,算法簡(jiǎn)單,但同步采樣不易實(shí)現(xiàn):二是基于兩端非同步采樣數(shù)據(jù)的算法,要求對(duì)采樣數(shù)據(jù)進(jìn)行同步化,算法復(fù)雜,計(jì)算量大 [1214]。 阻抗法線路故障時(shí)故障回路的阻抗(電抗)與故障距離成正比,阻抗法即通過故障時(shí)測(cè)量到的電壓、電流通過求解以差分或微分形式表示的電壓平衡方程計(jì)算出故障回路阻抗上海交通大學(xué)碩士學(xué)位論文 致謝(電抗)來(lái)估算故障距離。與此同時(shí),故障測(cè)距算法也得到了較快的發(fā)展。特別是隨著輸電線路電壓等級(jí)和輸送容量的不斷提高,輸電線路故障往往帶來(lái)巨大的經(jīng)濟(jì)損失甚至導(dǎo)致電網(wǎng)的崩潰。最后,總結(jié)全文的研究成果并在當(dāng)前研究的基礎(chǔ)上提出幾點(diǎn)改進(jìn)。但傳統(tǒng)互感器存在頻帶較窄,易飽和,高頻響應(yīng)差等問題,不易檢測(cè)故障后的暫態(tài)行波波頭,影響定位精度。本人完全意識(shí)到本聲明的法律結(jié)果由本人承擔(dān)。 學(xué)位論文作者簽名: 日期: 年 月 日 用于輸電線路故障定位的導(dǎo)線監(jiān)測(cè)裝置的研制上海交通大學(xué)學(xué)位論文版權(quán)使用授權(quán)書本學(xué)位論文作者完全了解學(xué)校有關(guān)保留、使用學(xué)位論文的規(guī)定,同意學(xué)校保留并向國(guó)家有關(guān)部門或機(jī)構(gòu)送交論文的復(fù)印件和電子版,允許論文被查閱和借閱。本文的前兩章首先對(duì)目前國(guó)內(nèi)外輸電線路故障定位的基本方法及其發(fā)展?fàn)顩r進(jìn)行了綜合分析與總結(jié),比較了各種定位方法的應(yīng)用情況及其優(yōu)缺點(diǎn)。關(guān)鍵詞:行波 分布式故障定位 Rogowski線圈 小波變換 模極大值線 用于輸電線路故障定位的導(dǎo)線監(jiān)測(cè)裝置的研制ABSTRACTWith the increasing of transmission capacity and the rising of voltage grade of transmission lines, transmission line faults will not only harm the secure and stable operation of power system but also affect the living of societal economy and polity. Consequently, it bees more and more important to rapidly and accurately determine the fault point according to different fault feature, which can not only restore power supply quickly, improve the reliability and safety of the overall power system, but also save much manpower and material of linetracking. Therefore, it is of great social and economic benefits.At present, fault location device of transmission line mostly use traveling wave location method, including twoterminal and oneterminal fault location method. As for traveling wave signal acquisition, voltage and current transformer that already in substation are mostly used. But traditional transformer has some drawbacks, such as much narrower frequency range, easy to saturate, poor high frequency response, ect. Therefore, it’s not easy to detect the transient traveling wave, hence, affects the location precision. In first two chapters, the monly used method and develop situation of transmission line fault location is prehensive analyzed and summarized, and then pare the advantages and disadvantages of various location methods and their applications. Based on traditional traveling wave location method, this paper poses a distributed traditional raveling wave location method. The third and fourth chapter mainly introduced the hardware design of fault location device, particularly about the fault current data acquisition unit, which including current sampling channel of Rogowski coil based on no hysteresis, high linear degree and good transient response, highspeed data acquisition and storage unit, transient traveling wave sampling trigger unit.In the fifth chapter, software design of fault location device is prehensively researched. The wavelet transform theory,espceially the singularitydetected theory is diseussed in this chapter. As for the detection of singularity and traveling wave head, the modulus maxima line is used.In the last chapter, a series of experiments is made to analysis the existing problems under real working condition, and then some solving measures are proposed. Finally, research results of this paper are summarized and based on present research some improvement is put forward.Keywords: Traveling Wave, Ditributed Fault Location , Rogowski Coin, Wavelet Transform,ModulusMaximumLine 用于輸電線路故障定位的導(dǎo)線監(jiān)測(cè)裝置的研制目 錄摘 要 ..............................................................................................................................................IIABSTRACT........................................................................................................................................III目 錄 .....................................................................................................................................