本文選題：接觸網(wǎng) + 絕緣子　； 參考：《西南交通大學(xué)》2015年碩士論文

【摘要】：鐵路作為我國的重要基礎(chǔ)設(shè)施,是人們在日常生活中首選的交通工具之一,是綜合交通運(yùn)輸體系中不可或缺的部分。電氣化鐵路在鐵路事業(yè)中的比重越來越大,這也是鐵路發(fā)展的趨勢。接觸網(wǎng)作為電氣化鐵路的重要部分,負(fù)責(zé)給電力機(jī)車提供電能。接觸網(wǎng)一般都是裸露在空氣中,這樣,接觸網(wǎng)的重要部件——絕緣子,就很容易被污染而降低絕緣特性。近年來,多地持續(xù)出現(xiàn)霧霾天氣,加劇了接觸網(wǎng)絕緣子的染污程度。這就很容易造成絕緣子表面放電,繼而發(fā)生污穢閃絡(luò),甚至線路跳閘,威脅著電氣化鐵路牽引供電系統(tǒng)的安全正常運(yùn)行。因此深入開展接觸網(wǎng)污穢絕緣子沿表面放電過程及其影響因素的研究很有必要,通過絕緣子污穢在線監(jiān)測裝置持續(xù)監(jiān)測絕緣子運(yùn)行狀態(tài),深入研究絕緣子表面污穢積累發(fā)展過程,探索導(dǎo)致污閃的潛在因素,及時做出相應(yīng)的防污方案,進(jìn)一步強(qiáng)化絕緣管理,防止突發(fā)事故發(fā)生,盡可能避免污穢閃絡(luò),對電氣化鐵路運(yùn)輸具有十分重要的意義,為電氣化鐵路的可持續(xù)發(fā)展提供技術(shù)支持。本文針對接觸網(wǎng)復(fù)合絕緣子和瓷質(zhì)絕緣子開展了人工污穢試驗(yàn),利用接觸網(wǎng)絕緣子污穢在線監(jiān)測裝置,采集并儲存泄漏電流信號和環(huán)境溫濕度信息,從試驗(yàn)現(xiàn)象和試驗(yàn)數(shù)據(jù)可以觀測出絕緣子泄漏電流隨污穢度和濕度變化的特征。低濕度情況下,泄漏電流值很小,隨污穢度變化特征不是很明顯；高濕度情況下,泄漏電流幅值隨污穢度的增加而明顯變大,脈沖含量和諧波含量也隨之增多。另外,由試驗(yàn)放電現(xiàn)象和泄漏電流數(shù)據(jù)說明復(fù)合絕緣子的抗污性能優(yōu)于瓷質(zhì)絕緣子。為了實(shí)現(xiàn)接觸網(wǎng)絕緣子污穢在線監(jiān)測,論文分析了鐵路現(xiàn)場對泄漏電流影響的大因素——過車影響。在機(jī)車經(jīng)過時,絕緣子泄漏電流信號中低頻(0～10Hz)含量明顯增加,利用這一特性,采用小波能量比的方法,可以有效識別過車時的泄漏電流波形,從而通過剔除這段數(shù)據(jù)來達(dá)到消除過車對泄漏電流影響的目的。絕緣子污穢在線監(jiān)測裝置中的電流傳感器會對采集到的泄漏電流信號造成偏移,文中對此進(jìn)行了分析,經(jīng)大量數(shù)據(jù)驗(yàn)證,信號除去經(jīng)驗(yàn)?zāi)B(tài)分解后的趨勢項可以有效地改善這種偏移。文中闡述了兩種針對泄漏電流信號的去噪方法,即奇異值分解去噪和小波閾值去噪。從去噪后的波形來看,奇異值分解去噪過多地濾除了細(xì)節(jié)特征,平滑了過多的噪聲,使信號損失了一些細(xì)節(jié)信息；而小波閾值去噪則合理地濾除了噪聲,使信號比較光滑,又很好地保留了信號本身的細(xì)節(jié)信息,因此小波閾值去噪方法比奇異值分解去噪方法更加適用于泄漏電流信號去噪。論文中分析了泄漏電流的時頻域特性。給出了泄漏電流有效值、最大值、和時域熵三個時域參考量,泄漏電流三次諧波幅值與基波幅值之比、泄漏電流總諧波畸變率兩個頻域參考量,來評估絕緣子表面污穢狀態(tài)。這五個參考量與絕緣子表面污穢度均呈現(xiàn)指數(shù)增長關(guān)系,擬合成指數(shù)曲線后擬合度都在0.95以上,滿足工程應(yīng)用要求,因此這五個參考量可以用來評估絕緣子表面污穢狀態(tài)。最后,文中采用支持向量機(jī)來識別接觸網(wǎng)絕緣子泄漏電流波形對應(yīng)絕緣子污穢等級的分類方法。將環(huán)境濕度RH、泄漏電流有效值Ie、泄漏電流最大值Ih、泄漏電流三次諧波幅值與基波幅值之比K13和泄漏電流總諧波畸變率THD這五個參考量作為支持向量機(jī)模型的輸入,污穢的四個等級作為支持向量機(jī)分類器的四類輸出,選取了高斯徑向基核函數(shù),通過樣本訓(xùn)練和測試,給出預(yù)測模型的結(jié)果,實(shí)驗(yàn)表明本文中建立的支持向量機(jī)預(yù)警模型的平均誤差能夠完全滿足實(shí)際工程要求。
[Abstract]:As an important infrastructure of our country, railway is one of the preferred transportation tools in our daily life. It is an indispensable part of the comprehensive transportation system. The proportion of the electrified railway in the railway industry is increasing, which is also the trend of the railway development. As an important part of the electrified railway, the contact network is responsible for the power machine. The car provides electrical energy. The contact net is generally exposed to the air, so that the insulators, the important parts of the catenary, are easily polluted and reduce the insulation. In recent years, more and more haze weather has been sustained, which aggravates the pollution degree of the contact insulator. It is easy to cause the insulator surface discharge, and then the pollution flashover, Even line tripping threatens the safe and normal operation of the traction power supply system of electrified railway. Therefore, it is necessary to carry out the research on the discharge process along the surface of the polluted insulator of the contact network and its influencing factors. The insulator contamination on-line monitoring device is continuously monitored and the insulator surface contamination accumulation is deeply studied. The development process, exploring the potential factors leading to the pollution flashover, making the corresponding anti fouling scheme in time, further strengthening the insulation management, preventing the accident from happening, avoiding the pollution flashover as much as possible, is of great significance to the electrified railway transportation, and provides technical support for the sustainable development of the electrified railway. The edge and porcelain insulators have carried out artificial pollution test. Using the on-line insulator contamination monitoring device of the contact network, the leakage current signal and the ambient temperature and humidity information are collected and stored. From the test and test data, the leakage current of the insulator can be measured with the pollution and humidity. The leakage current is very low. In the case of high humidity, the amplitude of leakage current increased obviously with the increase of pollution degree and the content of pulse content and harmonic wave increased. In addition, the pollution resistance of composite insulators was superior to porcelain insulators by experimental discharge and leakage current data. In order to achieve contact network insulation. On line monitoring of subpollution, the paper analyzes the influence of the leakage current on the railway field - the effect of passing on the vehicle. When the locomotive passes, the low frequency (0 to 10Hz) of the leakage current signal in the insulator is obviously increased. Using this characteristic, the wavelet energy ratio method can be used to identify the leakage current waveform of the vehicle, and then pass through the filter. In addition to this data, the current sensor in the insulator contamination on-line monitoring device will offset the collected leakage current signal. In this paper, an analysis is made in this paper. It is verified by a large number of data that the signal can effectively improve the migration after removing the trend term after the empirical mode separation. In this paper, two denoising methods for leakage current signal are described, namely singular value decomposition de-noising and wavelet threshold denoising. From the wave de-noising waveform, singular value decomposition de-noising too much to filter out the details, smoothing too much noise and losing some details of the signal; and the wavelet threshold denoising is reasonable to filter the noise. In order to make the signal more smooth and retain the details of the signal itself, the wavelet threshold denoising method is more suitable for the leakage current signal denoising than the singular value decomposition denoising method. In this paper, the characteristics of the leakage current in the time and frequency domain are analyzed. The leakage current effective value, the maximum value, and the time domain entropy three time domain reference quantities are given. The ratio of the three harmonic current of leakage current and the amplitude of the fundamental wave, the total harmonic distortion rate of the leakage current of two frequency domain reference amounts to evaluate the surface contamination of insulators. These five reference quantities have an exponential growth relationship with the surface contamination of insulators, and the fitting degree of the quasi synthetic index curve is above 0.95, which satisfies the requirements of the engineering application, thus five A reference quantity can be used to evaluate the contamination status of the insulator surface. Finally, the support vector machine is used to identify the classification method of the insulator contamination level by the contact insulator leakage current waveform. The environmental humidity RH, the leakage current effective value Ie, the maximum leakage current Ih, the ratio of the leakage current to the amplitude of the three harmonic current and the amplitude of the fundamental wave are K1 3 and the total harmonic distortion rate of the leakage current THD these five reference quantities as the input of the support vector machine model, the four levels of pollution as the four class of the support vector machine classifier, select the Gauss radial basis kernel function, and give the result of the prediction model through the sample training and test. The experiment shows the support vector machine set up in this paper. The average error of the police model can fully meet the actual engineering requirements.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：U225.43;TM216

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 焦尚彬,劉丁,鄭崗,張青;基于模糊邏輯方法的高壓絕緣子污穢程度評定[J];電力系統(tǒng)自動化;2005年07期

2 李t熝，

本文編號：2070666