本文選題：輸電線路 + 外絕緣��； 參考：《重慶大學》2014年博士論文

【摘要】：運行經(jīng)驗表明，霧中外絕緣放電對我國電網(wǎng)的安全和穩(wěn)定運行構(gòu)成了巨大威脅。國內(nèi)外采用蒸汽霧研究了輸電線路絕緣子的電氣特性，但尚未系統(tǒng)開展自然霧及其電導率對輸電線路外絕緣影響的研究。因此，系統(tǒng)研究輸電線路絕緣子與空氣間隙交流霧閃特性及其影響規(guī)律有助于更深入地認識霧閃的本質(zhì)規(guī)律，對濕霧天氣中輸電線路外絕緣防霧閃和保障電網(wǎng)的安全運行具有重要的參考意義。 在國家重大基礎研究發(fā)展計劃973項目的資金支持與國內(nèi)外研究成果的基礎上，論文在重慶大學高電壓實驗室和雪峰山試驗站對輸電線路絕緣子與棒－板短空氣間隙交流霧閃特性進行了系統(tǒng)的研究分析，，得到的主要成果有： 根據(jù)雪峰山試驗站自然環(huán)境的測量結(jié)果，統(tǒng)計近4年試驗站的月平均霧天氣分布與霧物理特征，使用最小二乘法擬合液態(tài)水含量、霧滴濃度綜合影響的能見度計算公式；采用霧發(fā)生裝置產(chǎn)生模擬霧方法開展了瓷、玻璃絕緣子交流霧閃試驗，其結(jié)果較蒸汽霧閃絡電壓高6.8%～7.2%；比較分析了染污方式對復合絕緣子交流霧閃特性的影響，即定量涂層法與噴涂法試驗結(jié)果的百分偏差為7.1%～9.3%，可忽略染污方法對污穢特征指數(shù)的影響。 基于人工模擬與自然環(huán)境試驗，分析了霧物理特征（霧的水含量、霧水電導率與霧水溫度）以及環(huán)境參數(shù)對棒－板短空氣間隙交流擊穿電壓的影響規(guī)律。結(jié)果表明，霧的水含量在1～3g/m3時，擊穿電壓增大了5.1%；而霧的水含量在3～4g/m3時無明顯變化；霧水電導率從100μS/cm增加至5150μS/cm時，擊穿電壓減小了2.7%～9.1%。 根據(jù)試驗結(jié)果及其分析，提出了濃霧地區(qū)霧水電導率對絕緣子交流閃絡電壓的附加影響規(guī)律，即絕緣子表面污穢度達Ⅲ級及以上嚴重污穢等級時（鹽密≥0.15mg/cm2），霧水電導率不影響其閃絡電壓；而對于Ⅰ級及以下污穢等級（鹽密≤0.06mg/cm2），霧水電導率從0.01mS/cm升至3.0mS/cm時將導致絕緣子交流閃絡電壓降低4.1%～25.6%。即嚴重污穢時可以不考慮霧水電導率的影響，清潔、輕度污穢時卻存在明顯影響；清潔、輕污穢絕緣子在高電導率濃霧環(huán)境中的交流閃絡電壓須進行校正，隨著霧水電導率的增加（0.01～3.0mS/cm），校正系數(shù)K為1.00～0.80，霧水電導率對憎水性絕緣子交流閃絡電壓的影響小于親水性絕緣子。 根據(jù)測量結(jié)果，分析了絕緣子表面凝露與濕潤特性，基于此建立了霧水電導率影響的附加鹽密與預染污鹽密的綜合等值鹽密計算模型，并提出了鹽密、霧水電導率附加鹽密綜合影響的絕緣子交流閃絡電壓計算模型，模型計算結(jié)果與試驗結(jié)果很吻合，百分偏差小于6.8%；分析了0級污穢時霧水電導率對四種絕緣子交流閃絡電壓梯度的影響。研究結(jié)果可為重污染濃霧地區(qū)絕緣子的污穢等級劃分提供參考建議。 根據(jù)雪峰山試驗站基地開展的自然霧中絕緣子交流閃絡試驗結(jié)果，提出了鹽密和環(huán)境溫度綜合影響的絕緣子交流閃絡電壓計算公式，與重慶大學青藏鐵路高海拔沿線的試驗結(jié)果吻合；提出與凍霧閃相比，復合絕緣子凝霧交流閃絡時貫穿絕緣子兩端的閃絡電弧的持續(xù)時間明顯變短，這主要由于凍霧時絕緣子傘群表面粗糙度發(fā)生改變，電弧將融化其表面凍結(jié)的霧滴而延長閃絡時間，使電弧的形狀極不規(guī)則，而呈現(xiàn)出彎曲或搖擺的劇烈燃燒現(xiàn)象。
[Abstract]:The operation experience shows that the insulation discharge of the fog is a great threat to the safe and stable operation of the power grid in China. The electric characteristics of the transmission line insulators are studied by steam fog at home and abroad, but the influence of natural fog and electrical conductivity on the external insulation of the transmission lines has not been systematically carried out. The characteristics of air gap AC flicker and its influence rules are helpful to understand the essential law of fog flicker more deeply. It is of great significance for the safe operation of transmission lines outside the transmission lines in wet fog and the safe operation of the power grid.
On the basis of capital support and domestic and foreign research results of national major basic research and development plan 973 project, the paper studies and analyses the communication flashover characteristics of transmission line insulators and rod plate short air gap in high voltage laboratory and Xuefeng mountain test station of Chongqing University. The main achievements are as follows:
According to the measurement results of the natural environment of the Xuefeng mountain test station, the monthly mean fog weather distribution and the physical characteristics of the fog in the last 4 years are calculated. The formula of the visibility calculation by the least square method is used to fit the liquid water content and the fog droplet concentration, and the fog flashover of porcelain and glass insulators is carried out by using the fog generator to produce the simulated fog method. The results are 6.8% to 7.2% higher than that of the steam fog flashover voltage, and the influence of the dyeing mode on the AC flashover characteristics of composite insulators is compared and analyzed. The deviation of the results of the quantitative coating method and the spray method is 7.1% to 9.3%, and the influence of the contamination method on the pollution characteristic index can be ignored.
Based on artificial simulation and natural environment test, the effects of fog physical characteristics (fog water content, fog water conductivity and fog water temperature) and environmental parameters on the AC breakdown voltage of rod plate short air gap are analyzed. The results show that the breakdown voltage increases by 5.1% when the water content of fog is from 1 to 3g/m3, while the water content of fog is from 3 to 4g/m3. The breakdown voltage decreased by 2.7% to 9.1%. when the conductivity of fog water increased from 100 S/cm to 5150 S/cm.
According to the test results and analysis, the additional influence of the fog water conductivity on the AC flashover voltage of insulators is put forward, that is, when the contamination degree of the insulator reaches the grade III and above the serious pollution level (salt density more than 0.15mg/cm2), the electrical conductivity of the fog water does not affect the flashover electric pressure, but the contamination level of the level I and below (salt density less than 0.06) Mg/cm2), when the electrical conductivity of the fog rises from 0.01mS/cm to 3.0mS/cm, the AC flashover voltage of the insulator will be reduced by 4.1% to 25.6%., that is, the influence of the electrical conductivity of the fog is not considered when the fog is seriously polluted, but there is a clear effect on the cleaning and light pollution; the AC flashover voltage of the clean, light polluted insulator in the high conductivity dense fog environment must be corrected. With the increase of the electrical conductivity of the fog (0.01 ~ 3.0mS/cm), the correction coefficient K is 1 ~ 0.80. The influence of the fog water conductivity on the AC flashover voltage of the hydrophobicity insulators is less than that of the hydrophilic insulators.
Based on the measurement results, the surface condensation and wetting characteristics of insulators are analyzed. Based on this, a comprehensive equivalent salt density calculation model of additional salt density and pre stained salt density is established, and a calculation model of insulator flashover voltage is proposed, and the calculation results and experiments of the model are put forward. The results are very consistent and the percentage deviation is less than 6.8%. The influence of the fog water conductivity on the AC flashover voltage gradient of the four insulators in the 0 grade pollution is analyzed. The results can provide a reference for the pollution grade division of the insulators in heavy polluted dense fog area.
According to the result of the AC flashover test of the insulators in the natural fog of the Xuefeng mountain test station base, the formula for calculating the AC flashover voltage of the insulator with the comprehensive influence of the salt density and the ambient temperature is put forward, which is in agreement with the experimental results along the high altitude along the Qinghai Tibet Railway in Chongqing University. The duration of the flashover arc running through the insulators is obviously shorter, which is mainly due to the change of the surface roughness of the insulators' umbrella group. The arc will melt the frozen droplets on the surface of the insulator to prolong the flashover time, making the shape of the arc extremely irregular, and presents a violent burning phenomenon of bending or rocking.
【學位授予單位】：重慶大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：TM216

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