發(fā)布時(shí)間：2019-04-03 11:06

【摘要】：近十幾年來,國內(nèi)外報(bào)道了數(shù)百起因變壓器絕緣油中含有腐蝕性硫而引發(fā)的設(shè)備絕緣事故,已受到電力部門和研究學(xué)者的廣泛關(guān)注。目前研究學(xué)者對(duì)硫腐蝕的腐蝕劣化機(jī)理和其對(duì)絕緣性能影響規(guī)律等方面已經(jīng)展開了諸多試驗(yàn)研究。同時(shí)提出了向變壓器油中添加鈍化劑延緩銅繞組的腐蝕的方法,并已得到工程應(yīng)用。但受到實(shí)驗(yàn)研究手段的限制,腐蝕性硫?qū)τ谟图埥^緣材料破壞機(jī)理仍不清晰,對(duì)于防止硫腐蝕的鈍化劑的有效添加濃度尤其在運(yùn)行油和新油中防護(hù)效果的差異與受到影響因素的關(guān)系仍有待探究。因此,研究腐蝕性硫?qū)τ图埥^緣材料劣化作用微觀機(jī)理及深入探索針對(duì)硫腐蝕的防護(hù)規(guī)律有重要的學(xué)術(shù)及工程應(yīng)用價(jià)值。應(yīng)用分子動(dòng)力學(xué)的仿真技術(shù),建立了基于纖維分子力學(xué)、均方位移、分子總能量計(jì)算的硫化物-纖維素模型,研究了不同硫化物在不同濃度下對(duì)絕緣紙纖維素材料的微觀影響機(jī)制,通過計(jì)算纖維素分子力學(xué)參數(shù),發(fā)現(xiàn)其機(jī)械剛性與韌性因H2S、十六硫醇的作用而削弱,且硫化物濃度愈高下降越明顯。同時(shí)這兩種硫化物的存在使纖維素玻璃化溫度顯著降低,而纖維素均方位移的計(jì)算顯示分子鏈運(yùn)動(dòng)更劇烈,穩(wěn)定度變差。反觀二芐基二硫醚(DBDS)對(duì)纖維素材料抗拉伸強(qiáng)度的減弱作用不強(qiáng),反而使其延展性和韌性隨DBDS的含量變大而增強(qiáng)。纖維素分子的總勢(shì)能和非鍵能部分計(jì)算顯示,加入硫化物后總勢(shì)能和靜電能增加不明顯,但H2S和十六硫醇造成氫鍵和范德華作用的減弱,即從能量角度給出材料機(jī)械性能下降的原因解釋。同時(shí)設(shè)計(jì)并開展了添加腐蝕性硫化物的油紙老化試驗(yàn),通過測(cè)量絕緣紙聚合度與抗張力,得出了與仿真較為吻合的規(guī)律。為獲得鈍化劑在運(yùn)行油和新油中最佳添加濃度,設(shè)計(jì)并開展了不同鈍化劑濃度的對(duì)比老化試驗(yàn)。通過測(cè)試變壓器油介質(zhì)損耗因素、工頻擊穿電壓、水分、糠醛等特征參量,綜合評(píng)判鈍化劑在最佳添加濃度下,對(duì)油品和絕緣紙性能的影響處在標(biāo)準(zhǔn)范圍以內(nèi)。同時(shí),兩種鈍化劑在溫度達(dá)到130℃后無論在運(yùn)行油還是新油中防護(hù)效果下降明顯,且其作用效果受水分和氧氣影響顯著。
[Abstract]:In the past ten years, hundreds of equipment insulation accidents caused by corrosive sulfur in transformer insulating oil have been reported at home and abroad, which have been paid more and more attention by electric power departments and researchers. At present, many experiments have been carried out on the corrosion degradation mechanism of sulfur corrosion and its influence on insulation properties. At the same time, the method of adding passivator to transformer oil to delay the corrosion of copper windings is put forward, and it has been applied in engineering. However, the damage mechanism of corrosive sulfur to oil-paper insulation materials is still unclear due to the limitation of experimental research methods. The relationship between the effective addition concentration of passivator to prevent sulfur corrosion, especially in running oil and fresh oil, and the affected factors remains to be explored. Therefore, it has important academic and engineering application value to study the micro-mechanism of corrosive sulfur on the deterioration of oil-paper insulation materials and to explore the protective law of sulfur corrosion deeply. A sulphide-cellulose model based on fiber molecular mechanics, average azimuth shift and molecular total energy calculation was established by using molecular dynamics simulation technique. The mechanism of the microcosmic effect of different sulfides on insulating paper cellulose was studied. By calculating the molecular mechanical parameters of cellulose, it was found that the mechanical rigidity and toughness of cellulose were weakened by the action of H 2S and hexadecyl mercaptan. The higher the sulfide concentration was, the more obvious the decrease was. At the same time, the existence of these two sulfides significantly reduced the glass transition temperature of cellulose, while the calculation of average orientation shift of cellulose showed that the molecular chain movement was more intense and the stability became worse. On the contrary, dibenzyl disulfide (DBDS) has little effect on the tensile strength of cellulose materials. On the contrary, the ductility and toughness of the cellulose materials increase with the increase of DBDS content. The partial calculation of total potential energy and non-bond energy of cellulose molecule shows that the total potential energy and electrostatic energy increase little after adding sulfides, but H _ 2S and hexadecosulfide weaken the hydrogen bond and van der Waals interaction. That is, from the energy point of view, the reasons for the decline of mechanical properties of materials are explained. At the same time, the aging test of oil paper with corrosive sulfides was designed and carried out. By measuring the degree of polymerization and tensile resistance of insulating paper, a more consistent law with simulation was obtained. In order to obtain the best adding concentration of passivator in running oil and fresh oil, the contrast aging test of different passivator concentration was designed and carried out. The influence of passivator on the performance of oil and insulating paper under the optimum concentration of passivator is evaluated by testing the characteristic parameters of transformer oil dielectric loss, power frequency breakdown voltage, water, furfural, etc. The effect of passivator on the performance of oil and insulating paper is within the standard range. At the same time, when the temperature reaches 130 鈩，

本文編號(hào)：2453160