本文關(guān)鍵詞： 油紙絕緣 操作過電壓 損傷生成物 電氣特性 機(jī)械特性 V-N特性　出處：《重慶大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：變壓器作為電網(wǎng)的核心設(shè)備，對(duì)電網(wǎng)安全運(yùn)行起著重要作用。研究表明導(dǎo)致變壓器失效的主要原因是其油紙絕緣的老化，油紙絕緣的老化是由溫度，電場(chǎng)，水分和氧氣等各種因素共同造成的。要準(zhǔn)確監(jiān)測(cè)變壓器油紙絕緣的狀態(tài)，就必須盡可能地了解每一種老化因素所能造成的損傷。在這些老化因素中，過電壓對(duì)于油紙絕緣的影響是不可忽略的，，但關(guān)于過電壓對(duì)于油紙絕緣的損傷方面的研究還比較少且主要集中在雷電過電壓方面，對(duì)于操作過電壓對(duì)油紙絕緣的影響方面的研究還鮮見報(bào)到。 本文通過建立操作沖擊電壓對(duì)油紙絕緣的損傷試驗(yàn)平臺(tái)，研究了操作沖擊電壓作用下油紙絕緣的損傷以及機(jī)械特性和電氣特性的變化規(guī)律。試驗(yàn)結(jié)果表明，在操作沖擊電壓的作用下，絕緣紙的表面會(huì)產(chǎn)生沿面的火花與電弧放電，放電會(huì)使得絕緣油中的H2以及烴類氣體含量上升，同時(shí)產(chǎn)生的極性物質(zhì)會(huì)使得絕緣油的介電常數(shù)和介質(zhì)損耗在低頻區(qū)上升并使其電導(dǎo)率增大，但對(duì)絕緣油的擊穿特性與局部放電特性幾乎沒有影響。另外，絕緣紙表面的沿面放電還會(huì)使得絕緣紙的表面電導(dǎo)率上升，導(dǎo)致其沿面放電起始電壓降低。操作過電壓還會(huì)使得絕緣紙內(nèi)部的分子鏈發(fā)生斷裂，使得其聚合度下降，并使其介電常數(shù)與損耗在低頻部出現(xiàn)上升，操作沖擊擊穿電壓發(fā)生下降，但其工頻擊穿特性沒有發(fā)生明顯變化，直流體積電導(dǎo)率也僅僅是輕微上升。 為了更加深入的研究油紙絕緣對(duì)操作沖擊電壓的耐受能力，本文也對(duì)操作沖擊電壓作用下油紙絕緣的擊穿壽命與電壓幅值的關(guān)系（V-N特性）進(jìn)行了研究，并研究了油紙絕緣的老化狀態(tài)以及操作沖擊電壓的波形變化對(duì)其V-N特性的影響。研究發(fā)現(xiàn)：隨著油紙絕緣老化程度的加深，油紙絕緣的操作沖擊耐受能力會(huì)出現(xiàn)下降趨勢(shì)，且這種趨勢(shì)在老化的初期下降較慢，而在老化的中后期下降較快；沖擊電壓的波形變化也會(huì)對(duì)油紙絕緣的操作沖擊耐受能力造成影響，波頭時(shí)間的變短與波尾時(shí)間的變長(zhǎng)均會(huì)使得油紙絕緣在的操作沖擊耐受能力下降，但波頭時(shí)間變化對(duì)油紙絕緣沖擊耐受能力的影響要高于波尾時(shí)間變化。
[Abstract]:As the core equipment of the power network, transformer plays an important role in the safe operation of the power network. The research shows that the main cause of transformer failure is the aging of its oil-paper insulation, and the aging of oil-paper insulation is caused by temperature and electric field. In order to accurately monitor the condition of oil paper insulation of transformers, it is necessary to understand as far as possible the damage caused by each ageing factor. The influence of overvoltage on oil-paper insulation can not be ignored, but the research on the damage of overvoltage to oil-paper insulation is relatively few and mainly focuses on lightning overvoltage. Research on the effect of operating overvoltage on oil-paper insulation is rare. In this paper, the damage and mechanical and electrical characteristics of oil-paper insulation under the action of operating impulse voltage are studied by setting up the damage test platform of operation impulse voltage. The experimental results show that, Under the action of the operating impulse voltage, the surface of the insulator paper will produce spark and arc discharge along the surface, and the discharge will increase the H _ 2 and hydrocarbon gas content in the insulating oil. At the same time, the dielectric constant and dielectric loss of insulating oil will increase in the low frequency region and the conductivity will increase, but the breakdown characteristics and partial discharge characteristics of insulating oil will have little effect on the dielectric constant and dielectric loss of the insulating oil. In addition, the dielectric constant and dielectric loss of the insulating oil will increase in the low frequency region. The surface discharge on the surface of the insulator paper will also increase the surface conductivity of the insulator paper, resulting in the decrease of the initial voltage of discharge along the surface. The operating overvoltage will also break the molecular chain inside the insulator paper and decrease the degree of polymerization. The dielectric constant and loss increase in the low frequency part, the operating impulse breakdown voltage decreases, but the power frequency breakdown characteristic does not change obviously, and the DC volume conductivity is only slightly increased. In order to further study the resistance of oil-paper insulation to operating impulse voltage, the relationship between breakdown life and voltage amplitude of oil-paper insulation under operation impulse voltage is also studied in this paper. The effects of aging state of oil-paper insulation and waveform change of operating impulse voltage on V-N characteristics of oil-paper insulation are studied. It is found that with the aging degree of oil-paper insulation, the operating impact resistance of oil-paper insulation will decrease. This trend decreases slowly in the early stage of aging, but decreases more rapidly in the middle and late stage of aging. The waveform changes of impulse voltage will also affect the operating impact resistance of oil-paper insulation. The shorter the wave head time and the longer the wave tail time, the lower the operating impact resistance of the oil-paper insulation, but the influence of the wave head time on the impact resistance of the oil-paper insulation is higher than the change of the wave-end time.
【學(xué)位授予單位】：重慶大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TM41

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