【摘要】：植物絕緣油是一種新型環(huán)保絕緣介質(zhì),已在日常生產(chǎn)中得到使用。然而植物絕緣油耐受雷電沖擊電壓的能力較弱,一定程度上限制了其在高電壓等級下的應(yīng)用。所以有必要進一步提高植物絕緣油的絕緣強度,這不僅可以保證電力變壓器的安全運行,還能夠減小特高壓變壓器尺寸,節(jié)約投資成本。 本文利用Ti02納米粒子對植物油進行改性,制備出具有穩(wěn)定分散性的納米改性植物絕緣油,測試了改性前后植物油的工頻擊穿特性、雷電沖擊擊穿特性和局部放電特性,使用高速相機進一步拍攝觀察了納米粒子對植物絕緣油中流注發(fā)展的影響,借助電聲脈沖法和熱刺激電流法測試分析了改性前后植物絕緣油中電荷輸運能力和陷阱特性。 研究結(jié)果表明,Ti02納米粒子能夠顯著改善植物絕緣油的絕緣性能,其中工頻擊穿電壓提高到1.24倍,雷電擊穿電壓提高到1.19倍,局部放電起始電壓提高到1.05倍。納米粒子能夠較有效的抑制植物絕緣油中快流注的發(fā)展,而且納米改性植物油中的流注發(fā)展通道更粗,發(fā)展時間更長。納米改性后的植物絕緣油中電荷消散速率明顯提高,局部場強減弱,淺陷阱密度顯著提高。 機理的研究結(jié)果說明,Ti02納米粒子的添加,增大了植物絕緣油中淺陷阱的密度,這些淺陷阱反復(fù)捕獲—釋放電荷的過程能夠提高電荷輸運的能力,減少空間電荷的數(shù)量,從而降低流注前端的局部場強,改善本已畸變的電場,抑制流注進一步的發(fā)展,從而提高植物油絕緣性能。
[Abstract]:Vegetable insulating oil is a new type of environmental protection insulating medium, which has been used in daily production. However, the ability of vegetable insulating oil to withstand lightning impulse voltage is weak, which limits its application in high voltage level to a certain extent. Therefore, it is necessary to further improve the insulation strength of vegetable insulating oil, which can not only ensure the power transformer. The safe operation can also reduce the size of UHV Transformer and save investment cost.
In this paper, vegetable oil was modified with Ti02 nanoparticles to prepare stable dispersible nano-modified vegetable insulation oil. The breakdown characteristics of power frequency, lightning impulse breakdown and partial discharge characteristics of vegetable oil before and after modification were tested. The development of streaming of vegetable insulation oil by nanoparticles was further observed by high-speed camera. The charge transport capacity and trapping characteristics of modified vegetable insulating oils were analyzed by means of electroacoustic pulse method and thermal stimulation current method.
The results show that Ti02 nanoparticles can significantly improve the insulation performance of vegetable insulating oil, including power frequency breakdown voltage increased to 1.24 times, lightning breakdown voltage increased to 1.19 times, partial discharge initiation voltage increased to 1.05 times. Nanoparticles can effectively inhibit the development of fast flow in vegetable insulating oil, and nano-modified plants. The flow channel in the oil is thicker and the development time is longer. The charge dissipation rate of the nano-modified vegetable insulation oil is obviously increased, the local field strength is weakened, and the shallow trap density is significantly increased.
The results of mechanism study show that the addition of Ti02 nanoparticles increases the density of shallow traps in vegetable insulating oils. The repeated capture-release process of these shallow traps can improve the ability of charge transport, reduce the number of space charges, thereby reducing the local field strength at the front end of the streamer, improving the distorted electric field and suppressing the streaming into the first one. Step by step, thereby enhancing the insulation performance of vegetable oils.
【學(xué)位授予單位】：華北電力大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TM215.4

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