【摘要】：直流電纜在運(yùn)行時(shí)如果電壓極性發(fā)生反轉(zhuǎn),會(huì)使得外加電場與累積空間電荷所產(chǎn)生的電場疊加而增強(qiáng),可能引起局部放電或介質(zhì)擊穿。目前的實(shí)驗(yàn)測量方法無法揭示極性反轉(zhuǎn)過程中空間電荷和電場的瞬態(tài)變化,尤其是微觀粒子之間的相互作用過程。為了深入研究高壓直流電纜在極性反轉(zhuǎn)下的內(nèi)絕緣機(jī)理,利用雙極電荷傳輸模型對低密度聚乙烯(LDPE)的空間電荷動(dòng)態(tài)特性進(jìn)行了數(shù)值模擬,并通過仿真研究了多次極性反轉(zhuǎn)下LDPE空間電荷和電場的瞬態(tài)分布。結(jié)果表明:極性反轉(zhuǎn)時(shí)表面電場大大增強(qiáng),并具有一定的極性效應(yīng),在由陽極轉(zhuǎn)變?yōu)殛帢O時(shí)更加顯著;極性反轉(zhuǎn)前陷阱電荷密度遠(yuǎn)大于自由電荷密度,極性反轉(zhuǎn)時(shí)電極表面電場的增強(qiáng)主要是由電極附近的陷阱電荷所決定。研究成果可為高壓直流電纜的絕緣設(shè)計(jì)提供參考,也可以為聚合物材料空間電荷的動(dòng)態(tài)仿真提供借鑒。
[Abstract]:If the voltage polarity is reversed during the operation of DC cable, the electric field produced by the applied electric field and the accumulated space charge will be superimposed and strengthened, which may cause partial discharge or dielectric breakdown. The current experimental methods cannot reveal the transient changes of space charge and electric field in the process of polarity inversion, especially the interaction between microparticles. In order to deeply study the internal insulation mechanism of HVDC cable under polarity reversal, the space charge dynamic characteristics of LDPE (LDPE) were numerically simulated by bipolar charge transfer model. The transient distribution of LDPE space charge and electric field under multiple polarity inversion is studied by simulation. The results show that the surface electric field increases greatly and has a certain polarity effect when the polarity is reversed, and it is more obvious when the anode is changed to the cathode. The trap charge density is much larger than the free charge density before polarity inversion, and the enhancement of the electric field on the electrode surface is mainly determined by the trap charge near the electrode. The results can be used as a reference for the insulation design of HVDC cables and for the dynamic simulation of space charge of polymer materials.
【作者單位】： 福州大學(xué)電氣工程與自動(dòng)化學(xué)院;清華大學(xué)電機(jī)工程與應(yīng)用電子技術(shù)系;
【基金】：國家重點(diǎn)基礎(chǔ)研究發(fā)展計(jì)劃(973計(jì)劃)(2014CB239500)~~
【分類號】：TM215.1

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