本文選題：交流XLPE電纜 + 增容改造　； 參考：《東北電力大學(xué)》2017年碩士論文

【摘要】：線路增容改造不僅可以充分利用原有輸電走廊,而且還能大幅提高線路的輸送能力。隨著直流輸電技術(shù)的成熟,將交流電纜線路改造為直流運行已成為線路增容改造的有效技術(shù)方案。交流電纜改為直流運行后,其直流載流量的計算以及絕緣電場分布的研究對電纜安全運行具有重要意義。本文以YJLW03-48/66kV-400mm2型單芯交流電纜為研究對象,分析改為直流運行后的載流量以及絕緣電場。首先從傳熱學(xué)角度分析了電纜的熱特性;使用解析法、數(shù)值法和試驗法分析了空氣中敷設(shè)交流交聯(lián)聚乙烯(XLPE)電纜的直流載流量。然后,采用解析法計算了三相交流直埋敷設(shè)交流電纜的交流載流量;結(jié)合實際增容改造工程,計算了直埋電纜改為雙極直流運行時的載流量。最后,分析了交流電纜材料在直流電壓下的電導(dǎo)率特性,建立了電導(dǎo)率-(溫度、場強)數(shù)學(xué)模型;借助COMSOL多物理場軟件對交流電纜改為直流運行時的絕緣電場進行仿真;開展了型式試驗,對電纜進行全面校驗,并對電纜線路改為直流運行的增容效果進行了評估。通過試驗確定了空氣中敷設(shè)交流XLPE電纜的直流載流量,且驗證了解析法在計算高壓電纜(66 kV)直流載流量的準(zhǔn)確性;確定了土壤直埋敷設(shè)下交流電纜改為直流運行時的載流量(710 A);電纜在100%負荷時,絕緣層電場發(fā)生明顯翻轉(zhuǎn);交流電纜通過電氣型式試驗的校驗,計算了改造后的增容倍數(shù)。研究成果不僅能為東北地區(qū)城市電網(wǎng)66 kV電纜線路增容改造提供技術(shù)支持,而且還為未來交流電纜線路改為直流運行奠定基礎(chǔ)。
[Abstract]:The line capacity increase can not only make full use of the original transmission corridor, but also greatly improve the transmission capacity of the line.With the maturity of HVDC transmission technology, transforming AC cable line into DC operation has become an effective technical scheme for line capacity increase and transformation.The calculation of DC current and the study of insulation electric field distribution are of great significance to the safe operation of AC cable.In this paper, YJLW03-48/66kV-400mm2 single core AC cable is taken as the research object, and the carrier current and insulation electric field after switching to DC operation are analyzed.The thermal characteristics of the cable are analyzed from the point of view of heat transfer, and the DC current of the AC XLPE cable laid in the air is analyzed by analytical method, numerical method and experimental method.Then, the AC load current of the three-phase AC direct-buried AC cable is calculated by analytical method, and the DC current when the buried cable is changed to bipolar DC operation is calculated.Finally, the electrical conductivity characteristics of AC cable materials under DC voltage are analyzed, and a mathematical model of conductivity (temperature, field strength) is established, and the insulation electric field of AC cable is simulated by COMSOL multi-physical field software.The type test was carried out, the cable was checked and the capacitive effect of the cable line changed to DC operation was evaluated.The DC current of AC XLPE cable laid in air is determined by experiments, and the accuracy of analytical method in calculating DC current of high voltage cable (66 kV) is verified.It is determined that the AC cable under direct buried soil is replaced by DC operation, the electric field of the insulation layer is obviously reversed when the cable is under 100% load, and the capacity increase multiple after modification is calculated by checking the electrical type test of the AC cable.The research results can not only provide technical support for the capacity increase and transformation of 66 kV cable lines in Northeast China urban power grid, but also lay a foundation for the conversion of AC cable lines to DC operation in the future.
【學(xué)位授予單位】：東北電力大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TM75

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本文編號：1765897