本文關鍵詞：高壓直流輸電系統(tǒng)不平衡運行時直流電流分布規(guī)律及直流偏磁現(xiàn)象分析　出處：《三峽大學》2014年碩士論文　論文類型：學位論文

  更多相關文章： 高壓直流 直流偏磁 中性點電流 網絡化建模 電流分布

【摘要】：隨著我國高壓直流輸電的發(fā)展，在直流系統(tǒng)單極-大地運行時對變壓器直流偏磁影響日益明顯。變壓器中性點電流作為變壓器直流偏磁情況的直接影響因素，反映了變壓器直流偏磁狀況，因此如何在電力系統(tǒng)角度全面計算交流電網中各變壓器中性點電流分布情況，深度解析變壓器直流電流分布機理是電網發(fā)展需求。 本文在此背景下，研究針對湖北省直流密集型地區(qū)宜昌電網進行直流偏磁仿真建模，在收集了宜昌電網交直流輸電系統(tǒng)工程的實際參數(shù)基礎上，采用交流系統(tǒng)網絡化建模的方法，基于PSCAD/EMTDC電磁暫態(tài)仿真軟件平臺建立了包含宜昌電網兩條500kV直流輸電線路以及直流接地極周圍220kV及以上交流變壓器中性點電流分布仿真模型。實現(xiàn)了基于電網實際參數(shù)建立反映全網變壓器中性點電流分布以及變壓器直流偏磁的交直流混聯(lián)仿真模型。模型經過電網運行的實測數(shù)據(jù)驗證有效。在建立的電網仿真模型基礎上，，仿真計算了葛洲壩上海直流輸電工程和宜都華新直流輸電工程在不同工況下交流電網各變壓器中性點電流分布情況，得出了各直流接地極與變壓器中性點電流間定量關系。同時對交流系統(tǒng)運行方式改變后變壓器中性點電流分布以及直流偏磁情況進行仿真分析。在解析各變壓器中性點電流分布規(guī)律基礎上得出了系統(tǒng)不同運行方式對變壓器直流偏磁影響機理。為后續(xù)研究如何從系統(tǒng)角度抑制、減輕交流電網各變壓器直流偏磁提供一定的理論基礎。
[Abstract]:With the development of HVDC transmission in China, the influence of DC bias on DC bias of transformer is becoming more and more obvious when unipole-earth operation of DC system. The neutral current of transformer is the direct influence factor of DC bias of transformer. It reflects the DC bias of the transformer, so how to calculate the neutral current distribution of the transformer in the AC network from the angle of the power system. The depth analysis of DC current distribution mechanism of transformer is the demand of power grid development. Under this background, this paper studies the simulation modeling of DC bias for Yichang power grid in the concentrated area of Hubei province, and collects the actual parameters of Yichang power grid AC / DC transmission system project. The network modeling method of AC system is adopted. Based on PSCAD/EMTDC electromagnetic transient simulation software platform, the neutral point of AC transformer including two 500kV HVDC transmission lines and 220 kV and above AC transformers around DC earths is established. Based on the actual parameters of the power network, an AC / DC hybrid simulation model reflecting the neutral point current distribution and DC bias of the transformer is established. The model is verified by the measured data of the operation of the power network. Based on the established power network simulation model. The distribution of neutral point current of transformer in Gezhouba Shanghai HVDC Project and Yidu Huaxin HVDC Project under different working conditions is simulated and calculated. The quantitative relationship between the DC earth electrode and the neutral current of the transformer is obtained. At the same time, the distribution of the neutral current and the DC bias of the transformer after the change of the operation mode of the AC system are simulated and analyzed. Based on the current distribution of neutral point, the influence mechanism of different operation modes on DC bias magnetic field of transformer is obtained. Reducing DC bias of AC power transformers provides a theoretical basis.
【學位授予單位】：三峽大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TM721.1

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本文編號：1431037