高壓直流輸電系統中存在直流偏磁問題,直流偏磁產生的諧波會嚴重危及電網的安全運行。文中基于變壓器鐵心的直流偏磁特性及變壓器自身結構特點提出了一種基于變壓器自身結構的變壓器直流偏磁抑制措施,達到變壓器直流偏磁抑制的目的。首先應用PSCAD軟件對試驗變壓建模并搭建仿真回路進行了原理驗證;其次研制了一臺變壓器模型樣機并開展了直流偏磁抑制試驗;最后將變壓器模型樣機與一臺同規格變壓器進行了性能對比試驗研究。試驗結果表明,該方法能在不增加變壓器損耗、溫升的條件下有效抑制變壓器直流偏磁,試驗數據證明了該方法的有效性和正確性。
DC parallel transmission lines lead to DC bias of converter transformer in the HVDC transmission. The harmonic caused by DC bias disturbs the safe operation of electrical network. Based on DC bias characteristic of transformer and internal structure, the new restricting method is added in way to transformer DC magnetic bias suppression. Firstly, PSCAD software is used to build the model and to make simulation circuit to carry out the principle verification; Secondly, a transformer model prototype is developed and the DC magnetic bias suppression test is carried out; Finally, the transformer model prototype and a transformer with the specifications of the performances are compared. The experimental results show that the scheme can not increase in transformer loss. The method in this design is proved to be effective and efficient one by the results of experiment.