换流变压器阀侧绝缘电场特性研究

采用Matlab软件仿真分析换流变压器阀侧绕组端部电场的励磁电压类别后建立了电容系数和电导率复合介质电场的数学模型,并对其复合绝缘结构建模,用有限元分析法分析计算各种励磁电压作用下的电场分布,得出了换流变压器阀侧绕组端部电场的复杂特性,为换流变压器阀侧绕组端部的安全绝缘设计提供了科学依据。

Study on Electric Field Characteristics at Ends of Valve-side Winding in Converter Transformer

Due to the influence of DC branch,there are considerable differences in the characteristics of electric field at ends of valve-side winding between a converter transformer and a power transformer.The insulation of HVDC apparatus must withstand the electric field caused by the PR(polarity reversal) voltage in operation or during a dielectric test at factory,it is quite significant for the design and development of HVDC apparatus to calculate the field stress in insulation and study the characteristics under compound electric field.The sorts of excitation voltage in the electric field are analyzed by Matlab software in this paper,the mathematic equations of transient field is established,the distribution characteristics of electric field and the maximal field intensity positions of oil-paper combination insulation under different excited voltages such as DC electric field,AC electric field and a polarity reversal voltage imposing on the insulation of HVDC apparatus are emulated with FEM(Finite Element Method),the method is proved by an example which can be calculated theoretically.Finally some distinguishing feature of the transient field are summarized and the calculation results of some illustrative examples including typical bushing barrier system of converter transformer gives some new understandings and scientific rules which can be referred to the insulation design and testing of HVDC apparatus.