基于电位系数矩阵的同塔双回直流输电线路故障选线方法

围绕同塔双回直流输电线路的故障分析与故障选线方法,基于麦克斯韦静电耦合理论,根据线路与杆塔的详细参数,考虑架空地线分段接地的特点及近端故障时滤波电容的影响,推算同塔双回直流输电线路的电位系统矩阵,并通过相模变换将线间静电不平衡耦合转换为线路各模量的电压变化量。进一步考虑地模与线模电压行波的传播特性差异,通过定义模电压变化比率以消除过渡电阻的影响,从而提出一种同塔双回直流输电线路的定量故障分析方法。基于所述故障分析方法,根据不同故障的边界条件进行特征分析,提出故障选线判据和定值整定方法。利用PSCAD/EMTDC构建同塔双回直流输电系统模型,通过全面的故障仿真分析,验证了所述方法的正确性,结果表明该故障选线方法不受过渡电阻的影响,能准确、灵敏地判定各种复杂故障类型。

Fault Line Selection Scheme of Double HVDC Transmission Lines on Same Tower Based on Potential Coefficient Matrix

Centering on the fault analysis and fault line selection scheme for the double HVDC transmission lines on same tower, based on the electrostatic coupling theory, according to the detailed parameters of lines and tower, considering the effects of overhead ground wire and the filter capacitors, a calculation method of the potential coefficient matrix is presented for the double HVDC transmission lines. Then the interline electrostatic unbalanced coupling effect is transformed into mode voltage variation by the phase-mode transformation. Based on the mode voltage variation, considering the different characteristics of ground-mode and line-mode quantum, by the definition of mode voltage variation ratio, this paper proposes a fault feature quantitative analysis scheme of double HVDC transmission lines on same tower to eliminate the influence of transition resistance. Based on the fault case of each mode voltage variation characteristics, a fault line selection method of the double HVDC transmission lines on same tower is proposed. Finally, the PSCAD/EMTDC is used to construct the double HVDC transmission lines on same tower to verify the correctness of the proposed method through all-round fault simulations. The results show that the proposed method is capable of accurately selecting a variety of complicated fault types unaffected by the fault transition resistance. This work is supported by National Natural Science Foundation of China(No. 51307065, No. 51577072), and Fundamental Research Funds for the Central Universities(No. 2013ZZ028).