计及线间互感的两回输电线路交叉跨越故障的短路电流计算方法

Short Circuit Current Calculation Method for Crossing Fault of Two Transmission Lines with Mutual Inductance

对于计及线间互感的两回输电线路,现有故障分析方法对于不同类型故障,大多要构建不同的复合序网,工作量太大且难以排错。为此,本文提出一种计及线间互感的两回输电线路短路电流计算方法。以故障相关线路的阻抗以及两端的节点阻抗矩阵作为输入,通过添加树支或连支对原节点阻抗矩阵进行参数修正或扩维,以处理线间互感或添加故障节点,进而构建两回输电线路在故障节点处的序网络方程。针对两回输电线路,给出构建故障边界条件矩阵的通用方法,并利用相序转换变换为各序网下的故障边界条件矩阵,联立序网络方程矩阵求解故障各端口的电压和电流。最后,利用PSCAD/EMTDC构建电网故障仿真模型,仿真结果验证了该方法的正确性。

Considering the mutual inductance between lines, most of the fault analysis methods construct different compound sequential networks for different fault types, which causes large workload and makes it difficult to debug. Therefore, this paper proposes a short circuit current calculation method for two transmission lines considering mutual inductance between lines. In this paper, the node im- pedance matrix of the both fault lines; ends and the impedance of fault lines are used as inputs. The parameters of the original node im- pedance matrix are modified or expanded by adding tree branches or link branches to deal with mutual inductance between lines or adding fault points. Then, the sequence network equations at the fault point of the two transmission lines can be constructed. This pa- per presents a universal method for constructing the fault boundary condition matrix for two transmission lines. The phase-sequence transformation is used to construct the fault boundary condition equations for each sequence network. The voltage and the current at each fault point can be solved in conjunction with the sequence network equations. Finally, a fault simulation model of power network is built by PSCAD/EMTDC, and the results verify the correctness of the method.