含中性点参数的三相变压器建模及其在潮流计算中的应用

Modeling of three-phase transformer with neutral parameters and its application in power flow calculation

建立变压器的三相模型对于配电网潮流计算非常重要。针对传统的关联矩阵法不再适用于中性点不接地星形接线的变压器的问题,文中提出计及中性点的三相变压器模型,此模型可以用关联矩阵法求得,应用于潮流计算可以直接方便地求出变压器中性点电压。当不接地星形接线方式的变压器模型含有中性点参数时,可以用关联矩阵借助转换矩阵推导所有连接组别的三相变压器模型,使得变压器模型的推导更加简洁。IEEE-4节点标准测试系统的计算结果验证了所建变压器模型的正确性与有效性。

The three-phase model of the transformer is especially important for power flow calculation in distribution system.In view of the problem that the traditional incidence matrix method is not suitable for the transformer with ungrounded wye connection,the three-phase transformer model with neutral parameters is proposed,which can be derived by incidence matrix method.This model can be applied in the power flow to calculate transformer neutral voltage directly.When the transformer model with ungrounded wye connection contains neutral parameters,the three-phase transformer model of all connection groups can be deduced by incidence matrix and the transformation matrix,which makes the derivation of the transformer model more concise.The results of the IEEE-4 node test system verify the correctness and effectiveness of the proposed transformer model.